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Sample records for radiation degraded chitosan

  1. Viscometric studies of chitosan radiation degradation

    International Nuclear Information System (INIS)

    Rapado, M.; Ceausoglu, I.; Hunkeler, D.

    2001-01-01

    The paper presents the preliminary results, related to the viscometric studies on chitosan gamma radiation degradation. To follow the effects on the processes of chitosan transformations caused by irradiation in vacuum irradiated solutions changes of viscosity, and viscosity average molecular weight were measured The influence of absorbed dose on the chitosan molecular weight was studied using the Mark-Houwink-Sakurada equation. Various relationships for the for the determination of the intrinsic viscosity were made vias the Huggins, Kramer and Schulz- Blaschke models. The distinct decrease of intrinsic viscosity indicates that the main change scission was the dominating process

  2. Degradation Of α-Chitosan By Combined Treatment With Hydroperoxide And Gamma 60Co Radiation

    International Nuclear Information System (INIS)

    Nguyen Quoc Hien; Dang Van Phu; Bui Phuoc Phuc; Ha Thuc Huy

    2008-01-01

    Chitosan samples prepared from shrimp shell (α-chitosan) with degree of deacetylation (DD) of 70, 84 and 94% were treated with H 2 O 2 1.5% at room temperature for degradation. The oxidative chitosan was irradiated by gamma 60 Co radiation for further reduction of molecular weight. Viscosity-average molecular weight of chitosan was measured by capillary viscometer. Results showed that H 2 O 2 was an effective reagent for chitosan degradation. Radiation degradation yield (G s ) increased for chitosan with higher DD. Interestingly Gs-values for oxidative degraded chitosan were found out of 0.96, 5.73 and 7.80 scissions/100 eV that were remarkably higher compared to 0.20, 1.05 and 1.69 scissions/100 eV for initial chitosan with DD 70, 84 and 94%, respectively. Based on results obtained it can be concluded that combined treatment with hydroperoxide and gamma 60 Co radiation was remarkably effective for degradation of chitosan. (author)

  3. Radiation degradation of chitosan

    International Nuclear Information System (INIS)

    Norzita Yacob; Maznah Mahmud; Norhashidah Talip; Kamarudin Bahari; Kamaruddin Hashim; Khairul Zaman Dahlan

    2010-01-01

    In order to obtain an oligo chitosan, degradation of chitosan s were carried out in solid state and liquid state. The effects of an irradiation on the molecular weight and viscosity of the chitosan were investigated using Ubbelohde Capillary Viscometer and Brookfield Viscometer respectively. The molecular weight and viscosity of the chitosan s were decreased with an increase in the irradiation dose. In the presence of hydrogen peroxide, the molecular weight of chitosan can be further decreased. (author)

  4. Degradation of chitosan for rice crops application

    International Nuclear Information System (INIS)

    Norzita Yacob; Maznah Mahmud; Norhashidah Talip; Kamaruddin Hashim; Abdul Rahim Harun; Khairul Zaman; Hj Dahlan

    2013-01-01

    A variety of techniques including chemical and enzymatic hydrolysis, and radiation degradation processes can be used to prepare low molecular weight chitosan. Degradation of chitosan by radiation can be carried out in solid state and liquid state. Radiation degraded polysaccharides has been reported to exhibit growth-stimulating activity like phytohormones that induce the promotion in germination, shoot and root elongation in variety of plants. In this study, the chitosan was irradiated in solid state (powder form) by gamma rays within the dose range of 25-75 kGy. And the irradiated chitosan was then irradiated in solution form in the presence of hydrogen peroxide. The effects of irradiation on the molecular weight and viscosity of the chitosan were investigated using Ubbelohde Capillary Viscometer. The molecular weight and viscosity of the chitosan decreased with increment of absorbed doses. In the presence of hydrogen peroxide, the molecular weight of chitosan could be further decreased. The effect of radiation degraded chitosan on the growth promotion of rice was investigated and it was shown during seedling period of 15 days for transplanting whereby the growth is 15%-20% faster than using chemicals growth promoters. (authors)

  5. Radiation-induced degradation of carboxymethylated chitosan and its application in preparation of ionic liquids and silver nanoparticles

    International Nuclear Information System (INIS)

    Zhai Maolin; Huang Ling; Peng Jing; Li Jiuqiang; Wei Genshuan

    2006-01-01

    Radiation effect of γ-ray on carboxymethylated chitosan (CM-chitosan) in solid state and aqueous solution were studied. The changes in molecular weight of CM-chitosan with absorbed dose were monitored by viscosity method. In solid state, there are random chain scissions in the radiation process of CM-chitosan. XRD patterns identified that the degradation of CM-chitosan occurred mostly in amorphous region. Radiation chemical yield (G d ) of CM-chitosan in solid state in N 2 atmosphere was 0.49, which showed CM-chitosan has high radiation stability. Biomaterials composed of CM-chitosan can be thought to sterilize with low absorbed doses. While aqueous solutions of CM-chitosan were irradiated with γ-rays in various conditions, degradations of CM-chitosan were faster in the presence of nitrous oxide or hydrogen peroxide, however, it was inhibited obviously by adding isopropanol because of concentration changes of hydroxyl radicals in different conditions. This indicated that hydroxyl radicals play an important role in radiation degradation of CM-chitosan. Furthermore, FTIR and UV spectra of CM-chitosan radiation-degraded in its solid state status or in aqueous solution showed that main chain structures of CM-chitosan were kept and some carbonyl/carboxyl groups formed during the irradiation were similar to radiation degradation products of chitosan. The method can be used to prepare low molecular weight CM-chitosan. Due to special physical and chemical properties, ionic liquids have attracted much attention in green chemistry field. Environment-friendly ionic liquids ([emim]CM-chitosan) were prepared in acid-base neutralization reactions based on 1-ethyl-3-methylimidazolium hydroxide and CM-chitosan with molecular weights ranging from 2000 to 600 Da. Results of thermal analysis showed that molecular weight of CM-chitosan have little influence on glass transition temperature, melting point and decomposing temperature of [emim]CM-chitosan ionic liquids. Conductivities

  6. Radiation degradation of alginate and chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, Naotsugu; Mitomo, Hiroshi [Department of Biological and Chemical Engineering, Faculty of Engineering, Gunma University, Kiryu, Gunma (Japan); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Alginate and chitosan were irradiated in solid or aqueous solution condition with Co{sup 60} gamma rays in the dose range of 20 to 500 kGy. Degradation was observed both in solid and solution conditions. The degradation in solution was remarkably greater than that in solid. For example, the molecular weight of alginate in 4%(w/v) solution decreased from 2 x 10{sup 5} for 0 kGy to 6 x 10{sup 3} for 50 kGy irradiation while the equivalent degradation by solid irradiation required 500 kGy. The activated species from irradiated water must be responsible for the degradation in solution. The degradation was also accompanied with the color change of alginate: the color became deep brown for highly degraded alginate. UV spectra showed a distinct absorption peak at 265 nm for colored alginates, increasing with dose. The fact that discoloration of colored alginate was caused on exposure to ozone suggests a formation of double bond in pyranose-ring by scission of glycosidic bond. Degradation behavior of chitosan in irradiation was almost the same as that of alginate. (author)

  7. Degradation of chitosan by gamma ray with presence of hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Mahmud, Maznah; Yacob, Norzita; Talip, Norhashidah; Abdullah, Zahid [Malaysian Nuclear Agency, Radiation Technology Division, Bangi, 43000 Kajang, Selangor (Malaysia); Naziri, Muhammad Ihsan [University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-02-12

    The radiation degraded chitosan samples were prepared by swelling the chitosan powder in water and exposed for gamma irradiation. The ratio chitosan to water was 1:6 with the presence of hydrogen peroxide (H{sub 2}O{sub 2}), 1%–5%. These chitosan-water mixtures were irradiated at 6kGy, which is the lowest irradiation dose that facility can offered. All samples were purified and proceed with characterization. The molecular weight (MW) study was monitored by size exclusion chromatography-multi angle laser light scattering (SEC-MALLS). Results showed that MW of chitosan reduced as the dose increased. Application of H{sub 2}O{sub 2} enhanced the degradation rate of chitosan even at very low irradiation dose. Homogenous degradation also occurred during treatment with H{sub 2}O{sub 2}based on the polydispersity index (PDI) derived from the calculation of weight average molecular weight over number average molecular weight (Mw/Mn). Mechanism of chitosan radiation degradation with and without hydrogen peroxide was also discussed in this paper. Structure of degraded products was characterized with Fourier-transform infrared spectra. The degree of deacetylation (DDA) values of the samples was determined by acid-base titration. Solubility test results showed that, chitosan powder even at low Mw was insoluble in water even at low pH water. Chitosan as well as irradiated chitosan powder are soluble in strong and weak acid solution. Further discussion on behaviours of radiation degraded chitosan will be elaborated more in this paper.

  8. Degradation of chitosan by gamma ray with presence of hydrogen peroxide

    Science.gov (United States)

    Mahmud, Maznah; Naziri, Muhammad Ihsan; Yacob, Norzita; Talip, Norhashidah; Abdullah, Zahid

    2014-02-01

    The radiation degraded chitosan samples were prepared by swelling the chitosan powder in water and exposed for gamma irradiation. The ratio chitosan to water was 1:6 with the presence of hydrogen peroxide (H2O2), 1%-5%. These chitosan-water mixtures were irradiated at 6kGy, which is the lowest irradiation dose that facility can offered. All samples were purified and proceed with characterization. The molecular weight (MW) study was monitored by size exclusion chromatography-multi angle laser light scattering (SEC-MALLS). Results showed that MW of chitosan reduced as the dose increased. Application of H2O2 enhanced the degradation rate of chitosan even at very low irradiation dose. Homogenous degradation also occurred during treatment with H2O2based on the polydispersity index (PDI) derived from the calculation of weight average molecular weight over number average molecular weight (Mw/Mn). Mechanism of chitosan radiation degradation with and without hydrogen peroxide was also discussed in this paper. Structure of degraded products was characterized with Fourier-transform infrared spectra. The degree of deacetylation (DDA) values of the samples was determined by acid-base titration. Solubility test results showed that, chitosan powder even at low Mw was insoluble in water even at low pH water. Chitosan as well as irradiated chitosan powder are soluble in strong and weak acid solution. Further discussion on behaviours of radiation degraded chitosan will be elaborated more in this paper.

  9. Radiation Synthesis and Application of Carboxymethylated Chitosan Hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Young Chang

    2007-08-15

    This research proposal is to investigate radiation effect of carboxymethylated chitosan in order to obtain the crosslinked carboxymethylated chitosan. The application studies on CM-chitosan- based intelligent hydrogels will be tried too. Chitin is the most abundant natural amino polysaccharide and estimated to be produced annually almost as much as cellulose. Chitosan is the deacetylated product of chitin showing the enhanced solubility in dilute acids, further, carboxymethylated chitosan (CM-chitosan) can solve in both acidic and basic physiological media, which might be good candidates as a kind of biomedical materials. Radiation technique is an important method for modification of chitin derivatives. It includes radiation-induced degradation, grafting, and crosslinking. It was found that CM-chitosan degraded in solid state or dilute aqueous solution under irradiation, but crosslinked at paste-like sate when the concentration of CM-chitosan is more than 10%. Both degraded and crosslinked CM-chitosan have antibacterial activity, so it is essential to investigate in detail the radiation effect of CM-chitosan. Study on radiation effect of CM-chitosan in different condition is beneficial to modification of CM-chitosan by irradiation technique. However, little study was reported on radiation crosslinking and application of CM-chitosan. The radiation-closslinked CM-chitosan synthesized from chitosan was characterized by a Fourier transform infrared spectroscopy (FT-IR) analysis. A kinetic swelling in water and the mechanical properties such as a gelation, water absorptivity, and gel strength were also investigated. For the preparation of crosslinked CM-chitosan by using gamma irradiation, the concentration of an aqueous CM-chitosan is above 10wt%. We confirmed that the gel contents was in the range of 15-63%, and when the irradiation dose was increased, the degree of gelation was decreased by disintegration of the CM-chitosan. In conclusion, we developed a new

  10. Radiation Synthesis and Application of Carboxymethylated Chitosan Hydrogels

    International Nuclear Information System (INIS)

    Noh, Young Chang

    2007-08-01

    This research proposal is to investigate radiation effect of carboxymethylated chitosan in order to obtain the crosslinked carboxymethylated chitosan. The application studies on CM-chitosan- based intelligent hydrogels will be tried too. Chitin is the most abundant natural amino polysaccharide and estimated to be produced annually almost as much as cellulose. Chitosan is the deacetylated product of chitin showing the enhanced solubility in dilute acids, further, carboxymethylated chitosan (CM-chitosan) can solve in both acidic and basic physiological media, which might be good candidates as a kind of biomedical materials. Radiation technique is an important method for modification of chitin derivatives. It includes radiation-induced degradation, grafting, and crosslinking. It was found that CM-chitosan degraded in solid state or dilute aqueous solution under irradiation, but crosslinked at paste-like sate when the concentration of CM-chitosan is more than 10%. Both degraded and crosslinked CM-chitosan have antibacterial activity, so it is essential to investigate in detail the radiation effect of CM-chitosan. Study on radiation effect of CM-chitosan in different condition is beneficial to modification of CM-chitosan by irradiation technique. However, little study was reported on radiation crosslinking and application of CM-chitosan. The radiation-closslinked CM-chitosan synthesized from chitosan was characterized by a Fourier transform infrared spectroscopy (FT-IR) analysis. A kinetic swelling in water and the mechanical properties such as a gelation, water absorptivity, and gel strength were also investigated. For the preparation of crosslinked CM-chitosan by using gamma irradiation, the concentration of an aqueous CM-chitosan is above 10wt%. We confirmed that the gel contents was in the range of 15-63%, and when the irradiation dose was increased, the degree of gelation was decreased by disintegration of the CM-chitosan. In conclusion, we developed a new

  11. Radiation-induced changes in carboxymethylated chitosan

    International Nuclear Information System (INIS)

    Huang Ling; Peng Jing; Zhai Maolin; Li Jiuqiang; Wei Genshuan

    2007-01-01

    This study focuses on the radiation effect of γ-ray on carboxymethylated chitosan (CM-chitosan) in solid state. The changes in molecular weight of CM-chitosan with absorbed dose were monitored by viscosity method. Experimental results indicated that random chain scissions took place under irradiation. Radiation chemical yield (G d ) of CM-chitosan in solid state with N 2 -saturated was 0.49, which showed CM-chitosan has high radiation stability. Biomaterials composed of CM-chitosan can be thought to sterilize with low absorbed dose. FTIR and UV spectra showed that main chain structures of CM-chitosan were retained, carbonyl/carboxyl groups were formed and partial amino groups were eliminated in high absorbed dose. XRD patterns identified that the degradation of CM-chitosan occurred mostly in amorphous region

  12. Application of Radiation Degraded Chitosan as Plant Growth Promoter. A Pilot Scale Production and Field Trial Study of Radiation Processed Chitosan as Plant Growth Promoter for Rice Crops

    International Nuclear Information System (INIS)

    Dahlan, Khairul Zaman Hj Mohd; Hashim, Kamaruddin; Bahari, Kamarudin

    2010-01-01

    The application of radiation processed chitosan as plant growth promoter has been carried out in the 24 hectares of rice crops. For the field trial, a pilot scale production of oligochitosan was established using gamma irradiation for partial degradation of chitosan powder of DDA 90% and followed by gamma irradiation of aqueous solution of 3% irradiated chitosan powder in 2% lactic acids (3CL2). Radiation dose of 50 kGy was selected for initial degradation of chitosan powder and followed by 12 kGy irradiation of 3CL2. A viscosity average molecular weight of ~10,000 of oligochitosan was obtained and subsequently used in the field trial of MR219 type of rice seeds on 24 hectares of rice plots. The seedlings were carried out after the rice seeds were soaked 24hrs in water and 30 minutes in 200ppm oligochitosan. The rice plots that were sprayed with oligochitosan were found to have higher resistant towards blast diseases. Oligochitosan of 40ppm was found to be effective as fungicides and resulted in the increase of yield of rice seeds of about 5%. (author)

  13. Application of radiation degraded CM-chitosan for preservation of fresh fruits

    International Nuclear Information System (INIS)

    Quynh, Tran Minh; Hien, Nuguyen Quoc; Yoshii, Fumio; Nagasawa, Naotsugu; Kume, Tamikazu

    2003-01-01

    CM-chitosan was irradiated with various doses in powder state and solution using Co 60 gamma source. The changes of viscosity in solution as well as molecular weight were also measured. The molecular weight reduced with increasing of radiation dose. The antimicrobial activity of CM-chitosan and irradiated CM-chitosan in solution against E.coli was investigated. In this studies, the sensitivity of E.coli depended on the concentration of CM-chitosan supplemented into medium and the antimicrobial activity of irradiated CM-chitosan was found to increase with radiation dose and reached to maximum with dose of 100 kGy. The 2% aqueous solutions prepared from CM-chitosan and 100 kGy irradiated CM-chitosan as mentioned above were applied for apple preservation. All coating fruits have significantly reduced the weight loss, spoilage ratio compared with control. Chemical and sensory quality of coated fruits were evaluated and compared, the best results were achieved with fruit coated using irradiated CM-chitosan. (author)

  14. Synthesis of PVA-Chitosan Hydrogels for Wound Dressing Using Gamma Irradiation. Part I: Radiation Degradation of Chitosan in Solid State and in Solution

    International Nuclear Information System (INIS)

    Mahlous, M.; Tahtat, D.; Benamer, S.; Nacer Khodja, A.; Larbi Youcef, S.

    2010-01-01

    Chitosan is a partially deacetylated product of chitin, a very abundant polysaccharide, existing in exoskeleton of crustaceans. It is a polymer consisting of glucosamine and N-acetylglucosamine units linked by β-1-4-glycosidic bonds. Chitosan, like others polysaccharides, such as cellulose derivatives, alginates and carrageenan is widely used in food, medicine and cosmetic fields. Chitosan presents a variety of distinctive properties, such as biocompatibility, biodegradability, nontoxicity and nonantigenicity. Chitosan obtained by the deacetylation of chitin has, generally, a high molecular weight, which limits its solubility in aqueous solvents. The reduction of its molecular weight by degradation is usually used in order to improve its water solubility. Water-soluble chitosan exhibit some specific properties, such as antifungal activity, antimicrobial activity and plant growth promotion. Among the methods that have been tried to produce low molecular weight chitosan, radiation processing is the most promising one, since the process is simple, it is carried out at room temperature and no purification of the product is required after processing

  15. Utilization of Degraded Chitosan for Growth Promoter and Blossom Blight Disease Controls in Okra

    International Nuclear Information System (INIS)

    Kewsuwan, Prartana

    2010-01-01

    The experiment focus on the comparison of the effect of gamma radiation and chemical reagent on degradation of chitosan and preliminary test of degraded chitosan with different molecular weight as plant growth promoter of okra in potting experiment. (author)

  16. Effect of molecular weight on radiation chemical degradation yield of chain scission of γ-irradiated chitosan in solid state and in aqueous solution

    International Nuclear Information System (INIS)

    Tahtat, Djamel; Mahlous, Mohamed; Benamer, Samah; Nacer Khodja, Assia; Larbi Youcef, Souad

    2012-01-01

    Chitosan A 1 , A 2 and A 3 with molecular weight of 471, 207 and 100 kDa respectively, produced from squid pen chitin was degraded by gamma rays in the solid state and in aqueous solution with various doses in air at ambient temperature. Effect of molecular weight on radiation chemical degradation yield of chain scission and degradation rate constants of γ-irradiated chitosan in solid state and in aqueous solution was investigated. The radiation chemical degradation yield G (s) and degradation rate values were calculated. The molecular weight changes were monitored by capillary viscometry method and the chemical structure changes were followed by UV analysis. The results showed that, the degradation of chitosan was faster in solution, than in solid state. The values of G (s) in solid state and in aqueous solution were respectively 1.1×10 −8 mol/J and 0.074×10 −7 mol/J for A 1 , 4.42×10 −8 mol/J and 0.28×10 −7 mol/J for A 2 and 6.08×10 −8 mol/J and 0.38×10 −7 mol/J for A 3 . Degradation rate constants values ranged from 0.41×10 −5 to 2.1×10 −5 kGy −1 in solid state, whereas in solution they ranged from 13×10 −5 to 68×10 −5 kGy −1 . The chitosan A 3 was more sensitive to radiolysis than A 1 and A 2 . The chain scission yield, G (s) and degradation rate constants seems to be greatly influenced by the initial molecular weight of the chitosan. Structural changes in irradiated chitosan are revealed by the apparition of absorption peaks at 261 and 295 nm, which could be attributed to the formation of carbonyl groups. In both conditions the peak intensity was higher in chitosan A 3 than in A 1 and A 2 , the oxidative products decreased with increasing molecular weight of chitosan. - Highlights: ► We investigated the effects of MW on G (s) value of γ-irradiated chitosan in solid and aqueous state. ► Chitosan with low molecular weight was more sensitive to radiolysis than high molecular weight. ► G (s) value and degradation rate

  17. Application of radiation degraded carbohydrates for plants

    International Nuclear Information System (INIS)

    Kume, T.; Nagasawa, N.; Yoshu, F.

    1999-01-01

    Radiation degraded carbohydrates such as chitosan, sodium alginate, carageenan, cellulose, pectin, etc. were applied for plant cultivation. Chitosan (poly-β -D-glucosamine) was easily degraded by irradiation and induced various kinds of biological activities such as anti-microbacterial activity, promotion of plant growth, suppression of heavy metal stress on plants, phytoalexins induction, etc. Pectic fragments obtained from degraded pectin also induced the phytoalexins such as glyceollins in soybean and pisafin in pea. The irradiated chitosan shows the higher elicitor activity for pisafin than that of pectin. For the plant growth promotion, alginate derived from brown marine algae, chitosan and ligno-cellulosic extracts show a strong activity. The hot water and ethanol extracts from EFB and sugar cane bagasse were increased by irradiation. These extracts promoted the growth of plants and suppressed the damage on barley with salt and Zn stress. The results show that the degraded polysaccharides by radiation have the potential to induce various biological activities and the products can be use for agricultural and medical fields

  18. In-Vitro Enzymatic Degradation of γ-irradiated Porous Chitosan Scaffold: Crystallinity and degree of deacetylation

    International Nuclear Information System (INIS)

    Ismail Zainol; Azreena Mastor; Suhaida Md Ghani; Ahmad Fuad Yahya; Hazizan Md Akil

    2009-01-01

    Full text: Enzymatic degradation behavior of porous chitosan membrane was carried out in vitro by using enzymatic hydrolysis of chitosan in lysozyme solution. Chitosan was first modified by reducing its molecular weight by gamma (γ) radiation in the solid state. The chitosan powder was irradiated with gamma Co 60 source with various doses of 10, 25, 50 and 100 kGy. The molecular weight of irradiated chitosan was measured using visco metric method. The modified chitosan was transform into a porous membrane by lyophilization method. Degree of deacetylation (DD) and crystallinity of samples were measured using FTIR and XRD respectively on both gamma irradiated and enzymatic degradation samples. The results suggested that the irradiated chitosan become less crystalline without changes in DD. The enzymatic degradation of chitosan however shows an increment in DD and crystallinity. (author)

  19. Chitosan-containing hydrogel wound dressings prepared by radiation technique

    International Nuclear Information System (INIS)

    Mozalewska, Wiktoria; Czechowska-Biskup, Renata; Olejnik, Alicja K.; Wach, Radoslaw A.; Ulański, Piotr; Rosiak, Janusz M.

    2017-01-01

    The aim of the study was to develop an antimicrobial hydrogel wound dressing by means of radiation-initiated crosslinking of hydrophilic polymers, i.e. by well-established technology comprising gel manufacturing and its sterilization in one process. The approach included admixture of chitosan of relatively low molecular weight dissolved in lactic acid (LA) into the initial regular components of the conventional hydrogel dressing based on poly(N-vinyl pyrrolidone) (PVP) and agar. Molecular weight of chitosan was regulated by radiation-initiated degradation in the range of 39–132 kg mol −1 . Optimum total concentration of LA in the resultant hydrogel dressing was evaluated as 0.05 mol dm −3 , that is ca. 0.5%. Presence of LA in the system influenced essential radiation and technological parameters of hydrogel manufacturing. The setting temperature of the pre-hydrogel mixture, resulting from agar ability to congeal, was reduced with LA concentration, yet remained significantly above the room temperature. 0.5% of chitosan was effectively dissolved in aqueous solution of lactic acid due to its pH (lower than 5.5). Radiation parameters of PVP crosslinking in the presence of LA, as determined with generalized Charlesby–Pinner equation, were reflected in slight reduction of the maximum gel fraction and increase in gelation dose and in the factor comparing yields of scission to crosslinking. Nevertheless, essentially physical characteristics of the hydrogel was not affected, except for somewhat increased water uptake capacity, what in turn improves functionality of the dressing as extensive exudate for the wound can be efficiently absorbed. Preliminary microbiological studies showed antimicrobial character of the chitosan-containing hydrogel towards Gram-positive bacterial strain. - Highlights: • Radiation synthesis of bioactive hydrogel wound dressing based on PVP. • Sol-gel analysis, radiation yield of crosslinking and degradation, gel fraction.

  20. Fragmentation of the radiation degraded chitosan by centrifugal filter and application of the fragmented chitosan in cotton fabrics finishing

    International Nuclear Information System (INIS)

    Luu Thi Tho; Nguyen Van Thong; Vu Thi Hong Khanh; Tran Minh Quynh

    2014-01-01

    Three kind of Vietnamese chitosans with the same deacetylation degrees of about 75% and viscosity average molecular weights are 69.000, 187.000 and 345.000 Da, respectively, were produced from shrimp shells and cuttle-bone at the MTV chitosan company (Kien Giang). These chitosans were irradiated at 25, 50, 75, 100, 200 and 500 kGy under Cobalt-60 gamma source at Hanoi Irradiation Center in order to prepare a series of chitosan segments with wide distribution of molecular weights. Different chitosan samples of the predetermined average molecular weight from 3,000 to 50,000 Da were separated from the irradiated chitosans by ultrafiltration with series of filter membranes (Centriprep devices). Molecular properties of the fragmented chitosans were analysed with gel permeation chromatography, Fourier transfer infra red spectrometry, and the results suggested that principal characteristics of chitosan were not affected by gamma irradiation, even its deacetylation degrees was increased. Solubility of the fragmented chitosans were much improved by radiation processing, and the chitosans having molecular weights below 5.000 Da were water-soluble polymers, which can easily apply as the auxiliary agent in textile. (author)

  1. Study on gamma-irradiation degradation of chitosan swollen in H2O2 solution and its antimicrobial activity for E. coli

    International Nuclear Information System (INIS)

    Dang Xuan Du; Bui Phuoc Phuc; Tran Thi Thuy; Le Anh Quoc; Dang Van Phu; Nguyen Quoc Hien

    2014-01-01

    Degradation of chitosan in swollen state with hydrogen peroxide solution (5% w/v) by γ-irradiation was investigated. Molecular weight (M w ) of irradiated chitosan was determined by gel permeation chromatography (GPC). Fourier transform infrared (FT-IR) and ultraviolet-visible (UV-vis) spectra were analyzed to study the structure changes of degraded chitosan. The results showed that the chitosan of low M w (30-45 kDa) was efficiently prepared by γ-irradiation of chitosan swollen in hydrogen peroxide solution at low dose less than 20 kGy. The main structure as well as the degree of deacetylation of the degraded chitosan was almost no significant change. Furthermore, the radiation degradation yield (G s ) was remarkably enhanced by the presence of H 2 O 2 . The obtained low M w chitosan revealed high antimicrobial activity for E. coli that can be used for food preservation and other purposes as well. (author)

  2. Amelioration of radiation induced oxidative stress using water soluble chitosan produced by Aspergillus niger

    International Nuclear Information System (INIS)

    EL-Sonbaty, S.M.; Swailam, H.M.; Noaman, E.

    2012-01-01

    Chitosan is a natural polysaccharide synthesized by a great number of living organisms and considered as a source of potential bioactive material and has many biological applications which are greatly affected by its solubility in neutral ph. In this study low molecular weight water soluble chitosan was prepared by chemical degradation of chitosan produced by Aspergillus niger using H 2 O 2 . Chitosan chemical structure was detected before and after treatment using FTIR spectrum, and its molecular weight was determined by its viscosity using viscometer. Its antioxidant activity against gamma radiation was evaluated in vivo using rats. Rats were divided into 4 groups; group 1: control, group 2: exposed to acute dose of gamma radiation (6 Gy), group 3: received water soluble chitosan, group 4: received water soluble chitosan then exposed to gamma radiation as group 2. Gamma radiation significantly increased malonaldehyde, decreased glutathione concentration, activity of superoxide dismutase, catalase, and glutatione peroxidase, while significantly increase the activity of alanine transferase, aspartate transferase, urea and creatinine concentration. Administration of water soluble chitosan has ameliorated induced changes caused by gamma radiation. It could be concluded that water soluble chitosan by scavenging free radicals directly or indirectly may act as a potent radioprotector against ionizing irradiation.

  3. Effect of enzymatic degradation of chitosan in polyhydroxybutyrate/chitosan/calcium phosphate composites on in vitro osteoblast response.

    Science.gov (United States)

    Giretova, Maria; Medvecky, Lubomir; Stulajterova, Radoslava; Sopcak, Tibor; Briancin, Jaroslav; Tatarkova, Monika

    2016-12-01

    Polyhydroxybutyrate/chitosan/calcium phosphate composites are interesting biomaterials for utilization in regenerative medicine and they may by applied in reconstruction of deeper subchondral defects. Insufficient informations were found in recent papers about the influence of lysozyme degradation of chitosan in calcium phosphate/chitosan based composites on in vitro cytotoxicity and proliferation activity of osteoblasts. The effect of enzymatic chitosan degradation on osteoblasts proliferation was studied on composite films in which the porosity of origin 3D scaffolds was eliminated and the surface texture was modified. The significantly enhanced proliferation activity with faster population growth of osteoblasts were found on enzymatically degraded biopolymer composite films with α-tricalcium phosphate and nanohydroxyapatite. No cytotoxicity of composite films prepared from lysozyme degraded scaffolds containing a large fraction of low molecular weight chitosans (LMWC), was revealed after 10 days of cultivation. Contrary to above in the higher cytotoxicity origin untreated nanohydroxyapatite films and porous composite scaffolds. The results showed that the synergistic effect of surface distribution, morphology of nanohydroxyapatite particles, microtopography and the presence of LMWC due to chitosan degradation in composite films were responsible for compensation of the cytotoxicity of nanohydroxyapatite composite films or porous composite scaffolds.

  4. Improved postharvest quality in patagonian squash (Cucurbita moschata) coated with radiation depolymerized chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, Maria Alicia; Goitia, Maria Teresa [Laboratorio de Investigaciones Basicas Aplicadas en Quitina, Departamento de Quimica, Universidad Nacional del Sur. Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina); Yossen, Mariana [Instituto de Desarrollo Tecnologico para la Industria Quimica (INTEC), CONICET-Universidad Nacional del Litoral, Ruta Nacional 168-Paraje ' El Pozo' , 3000 Santa Fe (Argentina); Cifone, Norma; Agullo, Enrique [Laboratorio de Investigaciones Basicas Aplicadas en Quitina, Departamento de Quimica, Universidad Nacional del Sur. Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina); Andreucetti, Noemi, E-mail: andreuce@criba.edu.ar [Laboratorio de Radioisotopos, Departamento de Quimica, Universidad Nacional del Sur, Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina)

    2011-12-15

    Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes (Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan. - Highlights: > Original Chitosan was radiation depolymerized producing chitosans with lower molecular weights. > Gamma-irradiated chitosans only exhibit chain scission. > SEC-MALLS-RI chromatography is a useful tool in molecular weight analysis. > Depolymerized chitosans were the best in maintaining the quality and the storage life of coated squashes.

  5. Improved postharvest quality in patagonian squash (Cucurbita moschata) coated with radiation depolymerized chitosan

    International Nuclear Information System (INIS)

    Pugliese, Maria Alicia; Goitia, Maria Teresa; Yossen, Mariana; Cifone, Norma; Agullo, Enrique; Andreucetti, Noemi

    2011-01-01

    Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes (Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan. - Highlights: → Original Chitosan was radiation depolymerized producing chitosans with lower molecular weights. → Gamma-irradiated chitosans only exhibit chain scission. → SEC-MALLS-RI chromatography is a useful tool in molecular weight analysis. → Depolymerized chitosans were the best in maintaining the quality and the storage life of coated squashes.

  6. Radiation degradation of carbohydrates and their biological activities for plants

    International Nuclear Information System (INIS)

    Kume, T.; Nagasawa, N.; Matsuhashi, S.

    2000-01-01

    Radiation effects on carbohydrates such as chitosan, sodium alginate, carrageenan, cellulose, pectin have been investigated to improve the biological activities. These carbohydrates were easily degraded by irradiation and induced various kinds of biological activities such as anti-bacterial activity, promotion of plant growth, suppression of heavy metal stress, phytoalexins induction. Pectic fragments obtained from degraded pectin induced the phytoalexins such as glyceollins in soybean and pisatin in pea. The irradiated chitosan shows the higher elicitor activity for pisatin than that of pectin. For the plant growth promotion, alginate derived from brown marine algae, chitosan and ligno-cellulosic extracts show a strong activity. Kappa and iota carrageenan derived from red marine algae can promote growth of rice and the highest effect was obtained with kappa irradiated at 100 kGy. Some radiation degraded carbohydrates suppressed the damage of heavy metals on plants. The effects of irradiated carbohydrates on transportation of heavy metals have been investigated by PETIS (Positron Emitting Tracer Imaging System) and autoradiography using 48 V and 62 Zn. (author)

  7. Improved postharvest quality in patagonian squash ( Cucurbita moschata) coated with radiation depolymerized chitosan

    Science.gov (United States)

    Pugliese, Maria Alicia; Goitia, Maria Teresa; Yossen, Mariana; Cifone, Norma; Agulló, Enrique; Andreucetti, Noemi

    2011-12-01

    Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes ( Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan.

  8. Degradation Behaviour of Gamma Irradiated Poly(Acrylic Acid)-graft-Chitosan Superabsorbent Hydrogel

    Science.gov (United States)

    Ria Barleany, Dhena; Ilhami, Alpin; Yusuf Yudanto, Dea; Erizal

    2018-03-01

    A series of superabsorbent hydrogels were prepared from chitosan and partially neutralized acrylic acid at room temperature by gamma irradiation technique. The effect of irradiation and chitosan addition to the degradation behaviour of polymer were investigated. The gel content, swelling capacity, Equillibrium Degree of Swelling (EDS), Fourier Transform Infra Red (FTIR), and Scanning Electron Microscopy (SEM) study were also performed. Natural degradation in soil and thermal degradation by using of TGA analysis were observed. The variation of chitosan compositions were 0.5, 1, 1.5, and 2 g and the total irradiation doses were 5, 10, 15, and 20 kGy. The highest water capacity of 583.3 g water/g dry hydrogel was resulted from 5 kGy total irradiation dose and 0,5 g addition of chitosan. From the thermal degradation evaluation by using of TGA analysis showed that irradiation dose did not give a significant influence to the degradation rate. The rate of thermal degradation was ranged between 2.42 to 2.55 mg/min. In the natural test of degradation behaviour by using of soil medium, the hydrogel product with chitosan addition was found to have better degradability compared with the poly(acrylic acid) polymer without chitosan.

  9. Radiation degradation of marine polysaccharides by low energy electron beam

    International Nuclear Information System (INIS)

    Yoshii, Fumio; Nagasawa, Naotsugu; Kume, Tamikazu

    2003-01-01

    The radiation degradations of marine polysaccharides by both gamma Co-60 and electron beam irradiations are investigated. Polysaccharides and oligosaccharides can be produced by degradation of corresponding polysaccharides including marine polysaccharides such as alginates, chitin chitosan and carrageenan. The viscosity of alginate, chitosan and carrageenan solution decreases markedly with increase of the low energy electron beam irradiation time and the beam current. Furthermore, the viscosity is reduced sharply in short time for polysaccharide solution with low concentration, for instance carrageenan solution of 1%. (author)

  10. Some features of irradiated chitosan and its biological effect

    International Nuclear Information System (INIS)

    Hai, Le; Hien, Nguyen Quoc; Luan, Le Quang; Hanh, Truong Thi; Man, Nguyen Tan; Ha, Pham Thi Le; Thuy, Tran Thi; Yoshii, Fumio; Kume, Tamikazu

    2001-01-01

    Preparation of chitosan oligomer by radiation degradation was carried out on the gamma Co-60 source. The radiation degradation yield (G d ) of the chitosan was found to be of 1.03. The oligochitosan with 50% of dp>8 fraction was obtained by irradiating the 10% (w/v) chitosan solution in 5% acetic acid at 45 kGy for the chitosan having the initial viscometric average molecular weight, Mv=60,000. Irradiated chitosan showed higher antifungal effect than that of unirradiated one. Furthermore, the irradiated chitosan also showed the growth-promotion effect for plants. (author)

  11. Degradation of chitosan-based materials after different sterilization treatments

    International Nuclear Information System (INIS)

    San Juan, A; Montembault, A; Royaud, I; David, L; Gillet, D; Say, J P; Rouif, S; Bouet, T

    2012-01-01

    Biopolymers have received in recent years an increasing interest for their potential applications in the field of biomedical engineering. Among the natural polymers that have been experimented, chitosan is probably the most promising in view of its exceptional biological properties. Several techniques may be employed to sterilize chitosan-based materials. The aim of our study was to compare the effect of common sterilization treatments on the degradation of chitosan-based materials in various physical states: solutions, hydrogels and solid flakes. Four sterilization methods were compared: gamma irradiation, beta irradiation, exposure to ethylene oxide and saturated water steam sterilization (autoclaving). Exposure to gamma or beta irradiation was shown to induce an important degradation of chitosan, regardless of its physical state. The chemical structure of chitosan flakes was preserved after ethylene oxide sterilization, but this technique has a limited use for materials in the dry state. Saturated water steam sterilization of chitosan solutions led to an important depolymerization. Nevertheless, steam sterilization of chitosan flakes bagged or dispersed in water was found to preserve better the molecular weight of the polymer. Hence, the sterilization of chitosan flakes dispersed in water would represent an alternative step for the preparation of sterilized chitosan solutions. Alternatively, autoclaving chitosan physical hydrogels did not significantly modify the macromolecular structure of the polymer. Thus, this method is one of the most convenient procedures for the sterilization of physical chitosan hydrogels after their preparation.

  12. Some features of irradiated chitosan and its biological effect

    Energy Technology Data Exchange (ETDEWEB)

    Hai, Le; Hien, Nguyen Quoc; Luan, Le Quang; Hanh, Truong Thi; Man, Nguyen Tan; Ha, Pham Thi Le; Thuy, Tran Thi [Nuclear Research Institute, VAEC, Dalat (Viet Nam); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Preparation of chitosan oligomer by radiation degradation was carried out on the gamma Co-60 source. The radiation degradation yield (G{sub d}) of the chitosan was found to be of 1.03. The oligochitosan with 50% of dp>8 fraction was obtained by irradiating the 10% (w/v) chitosan solution in 5% acetic acid at 45 kGy for the chitosan having the initial viscometric average molecular weight, Mv=60,000. Irradiated chitosan showed higher antifungal effect than that of unirradiated one. Furthermore, the irradiated chitosan also showed the growth-promotion effect for plants. (author)

  13. Study on the degradation of chitosan slurries

    Directory of Open Access Journals (Sweden)

    Benjamin Martini

    2016-01-01

    Full Text Available In the present work, we measured the degradation rate of different chitosan slurries. Several parameters were monitored such as temperature (25 °C, 37 °C, 50 °C; chitosan concentration (1% and 2% (w/V; and polymer molecular weight. The samples were tested in dynamic sweep test mode. This test is able to provide a reliable estimation of viscosity variations of the slurries; in turn, these variations could be related to degradation rate of the system in the considered conditions. The resulting information is particularly important especially in applications in which there is a close relationship between physical properties and molecular structure.

  14. Radiation depolymerization of chitosan to prepare oligomers

    International Nuclear Information System (INIS)

    Hai, Le; Bang Diep, Tran; Nagasawa, Naotsugu; Yoshii, Fumio; Kume, Tamikazu

    2003-01-01

    Radiation depolymerization of chitosan was carried out by gamma irradiation in the solid state. The radiation-chemical depolymerization yield of chitosan in the solid state, Gd, determined by gel permeation chromatography, is 0.9 for chitosan 10B and 1.8 for chitosan 8B. Low molecular weight chitosan/or oligochitosans were separated from a chitosan depolymerized by gamma radiation, using mixtures of methanol-water and acetone as the solvents. Due to the differences in solubility revealed upon radiolysis, extracts became subdivided into precipitates and soluble fractions. The biological effect of oligochitosan in each fraction was evaluated; the preliminary results indicated that the oligochitosan with M w -bar=2x10 4 inhibited the growth of fungi at 100 ppm and that with M w -bar=800 only enhanced the growth of the same typical fungi

  15. Research on oligochitosan production by gamma radiation degradation techniques in pilot scale for application in disease control and growth performance of chickens

    International Nuclear Information System (INIS)

    Tran Thi Thuy; Nguyen Duy Hang; Nguyen Tan Man; Nguyen Trong Hoanh Phong; Pham Thi Sam; Nguyen Tuong Ly Lan; Le Hai; Le Huu Tu; Pham Thi Le Ha; Phan Van Anh

    2015-01-01

    Degradation of chitosan to prepare the low molecular weight chitosan has been carried out by gamma irradiation of chitosan in H_2O_2 solution. The effects of radiation dose, dose rate, ratio of CTS:H_2O and H_2O_2 concentration to the degrading efficiency of chitosan have been investigated. The obtained results showed the chitosan molecular weight reduced with the increase of radiation dose. Chitosan was irradiated at radiation dose 10 kGy in the presence of H_2O_2 1% its molecular weight achieved 45 kDa. The effect of irradiated chitosan on the growth development and the survival ratio of breeding chickens in the process were also studied. The results shown that low molecular weight chitosan supplement in diets had positive effect of the resistant ability, growth performance and reduced chick mortality. With supplement ratio of 100 mg/kg diets, chitosan 45 kDa had positive affect on growth performance of chicks, the weight of chickens increased 6% and survival ratio was 94.8% while the normal survival ratio was only 92.6%. (author)

  16. Controlling Radiation Degradation of Natural Polymers for Industrial and Agricultural application

    International Nuclear Information System (INIS)

    Hegazy, E.A.; AbdEl-Rehim, H

    2008-01-01

    Radiation induced degradation technology is a new and promising application of ionizing radiation to develop viscose, pulp, paper, food preservation, pharmaceutical production, and natural bioactive agents industries. Controlling the degree of degradation, uniform molecular weight distribution, saving achieved in the chemicals (used in conventional methods) on a cost basis, and environmentally friendly process are the beneficial effects of using radiation technology in these industries. However, for some development countries such technology is not economic. Therefore, a great effort should be done to reduce the cost required for such technologies. One of the principle factors for reducing the cost is achieving the degradation at low irradiation doses. The addition of some additives such as potassium per-sulfate (KPS), ammonium per-sulfate (APS), or H 2O2 to natural polymers such as chitosan and Na-alginate during irradiation process accelerates their degradation. The highest degradation rate of polysaccharides obtained when APS was used. The end product of irradiated chitosan, and Na-alginate may be used as food additive or benefited in agricultural purposes. The prepared crosslinked copolymers possessed high and fast swelling properties in simulated urine media and the swelling ratios of CMC-Na /PAAm gels in urine are acceptable for diaper application. (author)

  17. Degradation of chitosan hydrogel dispersed in dilute carboxylic acids by solution plasma and evaluation of anticancer activity of degraded products

    Science.gov (United States)

    Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Theeramunkong, Sewan; Saito, Nagahiro

    2018-01-01

    Chitosan is a polysaccharide that has been extensively studied in the field of biomedicine, especially its water-soluble degraded products called chitooligosaccharides (COS). In this study, COS were produced by the degradation of chitosan hydrogel dispersed in a dilute solution (i.e., 1.55 mM) of various kinds of carboxylic acids using a non-thermal plasma technology called solution plasma (SP). The degradation rates of chitosan were influenced by the type of carboxylic acids, depending on the interaction between chitosan and each carboxylic acid. After SP treatment, the water-soluble degraded products containing COS could be easily separated from the water-insoluble residue of chitosan hydrogel by centrifugation. The production yields of the COS were mostly higher than 55%. Furthermore, the obtained COS products were evaluated for their inhibitory effect as well as their selectivity against human lung cancer cells (H460) and human lung normal cells (MRC-5).

  18. Study on the biological effect of radiation-degraded alginate and chitosan on plant in tissue culture

    International Nuclear Information System (INIS)

    Le Quang Luan; Vo Thi Thu Ha; Le Hai; Nguyen Quoc Hien; Nguyen Duy Hang; Nguyen Tuong Ly Lan; Le Huu Tu

    2003-01-01

    The solution of chitosan (10%) and alginate (4%) were irradiated at doses of 10-250 kGy for degradation and the products were used for testing of plant growth promotion effect. The chitosan and alginate irradiated at 100 kGy and 75 kGy, respectively showed the strongest growth-promotion effect for plants namely L. latifolium, E. grandiflorum and C. morifolium in tissue culture. For shoot multiplication, the suitable concentrations are found to be ca. 50-200 mg/l for C. morifolium, 70-100 mg/l for L. latifolium and 30-100 mg/l E. grandiflorum with irradiated chitosan, while with irradiated alginate, it was 30-200 mg/l, 30-50 mg/l and 10-200 mg/l, respectively. The optimum concentrations for C. morifolium, E. grandiflorum, L. latifolium incubated on rooting medium are ca. 100 mg/l, 30 mg/l and 40 mg/l, respectively for irradiated chitosan and 100 mg/l for irradiated alginate. After acclimatizing for 30 days in the greenhouse, the survival ratio of the transferred C. morifolium, E. grandiflorum, L. latifolium plantlets treated with irradiated chitosan was improved 18%, 39% and 13%, respectively. (author)

  19. Radiation Chemistry and Physical Chemistry of Chitosan and Other Polysaccharides. Fundamental Studies and Practical Applications

    International Nuclear Information System (INIS)

    Rosiak, Janusz M.; Czechowska-Biskup, Renata; Rokita, Bożena; Olejnik, Alicja K.

    2010-01-01

    This report summarizes the second year of activities performed at the Institute of Applied Radiation Chemistry (IARC) within the framework of the CRP project. It consists of two parts. Part I is a brief account of the activities related to design, tests, sample procurement and characterization and formulation of “Protocol for determination of intrinsic viscosity of chitosan” designed to be the basis of the interlaboratory study on viscometric determination of chitosan molecular weight as well as on radiation degradation of chitosan in controlled conditions. Part II contains the text of the Protocol, and is given in the Annex. (author)

  20. Controlling of degradation effects in radiation processing of polymers. Second RCM report

    International Nuclear Information System (INIS)

    2005-08-01

    The research and development works carried out by the participants of the CRP (Coordinated Research Project) dealt with natural polymers, synthetic polymers and new techniques for better understanding of radiation degradation of polymers. It includes progress in radiation degradation of polysaccharides from agricultural products (including sodium alginate, carrageenans, chitosan and gum acacia); use of radiation-degradation for doping of conductive polymers; controlling degradation processes in artificial joint implants, surface treatment of materials and food packaging; stabilizer additives for radiation environments; surface treatment of materials; and application of specialized analytical techniques (positron annihilation spectroscopy, ESR, RBS, ERDA, NMR/isotopic-labeling) to gain improved understanding of radiation degradation effects and mechanisms. Projects within the RCM group span the spectrum from fundamental studies through specific technological applications. Participants from Czech Republic, Spain and Turkey benefited from scientific collaboration with Bulgaria on PAS

  1. Mechanical property, degradation rate, and bone cell growth of chitosan coated titanium influenced by degree of deacetylation of chitosan.

    Science.gov (United States)

    Yuan, Youling; Chesnutt, Betsy M; Wright, Lee; Haggard, Warren O; Bumgardner, Joel D

    2008-07-01

    Chitosan has shown promise as a coating for dental/craniofacial and orthopaedic implants. However, the effects of degree of deacetylation (DDA) of chitosan on coating bond strength, degradation, and biological performance is not known. The aim of this project was to evaluate bonding, degradation, and bone cell growth on titanium coated with chitosans of different DDA and from different manufacturers. Three different chitosans, 80.6%, 81.7%, and 92.3% DDA were covalently bonded to titanium coupons via silane-glutaraldehyde molecules. Bond strengths were evaluated in mechanical tensile tests, and degradation, over 5 weeks, was conducted in cell culture medium with and without 100 microg/mL lysozyme. Cytocompatibility was evaluated for 10 days using UMR 106 osteoblastic cells. Results showed that mean chitosan coating bond strengths ranged from 2.2-3.8 MPa, and that there was minimal affect of DDA on coating bond strengths. The coatings exhibited little dissolution over 5 weeks in medium with or without lysozyme. However, the molecular weight (MW) of the chitosan coatings remaining on the titanium samples after 5 weeks decreased by 69-85% with the higher DDA chitosan coatings exhibiting less percent change in MW than the lower DDA materials. The growth of the UMR 106 osteoblast cells on the 81.7% DDA chitosan coating was lower on days 3 and 5, as compared with the other two coatings, but by day 10, there were no differences in growth among three coatings or to the uncoated titanium controls. Differences in growth were attributed to differences in manufacturer source material, though all coatings were judged to be osteocompatible in vitro. 2007 Wiley Periodicals, Inc.

  2. 166Ho-chitosan as a radiation synovectomy agent - biocompatibility study of 166Ho-chitosan in rabbits

    International Nuclear Information System (INIS)

    Kim, Sug Jun; Lee, Soo Yong; Jeon, Dae Geun; Lee Jong Seok

    1997-01-01

    Radiation synovectomy is a noninvasive therapy that has been investigated as an alternative to surgical synovectomy. It is been successfully employed in the treatment of synovitis in rheumatoid arthrits and other inflammatory arthropathies. We developed the 166 Ho-chitosan complex for possible use as a radiation synovectomy agent. Holmium is the more practical isotope based on its higher radioactivity and logner half-life. And isotope based on its higher radioactivity and logner half-life. And chitosan is ideal and suitable particles based on its soluble and biodegradable characteristics. So we investigated the biocompatibility of the 166 Ho-chitosan complex to evaluated the suitability as a radiation synovectomy agent. In this study, we performed in vivo and in vitro stability test and biodistribution test. Our results indicate that 166 Ho-chitosan may be an effective radiopharmaceutical for radiation synovectomy. (author). 30 refs., 7 tabs

  3. Study of compatibility of oligo-chitosan and ginkgo bilobal polyprenol influences on micronuclear rates and p53, gadd45 protein expression of radiated mice

    International Nuclear Information System (INIS)

    Guo Jianping; Wang Yongli; Wei Jinping; Yang Zhongtian; Liu Chunhui

    2012-01-01

    Study of compatibility of oligo-chitosan and ginkgo bilobal polyprenol (GP) influences on micronuclear rate and p53, gadd45 protein expression of radiated mice. Survival rate and survival time of 30-day-time of radiated mice was studied with the mixture of compatibility of oligo-chitosan and different density of GP. High survival rate of mixture density was screening. Another study on this mixture density was about micronuclear rates of marrow and p53, gadd45 protein of spleen after mice were radiated 12 h. The mixture of 300 mg/kg oligo-chitosan and 5 mg/kg GP could increase remarkably the survival rate and survival time of 30-day-time of radiated mice and degrade micronuclear rates and p53, gadd45 protein expression. Compatibility of oligo-chitosan and GP effectively raise the survival rate of radiated mice. It could proved initially that the mixture has the function of radiation protection. (authors)

  4. Enzymatic degradation behavior and cytocompatibility of silk fibroin-starch-chitosan conjugate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Baran, Erkan T., E-mail: erkantur@metu.edu.tr; Tuzlakoglu, Kadriye, E-mail: kadriye@dep.uminho.pt; Mano, Joao F., E-mail: jmano@dep.uminho.pt; Reis, Rui L., E-mail: rgreis@dep.uminho.pt

    2012-08-01

    The objective of this study was to investigate the influence of silk fibroin and oxidized starch conjugation on the enzymatic degradation behavior and the cytocompatability of chitosan based biomaterials. The tensile stress of conjugate membranes, which was at 50 Megapascal (MPa) for the lowest fibroin and starch composition (10 weight percent (wt.%)), was decreased significantly with the increased content of fibroin and starch. The weight loss of conjugates in {alpha}-amylase was more notable when the starch concentration was the highest at 30 wt.%. The conjugates were resistant to the degradation by protease and lysozyme except for the conjugates with the lowest starch concentration. After 10 days of cell culture, the proliferation of osteoblast-like cells (SaOS-2) was stimulated significantly by higher fibroin compositions and the DNA synthesis on the conjugate with the highest fibroin (30 wt.%) was about two times more compared to the native chitosan. The light microscopy and the image analysis results showed that the cell area and the lengths were decreased significantly with higher fibroin/chitosan ratio. The study proved that the conjugation of fibroin and starch with the chitosan based biomaterials by the use of non-toxic reductive alkylation crosslinking significantly improved the cytocompatibility and modulated the biodegradation, respectively. - Highlights: Black-Right-Pointing-Pointer Silk fibroin, starch and chitosan conjugates were prepared by reductive alkylation. Black-Right-Pointing-Pointer The enzymatic biodegradation and the cytocompatibility of conjugates were tested. Black-Right-Pointing-Pointer The conjugate with 30% starch composition was degraded by {alpha}-amylase significantly. Black-Right-Pointing-Pointer Higher starch composition in conjugates prevented protease and lysozyme degradation. Black-Right-Pointing-Pointer Fibroin incorporation effectively increased the cell proliferation of conjugates.

  5. Correction of MHS Viscosimetric Constants upon Numerical Simulation of Temperature Induced Degradation Kinetic of Chitosan Solutions

    Directory of Open Access Journals (Sweden)

    Vincenzo Maria De Benedictis

    2016-05-01

    Full Text Available The Mark–Houwink–Sakurada (MHS equation allows for estimation of rheological properties, if the molecular weight is known along with good understanding of the polymer conformation. The intrinsic viscosity of a polymer solution is related to the polymer molecular weight according to the MHS equation, where the value of the constants is related to the specific solvent and its concentration. However, MHS constants do not account for other characteristics of the polymeric solutions, i.e., Deacetilation Degree (DD when the solute is chitosan. In this paper, the degradation of chitosan in different acidic environments by thermal treatment is addressed. In particular, two different solutions are investigated (used as solvent acetic or hydrochloric acid with different concentrations used for the preparation of chitosan solutions. The samples were treated at different temperatures (4, 30, and 80 °C and time points (3, 6 and 24 h. Rheological, Gel Permeation Chromatography (GPC, Fourier Transform Infrared Spectroscopy (FT-IR, Differential Scanning Calorimetry (DSC and Thermal Gravimetric Analyses (TGA were performed in order to assess the degradation rate of the polymer backbones. Measured values of molecular weight have been integrated in the simulation of the batch degradation of chitosan solutions for evaluating MHS coefficients to be compared with their corresponding experimental values. Evaluating the relationship between the different parameters used in the preparation of chitosan solutions (e.g., temperature, time, acid type and concentration, and their contribution to the degradation of chitosan backbone, it is important to have a mathematical frame that could account for phenomena involved in polymer degradation that go beyond the solvent-solute combination. Therefore, the goal of the present work is to propose an integration of MHS coefficients for chitosan solutions that contemplate a deacetylation degree for chitosan systems or a more

  6. Structural and antimicrobial properties of irradiated chitosan and its complexes with zinc

    International Nuclear Information System (INIS)

    Khan, Azam; Mehmood, Shaukat; Shafiq, Muhammad; Yasin, Tariq; Akhter, Zareen; Ahmad, Shabir

    2013-01-01

    The aim of this research was to evaluate the structural and antimicrobial properties of irradiated chitosan and its complexes with zinc. Chitosan having a molecular weight (M η ) of 220 kDa was exposed to gamma rays in dry, wet and solution forms. The chitosan-zinc complexes were prepared by varying the M η of chitosan and Zn content. Viscometeric analysis revealed a sharp decrease in the M η of chitosan irradiated in solution form even at lower doses compared with the dry and wet forms. X-ray diffraction patterns demonstrated variation in the crystallinity of chitosan upon exposure to gamma rays. The antibacterial response of the irradiated chitosan and its complexes against gram-positive and gram-negative bacteria demonstrated wide spectrum of effective antimicrobial activities, which increased with the dose. Additionally, the complexes exhibited excellent antifungal activity with no growth of Aspergallious fumigatus and Fusarium solani even after two weeks. These results suggested that the irradiated chitosan and its complexes with Zn can be used as antimicrobial additives for various applications. - Highlights: • Gamma radiation is used to lower the molecular weight of chitosan. • The effect of environment on radiation degradation of chitosan is studied. • Its complexes with different amount of zinc are prepared and characterized. • Radiation-degraded chitosan and complexes showed good antibacterial properties

  7. {sup 166}Ho-chitosan as a radiation synovectomy agent - biocompatibility study of {sup 166}Ho-chitosan in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sug Jun; Lee, Soo Yong; Jeon, Dae Geun; Seok, Lee Jong [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1997-01-01

    Radiation synovectomy is a noninvasive therapy that has been investigated as an alternative to surgical synovectomy. It is been successfully employed in the treatment of synovitis in rheumatoid arthrits and other inflammatory arthropathies. We developed the {sup 166}Ho-chitosan complex for possible use as a radiation synovectomy agent. Holmium is the more practical isotope based on its higher radioactivity and logner half-life. And isotope based on its higher radioactivity and logner half-life. And chitosan is ideal and suitable particles based on its soluble and biodegradable characteristics. So we investigated the biocompatibility of the {sup 166}Ho-chitosan complex to evaluated the suitability as a radiation synovectomy agent. In this study, we performed in vivo and in vitro stability test and biodistribution test. Our results indicate that {sup 166}Ho-chitosan may be an effective radiopharmaceutical for radiation synovectomy. (author). 30 refs., 7 tabs.

  8. Biodegradable, pH-sensitive chitosan beads obtained under microwave radiation for advanced cell culture.

    Science.gov (United States)

    Piątkowski, Marek; Janus, Łukasz; Radwan-Pragłowska, Julia; Bogdał, Dariusz; Matysek, Dalibor

    2018-04-01

    A new type of promising chitosan beads with advanced properties were obtained under microwave radiation according to Green Chemistry principles. Biomaterials were prepared using chitosan as raw material and glutamic acid/1,5-pentanodiol mixture as crosslinking agents. Additionally beads were modified with Tilia platyphyllos extract to enhance their antioxidant properties. Beads were investigated over their chemical structure by FT-IR analysis. Also their morphology has been investigated by SEM method. Additionally swelling capacity of the obtained hydrogels was determined. Lack of cytotoxicity has been confirmed by MTT assay. Proliferation studies were carried out on L929 mouse fibroblasts. Advanced properties of the obtained beads were investigated by studying pH sensitivity and antioxidant properties by DPPH method. Also susceptibility to degradation and biodegradation by Sturm Test method was evaluated. Results shows that proposed chitosan beads and their eco-friendly synthesis method can be applied in cell therapy and tissue engineering. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Influences of gamma irradiation treatment on the molecular weight of chitosan

    International Nuclear Information System (INIS)

    Luu Thi Tho; Nguyen Viet Thong; Tran Minh Quynh; Vu Thi Hong Khanh

    2013-01-01

    Effects of gamma radiation on molecular properties of shrimp and squid chitosan (MTV, Vietnam) have been studied with three kind chitosan that having degree of deacetylation 75% and different molecular molecular weight of 69, 187 and 345 kDa, Chitosan samples were irradiated at the same dose rate of 4.3 kGy per hour with various radiation dose of 25, 50, 75, 100, 200 and 500 kGy. The viscosity average molecular weight and degree of deacetylation (DD) of chitosan before and after irradiation have been investigated via their intrinsic viscosity and Furrier transform infra-red (FT-IR). The data revealed the chitosan backbone chains has been degraded by gamma radiation, resulting in the smaller fragments with reduced molecular weight to 3000 Da, whereas their DD have not much changed. (author)

  10. Enhanced degradation of chitosan by applying plasma treatment in combination with oxidizing agents for potential use as an anticancer agent.

    Science.gov (United States)

    Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Watthanaphanit, Anyarat; Theeramunkong, Sewan; Saito, Nagahiro; Yamashita, Kazuko; Arakawa, Ryuichi

    2017-07-01

    Solution plasma (SP) treatment in combination with oxidizing agents, i.e., hydrogen peroxide (H 2 O 2 ), potassium persulfate (K 2 S 2 O 8 ) and sodium nitrite (NaNO 2 ) were adopted to chitosan degradation in order to achieve fast degradation rate, low chemicals used and high yield of low-molecular-weight chitosan and chitooligosaccharide (COS). Among the studied oxidizing agents, H 2 O 2 was found to be the best choice in terms of appreciable molecular weight reduction without major change in chemical structure of the degraded products of chitosan. By the combination with SP treatment, dilute solution of H 2 O 2 (4-60mM) was required for effective degradation of chitosan. The combination of SP treatment and dilute solution of H 2 O 2 (60mM) resulted in the great reduction of molecular weight of chitosan and water-soluble chitosan was obtained as a major product. The resulting water-soluble chitosan was precipitated to obtain COS. An inhibitory effect against cervical cancer cell line (HeLa cells) of COS was also examined. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Studies for improving and formulating of chitosan-based coatings by radiation treatment for fruit preservation

    International Nuclear Information System (INIS)

    Nguyen Duy Lam; Tran Bang Diep; Tran Minh Quynh; Le Thi Dinh; Nguyen Van Binh; Ho Minh Duc; Vo Van Thuan

    2003-01-01

    Presented are the investigations: effect of chitosan on fruit - spoiling microorganism and enhancement of antifungal activity by radiation treatment; improvement of antimicrobial activity of chitosan by its derivatives synthesis in combination with radiation treatment; dependence of chitosan antimicrobial activity on molecular weight and distribution of molecular weight; comparative study on the antifungal activity of chitosan of various origins tested in different conditions of radiation treatment and culture mediums; formulation of chitosan membranes and for their properties in mango coating; effectiveness of chitosan-based coatings on fresh fruit appearance and quality during storage; influence of irradiated chitosan on rice plant growing in media contaminated with salt and heavy metals; effect of chitosan solution varied in concentration and molecular weight on seed germination and seedling growth of groundnut, soybean and cabbage. (NHA)

  12. Preparation of Carbon-Chitosan-Polyvinyl Chloride (CC-PVC) Material and its Application to Electrochemical Degradation of Methylene Blue in Sodium Chloride Solution

    Science.gov (United States)

    Riyanto; Prawidha, A. D.

    2018-01-01

    Electrochemical degradation of methylene blue using Carbon-Chitosan-Polyvinyl Chloride (CC-PVC) electrode in sodium chloride have been done. The aim of this work was to degradation of methylene blue using Carbon-Chitosan-Polyvinyl Chloride (CC-PVC). Carbon chitosan composite electrode was preparing by Carbon and Chitosan powder and PVC in 4 mL tetrahydrofuran (THF) solvent and swirled flatly to homogeneous followed by drying in an oven at 100 °C for 3 h. The mixture was placed in stainless steel mould and pressed at 10 ton/cm2. Sodium chloride was used electrolyte solution. The effects of the current and electrolysis time were investigated using spectrophotometer UV-Visible. The experimental results showed that the carbon-chitosan composite electrode have higher effect in the electrochemical degradation of methylene blue in sodium chloride. Based on UV-visible spectra analysis shows current and electrolysis time has high effect to degradation of methylene blue in sodium chloride. Chitosan and polyvinyl chloride can strengthen the bond between the carbons so that the material has the high stability and conductivity. As conclusions is Carbon-Chitosan-Polyvinyl Chloride (CC-PVC) electrode have a high electrochemical activity for degradation of methylene blue in sodium chloride.

  13. Fish gelatin combined with chitosan coating inhibits myofibril degradation of golden pomfret (Trachinotus blochii) fillet during cold storage.

    Science.gov (United States)

    Feng, Xiao; Bansal, Nidhi; Yang, Hongshun

    2016-06-01

    Coating of gelatin and chitosan can improve fish fillet's quality, but the mechanism is not clear. Chitosan/gelatin coatings significantly prevented deterioration of golden pomfret fillet at 4 °C. Chitosan with 7.2% gelatin group showed the best effect on preserving the length of myofibril, which remained greater than 15 μm at day 17 of storage, while for control, chitosan and chitosan combined with 3.6% gelatin group, it was 5.03, 10.04 and 9.02 μm, respectively. The MALDI-TOF MS result revealed that the coatings slowed down the protein deterioration of fillet. On days 13 and 17, the myosin light chain and myoglobin in control group degraded, while the two proteins still existed in chitosan/gelatin coated groups. Overall, the chitosan with 7.2% gelatin coating had the best effect on preserving fillet's quality during storage. The coating may exert its protective effect via inhibiting myofibril degradation within fillet. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Radiation synthesis and characterization of nanosilver/gelatin/carboxymethyl chitosan hydrogel

    International Nuclear Information System (INIS)

    Zhou Ying; Zhao Yinghui; Wang Lu; Xu Ling; Zhai Maolin; Wei Shicheng

    2012-01-01

    A series of antibacterial hydrogels were fabricated from an aqueous solution of AgNO 3 , gelatin and carboxymethyl chitosan (CM-chitosan) by radiation-induced reduction and crosslinking at ambient temperature. The nanosilver particles were in situ synthesized accompanying with the formation of gelatin/CM-chitosan hydrogel. Transmission Electron Microscope and UV–vis analysis have verified the formation and homogeneous distribution of nanosilver particles in the hydrogel matrix. The nanosilver/gelatin/CM-chitosan hydrogels possessed interconnected porous structure, had a compressive modulus of 44 to 56 kPa, and could absorb 62 to 108 times of deionized water to its dry weight. Furthermore, the hydrogels were found to have sound antibacterial effect on Escherichia coli (E. coli), and their antibacterial ability could be significantly enhanced by the increasing of AgNO 3 content. The comprehensive results of this study suggest that nanosilver/gelatin/CM-chitosan hydrogels have potential as an antibacterial wound dressing. - Highlights: ► Nanosilver/gelatin/CM-chitosan hydrogel was synthesized by radiation crosslinking. ► Nanosilver particles distributed homogeneously in the hydrogel. ► The size of nanosilver increased with the increase of AgNO 3 concentration. ► The nanosilver/gelatin/CM-chitosan hydrogel has antibacterial ability.

  15. Non-isothermal kinetics of thermal degradation of chitosan

    Directory of Open Access Journals (Sweden)

    Georgieva Velyana

    2012-08-01

    Full Text Available Abstract Background Chitosan is the second most abundant nitrogen containing biopolymer in nature, obtained from the shells of crustaceans, particularly crabs, shrimp and lobsters, which are waste products of seafood processing industries. It has great potential application in the areas of biotechnology, biomedicine, food industries, and cosmetics. Chitosan is also capable of adsorbing a number of metal ions as its amino groups can serve as chelation sites. Grafted functional groups such as hydroxyl, carboxyl, sulfate, phosphate, and amino groups on the chitosan have been reported to be responsible for metal binding and sorption of dyes and pigments. The knowledge of their thermal stability and pyrolysis may help to better understand and plan their industrial processing. Results Thermogravimetric studies of chitosan in air atmosphere were carried out at six rates of linear increasing of the temperature. The kinetics and mechanism of the thermal decomposition reaction were evaluated from the TG data using recommended from ICTAC kinetics committee iso-conversional calculation procedure of Kissinger-Akahira-Sunose, as well as 27 mechanism functions. The comparison of the obtained results showed that they strongly depend on the selection of proper mechanism function for the process. Therefore, it is very important to determine the most probable mechanism function. In this respect the iso-conversional calculation procedure turned out to be the most appropriate. Conclusion Chitosan have excellent properties such as hydrophilicity, biocompatibility, biodegradability, antibacterial, non-toxicity, adsorption application. The thermal degradation of chitosan occurs in two stages. The most probable mechanism function for both stages is determined and it was best described by kinetic equations of n-th order (Fn mechanism. For the first stage, it was established that n is equal to 3.0 and for the second stage – to 1.0 respectively. The values of the

  16. Preparation and properties of hydrogels of PVA/PVP/chitosan by radiation

    International Nuclear Information System (INIS)

    Nho, Y. C.; Park, K. R.

    2001-01-01

    The radiation can induce chemical reaction to modify polymer under even the solid condition or in the low temperature. The radiation crosslinking can be easily adjusted and is easily reproducible by controlling the radiation dose. The finished product contains no residuals of substances required to initiate the chemical crosslinking which can restrict the application possibilities. In these studies, hydrogels from a mixture of chitosan and polyvinyl alcohol(PVA)/Poly-N-vinylpyrrolidone(PVP) were made by 'freezing and thawing', or gamma-ray irradiation or two steps of 'freezing and thawing', and gamma-ray irradiation or two steps of 'freezing and thawing' and gamma-ray irradiation for wound dressing. The mechanical properties such as gelation, water absorptivity, and gel strength were examined to evaluate the hydrogels for wound dressing. The composition of PVA:PVP was 60:40, PVA/PVP: chitosan ratio was in the range of 9:1 -7:3, and the solid concentration of PVA/PVP/chitosan solution was 15wt%. Gamma irradiation doses of 25, 35, 50, 60 and 70kGy, respectively were exposed to a mixture of PVA/PVP/chitosan to evaluate the effect of irradiation dose on the mechanical properties of hydrogels. Water-soluble chitosan was used to in this experiment. The mechanical properties of hydrogels such as gelation and gel strength was higher when two steps of 'freezing and thawing' and irradiation were used than only 'freezing and thawing' was utilized. Gel content was influenced slightly by PVA/PVP:chitosan composition and irradiation dose, but swelling was done greatly by them. Swelling percent was much increased as the composition of chitosan in PVA/PVP/chitosan increased

  17. Radiation synthesis of chitosan beads grafted with acrylic acid for metal ions sorption

    International Nuclear Information System (INIS)

    Benamer, S.; Mahlous, M.; Tahtat, D.; Nacer-Khodja, A.; Arabi, M.; Lounici, H.; Mameri, N.

    2011-01-01

    Radiation-induced grafting of acrylic acid onto chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of cobalt-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted material was performed by FTIR spectroscopy and the swelling measurements at different pHs. The grafting yield increased with the increase in dose, it reached 80% at 40 kGy irradiation dose. The removal of Pb and Cd ions from aqueous solutions was investigated with both ungrafted and grafted chitosan beads. The sorption behavior of the sorbents was examined through pH, kinetics and equilibrium measurements. Grafted chitosan beads presented higher sorption capacity for both metal ions than unmodified chitosan beads. - Highlights: → Pb and Cd ions are removed from aqueous solution by adsorption on chitosan beads. → Crosslinking process improves chemical stability of chitosan beads. → Radiation grafting of acrylic acid onto chitosan improves its metal adsorption capacity. → Increase in grafting degree enhances the adsorption capacity of the material. → Gamma radiation is a powerful tool for an accurate control of the grafting yield.

  18. Chitosan-poly(lactide-co-glycolide) microsphere-based scaffolds for bone tissue engineering: in vitro degradation and in vivo bone regeneration studies.

    Science.gov (United States)

    Jiang, Tao; Nukavarapu, Syam P; Deng, Meng; Jabbarzadeh, Ehsan; Kofron, Michelle D; Doty, Stephen B; Abdel-Fattah, Wafa I; Laurencin, Cato T

    2010-09-01

    Natural polymer chitosan and synthetic polymer poly(lactide-co-glycolide) (PLAGA) have been investigated for a variety of tissue engineering applications. We have previously reported the fabrication and in vitro evaluation of a novel chitosan/PLAGA sintered microsphere scaffold for load-bearing bone tissue engineering applications. In this study, the in vitro degradation characteristics of the chitosan/PLAGA scaffold and the in vivo bone formation capacity of the chitosan/PLAGA-based scaffolds in a rabbit ulnar critical-sized-defect model were investigated. The chitosan/PLAGA scaffold showed slower degradation than the PLAGA scaffold in vitro. Although chitosan/PLAGA scaffold showed a gradual decrease in compressive properties during the 12-week degradation period, the compressive strength and compressive modulus remained in the range of human trabecular bone. Chitosan/PLAGA-based scaffolds were able to guide bone formation in a rabbit ulnar critical-sized-defect model. Microcomputed tomography analysis demonstrated that successful bridging of the critical-sized defect on the sides both adjacent to and away from the radius occurred using chitosan/PLAGA-based scaffolds. Immobilization of heparin and recombinant human bone morphogenetic protein-2 on the chitosan/PLAGA scaffold surface promoted early bone formation as evidenced by complete bridging of the defect along the radius and significantly enhanced mechanical properties when compared to the chitosan/PLAGA scaffold. Furthermore, histological analysis suggested that chitosan/PLAGA-based scaffolds supported normal bone formation via intramembranous formation. 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  19. Properties of radiation-synthesized polyvinylpyrrolidone/chitosan hydrogel blends

    Energy Technology Data Exchange (ETDEWEB)

    Mahmud, Maznah [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia); Radiation Processing Technology Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia); Daik, Rusli [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia); Adam, Zainah [Radiation Processing Technology Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia)

    2015-09-25

    Poly(vinylpyrrolidone) (PVP)-crosslinked chitosan hydrogels were prepared by gamma radiation at various doses; 1, 3 5, 7, 10, 15, 20, 25 and 30kGy. Gamma radiation was used as a crosslinking tool which requires no chemical initiator, no heating process and need no purification step on the end products obtained. The hydrogel formulations were composed of 6% chitosan with average molecular weight (Mw) = 48 800 g/mol and 14% PVP with Mw = 10 000 g/mol in 2% lactic acid. Physical properties of hydrogels such as gel fraction and swelling property at pH 5.5 and pH 7.0 as well as syneresis activity were determined. It was found that different radiation dose induces different effect on hydrogels’ network formed. Morphological study of hydrogels has been carried out by scanning electron microscope (SEM). From these preliminary evaluations, it can be concluded that gamma radiation is an effective tool for network development of hydrogels and it also induces enhancement on characteristics of hydrogels synthesized.

  20. Characterizing the collagen stabilizing effect of crosslinked chitosan nanoparticles against collagenase degradation.

    Science.gov (United States)

    Kishen, Anil; Shrestha, Suja; Shrestha, Annie; Cheng, Calvin; Goh, Cynthia

    2016-08-01

    Antibacterial and chelating properties of chitosan has been widely studied for various dental applications. To characterize the interaction between chitosan-nanoparticles (CSnp) and collagen, and understand their stabilizing effect against collagenase degradation for dentin matrix stabilization. Phase-1: a single Type I collagen-fibril model was used to study the interaction with CSnp along with carbodiimides crosslinking treatment. Degradation of the crosslinked fibrils was studied with bacterial collagenase enzyme and monitored using Fourier Transform Infrared (FTIR) spectroscopy, turbidity measurement (400nm), ninhydrin assay and Atomic Force Microscopy (AFM). Interaction of CSnp with collagenase and Type I collagen, were evaluated using SDS-PAGE, and proteolytic cleavage potential of a synthetic peptide. Phase-2: degradation of dentin collagen crosslinked with/without CSnp was evaluated using FTIR, ninhydrin assay and Scanning Electron Microscopy (SEM). Glutaraldehyde crosslinking was used as a positive control. Both native collagen-fibrils and dentin collagen after crosslinking showed higher resistance to collagenase degradation, as observed in turbidity measurements and FTIR spectra. AFM images showed the interaction of CSnp with single collagen-fibril and crosslinked collagen resisted collagenase degradation up to 54h. The collagen and collagenase both formed complexes with CSnp resulting in thickening of bands and reduction in collagen degradation. CSnp treated collagenase showed significantly reduced cleavage of the fluorescent peptides. Dentin collagen was coated with CSnp following crosslinking with significant increase in resistance to collagenase degradation. Crosslinked CSnp on collagen stabilized and enhanced the resistance of dentin matrix against bacterial collagenase degradation due to non-specific interaction with both collagen and collagenase. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. Degradation behavior and compatibility of micro, nanoHA/chitosan scaffolds with interconnected spherical macropores.

    Science.gov (United States)

    Ruixin, Li; Cheng, Xu; Yingjie, Liu; Hao, Li; Caihong, Shi; Weihua, Su; Weining, An; Yinghai, Yuan; Xiaoli, Qin; Yunqiang, Xu; Xizheng, Zhang; Hui, Li

    2017-10-01

    Hydroxyapatite/Chitosan (HA/CS) composite have significant application in biomedical especially for bone replacement. Inorganic particle shape and size of composite affect the scaffold mechanical property, biological property, and degradation. The aim of this study was to fabricate HA/CS scaffold with good pore connectivity and analyze their biological, degradation properties. Microhydroxyapatite/chitosan (mHA/CS) and nanohydroxyapatite/chitosan (nHA/CS) composite scaffolds with interconnected spherical pore architectures were fabricated. Composite scaffolds structure parameters were analyzed using micro CT. Cell proliferation and morphology were tested and compared between two scaffolds using mouse osteoblastic cell line MC3T3-E1. To research the composite degradation in lysozyme PBS solution, degradation rate and reducing sugar content were tested, and scaffolds morphology were observed by SEM. The results showed that microHA and nanoHA were fabricated by being calcined and synthesis methods, and their infrared spectra are very similar. EDAX composition analysis demonstrated that both of microHA and nanoHA were calcium deficiency HA. Micro-CT results demonstrated the scaffolds had interconnected spherical pores, and the structure parameters were similar. Cell viabilities were significant increased with cultured time, but there were no significant difference between microHA/CS and nanoHA/CS scaffolds. Scaffold structure was gradually destroyed and inorganic composition HA particles are more prominent with degradation time. (1) Inorganic particle shape and size of composite affect the scaffold mechanical property, biological property, and degradation. NanoHA/CS and microHA/CS scaffolds with good pore connectivity were fabricated and their biological, degradation properties were studied in this manuscript. (2) The scaffold with interconnected porosity construct provides the necessary support for cells to proliferate and maintain their differentiated function, and

  2. Physicochemical characterization of irradiated high molar mass chitosan

    International Nuclear Information System (INIS)

    Rapado, Manuel; Paredes, Mayte; Altanes, Sonia; Barrera, Gisela; Otero, Isabel; Peniche, Carlos; Gonzalez, Maykel

    2006-01-01

    The present study is aimed to determination of the bio burden for assessing the sterilization dose and to identify the influence of the absorbed dose of gamma radiation on the molar mass and chemical structure of chitosan. The characterization includes the determination of the intrinsic viscosity, deacetylation degree as well as infrared spectrometry. The obtained results have been shown chain cleavage caused by irradiation. It was revealed by a decrease in the intrinsic viscosities of the polymers. The invariance of the infrared spectra of polymers indicated that chain degradation occurs without significant change of the chemical structure. The results obtained have practical implication in the field of radiation sterilization of chitosan used for microencapsulation of mammalian cells

  3. Cytocompatibility of chitosan and collagen-chitosan scaffolds for tissue engineering

    Directory of Open Access Journals (Sweden)

    Ligia L. Fernandes

    2011-01-01

    Full Text Available In this work, chitosan and collagen-chitosan porous scaffolds were produced by the freeze drying method and characterized as potential skin substitutes. Their beneficial effects on soft tissues justify the choice of both collagen and chitosan. Samples were characterized using scanning electron microscope, Fourier Transform InfraRed Spectroscopy (FTIR and thermogravimetry (TG. The in vitro cytocompatibility of chitosan and collagen-chitosan scaffolds was evaluated with three different assays. Phenol and titanium powder were used as positive and negative controls, respectively. Scanning electron microscopy revealed the highly interconnected porous structure of the scaffolds. The addition of collagen to chitosan increased both pore diameter and porosity of the scaffolds. Results of FTIR and TG analysis indicate that the two polymers interact yielding a miscible blend with intermediate thermal degradation properties. The reduction of XTT ((2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide and the uptake of Neutral Red (NR were not affected by the blend or by the chitosan scaffold extracts, but the blend and the titanium powder presented greater incorporation of Crystal Violet (CV than phenol and chitosan alone. In conclusion, collagen-chitosan scaffolds produced by freeze-drying methods were cytocompatible and presented mixed properties of each component with intermediate thermal degradation properties.

  4. Influence of irradiated chitosan on rice plants growing in hydroponic medium contaminated with salt and heavy metals

    International Nuclear Information System (INIS)

    Lam, N.D.; Diep, T.B.; Kume, Tamikazu

    2000-01-01

    Effect of chitosan and radiation-degraded chitosan on rice seedlings of a Vietnam's original variety was investigated. Potential of irradiated chitosan in plant tolerance for several stress factors (salt, zinc, and vanadium) also was studied as well. Chitosan represented in hydroponic medium clearly inhibited the growth of rice seedlings at concentrations arranging from 50 ppm. Radiation processing of chitosan with dose higher than 100 kGy reduced toxicity of chitosan and the efficacy was of dose proportion. Rice plant of 203 origin was almost normally grown in hydroponic solution containing chitosan that has been irradiated with dose of 150 and 200 kGy. Irradiated chitosan increased plant resistance to environmental stress caused by vanadium (V); thereby the seedlings could be recovered completely, even gained in biomass. This effect was not appeared when applied chitosan to rice in media contaminated by zinc (Zn) and salt (NaCl). The selectness of irradiated chitosan on various stress factors partly clarified the assistant action of chitosan in the vanadium intoxication because chelating with metal ions could not be evaluated as main mechanism. (author)

  5. In vitro degradation of chitosan composite foams for biomedical applications and effect of bioactive glass as a crosslinker

    Directory of Open Access Journals (Sweden)

    Martins Talita

    2018-02-01

    Full Text Available In tissue engineering applications, 3D scaffolds with adequate structure and composition are required to provide durability that is compatiblewith the regeneration of native tissue. In the present study, the degradation of novel flexible 3D composite foams of chitosan (CH combined with bioactive glass (BGwas evaluated, focusing on the role of BG as a physical crosslinker in the composites, and its effect on the degradation process. Highly porous CH/BG composite foams were obtained, and an elevated degradation temperature and lower degradation rate compared with pure chitosan were observed, probably as a result of greater intermolecular interaction between CH and BG. The Fourier transform infrared spectroscopy (FTIR data suggest that hydrogen bonds were responsible for the physical crosslinking between CH and BG. The results confirm that CH/BG foams can combine controllable bioactivity and degradation behavior and, therefore, could be useful for tissue regeneration matrices.

  6. Heavy Metal Removal by Chitosan and Chitosan Composite

    International Nuclear Information System (INIS)

    Abdel-Mohdy, F.A.; El-Sawy, S.; Ibrahim, M.S.

    2005-01-01

    Radiation grafting of diethyl aminoethyl methacrylate (DEAEMA) on chitosan to impart ion exchange properties and to be used for the separation of metal ions from waste water, was carried out. The effect of experimental conditions such as monomer concentration and the radiation dose on grafting were studied. On using chitosan, grafted chitosan and some chitosan composites in metal ion removal they show high up-take capacity for Cu 2+ and lower uptake capacities for the other divalent metal ions used (Zn and Co). Competitive study, performed with solutions containing mixture of metal salts, showed high selectivity for Cu 2+ than the other metal ion. Limited grafting of DEAEMA polymer -containing specific functional groups-onto the chitosan backbone improves the sorption performance

  7. Review of radiation processing of natural polymer

    International Nuclear Information System (INIS)

    Khairul Zaman

    2007-01-01

    In recent years, natural polymers are being investigated with renewed interest because of their abundant quantity and unique characteristics such as inherent biocompatibility, biodegradability and renewable. It is also known as green polymer. Natural polymers such as carrageen, alginate, chitin/chitosan and starch are traditionally used in food-based industry. But now, the applications of natural polymers are being sought in knowledge-driven areas such as healthcare, agro-technology and industry. Radiation degraded alginates, carrangeenan and chitosan as plant growth promoter and protector have been developed. Radiation degraded chitosan, carraneenan and starch have also been used together with synthetic polymers for hydrogel production to be used for wound dressing, skin moisturization and for biodegradable packaging films and foams. Radiation crosslinking of natural polymer derivatives such as carboxymethyl chitosan, carboxymethyl starch have been successfully developed in Japan and used for various applications such as removal of pollutants, removal of waters from liverstock excrete as well as for bedsores protection mat. (author)

  8. The mechanism of chitosan degradation by gamma and e-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gryczka, U. [Institute of Nuclear Chemistry and Technology, ul. Dorodna 16, P.O. Box 97, 03-195 Warsaw (Poland)], E-mail: urszulagryczka@wp.pl; Dondi, D. [General Chemistry Department, University of Pavia, Viale Taramelli 12, 27100 Pavia (Italy); Chmielewski, A.G.; Migdal, W. [Institute of Nuclear Chemistry and Technology, ul. Dorodna 16, P.O. Box 97, 03-195 Warsaw (Poland); Buttafava, A.; Faucitano, A. [General Chemistry Department, University of Pavia, Viale Taramelli 12, 27100 Pavia (Italy)

    2009-07-15

    The mechanism of the radiolytic degradation of chitosan under vacuum and under air is investigated in the dose range 30-300 kGy by EPR spectroscopy coupled with FTIR and gel permeation chromatography (GPC) analysis. A decrease of the number average molecular weights by a factor of 3-4 was monitored in the dose range from 0 to 300 kGy. A deconvolution of the EPR spectra is proposed leading to the identification of intermediate radicals and to a radiolysis mechanism which validity is assessed with respect to free radical and radiation chemistry knowledge of carbohydrate systems. An important result is the EPR identification of stable nitroxyl radicals in the samples irradiated in presence of oxygen. This detection is a proof of the involvement of the amino group in the radiolysis mechanism and prompts the expectation of other related products as hydroxylamine ethers. A practical implication of such observation concerns possible toxicity effects. However, on the base of the low-concentration level of the nitroxyl detected, such risk is considered of negligible importance.

  9. Modification of mechanical and thermal property of chitosan-starch blend films

    Science.gov (United States)

    Tuhin, Mohammad O.; Rahman, Nazia; Haque, M. E.; Khan, Ruhul A.; Dafader, N. C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

    2012-10-01

    Chitosan-starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan-starch films, glycerol and mustard oil of different composition were used. Chitosan-starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan-starch films. Water uptake of the films reduced significantly than the pure chitosan-starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively.

  10. Radiation processed polysaccharide products

    International Nuclear Information System (INIS)

    Nguyen, Quoc Hien

    2007-01-01

    Radiation crosslinking, degradation and grafting techniques for modification of polymeric materials including natural polysaccharides have been providing many unique products. In this communication, typical products from radiation processed polysaccharides particularly plant growth promoter from alginate, plant protector and elicitor from chitosan, super water absorbent containing starch, hydrogel sheet containing carrageenan/CM-chitosan as burn wound dressing, metal ion adsorbent from partially deacetylated chitin were described. The procedures for producing those above products were also outlined. Future development works on radiation processing of polysaccharides were briefly presented. (author)

  11. Research of the degradation products of chitosan's angiogenic function

    International Nuclear Information System (INIS)

    Wang Jianyun; Chen Yuanwei; Ding Yulong; Shi Guoqi; Wan Changxiu

    2008-01-01

    Angiogenesis is of great importance in tissue engineering and has gained large attention in the past decade. But how it will be influenced by the biodegradable materials, especially their degradation products, remains unknown. Chitosan (CS) is a kind of naturally occurred polysaccharide which can be degraded in physiological environment. In order to gain some knowledge of the influences of CS degradation products on angiogenesis, the interaction of vascular endothelial cells with the degradation products was investigated in the present study. The CS degradation products were prepared by keeping CS sample in physiological saline aseptically at 37 deg. C for 120 days. Endothelial cells were co-cultured with the degradation products and the angiogenic cell behaviors, including cell proliferation, migration and tube-like structure (TLS) formation, were tested by MTT assay, cell migration quantification method (CMQM), and tube-like structure quantification method (TLSQM) respectively. Furthermore, mRNA expressions of vascular endothelial growth factor (VEGF) and matrix metallo proteinase (MMP-2) were determined by real-time reverse transcriptional polymerase chain reaction (RT-PCR). Physiological saline served as a negative control. As the results showed, the degradation products obtained from 20th to 60th day significantly inhibited the proliferation, migration, and TLS formation of endothelial cells. However, degradation products of the first 14 days and the last 30 days were found to be proangiogenic. At the molecular level, the initial results indicated that the mRNA expressions of VEGF and MMP-2 were increased by the degradation products of 7th day, but were decreased by the ones of 60th day. According to all the results, it could be concluded that the angiogenic behaviors of endothelial cells at both cellular and molecular level could be significantly stimulated or suppressed by the degradation products of CS and the influences are quite time-dependent

  12. Application of gamma radiation and physicochemical treatment to improve the bioactive properties of chitosan extracted from shrimp shell

    Directory of Open Access Journals (Sweden)

    Aktar Jesmin

    2017-12-01

    Full Text Available The aim of this study is to exploit a suitable chitosan extraction method from the chitin of indigenous shrimp shells by employing different physicochemical treatments and to improve different bioactive properties of this extracted chitosan (CS by applying gamma radiation. Chitin was prepared from shrimp shell by pretreatment (deproteination, demineralization and oxidation. Chitosan was extracted from chitin by eight different methods varying different physicochemical parameters (reagent concentration, temperature and time and assessed with respect to the degree of deacetylation, requirement of time and reagents. The method where chitin was repeatedly treated with 121°C for 30 min with 20 M NaOH, produced the highest degree of deacetylation (DD value (92% as measured by potentiometric titration, with the least consumption of time and chemicals, and thus, selected as the best suitable extraction method. For further quality improvement, chitosan with highest DD value was irradiated with different doses (i.e., 5, 10, 15, 20 and 50 kGy of gamma radiation from cobalt-60 gamma irradiator. As the radiation dose was increased, the molecular weight of the wet irradiated chitosan, as measured by the viscosimetric method, decreased from 1.16 × 105 to 1.786 × 103, 1.518 × 103, 1.134 × 103, 1.046 × 103 and 8.23 × 102 dalton, respectively. The radiation treatment of chitosan samples increased the antimicrobial activity significantly in concentration dependent manner on both gram-positive (Staphylococcus aureus and gram-negative (Escherichia coli bacteria, as determined by the well-diffusion method. Four to five percent wet chitosan treated with a radiation dose range of 5.0–10.0 kGy rendered the highest antimicrobial activity with least energy and time consumption. Solubility, water binding capacity (WBC and fat binding capacity (FBC also improved due to irradiation of chitosan.

  13. Physicochemical characterization of irradiated high molecular weight chitosan

    International Nuclear Information System (INIS)

    Rapado, Manuel; Paredes, Mayte; Altanes, Sonia; Barrera, Gisela; Otero, Isabel; Peniche, Carlos; Gonzalez, Maykel

    2006-01-01

    Chitosan is obtained by mean of partial deacetylation of chitin. Due to the diverse biological properties of this polymer it has valuable medical applications. Some of these applications require sterile materials. For this purpose irradiation techniques seem to have advantages since they do not require any additives, which could contaminate the final sterile product with toxic residuals. The aims of the present study were to determinate the bio burden for assessing the sterilization dose and to identify the influence of the absorbed dose of gamma radiation on the molar mass and chemical structure of chitosan. Changes in polymer features were evaluated by comparing the results obtained from the characterization of treated and raw polymers. The obtained results have been shown chain cleavage caused by irradiation. It was revealed by a decrease in the intrinsic viscosities of the polymers. The invariance of the infrared spectra of polymer indicates that chain degradation occurs without significant change of the chemical structure. The results obtained have practical implication in the field of radiation sterilization of chitosan used for biotechnology, medicine and pharmacy

  14. Degradation of phenol and TCE using suspended and chitosan-bead immobilized Pseudomonas putida.

    Science.gov (United States)

    Chen, Yan-Min; Lin, Tsair-Fuh; Huang, Chih; Lin, Jui-Che; Hsieh, Feng-Ming

    2007-09-30

    The degradability of phenol and trichloroethene (TCE) by Pseudomonas putida BCRC 14349 in both suspended culture and immobilized culture systems are investigated. Chitosan beads at a size of about 1-2mm were employed to encapsulate the P. putida cells, becoming an immobilized culture system. The phenol concentration was controlled at 100 mg/L, and that of TCE was studied from 0.2 to 20 mg/L. The pH, between 6.7 and 10, did not affect the degradation of either phenol or TCE in the suspended culture system. However, it was found to be an important factor in the immobilized culture system in which the only significant degradation was observed at pH >8. This may be linked to the surface properties of the chitosan beads and its influence on the activity of the bacteria. The transfer yield of TCE on a phenol basis was almost the same for the suspended and immobilized cultures (0.032 mg TCE/mg phenol), except that these yields occurred at different TCE concentrations. The transfer yield at a higher TCE concentration for the immobilized system suggested that the cells immobilized in carriers can be protected from harsh environmental conditions. For kinetic rate interpretation, the Monod equation was employed to describe the degradation rates of phenol, while the Haldane's equation was used for TCE degradation. Based on the kinetic parameters obtained from the two equations, the rate for the immobilized culture systems was only about 1/6 to that of the suspended culture system for phenol degradation, and was about 1/2 for TCE degradation. The slower kinetics observed for the immobilized culture systems was probably due to the slow diffusion of substrate molecules into the beads. However, compared with the suspended cultures, the immobilized cultures may tolerate a higher TCE concentration as much less inhibition was observed and the transfer yield occurred at a higher TCE concentration.

  15. Characterization of Chitosan Produced from Fermented Shrimp Shell Waste by Bacillus subtilis NA12 Using Gamma Radiation

    International Nuclear Information System (INIS)

    Bashandy, A.S.; Raffat, E.A.; Ibrahim, H.M.M.; El Tayeb, T.S.; Gamal, R.F.

    2017-01-01

    This study focused on characterization of chitosan obtained in a previous study from fermented shrimp shell waste (SSW) by Bacillus subtilis NA12. Extracted chitin was exposed to different gamma radiation doses (5-35 kGy). The molecular weight of the resultant chitosan decreased constantly with increasing radiation dose from 1.9 × 10"6 (g/mol) (non-irradiated) to 3.7 ×10"4 (g/mol) (at 35 kGy). The degree of deacetylation (DDA %) was determined by using potentiometric titration. The structural properties of chitin and chitosan were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), and thermogravimetric analysis (TGA). The prepared chitosan has higher solubility and DDA % compared to the standard chitosan. FT-IR analysis clearly confirmed the successful extraction of pure chitin and chitosan. TGA showed that chitin exhibited a stable structure toward thermal decomposition than chitosan. XRD analysis revealed that extracted chitin was more crystalline than prepared chitosan. Chitosan with different molecular weights was evaluated as an antibacterial agent against representative pathogenic bacterial strains. Chitosan obtained at 35 kGy, with molecular weight 3.7×10"4 (g/mol ) and DDA of 87.9 %, showed the highest antimicrobial activity against Escherichia coli, Klebsiella sp., Staphylococcus aureus and Pseudomonas aeruginosa. It revealed inhibition zone diameter of 5.4 ± 0.2, 5.4 ± 0.12, 3.5 ± 0.21 and 1.4 ± 0.06 cm, respectively

  16. Effect of gamma radiation on the mechanical and barrier properties of HEMA grafted chitosan-based films

    International Nuclear Information System (INIS)

    Khan, Avik; Huq, Tanzina; Khan, Ruhul A.; Dussault, Dominic; Salmieri, Stephane; Lacroix, Monique

    2012-01-01

    Chitosan films were prepared by dissolving 1% (w/v) chitosan powder in 2% (w/v) aqueous acetic acid solution. Chitosan films were prepared by solution casting. The values of puncture strength (PS), viscoelasticity coefficient and water vapor permeability (WVP) of the films were found to be 565 N/mm, 35%, and 3.30 g mm/m 2 day kPa, respectively. Chitosan solution was exposed to gamma irradiation (0.1–5 kGy) and it was revealed that PS values were reduced significantly (p≤0.05) after 1 kGy dose and it was not possible to form films after 5 kGy. Monomer, 2-hydroxyethyl methacrylate (HEMA) solution (0.1–1%, w/v) was incorporated into the chitosan solution and the formulation was exposed to gamma irradiation (0.3 kGy). A 0.1% (w/v) HEMA concentration at 0.3 kGy dose was found optimal-based on PS values for chitosan grafting. Then radiation dose (0.1–5 kGy) was optimized for HEMA grafting. The highest PS values (672 N/mm) were found at 0.7 kGy. The WVP of the grafted films improved significantly (p≤0.05) with the rise of radiation dose. - highlights: ► HEMA and Silane monomer were incorporated into the MC-based formulation and films. ► Films were exposed to gamma radiation. ► HEMA containing films showed the highest PS values. ► Surface morphology of the grafted films suggested better appearance.

  17. Ligand-functionalized degradable polyplexes formed by cationic poly(aspartic acid)-grafted chitosan-cyclodextrin conjugates

    Science.gov (United States)

    Song, Hai-Qing; Li, Rui-Quan; Duan, Shun; Yu, Bingran; Zhao, Hong; Chen, Da-Fu; Xu, Fu-Jian

    2015-03-01

    Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE-FA/pDNA, and ternary CCPE-FA/CCPE/pDNA (prepared by layer-by-layer assembly) polyplexes were investigated in detail using different cell lines. The CCPE-based polyplexes displayed much higher transfection efficiencies than the CS-based polyplexes reported earlier by us. The ternary polyplexes of CCPE-FA/CCPE/pDNA produced excellent gene transfection abilities in the folate receptor (FR)-positive tumor cells. This work would provide a promising means to produce highly efficient polyplexes for future gene therapy applications.Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE

  18. Preparation of Low Molecular Weight Chitosan by Radiation and its Application for Plant Growth Promoter. Chapter 10

    Energy Technology Data Exchange (ETDEWEB)

    Darwis, D.; Puspitasari, T.; Iramani, D.; Susilowati, Sri; Pangerteni, D.S., E-mail: darmawan_p3tir@batan.go.id [National Nuclear Energy Agency, Centre for Application of Isotopes and Radiation Technology (Indonesia)

    2014-07-15

    Chitosan was prepared through the alkaline deacetylation of chitin from shrimp shell waste. Chitosan with a degree of deacetylation of about 70% was produced by hot alkaline deacetylation (DDA) at 90°C for 8 hours or at room temperature deacetylation for 7 days. Through these processes, chitosan with an average molecular weight (Mw) of 141 k Dalton was obtained. Low molecular weight chitosan, Mw 14 k Dalton called “Fitosan” was prepared by irradiating chitosan using gamma rays at a dose of 75 kGy. The results showed that gamma irradiation is an effective method of degrading chitosan by cleavages of glycosidic bond. To improve crop yields and suppress diseases due to virus, bacteria, and fungi, Fitosan was successfully applied to chili, potato, and soybean. Socio-economic impacts of the use of Fitosan on the plants include increased income and improvement of the welfare of farmers. (author)

  19. The chitosan - Porphyrazine hybrid materials and their photochemical properties.

    Science.gov (United States)

    Chełminiak-Dudkiewicz, Dorota; Ziegler-Borowska, Marta; Stolarska, Magdalena; Sobotta, Lukasz; Falkowski, Michal; Mielcarek, Jadwiga; Goslinski, Tomasz; Kowalonek, Jolanta; Węgrzynowska-Drzymalska, Katarzyna; Kaczmarek, Halina

    2018-04-01

    Three magnesium sulfanyl porphyrazines differing in the size of peripheral substituents (3,5-dimethoxybenzylsulfanyl, (3,5-dimethoxybenzyloxy)benzylsulfanyl, 3,5-bis[(3,5-bis[(3,5-dimethoxybenzyloxy)benzyloxy]benzylsulfanyl) were exposed to visible and ultraviolet radiation (UV A + B + C) in order to determine their photochemical properties. The course of photochemical reactions in dimethylformamide solutions and the ability of the systems to generate singlet oxygen were studied by UV-Vis spectroscopy, which additionally gave information on aggregation processes. The porphyrazines were found to be stable upon visible light irradiation conditions, but when exposed to high energy UV radiation, the efficient photodegradation of these macrocycles was observed. Therefore, these three magnesium sulfanyl porphyrazines were incorporated into chitosan matrix. The obtained thin films of chitosan doped with porphyrazines were subjected to polychromatic UV-radiation and studied by spectroscopic methods (UV-Vis, FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Application of chitosan as a polymer matrix for porphyrazines was found to be successful method that effectively stopped the unwelcome degradation of macrocycles, thus worth considering for their photoprotection. In addition, the surface properties of the hybrid material were determined by contact angle measurements and calculation of surface free energy. Intermolecular interactions between these novel porphyrazines and chitosan were detected. The mechanism of photochemical reactions occurring in studied systems has been discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Radiation processing of chitosan derivative and its characteristics

    International Nuclear Information System (INIS)

    Kamarudin Bahari; Kamarolzaman Hussein; Kamaruddin Hashim; Khairul Zaman Mohd Dahlan

    2002-01-01

    Chitosan is natural polymer derived from chitin, a polysaccharide found in the exoskeleton of shrimps, crabs, fungi and others. Chitosan is a naturally occurring substance that is chemically similar to cellulose. Chitosan possesses a positive ionic charge give ability to chemically bond with negatively charged fats. Chitosan is soluble in organic acid but insoluble in water. Carboxymethyl-chitosan (cm-chitosan) is a derivative of chitosan which is water-soluble was then prepared by a carboxymethylation process of chitosan produced from local shrimp shell. A simple method for synthesis of cm-chitosan has been developed at 55 degree C in aqueous sodium hydroxide / propanol with chloroacetic acid (CAA) or sodium chloroacetate salt (SCA). The modification of chitosan to water-soluble chitosan can be used in hydrogel as anti-bacterial agent and it overcome the problem of bad smell using acetic acid. (Author)

  1. Synthesis, characterization and radiation processing of carboxymethyl-chitosan

    International Nuclear Information System (INIS)

    Kamarudin Bahari; Kamarolzaman Hussein; Kamaruddin Hashim; Khairul Zaman Mohd Dahlan

    2002-01-01

    Chitosan is natural polymer derived from chitin, a polysaccharide found in the exoskeleton of shrimps, crabs, fungi and others. Chitosan is a naturally occurring substance that is chemically similar to cellulose. Chitosan possesses a positive ionic charge give ability to chemically bond with negatively charged fats. Chitosan is soluble in organic acid but insoluble in water. Carboxymethyl-chitosan (cm-chitosan) is a derivative of chitosan which is water-soluble was then prepared by carboxymethylation process of chitosan produced from local shrimp shell. A simple method for synthesis of cm-chitosan has been developed at 55 degree C in aqueous sodium hydroxide / propanol with chloroacetic acid (CAA) or sodium chloroacetate salt (SCA). The modification of chitosan to water-soluble chitosan can be used in hydrogel as anti-bacterial and anti-fungal agent, and it overcome the problem of bad smell using organic acid. (Author)

  2. The radiation degradation of polypropylene

    International Nuclear Information System (INIS)

    De Hollain, G.

    1977-04-01

    Polypropylene is used extensively in the manufacture of disposable medical devices because of its superior properties. Unfortunately this polymer does not lend itself well to radiation sterilization, undergoing serious degradation which affects the mechanical properties of the polymer. In this paper the effects of radiation on the mechanical and physical properties of polypropylene are discussed. A programme of research to minimize the radiation degradation of this polymer through the addition of crosslinking agents to counteract the radiation degradation is proposed. It is furthermore proposed that a process of annealing of the irradiated polymer be investigated in order to minimize the post-irradiation degradation of the polypropylene [af

  3. Bioremediation of crude oil polluted seawater by a hydrocarbon-degrading bacterial strain immobilized on chitin and chitosan flakes

    International Nuclear Information System (INIS)

    Gentili, A.R.; Cubitto, M.A.; Ferrero, M.; Rodriguez, M.S.

    2006-01-01

    In this laboratory-scale study, we examined the potential of chitin and chitosan flakes obtained from shrimp wastes as carrier material for a hydrocarbon-degrading bacterial strain. Flakes decontamination, immobilization conditions and the survival of the immobilized bacterial strain under different storage temperatures were evaluated. The potential of immobilized hydrocarbon-degrading bacterial strain for crude oil polluted seawater bioremediation was tested in seawater microcosms. In terms of removal percentage of crude oil after 15 days, the microcosms treated with the immobilized inoculants proved to be the most successful. The inoculants formulated with chitin and chitosan as carrier materials improved the survival and the activity of the immobilized strain. It is important to emphasize that the inoculants formulated with chitin showed the best performance during storage and seawater bioremediation. (author)

  4. Radiation synthesis of chitosan stabilized gold nanoparticles comparison between e− beam and γ irradiation

    International Nuclear Information System (INIS)

    Vo, Khoa Dang Nguyen; Kowandy, Christelle; Dupont, Laurent; Coqueret, Xavier; Hien, Nguyen Quoc

    2014-01-01

    Gold nanoparticles were synthesized via radiolytic reduction of Au(III) salts induced by e − beam or γ-irradiation, using chitosan as a stabilizer. The effect of irradiation dose, chitosan concentration and the conditioning of HAuCl 4 –chitosan solutions were studied. UV–visible absorption measurements reveal that the size of Au clusters formed immediately after irradiation is correlated with the extent of chitosan scission chain of chitosan and fall with the increase of dose absorbed. This effect is more pronounced with solution conditioned under Argon (Ar). Au clusters coalesce to form stable nanoparticles after two weeks. - Highlights: • This paper underlines the potential of ionizing radiations in the synthesis of AuNps. • The size of the nanoparticles, and their stability are controlled by the ratio [GLA]/[Au(III)] • This paper compares results obtained with e − beam and γ irradiation for the AuNps synthesis. • This paper points the influence of dose rate on the size of preformed Au clusters

  5. A novel analytical method for D-glucosamine quantification and its application in the analysis of chitosan degradation by a minimal enzyme cocktail

    DEFF Research Database (Denmark)

    Mekasha, Sophanit; Toupalová, Hana; Linggadjaja, Eka

    2016-01-01

    Enzymatic depolymerization of chitosan, a β-(1,4)-linked polycationic polysaccharide composed of D-glucosamine (GlcN) and N-acetyl-D-glucosamine (GlcNAc) provides a possible route to the exploitation of chitin-rich biomass. Complete conversion of chitosan to mono-sugars requires the synergistic...... action of endo- and exo- chitosanases. In the present study we have developed an efficient and cost-effective chitosan-degrading enzyme cocktail containing only two enzymes, an endo-attacking bacterial chitosanase, ScCsn46A, from Streptomyces coelicolor, and an exo-attacking glucosamine specific β...

  6. Irradiation gamma on chitosan films

    Energy Technology Data Exchange (ETDEWEB)

    Mello, Luana Miranda Lopes de; Souza, Adriana Regia Marques de; Arthur, Valter, E-mail: lumilopes@hotmail.com, E-mail: drilavras@yahoo.com.br, E-mail: arthur@cena.usp.br [Universidade Federal do Tocantins (UFT), Palmas,TO (Brazil). Departmento de Ciencia e Tecnologia de Alimentos; Universidade Federal de Goias (UFGO), Goiania (Brazil). Departmento de Ciencia e Tecnologia de Alimentos; Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2017-11-01

    Films are preformed structures, independent, that are used to wrap food after processing, increasing their shelf life and enhancing its bright and attractive appearance. They are prepared from biological materials as an alternative to the plastic synthetic containers to improve the quality of the environment. Chitosan is a biodegradable polymer composed of β-(1-4) linked D-glucosamine (deacetylated unit) and N-acetyl-D- glucosamine (acetylated unit). It is produced commercially by deacetylation of chitin, which is a structural component of the exoskeleton of crustaceans. She is able to form films and edible and/or biodegradable coatings. With the objective to evaluate the effect of different doses of gamma radiation (0, 5, 10 and 15 kGy) and chitosan concentrations (1 and 2%) in film properties, it was evaluated its optical, mechanical and morphological properties. The films were produced by casting. Irradiation did not affect the thickness of the films, but influenced its colors, increasing the tone of the film for a stronger yellowish color. This fact can be attributed to the increased concentration of C = O bonds of chitosan due to the breakdown of the chain reaction and the Maillard reaction. Irradiated films showed smoother surface and less rough, due to the degradation of the chitosan molecule and poor mechanical properties, not showing good flexibility and stretching. (author)

  7. Irradiation gamma on chitosan films

    International Nuclear Information System (INIS)

    Mello, Luana Miranda Lopes de; Souza, Adriana Regia Marques de; Arthur, Valter

    2017-01-01

    Films are preformed structures, independent, that are used to wrap food after processing, increasing their shelf life and enhancing its bright and attractive appearance. They are prepared from biological materials as an alternative to the plastic synthetic containers to improve the quality of the environment. Chitosan is a biodegradable polymer composed of β-(1-4) linked D-glucosamine (deacetylated unit) and N-acetyl-D- glucosamine (acetylated unit). It is produced commercially by deacetylation of chitin, which is a structural component of the exoskeleton of crustaceans. She is able to form films and edible and/or biodegradable coatings. With the objective to evaluate the effect of different doses of gamma radiation (0, 5, 10 and 15 kGy) and chitosan concentrations (1 and 2%) in film properties, it was evaluated its optical, mechanical and morphological properties. The films were produced by casting. Irradiation did not affect the thickness of the films, but influenced its colors, increasing the tone of the film for a stronger yellowish color. This fact can be attributed to the increased concentration of C = O bonds of chitosan due to the breakdown of the chain reaction and the Maillard reaction. Irradiated films showed smoother surface and less rough, due to the degradation of the chitosan molecule and poor mechanical properties, not showing good flexibility and stretching. (author)

  8. Radiation-induced enhancement of antifungal activity of chitosan on fruit-spoiling fungi during postharvest storage

    Energy Technology Data Exchange (ETDEWEB)

    Diep, Tran Bang; Lam, Nguyen Duy; Quynh, Tran Minh [Institute for Nuclear Science and Technique-VAEC, Hanoi (Viet Nam); Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Experiment conducted four fruit-spoiling fungal strains that were isolated from spoilt fruits (mango and dragon fruit) and were identified as follows: Fusarium dimerum Penzig, Aspergillus nidulans Wint, Aspergillus fumigatus Fresenius and Aspergillus japonicus Saito. Chitosan samples with various deacetylation degree (70-99%) were irradiated at doses ranging from 20 to 200kGy, then were supplemented to liquid medium for growth of fungi. We have found that chitosan possesses not only well known antibacterial activity but also the antifungal one on fruit-spoiling fungi. Method of fungal cultivation using liquid medium showed that it has higher sensitivity compared with the cultivation on agar plate, so we recommend this method should be used for evaluation of antimicrobial activity of chitosan. Our study also indicated that deacetylation degree of chitosan clearly affects its antifungal activity, the higher the deacetylation of chitosan, stronger antifungal activity can be observed. This finding recommends the use of chitosan with higher deacetylation for fruit coating and other pharmacology utilization. Results from the minimal inhibitory concentrations (MIC) on fungal growth showed that radiation treatment increased antifungal activity of chitosan and dose of 60kGy gave highest activity. (author)

  9. Radiation-induced enhancement of antifungal activity of chitosan on fruit-spoiling fungi during postharvest storage

    International Nuclear Information System (INIS)

    Diep, Tran Bang; Lam, Nguyen Duy; Quynh, Tran Minh; Kume, Tamikazu

    2001-01-01

    Experiment conducted four fruit-spoiling fungal strains that were isolated from spoilt fruits (mango and dragon fruit) and were identified as follows: Fusarium dimerum Penzig, Aspergillus nidulans Wint, Aspergillus fumigatus Fresenius and Aspergillus japonicus Saito. Chitosan samples with various deacetylation degree (70-99%) were irradiated at doses ranging from 20 to 200kGy, then were supplemented to liquid medium for growth of fungi. We have found that chitosan possesses not only well known antibacterial activity but also the antifungal one on fruit-spoiling fungi. Method of fungal cultivation using liquid medium showed that it has higher sensitivity compared with the cultivation on agar plate, so we recommend this method should be used for evaluation of antimicrobial activity of chitosan. Our study also indicated that deacetylation degree of chitosan clearly affects its antifungal activity, the higher the deacetylation of chitosan, stronger antifungal activity can be observed. This finding recommends the use of chitosan with higher deacetylation for fruit coating and other pharmacology utilization. Results from the minimal inhibitory concentrations (MIC) on fungal growth showed that radiation treatment increased antifungal activity of chitosan and dose of 60kGy gave highest activity. (author)

  10. Radiation degradation of short-cotton linters

    International Nuclear Information System (INIS)

    Ma Zue Teh; Zhou Rui Min

    1984-01-01

    Radiation degradation of short-cotton linters has been studied by using X-ray diffraction, an infrared spectrometer and a viscosimeter. Average molecular weight and crystallinity of short-cotton linters and the change of reducing sugar in γ-radiation degradation were examined. It was found that cellulosic saccharification in hydrolysis was enhanced with preirradiation of linter. This probably resulted from the radiation induced change of cellulosic structure. Sensitizers to promote radiation degradation effect were investigated. Carbon tetrachloride has been found to be effective. (author)

  11. Effect of chitosan addition and gamma radiation on polymeric blends of PVP and PVAL

    International Nuclear Information System (INIS)

    Terence, M.C.; Castro, P.J.; Miranda, L.F.; Faldini, S.B.

    2010-01-01

    The objective of this project is the study of the effect of chitosan addition and the radiation with gamma rays. The polymeric blend usage is a recent development that expanded the applications of the polymers, due to the improvement of the properties of a single polymer. The PVP and PVAL were chosen because they present the main required characteristics to the formation of a hydrogel, such as water absorption and crosslinking, and the chitosan to improve the interaction between the hydrogel and the organism. The flexibility of the PVP was added with the mechanical resistance of the PVAL and the chitosan biocompatibility. With a defined concentration of PVP and PVAL, films of this blend was irradiated and also solutions with different concentrations of chitosan was prepared to obtain new films of this blend. After obtaining the films, some assays were realized to evaluate the mechanical properties. (author)

  12. In vitro degradation of chitosan composite foams for biomedical applications and effect of bioactive glass as a crosslinker

    OpenAIRE

    Martins Talita; Moreira Cheisy D. F.; Costa-Júnior Ezequiel S.; Pereira Marivalda M.

    2018-01-01

    In tissue engineering applications, 3D scaffolds with adequate structure and composition are required to provide durability that is compatiblewith the regeneration of native tissue. In the present study, the degradation of novel flexible 3D composite foams of chitosan (CH) combined with bioactive glass (BG)was evaluated, focusing on the role of BG as a physical crosslinker in the composites, and its effect on the degradation process. Highly porous CH/BG composite foams were obtained, and an e...

  13. Intraperitoneal administration of chitosan/DsiRNA nanoparticles targeting TNFα prevents radiation-induced fibrosis

    International Nuclear Information System (INIS)

    Nawroth, Isabel; Alsner, Jan; Behlke, Mark A.; Besenbacher, Flemming; Overgaard, Jens; Howard, Kenneth A.; Kjems, Jorgen

    2010-01-01

    Background and purpose: One of the most common and dose-limiting long-term adverse effects of radiation therapy is radiation-induced fibrosis (RIF), which is characterized by restricted tissue flexibility, reduced compliance or strictures, pain and in severe cases, ulceration and necrosis. Several strategies have been proposed to ameliorate RIF but presently no effective one is available. Recent studies have reported that tumor necrosis factor-α (TNFα) plays a role in fibrogenesis. Material and methods: Male CDF1 mice were radiated with a single dose of 45 Gy. Chitosan/DsiRNA nanoparticles targeting TNFα were intraperitoneal injected and late radiation-induced fibrosis (RIF) was assessed using a modification of the leg contracture model. Additionally, the effect of these nanoparticles on tumor growth and tumor control probability in the absence of radiation was examined in a C3H mammary carcinoma model. Results: We show in this work, that targeting TNFα in macrophages by intraperitoneal administration of chitosan/DsiRNA nanoparticles completely prevented radiation-induced fibrosis in CDF1 mice without revealing any cytotoxic side-effects after a long-term administration. Furthermore, such TNFα targeting was selective without any significant influence on tumor growth or irradiation-related tumor control probability. Conclusion: This nanoparticle-based RNAi approach represents a novel approach to prevent RIF with potential application to improve clinical radiation therapeutic strategies.

  14. Utilization of polysaccharides by radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Radiation treatment has been applied for improvement or pasteurization of agro-resources to recycle the resources and to reduce the pollution of environment. By using the radiation effect for pasteurization, upgrading of cellulosic wastes of oil palm to animal feeds and mushroom has been studied under the bilateral research cooperation between JAERI and MINT (Malaysian Institute for Nuclear Technology Research). The necessary dose for pasteurization of oil palm empty fruit bunch (EFB), which is a main cellulosic by-product of palm oil industry, was determined as 10 kGy. After pasteurization, the EFB substrate was inoculated with Pleurotus sajor-caju and fermented for 1 month. The digestibility and nutritional value of fermented products were evaluated as ruminant feeds and the mushroom can be produced as by-product. For the improvement of resources, radiation effects on polysaccharides such as chitosan, sodium alginate, carrageenan, cellulose, pectin have been investigated to induce the biological activities. These carbohydrates were easily degraded by irradiation and induced various kinds of biological activities. The anti-bacterial activity and elicitor activity of chitosan were induced by irradiation. The induction of phytoalexins was also observed by irradiated pectin but the higher elicitor activity for pisatin was obtained by chitosan than pectin. For the plant growth promotion, alginate derived from brown marine algae, chitosan and ligno-cellulosic extracts show a strong activity. carrageenan derived from red marine algae can promote growth of rice and the highest effect was obtained with kappa carrageenan irradiated at 100 kGy. Furthermore, some radiation degraded polysaccharides suppressed the damage of environmental stress on plants. (author)

  15. Utilization of polysaccharides by radiation processing

    International Nuclear Information System (INIS)

    Kume, Tamikazu

    2000-01-01

    Radiation treatment has been applied for improvement or pasteurization of agro-resources to recycle the resources and to reduce the pollution of environment. By using the radiation effect for pasteurization, upgrading of cellulosic wastes of oil palm to animal feeds and mushroom has been studied under the bilateral research cooperation between JAERI and MINT (Malaysian Institute for Nuclear Technology Research). The necessary dose for pasteurization of oil palm empty fruit bunch (EFB), which is a main cellulosic by-product of palm oil industry, was determined as 10 kGy. After pasteurization, the EFB substrate was inoculated with Pleurotus sajor-caju and fermented for 1 month. The digestibility and nutritional value of fermented products were evaluated as ruminant feeds and the mushroom can be produced as by-product. For the improvement of resources, radiation effects on polysaccharides such as chitosan, sodium alginate, carrageenan, cellulose, pectin have been investigated to induce the biological activities. These carbohydrates were easily degraded by irradiation and induced various kinds of biological activities. The anti-bacterial activity and elicitor activity of chitosan were induced by irradiation. The induction of phytoalexins was also observed by irradiated pectin but the higher elicitor activity for pisatin was obtained by chitosan than pectin. For the plant growth promotion, alginate derived from brown marine algae, chitosan and ligno-cellulosic extracts show a strong activity. carrageenan derived from red marine algae can promote growth of rice and the highest effect was obtained with kappa carrageenan irradiated at 100 kGy. Furthermore, some radiation degraded polysaccharides suppressed the damage of environmental stress on plants. (author)

  16. Tailoring the degradation rate and release kinetics from poly(galactitol sebacate) by blending with chitosan, alginate or ethyl cellulose.

    Science.gov (United States)

    Natarajan, Janeni; Madras, Giridhar; Chatterjee, Kaushik

    2016-12-01

    Despite significant advances in recent times, the investigation of discovering a perfect biomaterial is perennial. In this backdrop, blending of natural and synthetic polymers is gaining popularity since it is the easiest way to complement the drawbacks and attain a superlative material. Based on this, the objective of this study was to synthesize a novel polyester, poly(galactitol sebacate), and subsequently blend this polymer with one of the three natural polymers such as alginate, chitosan or ethyl cellulose. FT-IR showed the presence of both the polymers in the blends. 1 H NMR confirmed the chemical structure of the synthesized poly (galactitol sebacate). Thermal characterization was performed by DSC revealing that the polymers were amorphous in nature and the glass transition temperatures increased with the increase in ratio of the natural polymers in the blends. SEM imaging showed that the blends were predominantly homogeneous. Contact angle measurements demonstrated that the blending imparted the hydrophilic nature into poly (galactitol sebacate) when blending with alginate or chitosan and hydrophobic when blending with ethyl cellulose. In vitro hydrolytic degradation studies and dye release studies indicated that the polymers became more hydrophilic in alginate and chitosan blends and thus accelerated the degradation and release process. The reverse trend was observed in the case of ethyl cellulose blends. Modeling elucidated that the degradation and dye release followed first order kinetics and Higuchi kinetics, respectively. In vitro cell studies confirmed the cytocompatible nature of the blends. It can be proposed that the chosen natural polymers for blending showed wide variations in hydrophilicity resulting in tailored degradation, release and cytocompatibility properties and thus are promising candidates for use in drug delivery and tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. The use of chitosan as bioadhesive and its property improvement by radiation treatment for water-stable shrimp feed production

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Nguyen Duy; Hung, Nguyen Manh; Quynh, Tran Minh; Diep, Tran Bang; Binh, Nguen Van [Vietnam Atomic Energy Commission, Institute for Nuclear Science and Techniques, Caugiay, Hanoi (Viet Nam); Dung, Vu [Ministry of Fisheries, Research Institute of Marine Product, Haiphong (Viet Nam); Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-03-01

    Among marine polysaccharides, only chitosan with small content in feed (0.48-0.75%) could be selected to prepare shrimp feed-pellet having so high water-stability that meet the Standard of Vietnam Ministry of Fisheries 28-TCN 102/1997. Solid-state radiation treatment of chitosan with dose ranging from 10 to 200 kGy not only increased its solubility in solvents of dilute acid, but also improved the water-stability of feed-pellet product. Radiation treatment at sterilization doses (20-40 kGy) was evaluated as the most practical technology because irradiated chitosan with reduced content of 0.34% has capacity to be prepared feed-pellets stable as comparable to imported products. Results from feeding trials shown that chitosan containing feed did not affect the growth response and feed utilization efficiency such as weight gain (WG), feed conversion ratio (FCR) and productivity at harvest. (author)

  18. A preliminary study on radiation treatment of chitosan for enhancement of antifungal activity tested on fruit - spoiling strains

    International Nuclear Information System (INIS)

    Nguyen Duy Lam; Tran Bang Diep

    2003-01-01

    Chitosan samples were irradiated at doses ranging from 20 to 200 kGy, and then were supplemented to liquid medium for growth of fungi. Method of fungal cultivation using liquid medium showed that it has higher sensitivity compared with the cultivation on agar plate. Our study indicated that degree of deacetylation of chitosan clearly affects its antifungal activity, the higher the deacetylation of chitosan, stronger antifungal activity can be observed. Radiation treatment at doses higher than 20 kGy increased clearly the antifungal activity of chitosan. In addition, dose of 60-75 kGy where the viscosity-average molecular weight reduced to 110,000, expressed the highest activity. (author)

  19. Proceedings of the FNCA 2007 workshop on application of electron accelerator. Radiation processing of natural polymer

    International Nuclear Information System (INIS)

    Tamada, Masao; Kume, Tamikazu

    2008-12-01

    This workshop was co-sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan and the Ministry of Science and Technology (MOST), Vietnam. The Vietnam Atomic Energy Commission and Japan Atomic Energy Agency (JAEA) jointly executed the workshop in cooperation with the International Atomic Energy Agency (IAEA). The main objectives of the workshop were the following: - to discuss for the promotion of the commercial applications of radiation processing of natural polymer. - to prepare the work plan for the FNCA activities for 2007-2008. The workshop was attended by experts on radiation processing from Bangladesh, China, Egypt, India, Indonesia, Japan, Korea, Malaysia, Pakistan, Philippines, Sri Lanka, Thailand and Vietnam. The radiation processing of natural polymer is divided into crosslinking, degradation and graft polymerization. The radiation crosslinked polysaccharides are mainly used to prepare hydrogel for healthcare and environment. Hydrogels were commercialized in India, Korea, and Malaysia and are going to be commercialized in Philippines and Vietnam as wound dressings. Radiation degraded polysaccharides (alginate and chitosan) are commercialized in China and Vietnam in aquaculture and agriculture, respectively. Indonesia successfully carried out field test of radiation degraded chitosan as plant growth promoter. Also the radiation degraded chitosan was demonstrated to preserve post harvest fruit and to extend the shelf life of papaya in Pakistan and Sri Lanka, respectively. Radiation graft polymerization onto polysaccharide is applied for production of soil conditioner in Vietnam. Several applications of grafting technique were also reported. Manuscripts submitted by presenters were compiled in the proceedings. The 31 of the presented papers are indexed individually. (J.P.N.)

  20. Radiation processing of natural polymers using low energy electron beam

    International Nuclear Information System (INIS)

    Kume, Tamikazu

    2004-01-01

    Radiation processing is widely used in Japan and the economic scale of radiation application amounted to about 71 b$ (ratio relative to GDP: 1.7%) in total. It consisted of 60 b$ (85%) in industry, 10 b$ (14%) in medicine and 1 b$ (1%) in agriculture. Irradiation using gamma-ray from 60 Co and electron beam is commercially used for the sterilization and modification of materials. Utilization of natural polymers by radiation has been investigated for recycling the natural resources and reducing the environmental pollution. Polysaccharides such as chitosan, sodium alginate, carrageenan, cellulose, pectin were easily degraded by irradiation and induced various kinds of biological activities, i.e. anti-bacterial activity, elicitor activity, plant growth promotion, suppression of environmental stress on plants. Radiation degraded chitosan was effective to enhance the growth of plants in tissue culture. Low energy electron beam (EB) irradiation has a variety of applications and good safety. A self-shielded low energy electron accelerator system needs an initial investment much lower than a 60 Co facility. It was demonstrated that the liquid sample irradiation system using low energy EB was effective not only for the preparation of degraded polysaccharides but also for radiation vulcanization of natural rubber latex (RVNRL). Some carbohydrate derivatives, carboxymethylcellulose (CMC), carboxymethyl-starch and carboxymethyl-chitin/chitosan, can be crosslinked under certain radiation condition and produced the biodegradable hydrogel for medical and agricultural use. Treatment of soybean seeds by low energy EB enhanced the growth and the number of rhizobia on the root. (author)

  1. Radiation synthesis of gelatin/CM-chitosan/{beta}-tricalcium phosphate composite scaffold for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Ying [College of Engineering, Peking University, Beijing 100871 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Xu Ling, E-mail: lingxu@pku.edu.cn [College of Engineering, Peking University, Beijing 100871 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang Xiangmei; Zhao Yinghui [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Wei Shicheng, E-mail: sc-wei@pku.edu.cn [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Zhai Maolin [Beijing National Laboratory for Molecular Sciences, Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

    2012-05-01

    A series of biodegradable composite scaffolds was fabricated from an aqueous solution of gelatin, carboxymethyl chitosan (CM-chitosan) and {beta}-tricalcium phosphate ({beta}-TCP) by radiation-induced crosslinking at ambient temperature. Ultrasonic treatment on the polymer solutions significantly influenced the distribution of {beta}-TCP particles. An ultrasonic time of 20 min, followed by 30 kGy irradiation induced a crosslinked scaffold with homogeneous distribution of {beta}-TCP particles, interconnected porous structure, sound swelling capacity and mechanical strength. Fourier Transform Infrared Spectroscopy and X-ray Diffraction analysis indicated that {beta}-TCP successfully incorporated with the network of gelatin and CM-chitosan. In vivo implantation of the scaffold into the mandible of beagle dog revealed that the scaffolds had excellent biocompatibility and the presence of {beta}-TCP can accelerate bone regeneration. The comprehensive results of this study paved way for the application of gelatin/CM-chitosan/{beta}-TCP composite scaffolds as candidate of bone tissue engineering material. - Highlights: Black-Right-Pointing-Pointer Radiation induced a crosslinked scaffold with interconnected porous structure. Black-Right-Pointing-Pointer Ultrasonic time of 20 min led to homogenerously distribution of {beta}-TCP. Black-Right-Pointing-Pointer Increasing amount of {beta}-TCP would restrict the swelling properties. Black-Right-Pointing-Pointer Proper fraction of {beta}-TCP will promote the mechanical properties of the scaffolds. Black-Right-Pointing-Pointer Hybrid of {beta}-TCP promoted the bone regeneration of the mandibles of beagle dogs.

  2. Country Report of Bangladesh on the Activities on “Modification of Natural Polymers by Radiation Processing for Value Added Products”

    International Nuclear Information System (INIS)

    Haque, M.E.; Khan, R.A.; Dafader, N.C.; Mollah, M.Z.I.

    2010-01-01

    Effects of chitosan on the morphological properties on the plants/fruits were investigated by applying on various vegetables as plant growth promoter. Chitosan enhances the vegetative growth in terms of the average values of stem length, number of growing leaves, including leaf width and length etc. In this investigation, irradiated chitosan was sprayed on local vegetable (Ammaranthus Cruentus, Local name: Datasakh) and green chili plant. Films of chitosan were made and the effects of gamma radiation on the tensile properties of the film were investigated. The tensile strength of the irradiated films increases from 14 to 27 MPa by applying 200 krad of gamma radiation. The elongation at break increases for up to 100 krad but after that dose it reduces to about 7 MPA at 500 krad. The chitsan was modified with HEMA monomer for biomedical application. Further investigation on its properties is going on. The chitosan films were characterized by using TG, DTA and DTG. The TG curve shows two stage degradations. The onset temperature was about 55°C. The residue content was about 40% after 600°C. The maximum slope was obtained at 149ºC. DTA curve of chitosan shows endothermic peak at 273ºC. It depicts one predominant peak at 320ºC where the maximum degradation rate was 57.3 μg/min. From this investigation this is clear that chitosan started degradation at low temperature which is common for natural biopolymers but the maximum degradation happened at higher temperature which is a good sign of thermal stability of chitosan. The surface of the prepared chitosan films were investigated by SEM. It is found that the surface is quite smooth. Sodium alginate was extracted from brown algae (Sargassum).150 ppm degraded alginate shows a positive effect on the growth parameters of red amaranth with varying gamma doses (12.5 to 50.0 kGy). A positive result on the growth rate of the vegetable was found. (author)

  3. Development and Characterization of VEGF165-Chitosan Nanoparticles for the Treatment of Radiation-Induced Skin Injury in Rats

    Directory of Open Access Journals (Sweden)

    Daojiang Yu

    2016-10-01

    Full Text Available Radiation-induced skin injury, which remains a serious concern in radiation therapy, is currently believed to be the result of vascular endothelial cell injury and apoptosis. Here, we established a model of acute radiation-induced skin injury and compared the effect of different vascular growth factors on skin healing by observing the changes of microcirculation and cell apoptosis. Vascular endothelial growth factor (VEGF was more effective at inhibiting apoptosis and preventing injury progression than other factors. A new strategy for improving the bioavailability of vascular growth factors was developed by loading VEGF with chitosan nanoparticles. The VEGF-chitosan nanoparticles showed a protective effect on vascular endothelial cells, improved the local microcirculation, and delayed the development of radioactive skin damage.

  4. Characteristics and degradation of chitosan/cellulose acetate microspheres with different model drugs

    Science.gov (United States)

    Zhou, Hui-yun; Chen, Xi-guang

    2008-12-01

    In this study, chitosan/cellulose acetate microspheres (CCAM) were prepared by W/O/W emulsification and solvent evaporation as a drug delivery system. The microspheres were spherical, free-flowing and non-aggregated. The CCAM had good flow and suspension ability. The loading efficiency of different model drugs increased with the increasing hydrophobicity of the drug. The loading efficiency of 6-mercaptopurine (6-MP) was more than 30% whereas that of ranitidine hydrochloride (RT) or acetaminophen (ACP) was only 10%. The pH values of solution affected the swelling ability of CCAM and the relative humidity had little effect on the characteristics of CCAM when it was not more than 75%. The CCAM system had a good effect on the controlled release of different model drugs. However, the release rate became slower with the increase of the hydrophobicity of drugs. The release rate of CCAM loaded with hydrophilic RT was almost 60% during 48 h and the release rate of CCAM loaded with hydrophobic drug of 6-MP was not more than 30%. In the meantime, the CCAM system was degradable in vitro and the degradation rate was faster in lysozyme solution than that in the medium of PBS. So the CCAM system was a degradable promising drug delivery system especially for hydrophobic drugs.

  5. Radiation induced degradation of dyes-An overview

    International Nuclear Information System (INIS)

    Rauf, M.A.; Ashraf, S. Salman

    2009-01-01

    Synthetic dyes are a major part of our life. Products ranging from clothes to leather accessories to furniture all depend on extensive use of organic dyes. An unfortunate side effect of extensive use of these chemicals is that huge amounts of these potentially carcinogenic compounds enter our water supplies. Various advanced oxidation processes (AOPs) including the use of high-energy radiation have been developed to degrade these compounds. In this review, dye decoloration and degradation as a result of its exposure to high energy radiation such as gamma radiation and pulsed electron beam are discussed in detail. The role of various transient species such as ·H, ·OH and e aq - are taken into account as reported by various researchers. Literature citations in this area show that e aq - is very effective in decolorization but is less active in the further degradation of the products formed. The degradation of the dyes is initiated exclusively by ·OH attack on electron-rich sites of the dye molecules. Additionally, various parameters that affect the efficiency of radiation induced degradation of dyes, such as effect of radiation dose, oxygen, pH, hydrogen peroxide, added ions and dye classes are also reviewed and summarized. Lastly, pilot plant application of radiation for wastewater treatment is briefly discussed.

  6. Radiation Processed Materials in Products from Polymers for Agricultural Applications in China. Chapter 7

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, M. [Beijing National Laboratory for Molecular Sciences, Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing (China); Wu, G. [Shanghai Institute of Applied Physics, Chinese Academy of Science (China); Xu, L. [Beijing Key Laboratory for Solid Waste Utilization and Management, Department of Energy and Resources Engineering, College of Engineering, Peking University, Beijing (China)

    2014-07-15

    Oligochitosan has been found to be water-soluble and effective to elicit multiple plant defense responses. In China, Peking University and Shanghai Institute of Applied Physics, Chinese Academy of Science investigated on the radiation degradation of chitosan. The results showed that the molecular weight (Mw) of more than 95% of chitosan was lower than 3000 with narrower Mw distribution when compared with enzyme radiolysis products. The mechanism of radiation degradation was well elucidated. The technology was transfer to Xiamen Blue Bay Co. Ltd and Jiaxing Kerui Biology Technology Co. Ltd by Peking University and Shanghai Applied Physics Institute, China Academic, respectively. The oligochitosan was used to produce animal feeds for health care drug, aquaculture feed for shrimp and fish, animal feed for bird species, animal feed for piglet and so on. Data for the mentioned applications as well as the promotion of cucumber growth was shown. In summary, oligochitosan prepared by radiation degradation has marvelous prospects on enhancing animal breed and plant growth at low cost. (author)

  7. Thermal degradation of ternary blend films containing PVA/chitosan/vanillin

    Science.gov (United States)

    Kasai, Deepak; Chougale, Ravindra; Masti, Saraswati; Narasgoudar, Shivayogi

    2018-05-01

    The ternary chitosan/poly (vinyl alcohol)/vanillin blend films were prepared by solution casting method. The influence of equal weight percent of poly (vinyl alcohol) and vanillin on thermal stability of the chitosan blend films were investigated by using thermogravimetric analysis (TGA). The kinetic parameters such as enthalpy (ΔH*), entropy (ΔS*), and Gibbs free energy (ΔG*) in the first and second decomposition steps based on the thermogravimetric data were calculated. The thermal stabilities of the blend films were confirmed by thermodynamic parameters obtained in the activation energies, which indicated that increase in the equal weight percent of PVA/vanillin decreased the thermal stability of the chitosan film.

  8. Study of Chemical Treatment Combined with Radiation to Prepare Biotic Elicitor for Utilization in Agriculture

    International Nuclear Information System (INIS)

    Nguyen Quoc Hien

    2010-01-01

    Chitosan was prepared from shrimp shell (alpha chitosan) and from squid pen (beta chitosan) with degree of deacetylation of about 70%. Degradation of chitosan in flake form by combined treatment with H 2 O 2 and gamma Co-60 radiation was carried out. Results showed that combined treatment was highly effective for degradation of chitosan to obtain low molecular weight of 1-2 × 10 5 . Oligochitosan was prepared by irradiation of chitosan solution of 50g/l (5%, w/v). The dose required for oligochitosan with water soluble content of more than 70% was of 32kGy and 48kGy for beta and alpha chitosan, respectively. Synergic effect of degradation of chitosan in solution with H 2 O 2 and gamma Co-60 radiation was also investigated. The dose to obtain oligochitosan was reduced from 32kGy to 4kGy for beta chitosan and from 48kGy to 8kGy for alpha chitosan. The elicitation and growth promotion effect of oligochiotsan for sugarcane and rice were investigated. Results showed that oligochitosan with water soluble content of 70-80% (Mw~5,000-10,000) exhibited the most effective elicitation and growth promotion for plant. The optimum oligochitosan concentration by spraying was of 30 and 15ppm for sugarcane and rice, respectively. The disease index of Ustilgo scitaminea and Collectotrichum falcatum on sugarcane were reduced to 44.5 and 72.3% compared to control (100%). The productivity of sugarcane was increased about 13% (8tons/ha). The disease index of Pyricularia grisea on rice was reduced to 53.0% for leaf and 34.1% for neck of bloom compared to control (100%). The productivity of rice was increased for 11-26% (0.6-1.4 tons/ha). The obtained results indicated that oligochitosan is promising to use as a biotic elicitor for plant particularly for sugarcane and rice. The procedure for production of oligochitosan elicitor by γ- irradiation method was described. (author)

  9. Degradation characteristics of irradiated poly-(caprolactonechitosan-hydroxyapatite) biomaterial in simulated body fluid solution

    International Nuclear Information System (INIS)

    Warastuti, Y.; Suryani, N.

    2013-01-01

    This investigation purpose was to study degradation characteristics of poly-(caprolactone -chitosan-hydroxyapatite) biomaterial in simulated body fluid (SBF) solution. A composite membrane has been synthesized using blending and stirring method with acetic acid solvent and then molded into thin film. Electron beam radiation dose 0 - 30 kGy were done in order to evaluate radiation effects. SBF absorption with various immersing times and degradation for 0 -12 weeks were conducted. Fourier Transform Infra Red Spectroscopy (FTIR) was used to identification functional groups of composite and Scanning Electron Microscopy (SEM) was applied to analyse micro structural surface of membrane before and after immersion. The irradiation process indicate that SBF absorption decrease because NH 2 groups in chitosan which contributes to the hydrophilicity was broken. The composite III indicate maximum absorption (58,2% ± 2,22) due to its smallest concentration of polycaprolactone and highest concentration of chitosan that caused decrease of hydrophobicity. Optimum degradation of composite III (1,3% ± 0,98) was reached after 8 weeks of immersion time. FTIR spectrum indicate the unity of typical peaks of the constituent materials and specific spectrum of CO 3 2- of carbonated apatite which was formed because immersion of SBF. Microstructural analysis using SEM indicate the formation of needle like apatite layer or calcium phosphate precipitate over all surface membrane. All the results indicate that these composite meet the requirements to biomaterial. (author)

  10. Preparation of alginate coated chitosan microparticles for vaccine delivery

    Directory of Open Access Journals (Sweden)

    Wei YuQuan

    2008-11-01

    Full Text Available Abstract Background Absorption of antigens onto chitosan microparticles via electrostatic interaction is a common and relatively mild process suitable for mucosal vaccine. In order to increase the stability of antigens and prevent an immediate desorption of antigens from chitosan carriers in gastrointestinal tract, coating onto BSA loaded chitosan microparticles with sodium alginate was performed by layer-by-layer technology to meet the requirement of mucosal vaccine. Results The prepared alginate coated BSA loaded chitosan microparticles had loading efficiency (LE of 60% and loading capacity (LC of 6% with mean diameter of about 1 μm. When the weight ratio of alginate/chitosan microparticles was greater than 2, the stable system could be obtained. The rapid charge inversion of BSA loaded chitosan microparticles (from +27 mv to -27.8 mv was observed during the coating procedure which indicated the presence of alginate layer on the chitosan microparticles surfaces. According to the results obtained by scanning electron microscopy (SEM, the core-shell structure of BSA loaded chitosan microparticles was observed. Meanwhile, in vitro release study indicated that the initial burst release of BSA from alginate coated chitosan microparticles was lower than that observed from uncoated chitosan microparticles (40% in 8 h vs. about 84% in 0.5 h. SDS-polyacrylamide gel electrophoresis (SDS-PAGE assay showed that alginate coating onto chitosan microparticles could effectively protect the BSA from degradation or hydrolysis in acidic condition for at least 2 h. The structural integrity of alginate modified chitosan microparticles incubated in PBS for 24 h was investigated by FTIR. Conclusion The prepared alginate coated chitosan microparticles, with mean diameter of about 1 μm, was suitable for oral mucosal vaccine. Moreover, alginate coating onto the surface of chitosan microparticles could modulate the release behavior of BSA from alginate coated chitosan

  11. Inhibitory effect of chitosan oligosaccharide on human hepatoma ...

    African Journals Online (AJOL)

    Background: Chitosan oligosaccharide, the degradation products of chitin, was reported to have a wide range of physiological functions and biological activities. In this study, we explored the inhibitory effect of Chitosan oligosaccharide on human hepatoma cells. Materials and Methods: MTT assay was applied to detect cell ...

  12. Alkyl chitosan film-high strength, functional biomaterials.

    Science.gov (United States)

    Lu, Li; Xing, Cao; Xin, Shen; Shitao, Yu; Feng, Su; Shiwei, Liu; Fusheng, Liu; Congxia, Xie

    2017-11-01

    Biofilm with strong tensile strength is a topic item in the area of tissue engineering, medicine engineering, and so forth. Here we introduced an alkyl chitosan film with strong tensile strength and its possibility for an absorbable anticoagulation material in vivo was tested in the series of blood test, such as dynamic coagulation time, plasma recalcification time and hemolysis. Alkyl chitosan film was a better biomaterial than traditional chitosan film in the anticoagulation, tissue compatibility and cell compatibility. The unique trait of alkyl chitosan film may be for its greater contact angle and hydrophobicity ability to reduce the adsorption capacity for the blood component and the activity of fibrinolytic enzymes, enhance the antibacterial capacity than chitosan film. Moreover, none of chitosan film or butyl chitosan film exhibited quick inflammation or other disadvantage and degraded quickly by implanted test. Therefore, Alkyl chitosan film is of prospective properties as an implantable, absorbable agent for tissue heals, and this material need further research. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3034-3041, 2017. © 2017 Wiley Periodicals, Inc.

  13. Enhancement of antimicrobial activity of chitosan by irradiation

    International Nuclear Information System (INIS)

    Matsuhashi, S.; Kume, T.

    1997-01-01

    Antimicrobial activity of irradiated chitosan was studied against Escherichia coli B/r. Irradiation of chitosan at 100 kGy under dry conditions was effective in increasing the activity, and inhibited the growth of E. coli completely. The molecular weight of chitosan significantly decreased with the increase in irradiation dose, whereas the relative surface charge of chitosan was decreased only 3% by 100 kGy irradiation. Antimicrobial activity assay of chitosan fractionated according to molecular weight showed that 1 x 10 5 -3 x 10 5 fraction was most effective in suppressing the growth of E coli. This fraction comprised only 8% of the 100 kGy irradiated chitosan. On the other hand, chitosan whose molecular weight was less than 1 x 10 5 had no activity. The results show that low dose irradiation, specifically 100 kGy, of chitosan gives enough degradation to increase its antimicrobial activity as a result of a change in molecular weight. (Author)

  14. Physicochemical and functional characteristics of radiation-processed shrimp chitosan

    International Nuclear Information System (INIS)

    Ocloo, F.C.K.; Quayson, E.T.; Adu-Gyamfi, A.; Quarcoo, E.A.; Asare, D.; Serfor-Armah, Y.; Woode, B.K.

    2011-01-01

    The effects of gamma irradiation on chitosan samples were determined in terms of physicochemical and functional properties. Shrimp chitosan was extracted from shell using a chemical process involving demineralization, deproteinization, decolorization and deacetylation. Commercial snow chitosan was also used. Samples (in a solid state) were given irradiation dose of 25 kGy at a dose rate of 1.1013 kGy/h in air and 0 kGy samples were used as controls. Results showed that moisture contents were between 8.690% and 13.645%. There were no significant differences (P>0.05) in the degree of deacetylation of the chitosan samples. Significant differences (P<0.05) were observed in the viscosity and viscosity-average molecular weight of the chistosan samples. Viscosity and molecular weight decreased when the samples were given the irradiation dose of 25 kGy. Chitosan samples had low antioxidant activity compared with BHT. Water binding capacity ranged from 582.40% to 656.75% and fat binding capacity was between 431.00% and 560.55%. Irradiation had a major effect on the viscosity and the viscosity-average molecular weight of the chitosan samples.

  15. Physicochemical and functional characteristics of radiation-processed shrimp chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Ocloo, F.C.K., E-mail: fidelis_ocloo@yahoo.co [Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon (Ghana); Quayson, E.T. [Department of Biochemistry, University of Cape Coast, Cape Coast (Ghana); Adu-Gyamfi, A.; Quarcoo, E.A.; Asare, D. [Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon (Ghana); Serfor-Armah, Y. [National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon (Ghana); Woode, B.K. [Department of Biochemistry, University of Cape Coast, Cape Coast (Ghana)

    2011-07-15

    The effects of gamma irradiation on chitosan samples were determined in terms of physicochemical and functional properties. Shrimp chitosan was extracted from shell using a chemical process involving demineralization, deproteinization, decolorization and deacetylation. Commercial snow chitosan was also used. Samples (in a solid state) were given irradiation dose of 25 kGy at a dose rate of 1.1013 kGy/h in air and 0 kGy samples were used as controls. Results showed that moisture contents were between 8.690% and 13.645%. There were no significant differences (P>0.05) in the degree of deacetylation of the chitosan samples. Significant differences (P<0.05) were observed in the viscosity and viscosity-average molecular weight of the chistosan samples. Viscosity and molecular weight decreased when the samples were given the irradiation dose of 25 kGy. Chitosan samples had low antioxidant activity compared with BHT. Water binding capacity ranged from 582.40% to 656.75% and fat binding capacity was between 431.00% and 560.55%. Irradiation had a major effect on the viscosity and the viscosity-average molecular weight of the chitosan samples.

  16. Degradation characteristics of waste polyurethane by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Seok; Ahn, Sung Jun; Gwon Hui Jeong; Jeong, Sung In; Nho, Young Chang; Lim, Youn Mook [Research Division for Industry and Environment, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2017-06-15

    Polyurethane (PU) is a very popular polymer that is used in a variety of applications due to its good mechanical, thermal, and chemical properties. However, waste PU recycling has received significant attention due to environmental issues. The aim of this work was to investigate the degradation characteristics of waste PU to recycle. Degradation of waste PU was carried out using a radiation techniques. Waste PUs were exposed to a gamma {sup 60}Co sources. To verify degradation, the irradiated PUs were characterized using FT-IR, gel permeation chromatography (GPC), and their thermal/mechanical properties are reported. When the radiation dose was 500 kGy, the molecular weight of the waste PU drastically decreased. Also, the mechanical properties of waste PU were approximately 4 times lower than those of non-irradiated PU. This study has confirmed the possibility of making fine particle of waste PU for recycling through radiation degradation techniques.

  17. A Series of Radiation Processed Nanostructural Chitosan Derivatives for Biomedicine, Agriculture, and Bioplastics

    International Nuclear Information System (INIS)

    Pasanphan, W.; Rattanawongwiboon, T.; Huajaikaew, E.; Kongkaoroptham, P.; Guven, O.; Suwanmala, P.; Hemvichian, K.

    2014-01-01

    The work includes a series of biopolymeric chitosan (CS) nanostructures prepared by irradiation techniques. The radiation processed nanostructural CS were designed, synthesized, and characterized to address a progress in radiation technology for developing value-added natural products for advanced biomedical, agricultural and bioplastic applications. The idea to create CS nanoparticles (CSNPs) using radiation was initiated from simple radiation- induced non-chemical modification to advance radiation-induced functionalization of CSNPs. The already-existing CS nanostructures are water-soluble CSNPs as a green antioxidant and reducing agent, amphiphilic core-shell CS nanocarrier as anticancer delivery system, CS nanogel for fungicide and fertilizer controlled-release, and CS nanofiller for biodegradable PLA blends. Irradiation techniques, chemical structures, nanostructural morphologies including performance of nanostructural CS derivatives in appropriate utilizations were demonstrated. The developing idea would be an alternative approach for nanoscaled-controlled synthesis of the natural polymers.

  18. Study on growth-promotion of paddy plants treated with oligo chitosan

    International Nuclear Information System (INIS)

    Norhashidah Talip; Maznah Mahmud; Norzita Yacob; Kamaruddin Hashim; Khairul Zaman Mohd Dahlan

    2010-01-01

    Chitosan has been degraded to produced oligo chitosan with different molecular weight using gamma ray irradiation from a Co-60 source in solid state (powder form) and liquid state (aqueous solution). Study on growth promotion of paddy plants was done using oligo chitosan and conventional plant growth promoter as a comparison. Oligo chitosan was used with different molecular weight and different concentrations. Smaller molecular weight of oligo chitosan with smaller concentration showed better result than bigger molecular weight of oligo chitosan as a plant growth promoter. This study also showed that conventional growth promoter can be replaced with oligo chitosan as it is more effective as plant growth promoter as well as more environmental friendly. (author)

  19. Radiation-induced degradation of pollutants

    International Nuclear Information System (INIS)

    Proksch, E.

    1988-01-01

    This article outlines the fundamentals of radiation-induced degradation of noxious substances in drinking water and waste water and discusses the relevant literature. Radiation methods present a number of advantages and disadvantages, which should carefully be considered in each case. In many cases, there seems to be merit in combining the radiation method with other techniques, as e.g. ozone treatement and biodegradation. 30 refs., 3 figs. (Author)

  20. Increased radiation degradation in methyl methacrylate copolymers

    International Nuclear Information System (INIS)

    Helbert, J.N; Wagner, G.E.; Caplan, P.J.; Poindexter, E.H.

    1975-01-01

    The effect of polar substituents at the quaternary carbon on degradation processes in several polymers and 10 to 20 percent copolymers of methyl methacrylate was explored. EPR was used to monitor radiation degradation products and to determine radiation G values. Irradiations were carried out at 77 0 K in a gamma irradiator at a dose rate of 0.3 Mrad/hr. (U.S.)

  1. Characterization and Cell Culture of a Grafted Chitosan Scaffold for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Wen-Chuan Hsieh

    2015-01-01

    Full Text Available Poly(vinyl alcohol (PVA was grafted to chitosan to form a porous scaffold. The PVA-g-chitosan 3D scaffold was then observed by Fourier transform infrared spectroscopy (FT-IR. The water absorbency of PVA-g-chitosan was increased 370% by grafting. Scanning electron microscope (SEM observations of the material revealed that the 3D scaffold is highly porous when formed using a homogenizer at 300 rpm. Compression testing demonstrated that as the amount of chitosan increases, the strength of the 3D scaffold strength reached showed that, by increasing the amount of chitosan, the strength of the 3D scaffold could be increased to 16 × 10−1 MPa. Over 35 days of enzymatic degradation, the 3D scaffold was degraded by various enzymes at rates of up to 10%. In vitro tests showed good cell proliferation and growth in the 3D scaffold.

  2. Application of controlled radiation-induced degradation in polymers: less exploited aspect of radiation processing of polymers

    International Nuclear Information System (INIS)

    Haji Saeid, M.; Guven, O.

    2007-01-01

    Industrial use of ionizing radiation treatment has been most successful in applications related to polymeric materials. The polymer, plastics and rubber industries have benefited from the unique advantages of ionizing radiation since its inception as an industrial tool to modify their properties and manufacture novel materials with value addition to the end product. The established and emerging applications of electron beam processing of polymers are based on the well known ultimate effects of ionizing radiation on polymers namely, crosslinking, curing, grafting and chain scissioning. Radiation-induced crosslinking dominates most applications, whereas the chain scissioning effect is much less explored and currently limited to radiation-induced degradation of Teflon, cellulose and polypropylene. The controlling of radiation-induced degradation for achieving a target average molecular weight or distribution has been evaluated for some polysaccharides, biopolymers and waste inner tubes whereas mitigation of the degradative effects of radiation has been analyzed from the point of view of using certain stabilizers, copolymers and annealing at an appropriate temperature. Several new or highly specialized techniques such as positron annihilation lifetime spectroscopy. Rutherford backscattering, elastic recoil detection analysis and solid waste NMR spectroscopy and gas chromatography-mass spectroscopy have been applied to the study or radiation-induced degradation. New information has been collected on the morphological changes associated with radiation-induced degradation processes, including chain scission, oxidation and free volume alteration. The IAEA coordinated research project (CRP) on Controlling of Degradation Effects in Radiation Processing of Polymers dealt with the role and importance of using ionizing radiation in controlling properties of natural and synthetic polymers through its degradative effect. This paper provides a summary of most important results

  3. Animal experiments and clinical trials of 166Ho-Chitosan for various cancers

    International Nuclear Information System (INIS)

    Lim, S.M.; Choi, C.W.; Park, S.Y.; Lee, S.H.; Lee, B.H.; Park, K.B.

    1998-01-01

    166 Ho-Chitosan is a complex of 166 Ho and N-glucosamine with 400 to 500 kD MW, which chelates metal ions and degrades slowly in vivo. In mice, 166 H-Chitosan administered intraperitoneally was uniformly bound to the peritoneal wall (94%), and the surface dose calculated by Monte Carlo simulation (EGS 4 code) was 81 Gy/uCi/cm 2 . 166 Ho-Chitosan was administered intraperitoneally as an adjunct in the treatment of ovarian cancer with diffuse spread of malignant cells in the peritoneal surfaces including the diaphragm. 97-99% of 166 Ho-Chitosan was localized within the peritoneal cavity, and more than 90% of 166 Ho-Chitosan was attached to the peritoneal wall. Partial response were observed in 4 among 5 patients with ovarian cancer without severe toxicity. Intracavitary radiation therapy with 166 Ho-Chitosan in the cystic brain tumor, 5 or 8 cysts were shrunken in size with thinning of the wall, 2 out of 8 showed growth retardation. For large or multiple primary liver cancers, which were inoperable and resistent to chemotherapy. 166 Ho-Chitosan was used for intraarterial injection, because this solution became gel with neutral pH. In the primary liver cancer, radioactivity was distributed in the territory of selected hepatic arterial branch, and partial responses were observed in 2 cases. For the large solitary liver tumor, which was not operable due to its location, direct intratumoral injection of the radioisotope had a limited response. 18 FDG PET was a useful tool to follow up those radionuclide therapy, and guide to plan the next therapy. In one case of the large single metastatic stomach cancer in the liver, 18 FDG PET was done two weeks after intratumoral injection of 166 Ho-Chitosan, which showed cold defects matched with distribution of 166 Ho-Chitosan, and second injection was guided by PET image. Various methods of the administration of 166 Ho-Chitosan could be used for the treatment of the cancers. (author)

  4. Radiation Processing of Natural Polymers for Industrial Applications

    International Nuclear Information System (INIS)

    Hegazy, E.A.

    2008-01-01

    Radiation induced degradation technology is a new and promising application of ionizing radiation to develop viscose, pulp, paper, food preservation, pharmaceutical production, and natural bioactive agents industries. Controlling the degree of degradation, uniform molecular weight distribution, saving achieved in the chemicals (used in conventional methods) on a cost basis, and environmentally friendly process are the beneficial effects of using radiation technology in these industries. However, for some development countries such technology is not economic. Therefore, a great effort should be done to reduce the cost required for such technologies. One of the principle factors for reducing the cost is achieving the degradation at low irradiation doses. The addition of some additives such as potassium per-sulfate (KPS), ammonium per-sulfate (APS), or H 2 O 2 to natural polymers (carboxy-methylcellulose (CMC), chitosan, carrageenan and Na-alginate) during irradiation process accelerates their degradation. The highest degradation rate of polysaccharides obtained when APS was used. The end product of irradiated CMC, chitosan, carrageenan and Na-alginate may be used as food additive or benefited in agricultural purposes. On the other hand, radiation crosslinking of PAAm or PNIPAAm is affected by the presence of natural polymer like CMC-Na and carrageenan due to their degradability which could be controlled according to its concentration in the bulk medium and irradiation dose. Accordingly, the gel content, thermo-sensitivity (LCST) and swelling properties of PNIPAAm based natural polymers could be controlled. The swelling of the prepared copolymer hydrogels was investigated for its possible use in personal care articles particularly diapers or as carriers for drug delivery systems. The prepared crosslinked copolymers possessed high and fast swelling properties in simulated urine media and the swelling ratios of CMC-Na /PAAm gels in urine are acceptable for diaper

  5. Synthesis and Study the Effect of HNTs on PVA/Chitosan Composite Material

    OpenAIRE

    Malek Ali

    2016-01-01

    Composites materials of Poly (vinyl alcohol) (PVA)/Chitosan (CS) have been synthesized and characterized successfully. HNTs have been added to composites to enhance the mechanical and degradation properties by hydrogen bonding interactions, compatibility, and chemical crosslink between HNTs and PVA. PVA/CS/HNTs composites prepared with different concentration ratio. SEM micrographs of composites surface showed that more agglomeration with more chitosan ratio. Mechanical and degradation proper...

  6. Development of hydroxyapatite-chitosan gel sunscreen combating clinical multidrug-resistant bacteria

    Science.gov (United States)

    Morsy, Reda; Ali, Sameh S.; El-Shetehy, Mohamed

    2017-09-01

    The several harmful effects on infected human skin resulting from exposure to the sun's UV radiation generate an interest in the development of a multifunctional hydroxyapatite-chitosan (HAp-chitosan) gel that works as an antibacterial sunscreen agent for skin care. In this work, HAp-chitosan gel was synthesized via coprecipitation method by dissolving chitosan in phosphoric acid and adding HAp. The characteristics of HAp-chitosan composite were investigated by conventional techniques, such as XRD, FTIR, and SEM techniques, while its sunscreen property was investigated by UV-spectroscopy. In addition to the influence of the gel on bacterial cell morphology, the antibacterial activity of HAp-chitosan gel against clinical multidrug resistant skin pathogens, such as Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa has been studied. The results revealed the formation of HAp-chitosan gel having nanosized particles, which confers protection against UV-radiation. The antibacterial activity records showed that chitosan-HAp gel exhibits a significant effect on the growth and ultrastructure of multi-drug resistant bacterial activities. Therefore, the chitosan-HAp gel is promising for skin health care as an antibacterial sunscreen.

  7. Chitosan and Its Derivatives for Application in Mucoadhesive Drug Delivery Systems

    Directory of Open Access Journals (Sweden)

    Twana Mohammed M. Ways

    2018-03-01

    Full Text Available Mucoadhesive drug delivery systems are desirable as they can increase the residence time of drugs at the site of absorption/action, provide sustained drug release and minimize the degradation of drugs in various body sites. Chitosan is a cationic polysaccharide that exhibits mucoadhesive properties and it has been widely used in the design of mucoadhesive dosage forms. However, its limited mucoadhesive strength and limited water-solubility at neutral and basic pHs are considered as two major drawbacks of its use. Chemical modification of chitosan has been exploited to tackle these two issues. In this review, we highlight the up-to-date studies involving the synthetic approaches and description of mucoadhesive properties of chitosan and chitosan derivatives. These derivatives include trimethyl chitosan, carboxymethyl chitosan, thiolated chitosan, chitosan-enzyme inhibitors, chitosan-ethylenediaminetetraacetic acid (chitosan-EDTA, half-acetylated chitosan, acrylated chitosan, glycol chitosan, chitosan-catechol, methyl pyrrolidinone-chitosan, cyclodextrin-chitosan and oleoyl-quaternised chitosan. We have particularly focused on the effect of chemical derivatization on the mucoadhesive properties of chitosan. Additionally, other important properties including water-solubility, stability, controlled release, permeation enhancing effect, and in vivo performance are also described.

  8. Radiosensitizing effect of Chitosan on HeLa and LN 18 brain tumor cells exposed to electron beam radiation

    International Nuclear Information System (INIS)

    Rao, Shama; Shetty, Sukanya; Suchetha Kumari, N.; Madhu, L.N.

    2014-01-01

    Chitosan has been widely used for multiple applications because it is a non-toxic biocompatible, biodegradable, and adsorptive material. A previous study has shown that low-molecular-weight chitosan (LMWC) exerts a cytotoxic effect on oral cancer cells. Although a higher concentration of LMWC in comparison to cisplatin was needed in order to kill cancer cells, it was relatively less cytotoxic to non-cancer cells. Some of the well known anticancer drugs have the property of sensitizing the cell to radiation, which will be more applicable during combination therapy of cancer. The present study was undertaken to find the radiosensitizing effect of chitosan on Hela and Brain tumor (LN18) cells against electron beam radiation (EBR). Both the cancer cell lines, Hela and LN 18 were treated with different concentration of chitosan (50 and 100 μg/ml) pre and post exposure to 4 Gy EBR. The percentage of cell viability, percentage of apoptosis and ssDNA damage in the treated cells were assessed by MTT assay, DNA diffusion assay and comet assay respectively. The obtained results showed 62.13 1 5.08 and 65.24 1 2.45 percent Hela and LN 18 viable cells at 24 hour after the exposure to 4 Gy EBR. The percentage of viability was found to be decreased in cells exposed to EBR in the presence of chitosan. Supporting to this, percentage of apoptotic cells was found to be more in treated groups (28.13 1 4.34 and 25.13 1 3.76) when compared with control (23.19 1 1.07 and 20.79 1 4.86). Treatment of HeLa and LN18 before and after the exposure of EBR showed significantly (P<0.05) more frequency of micronucleus and % of DNA damage than the 4 Gy EBR control group. These results conclude the sensitizing effect of chitosan on cancer cell line against EBR exposure. (author)

  9. Preliminary Studies on Antifungal Properties of Radiation Processed Chitosan from Crab Shells

    International Nuclear Information System (INIS)

    Ocloo, Fidelis C.K.; Adu-Gyamfi, Abraham; Quarcoo, Emmanuel A.; Asare, Daniel; Yaw, Serfor-Armah

    2010-01-01

    Chitosan extracted from sea crab shells was used to determine antifungal properties against Aspergillus niger. Chitosan powder irradiated at 100 kGy and dissolved in 1% acetic acid (v/v) with pH adjusted to approximately 6.0 was used in preparing chitosan concentrations of 2%, 1.5%, 1% and 0.5%. The agar dilution method was used to test the antifungal activity of the various chitosan solutions at concentrations of 0.20%, 0.15%, 0.10% and 0.05%. Both media containing irradiated and unirradiated chitosan inhibited the mycelial growth of Aspergillus niger and the degree of inhibition was dependent on the concentration of the chitosan in the fungal growth medium. Results show that the media containing irradiated chitosan inhibited the mycelia growth of Aspergillus niger to a greater extent than the media containing unirradiated chitosan. (author)

  10. Effect of solution plasma process with bubbling gas on physicochemical properties of chitosan.

    Science.gov (United States)

    Ma, Fengming; Li, Pu; Zhang, Baiqing; Zhao, Xin; Fu, Qun; Wang, Zhenyu; Gu, Cailian

    2017-05-01

    In the present work, solution plasma process (SPP) with bubbling gas was used to prepare oligochitosan. The effect of SPP irradiation with bubbling gas on the degradation of chitosan was evaluated by the intrinsic viscosity reduction rate and the degradation kinetic. The formation of OH radical was studied. Changes of the physicochemical properties of chitosan were measured by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis, as well as ultraviolet-visible, Fourier-transform infrared, and 13 C nuclear magnetic resonance spectroscopy. The results indicated an obvious decrease in the intrinsic viscosity reduction rate after SPP irradiation with bubbling gas, and that the rate with bubbling was higher than that without. The main chemical structure of chitosan remained intact after irradiation, but changes in the morphology, crystallinity, and thermal stability of oligochitosan were observed. In particular, the crystallinity and thermal stability tended to decrease. The present study indicated that SPP can be effectively used for the degradation of chitosan. Copyright © 2017. Published by Elsevier B.V.

  11. Effects of irradiation-degradated chitosan coating on quality and shelf-life of the fruits of Shatang Mandarin, Fortunella Margariat (LOUR) swingle and Lycopersicon Esculentum MILL. var. cerasiforme alef

    International Nuclear Information System (INIS)

    Chen Hao; Gao Peng; Gao Ya; Yang Zhirong; Sun Qun

    2008-01-01

    Effects of irradiation-degradated chiotosan of different molecular weight on weight loss, rotting rate, total acid, soluble solid content, and ascorbic acid in Shatang mandarin, Fortunella margarita (lour) Swingle, and Lycopersicon esculentum Mill. var. cerasiforme Alef during storage were investigated. The result showed that, compared to control, all chitosan treatment could significantly reduce weight loss and rotting rate, and maintain the content of total acid, soluble solid, and ascorbic acid. After 18 days of storage, treatment of chitosan with molecular weight of 6.6 x 10 4 Da showed the highest capability of decreasing the rotting rate in S. mandarin, F. margarita, L. esculentum by 71.11%, 66.01% and 70.22%, respectively; increasing total acid by 55.60%, 36.75% and 36.68%, soluble solid content by 49.06%, 25.75% and 49.46%, and ascorbic acid by 42.80%, 41.65% and 51.70%, respectively. Accordingly, irradiation-degradated chitosan coating could effectively prevent the rotting rate and preserve the quality of the three kinds of fruit during storage and thus prolong their shelf life to 18 days. (authors)

  12. Application of irradiated chitosan for fruit preservation

    Energy Technology Data Exchange (ETDEWEB)

    Kieu N. Lan [Post Harvest Technology Inst. of Vietnam (Viet Nam)

    2000-09-01

    Application of irradiated chitosan has been investigated for coating of fruit preservation. Anti-fungal activity of chitosan was induced by {gamma}-ray irradiation in dry condition at 25 kGy. The irradiated chitosan can suppress the growth of Aspergillus. spp. and Fusarium. spp. isolated from Vietnam mango. Fusarium. spp. was sensitive for irradiated chitosan than the other strains. The coating from irradiated chitosan solution at dose 31 kGy has prolonged the storage life of mango from 7 to 15 days. At the 15th day mango keeps good colour, natural ripening, without spoilage, weight loss 10%, whereas the control is spoiled completely and the sample of fruit with unirradiated chitosan coating could not ripe. The effect is due to the anti-fungal activity and change in physico-chemical properties of chitosan by irradiation. Radiation causes the decrease in viscosity affecting the gas permeability of coating film. The irradiated chitosan coating has positive effect on mango that is susceptible to chilling injury at low storage temperature. (author)

  13. Application of irradiated chitosan for fruit preservation

    International Nuclear Information System (INIS)

    Kieu N, Lan; Nguyen D, Lam; Yoshii, Fumio; Kume, Tamikazu

    2000-01-01

    Application of irradiated chitosan has been investigated for coating of fruit preservation. Anti-fungal activity of chitosan was induced by γ-ray irradiation in dry condition at 25 kGy. The irradiated chitosan can suppress the growth of Aspergillus. spp. and Fusarium. spp. isolated from Vietnam mango. Fusarium. spp. was sensitive for irradiated chitosan than the other strains. The coating from irradiated chitosan solution at dose 31 kGy has prolonged the storage life of mango from 7 to 15 days. At the 15th day mango keeps good colour, natural ripening, without spoilage, weight loss 10%, whereas the control is spoiled completely and the sample of fruit with unirradiated chitosan coating could not ripe. The effect is due to the anti-fungal activity and change in physico-chemical properties of chitosan by irradiation. Radiation causes the decrease in viscosity affecting the gas permeability of coating film. The irradiated chitosan coating has positive effect on mango that is susceptible to chilling injury at low storage temperature. (author)

  14. Radiation degradation of alginate and some results of biological effect of degraded alginate on plants

    International Nuclear Information System (INIS)

    Hien, N.Q.; Hai, L.; Luan, L.Q.; Hanh, T.T.; Nagasawa, Naotsugu; Yoshii, Fumio; Makuuchi, Keizo; Kume, Tamikazu

    2000-01-01

    Radiation degradation yields (Gd) of alginate in aqueous solution with different concentration were determined by viscometry method. The relationship between Gd and the alginate concentration was found out as: Gd=33.5 x C -0.68 , with C% (w/v) and dry alginate referred to C=100%. An empirical equation for preparing degraded alginate with the desired low viscometry average molecular weight (Mv) by radiation was proposed. Alginate extracted directly horn seaweed'Sagassum, degraded by radiation was used for field experiments and results of the biological effect on plants (tea, carrot, chrysanthemum) were presented. (author)

  15. Development of Cy5.5-Labeled Hydrophobically Modified Glycol Chitosan Nanoparticles for Protein Delivery

    Science.gov (United States)

    Chin, Amanda

    Therapeutic proteins are often highly susceptible to enzymatic degradation, thus restricting their in vivo stability. To overcome this limitation, delivery systems designed to promote uptake and reduce degradation kinetics have undergone a rapid shift from macro-scale systems to nanomaterial based carriers. Many of these nanomaterials, however, elicit immune responses and may have cytotoxic effects both in vitro and in vivo. The naturally derived polysaccharide chitosan has emerged as a promising biodegradable material and has been utilized for many biomedical applications; nevertheless, its function is often constrained by poor solubility. Glycol chitosan, a derivative of chitosan, can be hydrophobically modified to impart amphiphilic properties that enable the self-assembly into nanoparticles in aqueous media at neutral pH. This nanoparticle system has shown initial success as a therapeutic agent in several model cell culture systems, but little is known about its stability against enzymatic degradation. Therefore, the goal of this research was to investigate the resistance of hydrophobically modified glycol chitosan against enzyme-catalyzed degradation using an in vivo simulated system containing lysozyme. To synthesize the nanoparticles, hydrophobic cholanic acid was first covalently conjugated to glycol chitosan using of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). Conjugates were purified by dialysis, lyophilized, and ultra-sonicated to form nanoparticles. Fourier transform infrared (FT-IR) spectroscopy confirmed the binding of 5beta-cholanic acid to the glycol chitosan. Particle size and stability over time were determined with dynamic light scattering (DLS), and particle morphology was evaluated by transmission electron microscopy (TEM). The average diameter of the nanoparticles was approximately 200 nm, which remained stable at 4°C for up to 10 days. Additionally, a near infrared fluorescent (NIRF) dye

  16. Radiation degradation of polymethacrylamide

    International Nuclear Information System (INIS)

    O'Connor, D.J.

    1984-01-01

    The effects of radiation on polymers have been studied for many years. When polymers are subjected to ultraviolet light or ionizing radiation, chain scission and crosslinking are possible. The radiation degradations of several methacrylate type polymers were investigated. The primary polymer studied was polymethacrylamide (PMAAm). Ultraviolet irradiated PMAAm yielded a five line ESR spectrum with 22 gauss splitting which is believed to arise from a polymeric radical ending with a methacrylamide unit. The results obtained indicate that polymethacrylamide is a polymer which undergoes main chain cleavage upon irradiation. As such this polymer may have potential applicability as a positive resist for fabrication of microelectronic devices

  17. Radiation Degradation of some Commercial Dyes in Wastewater

    International Nuclear Information System (INIS)

    Dessouki, A.M.; Abdel-Aal, S.E.

    1999-01-01

    The degradation Kinetic due to irradiation of aqueous solutions of some commercial dyes, (Reactive Blue Brilliant, Reactive Yellow and Basic Blue 9 Dye (Methylene Blue 2 B), was studied. Factors affecting radiolysis of the dye such as dye concentration, irradiation dose, dose rate and ph of the solutions were studied. The effects of different additives such as nitrogen oxygen, hydrogen peroxide and sodium hypochlorite on the degradation process were investigated. The effect of irradiation dose on the different dye solutions at various concentrations, showed that the Reactive Yellow G. was very sensitive to gamma radiation. The effect of the ph of the dye solutions proved to very according type of the dye. Synergistic treatment of the dye solutions by irradiation and conventional method showed that saturation of the dye solutions with nitrogen did not enhance the radiation degradation of the dyes, while addition of oxygen resulted in a remarkable enhancement of the degradation of the dyes. Also, the addition of sodium hypochlorite (5%) and the oxidation by hydrogen peroxide resulted in more radiation degradation, Also, adsorption of the dyes onto Ga and some ion exchangers showed that Ga has the highest adsorption capacity. Radiation degradation of the toxic dye pollutants and their removal from wastewater down to concentrations not exceeding the maximum permissible concentration (Mpc) according to international standards, proved to be better than conventional methods of purification alone

  18. Radiolysis of chitosan derivatives exhibiting antimutagenic activity

    International Nuclear Information System (INIS)

    Aleksandrova, V.A.; Kuzina, S.I.; Shilova, I.A.; Mikhajlov, A.I.

    2006-01-01

    The radiolysis of antimutagens extracted from natural biopolymer chitosan was studied by the EPR. The radiolysis of test samples of biopolymers and gallic acid was performed in vacuum at 77 K using a 60 Co γ-radiation source, with radiation doses 50 kGy. It was shown that addition of gallic acid (2 mol %) to quaternized chitosan results in a 2.5-fold decrease in the radiation-chemical yield of radicals and a nearly complete inhibition of the formation of ion radicals. Gallic acid units likely play the role of a stabilizer that protects the polycation from radiation damage and, hence, the structure of the cationogenic units from changes, thereby improving the antimutagenic properties of the system [ru

  19. Radiation-thermal transformation of degraded oils

    International Nuclear Information System (INIS)

    Guliyeva, N.G.; Aliyeva, S.F.

    2010-01-01

    Full text :In order to elucidate the role of radiation in the process of oil degradation in the environment, and to identify opportunities for application of radiation-chemical technology to clean oil-contaminated soil were studied some regularities of radiation-chemical transformations of oil samples taken from wells, as well as after long-term presence on the surface of the water and soil. The most high radiation resistances of oil are samples taken from surface water. This is due to structural changes in the process of oil degradation, namely an increase in their part of the radiation-resistant resins and aspartames. This is due to evaporation of light hydrocarbons and heavy destructive transformations under the influence of oxygen, microorganisms, as well as components of the surface layer of soil. This phenomenon is explained by the specificity of action of the beam of accelerated electrons, namely the possible heating of the reaction zone due to inhibition of the electron. In this case the acceleration of diffusion processes results in an increase in the yield of gases.

  20. Radiation degradation of alginate and some results of biological effect of degraded alginate on plants

    Energy Technology Data Exchange (ETDEWEB)

    Hien, N.Q.; Hai, L.; Luan, L.Q.; Hanh, T.T. [Nuclear Research Institute, Dalat (Viet Nam); Nagasawa, Naotsugu; Yoshii, Fumio; Makuuchi, Keizo; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Radiation degradation yields (Gd) of alginate in aqueous solution with different concentration were determined by viscometry method. The relationship between Gd and the alginate concentration was found out as: Gd=33.5 x C{sup -0.68}, with C% (w/v) and dry alginate referred to C=100%. An empirical equation for preparing degraded alginate with the desired low viscometry average molecular weight (Mv) by radiation was proposed. Alginate extracted directly horn seaweed'Sagassum, degraded by radiation was used for field experiments and results of the biological effect on plants (tea, carrot, chrysanthemum) were presented. (author)

  1. Method of radiation degradation of PTFE under vacuum conditions

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, Sergey E-mail: sergey_korenev@steris.com

    2004-10-01

    A new method of radiation degradation of Polytetrafluoroethylene (PTFE) under vacuum conditions is considered in this report. The combination of glow gas discharge and electrical surface discharge (on surface and inside PTFE) increases the efficiency of thermal-radiation degradation. The main mechanism of this degradation method consists of the breaking of C-C and C-F bonds. The vacuum conditions allow decreasing of the concentration of toxic compounds, such as a HF. Experimental results for degradation of PTFE are presented.

  2. Method of radiation degradation of PTFE under vacuum conditions

    Science.gov (United States)

    Korenev, Sergey

    2004-09-01

    A new method of radiation degradation of Polytetrafluoroethylene (PTFE) under vacuum conditions is considered in this report. The combination of glow gas discharge and electrical surface discharge (on surface and inside PTFE) increases the efficiency of thermal-radiation degradation. The main mechanism of this degradation method consists of the breaking of C-C and C-F bonds. The vacuum conditions allow decreasing of the concentration of toxic compounds, such as a HF. Experimental results for degradation of PTFE are presented.

  3. Omics for Investigating Chitosan as an Antifungal and Gene Modulator

    Directory of Open Access Journals (Sweden)

    Federico Lopez-Moya

    2016-03-01

    Full Text Available Chitosan is a biopolymer with a wide range of applications. The use of chitosan in clinical medicine to control infections by fungal pathogens such as Candida spp. is one of its most promising applications in view of the reduced number of antifungals available. Chitosan increases intracellular oxidative stress, then permeabilizes the plasma membrane of sensitive filamentous fungus Neurospora crassa and yeast. Transcriptomics reveals plasma membrane homeostasis and oxidative metabolism genes as key players in the response of fungi to chitosan. A lipase and a monosaccharide transporter, both inner plasma membrane proteins, and a glutathione transferase are main chitosan targets in N. crassa. Biocontrol fungi such as Pochonia chlamydosporia have a low content of polyunsaturated free fatty acids in their plasma membranes and are resistant to chitosan. Genome sequencing of P. chlamydosporia reveals a wide gene machinery to degrade and assimilate chitosan. Chitosan increases P. chlamydosporia sporulation and enhances parasitism of plant parasitic nematodes by the fungus. Omics studies allow understanding the mode of action of chitosan and help its development as an antifungal and gene modulator.

  4. Radiation processing of natural polymers for industrial and agricultural applications

    International Nuclear Information System (INIS)

    Hegazy, El-Sayed A.; AbdEl-Rehim, H.; Diaa, D.A.; El-Barbary, A.

    2008-01-01

    Radiation induced degradation technology is a new and promising application of ionizing radiation to develop viscose, pulp, paper, food preservation, pharmaceutical production, and natural bioactive agents industries. Controlling the degree of degradation, uniform molecular weight distribution, saving achieved in the chemicals (used in conventional methods) on a cost basis, and environmentally friendly process are the beneficial effects of using radiation technology in these industries. However, for some development countries such technology is not economic. Therefore, a great efforts should be done to reduce the cost required for such technologies. One of the principle factors for reducing the cost is achieving the degradation at low irradiation doses. The addition of some additives such as potassium per-sulfate (KPS), ammonium per-sulfate (APS), or H 2 O 2 to natural polymers (carboxymethylcellulose (CMC), chitosan, carrageenan and Na-alginate) during irradiation process accelerates their degradation. The highest degradation rate of polysaccharides obtained when APS was used. The end product of irradiated CMC, chitosan, carrageenan and Na-alginate may be used as food additive or benefited in agricultural purposes. On the other hand, radiation crosslinking of PAAm or PNIPAAm is affected by the presence of natural polymer like CMC-Na and carrageenan due to their degradability which could be controlled according to its concentration in the bulk medium and irradiation dose. Accordingly, the gel content, thermo-sensitivity (LCST) and swelling properties of PNIPAAm based natural polymers could be controlled. The swelling of the prepared copolymer hydrogels was investigated for its possible use in personal care articles particularly diapers or as carriers for drug delivery systems. The prepared crosslinked copolymers possessed high and fast swelling properties in simulated urine media and the swelling ratios of CMC-Na/PAAm gels in urine are acceptable for diaper

  5. Preparation of metal adsorbents from chitin/chitosan by radiation technology

    International Nuclear Information System (INIS)

    Nguyen Van Suc; Nguyen Quoc Hien; Ngo Quang Huy; Thai My Phe; Dao Van Hoang; Nguyen Van Hung

    2004-01-01

    The methods of preparation of metal adsorbents basing on chitin/chitosan were developed. That include the adsorbent from chitin grafted with acrylic acid by different irradiation doses; the clinging chitosan gel beads; the coagulable solution and the chitosan composite filter. The process of metal adsorption for each adsorbent was studied as adsorption kinetic, isothermal adsorption. The results have been applied for removal of some elements as Hg, Pb, Cd, U, Cu, ect. in the wastewater. (NHA)

  6. Animal experiments and clinical trials of {sup 166}Ho-chitosan for various cancers

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang Moo; Choi, C W; Kim, E H; Woo, K S; Chung, W S; Lee, J I; Park, S Y; Son, Y S; Lee, S H; Kim, S J; Kim, B G; Kim, J H; Lee, C H [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1997-07-01

    {sup 166}Ho is a good therapeutic radionuclide because of its suitable half-life (26.8 hours), high beta energy and 6% gamma ray for imaging. Chitosan is a kind of N-glucosamine with 400 to 500 kD MW, which chelates metal ions and degrades slowly in vivo. As a preclinical studies, we performed cytotoxic effect of {sup 166}Ho-chitosan in a variety of cancer cell lines derived from stomach or ovarian cancer based on MTT assay and HTCA method. To evaluated the absorbed dose to the cavitary wall from {sup 166}Ho-chitosan, intraperitoneal administration of {sup 166}Ho-chitosan in the rat and simulation of energy transfer from the beta particles to the cavity wall using the Monte Carlo code EGS4 was done, and used as a standard for the planning therapy. Intracavitary {sup 166}Ho-chitosan therapy were tried in peritoneal metastatic ovarian and stomach cancers and cystic brain tumors. Intraarterial injection in inoperable primary liver cancer was also tried. As a radiation synovectomy agent, biocompatibility study in the knee joints of rabbits were performed. {sup 166}Ho-chitosan showed synergistic effects with 5-FU or cisplatin in vitro. 97-99% of {sup 166}Ho-chitosan was localized within the peritoneal cavity, and more than 90% of {sup 166}Ho-chitosan was attached to the peritoneal wall. Partial response were observed in 4 among 5 patients with ovarian cancer without severe toxicity. In the cystic brain tumor, 5 of 8 cysts were shrunken in size with thinning of the wall, 2 out of 8 showed growth retardation. In the primary liver cancer, radioactivity was distributed in the teritory of selected hepatic arterial branch, and partial responses were observed in 2 cases. In the knee joints of the rabbits, more than 98% of {sup 166}Ho-chitosan remained in the joint cavity and was stable upto 1 week. 49 refs., 22 tabs. (author)

  7. Preparation and characterization of blends containing silk fibroin and chitosan

    International Nuclear Information System (INIS)

    Moraes, Mariana A. de; Nogueira, Grinia M.; Weska, Raquel F.; Beppu, Marisa M.

    2009-01-01

    The aim of this study was to prepare and characterize blend membranes of silk fibroin and chitosan. Moreover, a conformation of fibroin to a more stable form induced by the addition of chitosan was verified. Blend membranes of fibroin/chitosan were prepared in different proportions and had their crystallinity, structural conformation and thermal stability characterized. The results of crystallographic analysis (XRD) indicated the tendency to higher structural organization caused by the addition of chitosan. FTIR showed that, mainly in a content of chitosan of only 25%, fibroin is present in a more stable form. Thermal analyzes indicate that fibroin is thermally stable and that when its proportion in the blend increases, the temperature in which the degradation is initiated also does so. (author)

  8. Radiation degradation and crosslinking of polytetrafluoroethylene and its application

    International Nuclear Information System (INIS)

    Wu Guozhong; Wang Mouhua; Tang Zhongfeng

    2009-01-01

    Polytetrafluoroethylene (PTFE) is a high-performance engineering plastic and known as a typical material of radiation degradation. PTFE can be degraded by radiation under various conditions and PTFE micro-powder is usually fabricated by a combination of radiation and milling. PTFE can also be crosslinked by irradiation in the melt state (330∼340 degree C). The materials can be applied as a special additive due to its excellent wear resistance. Crosslinked PTFE may also be applied in lithography and fuel cell membrane in the future. In this paper, history and application of PTFE degradation and crosslinking products are reviewed. (authors)

  9. Surface grafted chitosan gels. Part II. Gel formation and characterization

    DEFF Research Database (Denmark)

    Liu, Chao; Thormann, Esben; Claesson, Per M.

    2014-01-01

    Responsive biomaterial hydrogels attract significant attention due to their biocompatibility and degradability. In order to make chitosan based gels, we first graft one layer of chitosan to silica, and then build a chitosan/poly(acrylic acid) multilayer using the layer-by-layer approach. After...... cross-linking the chitosan present in the polyelectrolyte multilayer, poly(acrylic acid) is partly removed by exposing the multilayer structure to a concentrated carbonate buffer solution at a high pH, leaving a surface-grafted cross-linked gel. Chemical cross-linking enhances the gel stability against...... detachment and decomposition. The chemical reaction between gluteraldehyde, the cross-linking agent, and chitosan was followed in situ using total internal reflection Raman (TIRR) spectroscopy, which provided a molecular insight into the complex reaction mechanism, as well as the means to quantify the cross...

  10. Morphology and characterization of 3D micro-porous structured chitosan scaffolds for tissue engineering.

    Science.gov (United States)

    Hsieh, Wen-Chuan; Chang, Chih-Pong; Lin, Shang-Ming

    2007-06-15

    This research studies the morphology and characterization of three-dimensional (3D) micro-porous structures produced from biodegradable chitosan for use as scaffolds for cells culture. The chitosan 3D micro-porous structures were produced by a simple liquid hardening method, which includes the processes of foaming by mechanical stirring without any chemical foaming agent added, and hardening by NaOH cross linking. The pore size and porosity were controlled with mechanical stirring strength. This study includes the morphology of chitosan scaffolds, the characterization of mechanical properties, water absorption properties and in vitro enzymatic degradation of the 3D micro-porous structures. The results show that chitosan 3D micro-porous structures were successfully produced. Better formation samples were obtained when chitosan concentration is at 1-3%, and concentration of NaOH is at 5%. Faster stirring rate would produce samples of smaller pore diameter, but when rotation speed reaches 4000 rpm and higher the changes in pore size is minimal. Water absorption would reduce along with the decrease of chitosan scaffolds' pore diameter. From stress-strain analysis, chitosan scaffolds' mechanical properties are improved when it has smaller pore diameter. From in vitro enzymatic degradation results, it shows that the disintegration rate of chitosan scaffolds would increase along with the processing time increase, but approaching equilibrium when the disintegration rate reaches about 20%.

  11. Proceedings of the FNCA 2006 workshop on application of electron accelerator. Radiation processing of natural polymer

    International Nuclear Information System (INIS)

    Tamada, Masao; Kume, Tamikazu

    2007-08-01

    This workshop was co-sponsored by the Ministry of Education, Culture, Sports, Science and Technology, Japan and the Ministry of Science, Technology and Innovation, Malaysia and jointly organized by the Japan Atomic Energy Agency and the Malaysian Nuclear Agency. The main objectives of the workshop were to discuss the commercial status of radiation processing of natural polymer in the participating countries and to prepare the work plan for the Forum for Nuclear Cooperation in Asia (FNCA) activities on radiation processing of natural polymer. The workshop was attended by experts on radiation processing from China, Indonesia, Japan, Korea, Malaysia, Philippines, Thailand and Vietnam. The radiation processing of natural polymer is divided into radiation crosslinking and degradation of polysaccharides. The radiation crosslinking of polysaccharides is mainly used to prepare hydrogel for healthcare and environment. Several hydrogels were commercialized in Korea, Japan and Malaysia, respectively. Hydrogels containing chitosan and carrageenan are currently in trial in China, Indonesia, Philippines and Vietnam. Cassava hydrogel is developing in Thailand. Radiation degraded chitosan is actually used in Vietnam and China in agriculture and aquaculture, respectively. Indonesia, Philippines and Thailand are trying in laboratory and pilot scale as plant growth promoter. All manuscripts submitted by every speaker were included in the proceedings. (author)

  12. Chitosan Dermal Substitute and Chitosan Skin Substitute Contribute to Accelerated Full-Thickness Wound Healing in Irradiated Rats

    Directory of Open Access Journals (Sweden)

    Abu Bakar Mohd Hilmi

    2013-01-01

    Full Text Available Wounds with full-thickness skin loss are commonly managed by skin grafting. In the absence of a graft, reepithelialization is imperfect and leads to increased scar formation. Biomaterials can alter wound healing so that it produces more regenerative tissue and fewer scars. This current study use the new chitosan based biomaterial in full-thickness wound with impaired healing on rat model. Wounds were evaluated after being treated with a chitosan dermal substitute, a chitosan skin substitute, or duoderm CGF. Wounds treated with the chitosan skin substitute showed the most re-epithelialization (33.2 ± 2.8%, longest epithelial tongue (1.62 ± 0.13 mm, and shortest migratory tongue distance (7.11 ± 0.25 mm. The scar size of wounds treated with the chitosan dermal substitute (0.13 ± 0.02 cm and chitosan skin substitute (0.16 ± 0.05 cm were significantly decreased (P<0.05 compared with duoderm (0.45 ± 0.11 cm. Human leukocyte antigen (HLA expression on days 7, 14, and 21 revealed the presence of human hair follicle stem cells and fibroblasts that were incorporated into and surviving in the irradiated wound. We have proven that a chitosan dermal substitute and chitosan skin substitute are suitable for wound healing in full-thickness wounds that are impaired due to radiation.

  13. Comparative study on the effects of negatively-charged biopolymers on chitosan-based gels for the development of instantaneous gels

    International Nuclear Information System (INIS)

    Jimeno, Austin Ed B.; Chakraborty, Soma

    2015-01-01

    Polymeric electrolytic complexes are solutions of charged/ionized chains. These solutions of positive and negative charge can be combined to make instantaneous networks bonded by electrostatic interactions, a gel network. These electrostatic interaction allows for easy application in injectable gels as the network can be temporarily distributed with the application of force and reformed on the relief of it. Possible applications for these injectable gels include drug delivery and wound-healing. κ-Carrageenan, dextran sulfate, alginate, and chitosan are polyelectrolytic biocompatible polymers which are widely studied and used for a variety of biomedical applications. Gel networks are made by combining a negatively-charged (κ-Carrageenan, dextran sulfate, or alginate) and positively charged (chitosan) solutions. The strong electrostatic interaction between the opposite charges from the gel network and the inherent biocompatibility of the polymers allow future biomedical applications. Quat 188-modified chitosan has additional sites for electrostatic bonding, can be dissolved in neutral, basic, and acidic pH, and has shown inherent antibacterial activity. The objectives of this study are the following: to formulate chitosan-based gels mixing solutions of chitosan with solutions of either κ-Carrageenan, dextran sulfate, or alginate, study the gelation of the gels as function of time and pH (4, 7, and 9) using UV-Vis, characterize the chitosan-based gels through DSC and DMA, characterize the physiological degradation of the chitosan-based gels, and compare results with those from Quat 188-modified chitosan-based gels. Polyelectrolytic solutions of chitosan and negatively-charged biopolymer of similar viscosities were mixed. It was determined from the UV-Vis spectroscopy of the chitosan-carrageenan gels under pH7 buffer that the increase of concentration by a factor of 5 for 0.006M-0.0095M and 1.25 for 0.0095M-0.0150M Chitosan-Carrageenan gels improved gelation by the

  14. Total-dose radiation-induced degradation of thin film ferroelectric capacitors

    International Nuclear Information System (INIS)

    Schwank, J.R.; Nasby, R.D.; Miller, S.L.; Rodgers, M.S.; Dressendorfer, P.V.

    1990-01-01

    Thin film PbZr y Ti 1-y O 3 (PZT) ferroelectric memories offer the potential for radiation-hardened, high-speed nonvolatile memories with good retention and fatigue properties. In this paper we explore in detail the radiation hardness of PZT ferroelectric capacitors. Ferroelectric capacitors were irradiated using x-ray and Co-60 sources to dose levels up to 16 Mrad(Si). The capacitors were characterized for their memory properties both before and after irradiation. The radiation hardness was process dependent. Three out of four processes resulted in capacitors that showed less than 30% radiation-induced degradation in retained polarization charge and remanent polarization after irradiating to 16 Mrad(Si). On the other hand, one of the processes showed significant radiation-induced degradation in retained polarization charge and remanent polarization at dose levels above 1 Mrad(Si). The decrease in retained polarization charge appears to be due to an alteration of the switching characteristics of the ferroelectric due to changes in the internal fields. The radiation-induced degradation is recoverable by a postirradiation biased anneal and can be prevented entirely if devices are cycled during irradiation. The authors have developed a model to simulate the observed degradation

  15. Preparation and characterization of nano-hydroxyapatite within chitosan matrix

    International Nuclear Information System (INIS)

    Rogina, A.; Ivanković, M.; Ivanković, H.

    2013-01-01

    Nano-composites that show some features of natural bone both in composition and in microstructure have been prepared by in situ precipitation method. Apatite phase has been prepared from cost-effective precursors (calcite and urea phosphate) within chitosan (CS) matrix dissolved in aqueous acetic acid solution. The compositional and morphological properties of composites were studied by means of Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). Depending on the reaction conditions (temperature, reaction time, glucose addition and pH control) in addition to hydroxyapatite (HA) as a major phase, octacalcium hydrogen phosphate pentahydrate (OCP) and dicalcium phosphate anhydrate (DCPD) were formed as shown by XRD and FTIR. Crystallite lengths of precipitated HA estimated by Scherrer's equation were between 20 and 30 nm. A fibrous morphology (∼ 400 nm) of HA observed by TEM indicates that HA nucleates on chitosan chains. - Highlights: • Nano-hydroxyapatite (HA) was prepared by in situ precipitation within chitosan hydrogels and colloidal chitosan solution. • pH control was regulated by ammonia and urea degradation. • In situ urea degradation provides homogenous HA formation. • TEM imaging indicates fibrous morphology of HA with crystalline size of 400 nm. • Glucose addition and temperature variation affect inorganic phase formation

  16. One-step fabrication of biocompatible chitosan-coated ZnS and ZnS:Mn2+ quantum dots via a γ-radiation route

    Science.gov (United States)

    Chang, Shu-Quan; Kang, Bin; Dai, Yao-Dong; Zhang, Hong-Xu; Chen, Da

    2011-11-01

    Biocompatible chitosan-coated ZnS quantum dots [CS-ZnS QDs] and chitosan-coated ZnS:Mn2+ quantum dots [CS-ZnS:Mn2+ QDs] were successfully fabricated via a convenient one-step γ-radiation route. The as-obtained QDs were around 5 nm in diameter with excellent water-solubility. These QDs emitting strong visible blue or orange light under UV excitation were successfully used as labels for PANC-1 cells. The cell experiments revealed that CS-ZnS and CS-ZnS:Mn2+ QDs showed low cytotoxicity and good biocompatibility, which offered possibilities for further biomedical applications. Moreover, this convenient synthesis strategy could be extended to fabricate other nanoparticles coated with chitosan. PACS: 81.07.Ta; 78.67.Hc; 82.35.Np; 87.85.Rs.

  17. Physico-chemical/biological properties of tripolyphosphate cross-linked chitosan based nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Soumi Dey [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur-721302 (India); Farrugia, Brooke L.; Dargaville, Tim R. [Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Groove, Queensland-4059 (Australia); Dhara, Santanu, E-mail: sdhara@smst.iitkgp.ernet.in [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur-721302 (India)

    2013-04-01

    In this study, chitosan-PEO blend, prepared in a 15 M acetic acid, was electrospun into nanofibers (∼ 78 nm diameter) with bead free morphology. While investigating physico-chemical parameters of blend solutions, effect of yield stress on chitosan based nanofiber fabrication was clearly evidenced. Architectural stability of nanofiber mat in aqueous medium was achieved by ionotropic cross-linking of chitosan by tripolyphosphate (TPP) ions. The TPP cross-linked nanofiber mat showed swelling up to ∼ 300% in 1 h and ∼ 40% degradation during 30 day study period. 3T3 fibroblast cells showed good attachment, proliferation and viability on TPP treated chitosan based nanofiber mats. The results indicate non-toxic nature of TPP cross-linked chitosan based nanofibers and their potential to be explored as a tissue engineering matrix. - Highlights: ► Chitosan based nanofiber fabrication through electrospinning. ► Roles of solution viscosity and yield stress on spinnability of chitosan evidenced. ► Tripolyphosphate (TPP) cross-linking rendered structural stability to nanofibers. ► TPP cross-linking also improved cellular response on chitosan based nanofibers. ► Thus, chitosan based nanofibers are suitable for tissue engineering application.

  18. Physico-chemical/biological properties of tripolyphosphate cross-linked chitosan based nanofibers

    International Nuclear Information System (INIS)

    Sarkar, Soumi Dey; Farrugia, Brooke L.; Dargaville, Tim R.; Dhara, Santanu

    2013-01-01

    In this study, chitosan-PEO blend, prepared in a 15 M acetic acid, was electrospun into nanofibers (∼ 78 nm diameter) with bead free morphology. While investigating physico-chemical parameters of blend solutions, effect of yield stress on chitosan based nanofiber fabrication was clearly evidenced. Architectural stability of nanofiber mat in aqueous medium was achieved by ionotropic cross-linking of chitosan by tripolyphosphate (TPP) ions. The TPP cross-linked nanofiber mat showed swelling up to ∼ 300% in 1 h and ∼ 40% degradation during 30 day study period. 3T3 fibroblast cells showed good attachment, proliferation and viability on TPP treated chitosan based nanofiber mats. The results indicate non-toxic nature of TPP cross-linked chitosan based nanofibers and their potential to be explored as a tissue engineering matrix. - Highlights: ► Chitosan based nanofiber fabrication through electrospinning. ► Roles of solution viscosity and yield stress on spinnability of chitosan evidenced. ► Tripolyphosphate (TPP) cross-linking rendered structural stability to nanofibers. ► TPP cross-linking also improved cellular response on chitosan based nanofibers. ► Thus, chitosan based nanofibers are suitable for tissue engineering application

  19. Radiation induced degradation of xanthan gum in aqueous solution

    Science.gov (United States)

    Hayrabolulu, Hande; Demeter, Maria; Cutrubinis, Mihalis; Güven, Olgun; Şen, Murat

    2018-03-01

    In our previous study, we have investigated the effect of gamma rays on xanthan gum in the solid state and it was determined that dose rate was an important factor effecting the radiation degradation of xanthan gum. In the present study, in order to provide a better understanding of how ionizing radiation effect xanthan gum, we have investigated the effects of ionizing radiation on aqueous solutions of xanthan at various concentrations (0.5-4%). Xanthan solutions were irradiated with gamma rays in air, at ambient temperature, at different dose rates (0.1-3.3-7.0 kGy/h) and doses (2.5-50 kGy). Change in their molecular weights was followed by size exclusion chromatography (SEC). Chain scission yield (G(S)), and degradation rate constants (k) were calculated. It was determined that, solution concentration was a factor effecting the degradation chemical yield and degradation rate of xanthan gum. Chain scission reactions were more effective for lower solution concentrations.

  20. Experimental evaluation of photocrosslinkable chitosan as a biologic adhesive with surgical applications.

    Science.gov (United States)

    Ono, K; Ishihara, M; Ozeki, Y; Deguchi, H; Sato, M; Saito, Y; Yura, H; Sato, M; Kikuchi, M; Kurita, A; Maehara, T

    2001-11-01

    In various surgical cases, effective tissue adhesives are required for both hemostasis (eg, intraoperative bleeding) and air sealing (eg, thoracic surgery). We have designed a chitosan molecule (Az-CH-LA) that can be photocrosslinked by ultraviolet (UV) light irradiation, thereby forming a hydrogel. The purpose of this work was to evaluate the effectiveness and safety of the photocrosslinkable chitosan hydrogel as an adhesive with surgical applications. The sealing ability of the chitosan hydrogel, determined as a bursting pressure, was assessed with removed thoracic aorta, trachea, and lung of farm pigs and in a rabbit model. The carotid artery and lung of rabbits were punctured with a needle, and the chitosan hydrogel was applied to, respectively, stop the bleeding and the air leakage. In vivo chitosan degradability and biologic responses were histologically assessed in animal models. The bursting pressure of chitosan hydrogel (30 mg/mL) and fibrin glue, respectively, was 225 +/- 25 mm Hg (mean +/- SD) and 80 +/- 20 mm Hg in the thoracic aorta; 77 +/- 29 mm Hg and 48 +/- 21 mm Hg in the trachea; and in the lung, 51 +/- 11 mm Hg (chitosan hydrogel), 62 +/- 4 mm Hg (fibrin glue, rubbing method), and 12 +/- 2 mm Hg (fibrin glue, layer method). The sealing ability of the chitosan hydrogel was stronger than that of fibrin glue. All rabbits with a carotid artery (n = 8) or lung (n = 8) that was punctured with a needle and then sealed with chitosan hydrogel survived the 1-month observation period without any bleeding or air leakage from the puncture sites. Histologic examinations demonstrated that 30 days after application, a fraction of the chitosan hydrogel was phagocytosed by macrophages, had partially degraded, and had induced the formation of fibrous tissues around the hydrogel. A newly developed photocrosslinkable chitosan has demonstrated strong sealing ability and a great potential for use as an adhesive in surgical operations.

  1. The chitosan affects severely the carbon metabolism in mango (Mangifera indica L. cv. Palmer) fruit during storage.

    Science.gov (United States)

    Cosme Silva, Gláucia Michelle; Silva, Willian Batista; Medeiros, David B; Salvador, Acácio Rodrigues; Cordeiro, Maria Helena Menezes; da Silva, Natália Martins; Santana, Diederson Bortolini; Mizobutsi, Gisele Polete

    2017-12-15

    Mango is a highly perishable fruit with a short post-harvest time due to the intense metabolic activity after harvesting. In attempt to evaluate the effects of chitosan in mango fruits, it was treated with 0%, 1%, 2% or 3% of chitosan solutions, placed into plastic trays, and stored at room temperature. Changes in physical and chemical parameters were evaluated. Chitosan delayed the climacteric peak, water loss and firmness. Further, few changes in soluble solid content, titratable acidity, pH of the pulp as well as in sugar content and decreased starch degradation were observed. Altogether, our results suggest chitosan edible coating effectively prolongs the quality attributes, affecting basic mitochondrial respiration and starch degradation rate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Fabrication and In Vitro Evaluation of Nanosized Hydroxyapatite/Chitosan-Based Tissue Engineering Scaffolds

    Directory of Open Access Journals (Sweden)

    Tao Sun

    2014-01-01

    Full Text Available Composite scaffolds based on biodegradable natural polymer and osteoconductive hydroxyapatite (HA nanoparticles can be promising for a variety of tissue engineering (TE applications. This study addressed the fabrication of three-dimensional (3D porous composite scaffolds composed of HA and chitosan fabricated via thermally induced phase separation and freeze-drying technique. The scaffolds produced were subsequently characterized in terms of microstructure, porosity, and mechanical property. In vitro degradation and in vitro biological evaluation were also investigated. The scaffolds were highly porous and had interconnected pore structures. The pore sizes ranged from several microns to a few hundred microns. The incorporated HA nanoparticles were well mixed and physically coexisted with chitosan in composite scaffold structures. The addition of 10% (w/w HA nanoparticles to chitosan enhanced the compressive mechanical properties of composite scaffold compared to pure chitosan scaffold. In vitro degradation results in phosphate buffered saline (PBS showed slower uptake properties of composite scaffolds. Moreover, the scaffolds showed positive response to mouse fibroblast L929 cells attachment. Overall, the findings suggest that HA/chitosan composite scaffolds could be suitable for TE applications.

  3. Radiation degradation of cellulose

    International Nuclear Information System (INIS)

    Leonhardt, J.W.; Arnold, G.; Baer, M.; Gey, M.; Hubert, S.; Langguth, H.

    1984-01-01

    The application of straw and other cellulose polymers as feedstuff for ruminants is limited by its low digestibility. During recent decades it was attempted to increase the digestibility of straw by several chemical and physical methods. In this work some results of the degradation of gamma and electron treated wheat straw are reported. Complex methods of treatment (e.g. radiation influence and influence of lyes) are taken into consideration. In vitro-experiments with radiation treated straw show that the digestibility can be increased from 20% up to about 80%. A high pressure liquid chromatography method was used to analyze the hydrolysates. The contents of certain species of carbohydrates in the hydrolysates in dependence on the applied dose are given

  4. Degrading radiation effects on properties of bromobutyl rubber compounds

    Energy Technology Data Exchange (ETDEWEB)

    Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Pozenato, Cristina A.; Lugao, Ademar B., E-mail: srscagliusi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The understanding of chemistry involved in degradation induced radiation is becoming more and more relevant in the re-use of polymeric materials, as well in beneficial radiation uses. Degrading radiation effects have been considered from viewpoint of controlled degradation for isoprene/isobutene in rubbers for recycling purposes. Bromobutyl rubber (BIIR) is an isobutylene/isoprene copolymer comprising 1.9 to 2.1% bromine and has a lot of applications including in tires air-chambers. In this work there were evaluated gamma-irradiation effects for re-use or recycling objectives in elastomeric bromobutyl compositions irradiated at 5, 15, 25, 50, 100,150 and 200 kGy. Mechanical properties, hardness and swelling were assessed in non-vulcanized and vulcanized rubber, non-irradiated and irradiated at different doses. The major gamma radiation effect in butyl rubber is the generation of free radicals along changes in mechanical properties. Irradiation effects in bromobutyl rubber compounds were comprehensively investigated, demonstrated and discussed. (author)

  5. Degrading radiation effects on properties of bromobutyl rubber compounds

    International Nuclear Information System (INIS)

    Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Pozenato, Cristina A.; Lugao, Ademar B.

    2013-01-01

    The understanding of chemistry involved in degradation induced radiation is becoming more and more relevant in the re-use of polymeric materials, as well in beneficial radiation uses. Degrading radiation effects have been considered from viewpoint of controlled degradation for isoprene/isobutene in rubbers for recycling purposes. Bromobutyl rubber (BIIR) is an isobutylene/isoprene copolymer comprising 1.9 to 2.1% bromine and has a lot of applications including in tires air-chambers. In this work there were evaluated gamma-irradiation effects for re-use or recycling objectives in elastomeric bromobutyl compositions irradiated at 5, 15, 25, 50, 100,150 and 200 kGy. Mechanical properties, hardness and swelling were assessed in non-vulcanized and vulcanized rubber, non-irradiated and irradiated at different doses. The major gamma radiation effect in butyl rubber is the generation of free radicals along changes in mechanical properties. Irradiation effects in bromobutyl rubber compounds were comprehensively investigated, demonstrated and discussed. (author)

  6. Improving degradation of paracetamol by integrating gamma radiation and Fenton processes.

    Science.gov (United States)

    Cruz-González, Germán; Rivas-Ortiz, Iram B; González-Labrada, Katia; Rapado-Paneque, Manuel; Chávez-Ardanza, Armando; Nuevas-Paz, Lauro; Jáuregui-Haza, Ulises J

    2016-10-14

    Degradation of paracetamol (N-(4-hydroxiphenyl)acetamide) in aqueous solution by gamma radiation, gamma radiation/H2O2 and gamma radiation/Fenton processes was studied. Parameters affecting the radiolysis of paracetamol such as radiation dose, initial concentration of pollutant, pH and initial oxidant concentration were investigated. Gamma radiation was performed using a (60)Co source irradiator. Paracetamol degradation and mineralization increased with increasing absorbed radiation dose, but decreased with increasing initial concentration of the drug in aqueous solution. The addition of H2O2 resulted in an increased effect on irradiation-driven paracetamol degradation in comparison with the performance of the irradiation-driven process alone: paracetamol removal increased from 48.9% in the absence of H2O2 to 95.2% for H2O2 concentration of 41.7 mmol/L. However, the best results were obtained with gamma radiation/Fenton process with 100% of the drug removal at 5 kGy, for optimal H2O2 and Fe(2+) concentrations at 13.9 and 2.3 mmol/L, respectively, with a high mineralization of 63.7%. These results suggest gamma radiation/H2O2 and gamma radiation/Fenton processes as promising methods for paracetamol degradation in polluted wastewaters.

  7. Chitosan nanofibers for transbuccal insulin delivery.

    Science.gov (United States)

    Lancina, Michael G; Shankar, Roopa Kanakatti; Yang, Hu

    2017-05-01

    In this work, they aimed at producing chitosan based nanofiber mats capable of delivering insulin via the buccal mucosa. Chitosan was electrospun into nanofibers using poly(ethylene oxide) (PEO) as a carrier molecule in various feed ratios. The mechanical properties and degradation kinetics of the fibers were measured. Insulin release rates were determined in vitro using an ELISA assay. The bioactivity of released insulin was measured in terms of Akt activation in pre-adipocytes. Insulin permeation across the buccal mucosa was measured in an ex-vivo porcine transbuccal model. Fiber morphology, mechanical properties, and in vitro stability were dependent on PEO feed ratio. Lower PEO content blends produced smaller diameter fibers with significantly faster insulin release kinetics. Insulin showed no reduction in bioactivity due to electrospinning. Buccal permeation of insulin facilitated by high chitosan content blends was significantly higher than that of free insulin. Taken together, the work demonstrates that chitosan-based nanofibers have the potential to serve as a transbuccal insulin delivery vehicle. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1252-1259, 2017. © 2017 Wiley Periodicals, Inc.

  8. Physico-mechanical analysis data in support of compatibility of chitosan/κ-carrageenan polyelectrolyte films achieved by ascorbic acid, and the thermal degradation theory of κ-carrageenan influencing the properties of its blends

    Directory of Open Access Journals (Sweden)

    Mahdiyar Shahbazi

    2016-12-01

    Full Text Available This article presents the complementary data regarding compatibilization of chitosan/κ-carrageenan polyelectrolyte complex for synthesizing of a soft film using ascorbic acid. It includes the thermal-theory for estimating the degradation of κ-carrageenan, as reflected in alteration of the structural properties of the blend. The data has been provided to demonstrate that the blend solution based on chitosan, a polycation, and κ-carrageenan, a polyanion polymer, produces an incompatible polyelectrolyte composite, susceptible to coaservative phase separation. We present further data on water resistance, water barrier property, mechanical parameters, scanning electron micrograph, as well as contact angle image dataset of the chitosan/κ-carrageenan film. The physical data were collected by water solubility and water permeability assays, with a view to elucidate the role of ascorbic acid in the compatibility of polyelectrolyte blends. The mechanical data is obtained from a stress–strain curve for evaluation of tensile strength and elongation at break point of the chitosan/κ-carrageenan film. The microstructure observations were performed using scanning electron micrograph. These dataset confirm fabrication of a soft film in the presence of ascorbic acid, with reduced heterogeneities in the polyelectrolyte film structure. The κ-carrageenan was also treated by a thermal process, prior to inclusion into the chitosan solution, to investigate the impact of this on the mechanical and structural features of the resulting blend. We present the required data and the theoretical analysis supporting the thermal chain degradation of a polymer and its effects on behavior of the film. Additional information, characterizing the hydrophobicity of the surface of the blend layers is obtained by measuring water contact angles using a contact anglemeter.

  9. The role of chitosan on oral delivery of peptide-loaded nanoparticle formulation.

    Science.gov (United States)

    Wong, Chun Y; Al-Salami, Hani; Dass, Crispin R

    2017-12-01

    Therapeutic peptides are conventionally administered via subcutaneous injection. Chitosan-based nanoparticles are gaining increased attention for their ability to serve as a carrier for oral delivery of peptides and vaccination. They offered superior biocompatibiltiy, controlled drug release profile and facilitated gastrointestinal (GI) absorption. The encapsulated peptides can withstand enzymatic degradation and various pH. Chitosan-based nanoparticles can also be modified by ligand conjugation to the surface of nanoparticle for transcellular absorption and specific-targeted delivery of macromolecules to the tissue of interest. Current research suggests that chitosan-based nanoparticles can deliver therapeutic peptide for the treatment of several medical conditions such as diabetes, bacterial infection and cancer. This review summarises the role of chitosan in oral nanoparticle delivery and identifies the clinical application of peptide-loaded chitosan-based nanoparticles.

  10. Radiation damage calculations for the LANSCE degrader

    International Nuclear Information System (INIS)

    Ferguson, P.D.; Sommer, W.F.; Dudziak, D.J.; Wechsler, M.S.; Barnett, M.H.; Corzine, R.K.

    1998-01-01

    The A-6 water degrader at the Los Alamos Neutron Science Center (LANSCE) linear proton accelerator has an outer shell of Inconel 718. The degrader was irradiated by 800-MeV protons during 1988--1993 to an exposure of 5.3 ampere-hours (A h). As described in Ref. 1, material from the Inconel is currently being cut into specimens for microhardness, three-point bending, ball punch, microscopy, and corrosion tests. This paper is devoted to calculations of radiation damage, particularly displacement and He production, sustained by the degrader Inconel

  11. Radiation-induced degradation of chlorophenols in aqueous solution

    International Nuclear Information System (INIS)

    Hu Jun; Wang Jianlong

    2005-01-01

    Radiation processing is a promising technology for applications in environmental protection, which includes wastewater treatment, micro-polluted drinking water treatment and the treatment of industrial wastewater containing various toxic and nonbiodegradable pollutants, municipal sewage and sludge disinfection, and flue gas desulfuration, etc. The paper reviews manly the recent progresses in radiolysis of chlorinated phenols in aqueous solution. Advantages and existing problems of the method in this particular application ar discussed. Mechanisms of radiation-induced degradation of chlorophenols, and the factors affecting the degradation efficiency, are discussed, too. It is concluded that combined approaches, such ozone oxidation and other methods, are of great help to the radiation processing application, in terms of lowering down the dose and increasing the efficient of pollutant removal. (authors)

  12. Green Chemistry: Effect of Microwave Irradiationon Synthesis of Chitosan for Biomedical Grade Applications of Biodegradable Materials

    Directory of Open Access Journals (Sweden)

    Amri Setyawati

    2016-10-01

    Full Text Available Microwave assisted chitosan synthesis as biodegradable material for biomedical application has been done. The purpose of this research is to synthesis of chitosan with high DD and low molecular weight using microwave energy, the study of reaction conditions include parameters of power and reaction time. Chitosan was prepared by deacetylation of chitin with 60% NaOH solution. Conventional method has been done by reflux for 90minutes, resulting chitosan with DD of 79.5%, 72.6% yields and molecular weight 6051 g/mol. Green chemistry method using microwave radiation at 800 Watts for 5 minutes has produced chitosan with highest DD, yield and molecular weight of 86%, 75% and 3797 g/mole respectively. Synthesis of Chitosan by microwave radiation method can save 10x electrical energy for the reaction, also rapidly and effectively to produce chitosan with low molecular weight compared to conventional methods

  13. Effect of γ-irradiation on the physical and mechanical properties of chitosan powder

    International Nuclear Information System (INIS)

    Zainol, Ismail; Akil, Hazizan Md; Mastor, Azreena

    2009-01-01

    In this study, locally produced chitosan powder was irradiated with pre-determined doses of γ-ray (Co-60) of 10 kGy, 25 kGy, 50 kGy and 100 kGy respectively. The properties of both chitosan powder and the chitosan film were examined and compared with unradiated chitosan. Physical characteristic of the irradiated powder and film was studied using stereo microscope. It was observed that the γ-ray induces a noticeable colour tone intensity change to the chitosan. Further investigation using Fourier Transformed Infrared Spectroscopy (FT-IR) analysis has confirmed that the chain scission reaction was occurred as a result of γ-ray exposure through the depolymerization mechanisms. Interestingly, the degree of deacetylation (DD) of chitosan measured using FT-IR showed a negligible effect due to the exposure of γ-ray radiation. Further investigation on the viscosity average molecular weight (M v ) showed a reduction of M v from 577 kD of pure chitosan to 458 kD, 242 kD, 159 kD and 106 kD for 10 kGy, 25 kGy, 50 kGy and 100 kGy of γ-radiated chitosan respectively. In addition, the tensile strength and elongation at break showed a similar decreasing trend with increasing dosage of γ-ray

  14. Radiation degradation of silk protein

    International Nuclear Information System (INIS)

    Pewlong, W.; Sudatis, B.; Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu

    2000-01-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated using an electron beam accelerator to investigate the application of the radiation degradation technique as a means to solubilize fibroin. The irradiation caused a significant degradation of the fiber. The tensile strength of fibroin fiber irradiated up to 2500 kGy decreased rapidly with increasing dose. The presence of oxygen in the irradiation atmosphere enhanced degradation of the tensile strength. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: a calcium chloride solution(CaCl 2 /C 2 H 5 OH/H 2 O=1:2:8 in mole ratio), a hydrochloric acid (0.5 N) and a distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water soluble proteins was extracted by a distilled water. (author)

  15. Radiation degradation of silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Pewlong, W; Sudatis, B [Office of Atomic Energy for Peace, Bangkok (Thailand); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated using an electron beam accelerator to investigate the application of the radiation degradation technique as a means to solubilize fibroin. The irradiation caused a significant degradation of the fiber. The tensile strength of fibroin fiber irradiated up to 2500 kGy decreased rapidly with increasing dose. The presence of oxygen in the irradiation atmosphere enhanced degradation of the tensile strength. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: a calcium chloride solution(CaCl{sub 2}/C{sub 2}H{sub 5}OH/H{sub 2}O=1:2:8 in mole ratio), a hydrochloric acid (0.5 N) and a distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water soluble proteins was extracted by a distilled water. (author)

  16. Fungal chitosan production from potato processing wastewater and its characterization

    International Nuclear Information System (INIS)

    Khalaf, S.A.; Khalaf, M.A.

    2005-01-01

    Potato processing wastewater (PPW) was collected and analyzed for biological oxygen demand BOD, chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen and starch content. A fungal strain of Aspergillus niger treated with ultraviolet (UV) radiation was evaluated for its ability to produce chitosan from PPW. Active UV-irradiated isolate, coded A. niger UV-2, was able to reduce COD by about 86.15% with over productivity of chitosan of 1630 mgl -1 after 5 days of its cultivation in PPW. Extractable chitosan from this isolate had a degree of deacetylation of 88.4% and a molecular weight l.lxlo 5 Da. Also, the extractable chitosan at concentration 600 mgl -1 exhibited the maximum antibacterial activity compared with crab shell chitosan

  17. Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation

    Science.gov (United States)

    Ho, Ming-Hua; Liao, Mei-Hsiu; Lin, Yi-Ling; Lai, Chien-Hao; Lin, Pei-I; Chen, Ruei-Ming

    2014-01-01

    Osteoblast maturation plays a key role in regulating osteogenesis. Electrospun nanofibrous products were reported to possess a high surface area and porosity. In this study, we developed chitosan nanofibers and examined the effects of nanofibrous scaffolds on osteoblast maturation and the possible mechanisms. Macro- and micro observations of the chitosan nanofibers revealed that these nanoproducts had a flat surface and well-distributed fibers with nanoscale diameters. Mouse osteoblasts were able to attach onto the chitosan nanofiber scaffolds, and the scaffolds degraded in a time-dependent manner. Analysis by scanning electron microscopy further showed mouse osteoblasts adhered onto the scaffolds along the nanofibers, and cell–cell communication was also detected. Mouse osteoblasts grew much better on chitosan nanofiber scaffolds than on chitosan films. In addition, human osteoblasts were able to adhere and grow on the chitosan nanofiber scaffolds. Interestingly, culturing human osteoblasts on chitosan nanofiber scaffolds time-dependently increased DNA replication and cell proliferation. In parallel, administration of human osteoblasts onto chitosan nanofibers significantly induced osteopontin, osteocalcin, and alkaline phosphatase (ALP) messenger (m)RNA expression. As to the mechanism, chitosan nanofibers triggered runt-related transcription factor 2 mRNA and protein syntheses. Consequently, results of ALP-, alizarin red-, and von Kossa-staining analyses showed that chitosan nanofibers improved osteoblast mineralization. Taken together, results of this study demonstrate that chitosan nanofibers can stimulate osteoblast proliferation and maturation via runt-related transcription factor 2-mediated regulation of osteoblast-associated osteopontin, osteocalcin, and ALP gene expression. PMID:25246786

  18. Bromine pretreated chitosan for adsorption of lead

    Indian Academy of Sciences (India)

    Pollution by heavy metals like lead (II) is responsible for health hazards and environmental degradation. Adsorption is a prevalent method applied for removal of heavy metal pollutants from water. This study explored adsorption performances of 30% bromine pretreated chitosan for lead (II) abatement from water. Bromine ...

  19. Radiation-chemical destruction of cellulose and other polysaccharides

    International Nuclear Information System (INIS)

    Ershov, B.G.

    1998-01-01

    The studies concerning the radiation-chemical destruction of cellulose, its ethers and some polysaccharides (xylan, starch, decstrans, chitin, chitosan and geparin) are discussed. Ionising irradiation causes the destruction of these compounds with the decay of pyranose ring, accompanied by the formation of compounds containing carbonyl or carboxyl groups, as well as hydrogen, carbon dioxide, and carbon oxide. The efficiency of radiation degradation increases with increasing the temperature and depends on the structure of polysaccharides and the nature of substituents. The mechanism of radiation-chemical transformations of cellulose and others polysaccharides is proposed. Prospects of the application of radiation-chemical methods of treatment of cellulose and other polysaccharides in industry and agriculture considered [ru

  20. Chitosan microspheres in novel drug delivery systems.

    Science.gov (United States)

    Mitra, Analava; Dey, Baishakhi

    2011-07-01

    The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems.

  1. Radiation degradation of aromatic pollutants exit in wastewater and ph dependence

    International Nuclear Information System (INIS)

    Takriti, S.

    2002-12-01

    The effect of gamma radiation on the degradation of phenol (hydroxybenzene), resorcinol (1,3 dihydroxybenzen) and hydroquinone (1,4 dihydroxybenzen) exit in waste water was investigated. The concentrations of these pollutants as well as the irradiated solution ph were studied. The results showed that the phenol is very resistance against the radiation doses comparing the other phenol compounds. Phenol was also a product of radiolysis of resorcinol and hydroquinone. On the other hand, the acid phase of the irradiation sample increased the degradation rate of pollutants. Spectrophotometer (UV-VIS) and chromatography (HPLC) were used to monitor the analysis of the radiation product solution. The results illustrated the existing of many substances such as organic alcohol, aldehyde, ketone and acidic functional groups as a final radiation products. The degradation of benzene, monochlorobenzene (CB) and 1,2 dichlorobenzene (1,2 DCB) exit in waste water by gamma irradiation was investigated. The effect of the irradiated solution composition was studied. The results showed that the benzene is very resistance against the radiation doses comparing to other chlorobenzene. However, the existence of oxidizing substances in the irradiation phase leads to increase the degradation rate of pollutants. The dechlorination of CB and 1,2 DCB that is a result of the hydrated electron reaction with studied compounds was observed. Chromatography (HPLC) and spectrophotometer (UV-VIS) were used to monitor the analysis of the radiation product solution. The results illustrated the existing of many species as a final radiation product. On the other, the irradiation phase containing scavengers such as methanol and ethanol requires large doses to decompose the pollutants, while the oxidizing phase accelerates the degradation. (author)

  2. Radiation Modification of Some Natural Polymers and Their Potential Applications

    International Nuclear Information System (INIS)

    Refaee, A.M.E.A.

    2012-01-01

    In recent years, antioxidants received remarkable attention due to the ability to preserve foodstuffs by retarding deterioration, rancidity and/or discoloration caused by oxidation of fats and oils in foods. In addition, they have the ability to protect against detrimental change of oxidizable nutrients and extend shelf life of foods. Nowadays, polysaccharides have been demonstrated to scavenge free radicals in vitro and to be used as antioxidants for the prevention of oxidative damage in foods. The antioxidant activity of polysaccharides depends upon several structural parameters, such as the molecular weight, amount, type and position of functional groups. For these applications, specific molecular weights are required. Thus, modification and preparation of low molecular weight fractions or oligosaccharides from chitosan, Na-alginate and carrageenan using ionizing radiation will be carried out and their antioxidant properties will be determined. The molecular weights and structure changes upon the radiation degradation process of these natural polymers in solid and solution form will be investigated using GPC, FT-IR, UV-Vis spectrophotometers. In an attempt to improve the functionality and water solubility of chitosan, chemical modifications will be done to introduce hydrophilic groups and enhance its antioxidant activity. Radical mediated lipid peroxidation inhibition, scavenging effect on DPPH radicals, reducing power and the ferrous ion chelating activity assays will be used to evaluate the antioxidant activity of oligosaccharides. Effectiveness of irradiated chitosan derivatives in reducing the lipid peroxidation in minced chicken will be investigated for improving the oxidative deterioration of minced chicken during refrigerated storage. On the other hand, there is a strong need for new plant growth media with increased water and nutrient holding capacity. Hydrogels have the ability to absorb large quantities of water. Among of these hydrogels polyacrylamide

  3. Radiation induced degradation of DNA in photodynamic therapy of cancer

    International Nuclear Information System (INIS)

    Ion, Rodica; Scarlat, F.; Niculescu, V.I.R.; Scarlat, Fl.; Gunaydin, Keriman

    2001-01-01

    DNA is a critical cellular target for oxidative processes induced by physical and chemical stresses. It is known that the direct effect of ionizing radiation on DNA results mainly in base ionization and may lead to mutation, carcinogenesis and cell death. The degradation of DNA induced by laser and ionizing radiation (electron and photon beam) is analyzed in this paper. The ionizing radiation degradation of DNA is a radical process. A series of lesions among the major base degradation product has been measured in isolated DNA exposed to gamma radiation in aerated aqueous solution. Degradation can be accounted for by the formation of hydroxyl radicals upon radiolysis of water (indirect effect). The production of DNA damage by ionizing radiation involves two mechanisms, direct and indirect effects. Direct effect leads to ionization and excitation of DNA molecules, while indirect effect is due to the interaction of reactive species, in particular of OH radicals produced by water radiolysis, with targets in DNA. The relative contribution of the two mechanisms in damaging DNA depends on the type of radiation. Single strand breaks and base damage seem to be mainly produced by the attack of hydroxyl radicals on DNA, whereas double strand breaks result predominantly of direct energy deposition. The four bases are degraded in high yield. Direct effect has been mimicked by photo-induced electron abstraction from the bases producing their radical cation. The base damage may also occur from the formation of radical cation of purine and pyrimidine components. When DNA is irradiated in solution, single strand breaks are mainly due to the abstraction of an H atom from the 4 ' position of 2 ' -deoxyribose by the attack of OH radicals produced by water radiolysis. Quantification of the modified bases showed the guanine is the preferential target. Ionizing radiation induces several types of DNA modifications, including chain breaks, DNA-protein cross-links, oxidized DNA bases

  4. Spectroscopic analysis of the powdery complex chitosan-iodine

    Science.gov (United States)

    Gegel, Natalia O.; Babicheva, Tatyana S.; Belyakova, Olga A.; Lugovitskaya, Tatyana N.; Shipovskaya, Anna B.

    2018-04-01

    A chitosan-iodine complex was obtained by modification of polymer powder in the vapor of an iodine-containing sorbate and studied by electron and IR spectroscopy, optical rotation dispersion. It was found that the electronic spectra of an aqueous solution of the modified chitosan (the source one and that stored for a year) showed intense absorption bands of triiodide and iodate ions, and also polyiodide ions, bound to the macromolecule by exciton bonding with charge transfer. Analysis of the IR spectra shows destruction of the network of intramolecular and intermolecular hydrogen bonds in the iodinated chitosan powder in comparison with the source polymer and the formation of a new chemical substance. E.g., the absorption band of deformation vibrations of the hydroxyl group disappears in the modified sample, and that of the protonated amino group shifts toward shorter wavelengths. The intensity of the stretching vibration band of the glucopyranose ring atoms significantly reduces. Heating of the modified sample at a temperature below the thermal degradation point of the polymer leads to stabilization of the chitosan-iodine complex. Based on our studies, the hydroxyl and amino groups of the aminopolysaccharide have been recognized as the centers of retention of polyiodide chains in the chitosan matrix.

  5. Degradation of 4-chlorophenol by ozonation, γ radiation as well as ozonation combined with γ radiation

    International Nuclear Information System (INIS)

    Hu, J.; Wang, J.L.

    2005-01-01

    The radiolysis of aqueous 4-chlorophenol (4-CP) by gamma radiation in the presence of air and ozone was investigated. The 4-CP degradation, release of chloride ion, UV absorption spectrum, total organic carbon (TOC) and adsorbable organic halogens (AOX) was measured. Under the conditions of synergistic effect of ozone and radiation a complete degradation of 100 mg/L 4-CP was obtained at a dose of 6 kGy, without ozone the 4-chlorophenol was completely decomposed at 15 kGy. The total organic carbon (TOC) was reduced by 26% when ionizing radiation (at 15 kGy) combined with ozonation, and by 17% without ozone, respectively. Analysis of intermediate products resulting from synergistic effect of ozone and radiation of 4-CP was performed by using the GC/MS method. Some primary influencing factors such as irradiation time and initial 4-CP concentration were also discussed. The results showed that the degradation of 4-chlorophenol could described by first-order reaction kinetic model. There is potential for combination of irradiation with ozonation, which can remarkably reduce the irradiation dose increase the degradation efficiency of 4-CP.

  6. Thiolated chitosan nanoparticles: transfection study in the Caco-2 differentiated cell culture

    International Nuclear Information System (INIS)

    Martien, Ronny; Loretz, Brigitta; Sandbichler, Adolf Michael; Schnuerch, Andreas Bernkop

    2008-01-01

    The aim of this study was to monitor the expression of secreted protein in differentiated Caco-2 cells after transfection with nanoparticles, in order to improve gene delivery. Based on unmodified chitosan and thiolated chitosan conjugates, nanoparticles with the gene reporter pSEAP (recombinant Secreted Alkaline Phosphatase) were generated at pH 4.0. Transfection studies of thiolated chitosan in Caco-2 cells during the exponential growth phase and differentiation growth phase of the cells led to a 5.0-fold and 2.0-fold increase in protein expression when compared to unmodified chitosan nanoparticles. The mean particle size for both unmodified chitosan and cross-linked thiolated chitosan nanoparticles is 212.2 ± 86 and 113.6 ± 40 nm, respectively. The zeta potential of nanoparticles was determined to be 7.9 ± 0.38 mV for unmodified chitosan nanoparticles and 4.3 ± 0.74 mV for cross-linked thiolated chitosan nanoparticles. Red blood cell lysis evaluation was used to evaluate the membrane damaging properties of unmodified and thiolated chitosan nanoparticles and led to 4.61 ± 0.36% and 2.29 ± 0.25% lysis, respectively. Additionally, cross-linked thiolated chitosan nanoparticles were found to exhibit higher stability toward degradation in gastric juices. Furthermore the reversible effect of thiolated chitosan on barrier properties was monitored by measuring the transepithelial electrical resistance (TEER) and is supported by immunohistochemical staining for the tight junction protein claudin. According to these results cross-linked thiolated chitosan nanoparticles have the potential to be used as a non-viral vector system for gene therapy

  7. Radiation Modification of Natural Polysaccharides for Application in Agriculture

    International Nuclear Information System (INIS)

    AbdEl-Rehim, Hassan A.; Hegazy, El-Sayed A.; El-Barbary, Ahmed M.

    2010-01-01

    Controlling the degradation process of natural polymer like chitosan by gamma ray from a 60 Co source at different doses in, powder form, and in presence of additives was investigated. The efficiency of these methods were verified by viscometric and GPC analysis through determination the average molecular weights of degraded natural polymers. The chemical-irradiation degradation method was much more appropriate from economical point of view. Characterization of degraded polymer by FTIR spectroscopy, UV-Vis spectroscopy, XRD, ESR and TGA analysis were done. The degraded sodium alginate with different doses were used for wheat plant. It was observed that spraying treated plants with alginate solutions improved plant growth and increasing its yields. Significant changes in amino acids content of the plants was observed as a result of treating them with irradiated alginate solutions. Irradiated Na alginate induced changes in plant DNA, which may be appear as increase in growth and yield characters. The degraded natural polymer chitosans were also tested as growth promoters for some plants like Zea maize and bean plant . It was found that the degraded chitosan has a great effect on the productivity and properties of these plants. Antiviral activity of irradiated alginate against plant infection by tobacco mosaic virus was investigated. It is clear that the relatively high Molecular weigh alginate inhibits and reduces the plant infection . The effects of chitosan oligomers on gray mould caused by Botrytis cinerea in tomato plants was investigated. It was found that degraded chitosan controlled the gray mould disease caused by B. cinerea compared with control. (author)

  8. Chitosan-based hydrogel tissue scaffolds made by 3D plotting promotes osteoblast proliferation and mineralization.

    Science.gov (United States)

    Liu, I-Hsin; Chang, Shih-Hsin; Lin, Hsin-Yi

    2015-05-13

    A 3D plotting system was used to make chitosan-based tissue scaffolds with interconnected pores using pure chitosan (C) and chitosan cross-linked with pectin (CP) and genipin (CG). A freeze-dried chitosan scaffold (CF/D) was made to compare with C, to observe the effects of structural differences. The fiber size, pore size, porosity, compression strength, swelling ratio, drug release efficacy, and cumulative weight loss of the scaffolds were measured. Osteoblasts were cultured on the scaffolds and their proliferation, type I collagen production, alkaline phosphatase activity, calcium deposition, and morphology were observed. C had a lower swelling ratio, degradation, porosity and drug release efficacy and a higher compressional stiffness and cell proliferation compared to CF/D (p 3D-plotted samples, cells on CP exhibited the highest degree of mineralization after 21 d (p 3D-plotted scaffolds were stronger, less likely to degrade and better promoted osteoblast cell proliferation in vitro compared to the freeze-dried scaffolds. C, CP and CG were structurally similar, and the different crosslinking caused significant changes in their physical and biological performances.

  9. Scaffold of chitosan/poly(vinyl alcohol) blend chemically crosslinked by glutaraldehyde for tissue engineering applications

    International Nuclear Information System (INIS)

    Costa Junior, Ezequiel de S.; Laguardia-Nascimento, Mateus; Barbosa-Stancioli, Edel F.; Mansur, Herman S.

    2009-01-01

    Chitosan/PVA based films were chemically crosslinked by glutaraldehyde (GA) in order to achieve scaffolds for potential tissue engineering application. Both precursors and developed films were characterized by FTIR and XRD in order to determine the presence of chemicals groups and nanostructural order, respectively. The results have showed that the GA crosslinking have altered the crystallinity of the chitosan and the increase on the C=N bands and decreasing of NH 2 bands suggest that Chitosan/GA crosslinking has preference to occur in the carbon 2 by Schiff's base. The mechanical properties, swelling behavior, degradation rate in vitro and cellular viability were compatible with the characteristic of an epithelial tissue. The material presented a toughness range from 1.4 to 34MJ/m3, swelling from 150% to 700% in 24h, degradation rate from 20% to 75% (wt%) in 24h and cellular viability in vitro above 60% compared to the cellular control. The developed scaffolds from the films have also showed swelling and degradation in vitro properties well-matched for biomedical applications in tissue engineering (author)

  10. Application of radiation processing to produce biotic elicitor for sugarcane in Vietnam

    International Nuclear Information System (INIS)

    Nguyen, Quoc Hien; Tran, Tich Canh; Truong, Thi Hanh; Vo, Thi Kim Lang; Dang, Van Phu; Cao, Anh Duong

    2007-01-01

    Sugarcane is the main raw material for production of sugar and ethanol. In Vietnam, it was reported in 1998 that the area for sugarcane growth was about 257,000ha. Up to now, the biotic elicitor, oligosaccharide has not been used for sugarcane yet. This study has been carried out to investigate the elicitation and the growth promotion effect of irradiated chitosan (oligochitosan) for sugarcane. The field test results indicated that alpha chitosan (shrimp shell) and beta chitosan (squid pen) samples with the content of water soluble oligomer of about 70% were the most effective. The disease ratio of sugarcane tree-trunk treated with irradiated chitosan before harvesting time decreased to 30-40% compared to non-treated one (100%). In addition, the productivity of sugarcane increased to about 20%. The combination of metal ion (Zn ++ , Cu ++ ) with oligochitosan did not show the synergic elicitation effect. The results revealed that biotic elicitor made from chitosan by radiation degradation method is very promising for field application not only for protection of disease infection but also for growth promotion of plants. It is believed that this biotic elicitor could be largely used for safe and sustainable development of agriculture. (author)

  11. Degradation of polycarbonate induced by gamma radiation

    International Nuclear Information System (INIS)

    Araujo, E.S. de; Guedes, S.M.L.

    1992-01-01

    Polycarbonate (PC) DUROLON amorphous, of molecular weight 22000 g/mol is used in medical supplies and may be sterilized by gamma radiation. The main chain scission and polymer degradation occur when this polymer is irradiated. The value G = 1.54 to DUROLON was obtained by equation: 10 6 /M v = 10 6 /M v' + 0.054 G R. The degradation without crosslinking it is not general rule to all types of polycarbonates; an comparison was realized. The infrared (FT-IR) spectra of irradiated PC by gamma rays with different doses showed the main chain scissions in carbonyl groups. The mechanism of polymeric degradation to DUROLON, observed by NMR spectra, is a recombination of phenoxy and phenyl radicals. (author)

  12. Glycol chitosan

    DEFF Research Database (Denmark)

    Danielsen, E Thomas; Danielsen, E Michael

    2017-01-01

    Chitosan is a polycationic polysaccharide consisting of β-(1-4)-linked glucosamine units and due to its mucoadhesive properties, chemical derivatives of chitosan are potential candidates as enhancers for transmucosal drug delivery. Recently, glycol chitosan (GC), a soluble derivative of chitosan...

  13. Utilization of carbohydrates by radiation processing

    International Nuclear Information System (INIS)

    Kume, T.; Nagasawa, N.; Yoshii, F.

    2002-01-01

    Upgrading and utilization of carbohydrates such as chitosan, sodium alginate, carrageenan, cellulose, pectin have been investigated for recycling these bio-resources and reducing the environmental pollution. These carbohydrates were easily degraded by irradiation and various kinds of biological activities such as anti-microbial activity, promotion of plant growth, suppression of heavy metal stress, phytoalexins induction, etc. were induced. On the other hand, some carbohydrate derivatives, carboxymethylcellulose and carboxymethylstarch, could be crosslinked under certain radiation condition and produce the biodegradable hydrogel for medical and agricultural use

  14. Radiation degradation of silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Wachiraporn Pewlong; Boonya Sudatis [Office of Atomic Energy for Peace, Bangkok (Thailand); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-09-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated in the dose range up to 2500 kGy using an electron beam accelerator to apply the radiation degradation technique as a means to solubilize fibroin. The tensile strength of irradiated fibroin fiber decreased with increasing dose and the presence of oxygen in the irradiation atmosphere enhanced the degradation. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: calcium chloride solution (CaCl{sub 2}/C{sub 2}H{sub 5}OH/H{sub 2}O = 1 : 2 : 8 in mole ratio), hydrochloric acid (0.5N) and distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water-soluble protein was extracted by distilled water. (author)

  15. Cartilaginous extracellular matrix-modified chitosan hydrogels for cartilage tissue engineering.

    Science.gov (United States)

    Choi, Bogyu; Kim, Soyon; Lin, Brian; Wu, Benjamin M; Lee, Min

    2014-11-26

    Cartilaginous extracellular matrix (ECM) components such as type-II collagen (Col II) and chondroitin sulfate (CS) play a crucial role in chondrogenesis. However, direct clinical use of natural Col II or CS as scaffolds for cartilage tissue engineering is limited by their instability and rapid enzymatic degradation. Here, we investigate the incorporation of Col II and CS into injectable chitosan hydrogels designed to gel upon initiation by exposure to visible blue light (VBL) in the presence of riboflavin. Unmodified chitosan hydrogel supported proliferation and deposition of cartilaginous ECM by encapsulated chondrocytes and mesenchymal stem cells. The incorporation of native Col II or CS into chitosan hydrogels further increased chondrogenesis. The incorporation of Col II, in particular, was found to be responsible for the enhanced cellular condensation and chondrogenesis observed in modified hydrogels. This was mediated by integrin α10 binding to Col II, increasing cell-matrix adhesion. These findings demonstrate the potential of cartilage ECM-modified chitosan hydrogels as biomaterials to promote cartilage regeneration.

  16. Factors influencing the efficiency of radiation-induced degradation of water pollutants

    International Nuclear Information System (INIS)

    Getoff, Nikola

    2002-01-01

    The efficiency of the radiation-induced degradation of water pollutants depends on several factors, such as kind and energy of radiation, absorbed dose, dose rate, pollutant concentration as well as synergistic effects of radiation and ozone or/and catalysts (e.g. TiO 2 ) and of the molecular structure of the pollutants. The role of the individual factors is illustrated by examples. The application of pulse radiolysis in addition to chemical analysis for elucidation of reaction mechanisms and optimization of the degradation treatment is also mentioned

  17. Ethanol production from chitosan by the nematophagous fungus Pochonia chlamydosporia and the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana.

    Science.gov (United States)

    Aranda-Martinez, Almudena; Naranjo Ortiz, Miguel Ángel; Abihssira García, Isabel Sofía; Zavala-Gonzalez, Ernesto A; Lopez-Llorca, Luis Vicente

    2017-11-01

    Chitin is the second most abundant biopolymer after cellulose and virtually unexplored as raw material for bioethanol production. In this paper, we investigate chitosan, the deacetylated form of chitin which is the main component of shellfish waste, as substrate for bioethanol production by fungi. Fungal parasites of invertebrates such as the nematophagous Pochonia chlamydosporia (Pc) or the entomopathogens Beauveria bassiana (Bb) and Metarhizium anisopliae (Ma) are biocontrol agents of plant parasitic nematodes (eg. Meloidogyne spp.) or insect pests such as the red palm weevil (Rhynchophorus ferrugineus). These fungi degrade chitin-rich barriers for host penetration. We have therefore tested the chitin/chitosanolytic capabilities of Pc, Bb and Ma for generating reducing sugars using chitosan as only nutrient. Among the microorganisms used in this study, Pc is the best chitosan degrader, even under anaerobic conditions. These fungi have alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) encoding genes in their genomes. We have therefore analyzed their ethanol production under anaerobic conditions using chitosan as raw material. P. chlamydosporia is the largest ethanol producer from chitosan. Our studies are a starting point to develop chitin-chitosan based biofuels. Copyright © 2017 Elsevier GmbH. All rights reserved.

  18. Research on degradation of vacuum O-rings under gamma radiation

    CERN Document Server

    Ino, H; Saitô, Y; Kubo, T; Kinsho, M

    2003-01-01

    The high-intensity proton accelerator being constructed by JAERI and KEK will generates greater beam power than conventional accelerators. The radiation emission due to beam losses will therefore increase. Since vacuum O-rings installed in the accelerator will be degraded badly by the radiation, there is need to find an O-ring that has more resistant to radiation. To find an O-ring that has better radiation resistant than that of the fluororubber used for conventional accelerators in general, some O-rings which are expected to have enough resistant to the radiation were irradiated, and estimated a degradation by measurement of outgassing rate, hardness, permeation time of helium gas, and an outward observation. Most of the O-rings were irradiated in an oxygen free atmosphere and in the air. The irradiations were carried out at room temperature in Co-60 gamma irradiation facility until a dose of 1 MGy was reached. The radiation resistance of PURE-RUBBER O-ring showed somewhat better than that of the fluororubb...

  19. Chitosan-carboxymethylcellulose based microcapsules formulation for controlled release of active ingredients from cosmeto textile

    Science.gov (United States)

    Roy, J. C.; Ferri, A.; Salaün, F.; Giraud, S.; Chen, G.; Jinping, G.

    2017-10-01

    Chitosan-based emulsions were prepared at pH from 4.0 to 6.0. The zeta potential and droplet size were monitored at different pH. Double emulsions (wateroil- water) were observed due to the stiff conformation of chitosan at pH 4.0. At pH 5.0, the emulsion droplets were the smallest (2.9 μm) of the experimental pH range. The emulsion droplets were well dispersed due to high surface charge of chitosan (for example, +50 mV at pH 5.5) in entire pH range. The emulsion was treated with carboxymethyl cellulose (CMC) for neutralizing the charged chitosan on the surface of emulsion droplets. Above 10×10-2 mg/ml of CMC, no change in zeta potential was observed indicating no more free chitosan existed after neutralization with CMC. The emulsion was then crosslinked with different amount of glutaraldehyde. Upon increasing the amount of glutaraldehyde, the amount of core content inside the microcapsule and encapsulation efficiency of shell materials decreased gradually. The Dynamic Scanning Calorimetry data confirmed no interaction between core and shell material in the microencapsulation process. The thermal degradation of the microcapsules was examined by thermogravimetric analysis and a gradual decrease in the degradation temperature upon increasing glutaraldehyde concentration was found. The tuning of CMC concentration can provide valuable information regarding stable emulsion and efficient microcapsule formulation via coacervation.

  20. Radiation degradation of aromatic pollutants exit in wastewater and ph dependence

    CERN Document Server

    Takriti, S

    2002-01-01

    The effect of gamma radiation on the degradation of phenol (hydroxybenzene), resorcinol (1,3 dihydroxybenzen) and hydroquinone (1,4 dihydroxybenzen) exit in waste water was investigated. The concentrations of these pollutants as well as the irradiated solution ph were studied. The results showed that the phenol is very resistance against the radiation doses comparing the other phenol compounds. Phenol was also a product of radiolysis of resorcinol and hydroquinone. On the other hand, the acid phase of the irradiation sample increased the degradation rate of pollutants. Spectrophotometer (UV-VIS) and chromatography (HPLC) were used to monitor the analysis of the radiation product solution. The results illustrated the existing of many substances such as organic alcohol, aldehyde, ketone and acidic functional groups as a final radiation products. The degradation of benzene, monochlorobenzene (CB) and 1,2 dichlorobenzene (1,2 DCB) exit in waste water by gamma irradiation was investigated. The effect of the irradi...

  1. Radiation degradation and hemolytic toxicity evaluation of mono azo reactive dyes

    International Nuclear Information System (INIS)

    Saeed, Q.U.; Bhatti, I.A.; Ashraf, A.

    2017-01-01

    Monoazo reactive dyes have been synthesized and subjected to degradation before their application. Advanced oxidation process has been recognized as a promising radiation technology for the remediation of hazardous organic compounds. Radiation induced degradation of two mono azo reactive dyes have been tried at different absorbed dose, 5 kGy,10 kGy and 15 kGy. Aqueous solutions of these dyes were treated with gamma radiation using Cs 137 radiation source at Nuclear Institute of Agriculture and Biology (NIAB) Faisalabad. Dyes were evaluated spectrophotometrically by UV-visible and fourier transform infra red (FT-IR) spectroscopic techniques before and after irradiation to analyse their percentage decolorization and degradation. Maximum percentage decolorization of 93% and 63% was achieved for mono azo dyes D1 and D2 at 15 kGy absorbed dose. Toxicity study of these dyes was also tested by haemolytic activity assay. Percentage haemolytic activity of untreated dyes was found within permissible limit showing non toxicity of dye solutions. (author)

  2. Super water-absorbing new material from chitosan, EDTA and urea.

    Science.gov (United States)

    Narayanan, Abathodharanan; Dhamodharan, Raghavachari

    2015-12-10

    A new, super water-absorbing, material is synthesized by the reaction between chitosan, EDTA and urea and named as CHEDUR. CHEDUR is probably formed through the crosslinking of chitosan molecules (CH) with the EDTA-urea (EDUR) adduct that is formed during the reaction. CHEDUR as well as the other products formed in control reactions are characterized extensively. CHEDUR exhibits a very high water uptake capacity when compared with chitosan, chitosan-EDTA adduct, as well as a commercial diaper material. A systematic study was done to find the optimum composition as well as reaction conditions for maximum water absorbing capacity. CHEDUR can play a vital role in applications that demand the rapid absorption and slow release of water such as agriculture, as a three in one new material for the slow release of urea, water and other metal ions that can be attached through the EDTA component. The other potential advantage of CHEDUR is that it can be expected to degrade in soil based on its chitosan backbone. The new material with rapid and high water uptake could also find potential applications as biodegradable active ingredient of the diaper material. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Mechanism of radiation-induced degradation of poly(methyl methacrylate)

    International Nuclear Information System (INIS)

    Ichikawa, Tsuneki; Oyama, Ken-ichi; Yoshida, Hiroshi

    1995-01-01

    ESR and gel permeation chromatographic measurements of poly(methyl methacrylate) γ-irradiated between 77 K and 300 K have been carried out to elucidate the mechanism of radiation-induced degradation of the polymer. It is revealed that the scission of the main chain is not taken place immediately after the absorption of radiation energy but is induced by the intramolecular radical conversion of the side-chain -COOCH 2 radical to the tertiary -CH 2 -C(CH 3 )- radical followed by the main-chain β-scission of the latter radical. The degradation is not taken place below 190 K, because the side-chain radical starts to convert only above 190 K. The residual monomer in the polymer reacts with the side-chain radical below 190 K to generate the stable propagating-type radical, so that the degradation is suppressed even after warming the polymer to the ambient temperature. (author)

  4. Chitosan/siRNA nanoparticles encapsulated in PLGA nanofibers for siRNA delivery

    DEFF Research Database (Denmark)

    Chen, Menglin; Gao, Shan; Dong, Mingdong

    2012-01-01

    Composite nanofibers of biodegradable poly(d,l-lactic-co-glycolic acid) (PLGA) encapsulating chitosan/siRNA nanoparticles (NPs) were prepared by electrospinning. Acidic/alkaline hydrolysis and a bulk/surface degradation mechanism were investigated in order to achieve an optimized release profile...... for prolonged and efficient gene silencing. Thermo-controlled AFM in situ imaging not only revealed the integrity of the encapsulated chitosan/siRNA polyplex but also shed light on the decreasing Tg of PLGA on the fiber surfaces during release. A triphasic release profile based on bulk erosion was obtained at p......RNA transfection, where the encapsulated chitosan/siRNA NPs exhibited up to 50% EGFP gene silencing activity after 48 h post-transfection on H1299 cells....

  5. PREPARATION AND CHARACTERIZATION OF CHITOSAN TABLETS OF ACECLOFENAC FOR COLON TARGETED DRUG DELIVERY

    OpenAIRE

    UMA DEVI,THIRUGANESH, SURESH

    2013-01-01

    The present study objective was to develop novel colon specific drug delivery systems for aceclofenac using chitosan as a microbially degradable polymeric carrier and to coat the optimized batches with a pH dependent polymeric coating solution containing Eudragit L 100 and S 100 (1:4). Tablets containing four proportions of chitosan were prepared. The tablets were evaluated for physicochemical properties, drug content, dissolution, water uptake & erosion characteristics, in vitro drug rel...

  6. Radiation degradation of poly(olefin sulphone)s - Fundamental research to practical applications

    International Nuclear Information System (INIS)

    Bowden, M.J.; O'Donnell, J.H.

    1985-01-01

    The degradation of poly(olefin sulphone)s by high energy radiation, particularly by γ-rays and electron beams, provides an example of the application of fundamental science to high technology industry. Scientific interest in the radiation degradation of these polymers was first aroused by the discovery that they underwent highly specific bond scission in the backbone chain as the primary result of absorption of high energy radiation and in fact they were the first polymers in which such an effect had been demonstrated. This conclusion was initially based mainly on evidence from electron spin resonance spectroscopy and was subsequently verified by studies of molecular weight changes. These studies showed that the poly(olefin sulphone)s not only degraded by main chain scission but were also among the most radiation-sensitive polymers known. The extremely high sensitivity of poly(olefin sulphone)s to radiation-induced main-chain scission has found application in the field of microelectronics. Electron beam writing on poly(olefin sulphone) films is used to produce lithographic masks for the manufacture of integrated circuits on silicon wafers. Poly(1-butene sulphone) (PBS) is currently used in the production of a substantial proportion of the masks for the industry. The fundamental aspects of the radiation degradation of poly(olefin sulphone)s and the practical applications to high technology are reviewed. (author)

  7. Radiation Processing of Bio-Polymers for Agriculture Applications. Chapter 21

    Energy Technology Data Exchange (ETDEWEB)

    Quynh, Tran Minh [Hanoi Irradiation Center, Vietnam Atomic Energy Institute (Viet Nam)

    2014-07-15

    Antimicrobial activity of chitosan, a well-known natural polysaccharide has been greatly improved by gamma irradiation. The highest antibacterial activity for E.coli and antifungal activity for Fusarium dimerum Penzig was obtained with chitosan irradiated at about 50–75 kGy. Other chemical properties of chitosan e.g. viscosity, molecular weight, and degree of deacetylation (DD) were also changed by radiation. The number average molecular weight of chitosan significantly reduced from 300 000–100 000 g.mol{sup -1}, whereas its DD slightly increased. A study of the chitosan membrane indicated that radiation treatment strongly influenced its mechanical properties. Both tensile and elongation at break of the irradiated chitosan were reduced with radiation dose. Irradiated chitosan can be applied as a preservative solution for the coating of fresh fruits. Also, antimicrobial packaging films from irradiated chitosan can be produced for ready-to-eat foods. Recent studies on radiation cross-linked cassava starch based hydrogels suggest that superabsorbent materials can absorb not only water but also nutrient solutions containing N, P, and K ions. This can be prepared through gamma radiation using a suitable formulation. Superabsorbent materials, swollen in NPK solution, can be used as slow-release fertilizers and considered as one of the technological advances in agricultural production. (author)

  8. Preparation and characterization of complexes of RE3+ with furfural modified water-soluble chitosan

    Institute of Scientific and Technical Information of China (English)

    WANG Maoyuan; QIU Ligan; MA Guilin

    2008-01-01

    Degraded chitosan, with highly water-solubility, was obtained by the oxidation of chitosan with H2O2, and then reacted with furfural The final product coordinated with the rare earth ions (RE3+ = Sm3+,Eu3+), which led to the formation of the complexes. The prepared complexes were characterized with Inflated Spectroscopy (IR), Ultra Violet (UV), fluorescence, X-Ray Diffraction (XRD), and Thermogravimetric-Differential Scanning Calorimetry (TG-DSC) measurements.

  9. Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation

    Directory of Open Access Journals (Sweden)

    Ho MH

    2014-09-01

    Full Text Available Ming-Hua Ho,1,2 Mei-Hsiu Liao,3 Yi-Ling Lin,2 Chien-Hao Lai,3 Pei-I Lin,3 Ruei-Ming Chen2–4 1Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan; 2Cell Physiology and Molecular Image Research Center and Department of Anesthesiology, Wan Fang Hospital, 3Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan; 4Anesthetics and Toxicology Research Center, Taipei Medical University Hospital, Taipei, Taiwan Abstract: Osteoblast maturation plays a key role in regulating osteogenesis. Electrospun nanofibrous products were reported to possess a high surface area and porosity. In this study, we developed chitosan nanofibers and examined the effects of nanofibrous scaffolds on osteoblast maturation and the possible mechanisms. Macro- and micro observations of the chitosan nanofibers revealed that these nanoproducts had a flat surface and well-distributed fibers with nanoscale diameters. Mouse osteoblasts were able to attach onto the chitosan nanofiber scaffolds, and the scaffolds degraded in a time-dependent manner. Analysis by scanning electron microscopy further showed mouse osteoblasts adhered onto the scaffolds along the nanofibers, and cell–cell communication was also detected. Mouse osteoblasts grew much better on chitosan nanofiber scaffolds than on chitosan films. In addition, human osteoblasts were able to adhere and grow on the chitosan nanofiber scaffolds. Interestingly, culturing human osteoblasts on chitosan nanofiber scaffolds time-dependently increased DNA replication and cell proliferation. In parallel, administration of human osteoblasts onto chitosan nanofibers significantly induced osteopontin, osteocalcin, and alkaline phosphatase (ALP messenger (mRNA expression. As to the mechanism, chitosan nanofibers triggered runt-related transcription factor 2 mRNA and protein syntheses. Consequently, results of ALP-, alizarin red-, and von Kossa-staining analyses

  10. Determination of viscosity-average molecular weight of chitosan using intrinsic viscosity measurement

    International Nuclear Information System (INIS)

    Norzita Yacob; Norhashidah Talip; Maznah Mahmud; Nurul Aizam Idayu Mat Sani; Nor Akma Samsuddin; Norafifah Ahmad Fabillah

    2013-01-01

    Determination of molecular weight by intrinsic viscosity measurement is a simple method for characterization of chitosan. To study the effect of radiation on molecular weight, chitosan was first irradiated using electron beam at different doses prior to measurement. Different concentrations of chitosan were prepared and measurement was done at room temperature. The flow time data was used to calculate the intrinsic viscosity by extrapolating the reduced viscosity to zero concentration. The value of intrinsic viscosity was then recalculated into the viscosity-average molecular weight using Mark-Houwink equation. (Author)

  11. Synthesis of PVA-Chitosan Hydrogels for Wound Dressing Using Gamma Irradiation. Part II: Antibacterial Activity of PVA/Chitosan Hydrogel Synthesized by Gamma Irradiation

    International Nuclear Information System (INIS)

    Mahlous, M.; Tahtat, D.; Benamer, S.; Nacer Khodja, A.; Larbi Youcef, S.

    2010-01-01

    Poly(vinyl alcohol) (PVA) is a synthetic polymer used in a large range of medical, commercial, industrial and food applications, manufacture of paper products, surgical threads, wound care, and food-contact applications. It was recently used as a coating for dietary supplements and pharmaceutical capsules. Cross-linked PVA microspheres are also used for controlled release of oral drugs. Chitin, a polysaccharide from which chitosan is derived, is the second most abundant natural polysaccharide after cellulose. Chitin is obtained from the exoskeletons (crab, shrimps and squid pen) fungi, insects, and some algae. Chitosan, a non toxic and biocompatible cationic polysaccharide, is produced by partial deacetylation of chitin; these properties of chitosan provide high potential for many applications. Chitosan has been widely used in vastly diverse fields, such as in biomedical applications drug delivery in agriculture metal ion sorption. The most important characteristic of chitosan is the deacetylation degree (DD) which influences its physical and chemical behaviors. Evaluation of DD can be carried out by FT-IR spectroscopy potentiometric titration, first derivative UV spectrophotometry, 1 H-NMR and X-ray diffraction. Chitosan extracted from squid pen chitin is inherently purer than crustacean chitosans, it does not contain large amounts of calcium carbonate, and it does contain large amounts of protein. The purity of squid pen chitosan makes it particularly suitable for medical and cosmetic application. Application of radiation for the formation of hydrogels for medical use offers a unique possibility to combine the formation and sterilization of the product in a single technological step. The main aim of this study is to synthesis poly(vinyl alcohol) hydrogels containing different moieties of chitosan by gamma irradiation at a dose of 25 kGy, and investigate the antibacterial effect of chitosan contained in the hydrogel

  12. Biokinetic studies on 14C-chitosan in rats

    International Nuclear Information System (INIS)

    Jia Minghong; Nishimura, Y.; Watanabe, Y.; Yukawa, M.

    1998-05-01

    The absorption and the basic metabolism of chitosan in rats are investigated. The results indicated that 14 C-chitosan from gastrointestinal tract was absorbed, metabolized and excreted quickly without re-bioavailability. The radioactive compounds perhaps with specifically chemical forms in serum, liver and the contents of small intestines were separated on GPC column and measured by radioactivity counting. A big pile of peaks with the retention volume almost same as that of standard 14 C-chitosan and another sharp one with the retention volume in the range of higher molecular weight same as that of BSA were discovered in analysis respectively for contents of intestine and serum or liver. The sharp peak would disappear if the proteins contained in the serum or liver were removed. In addition, and interesting tail peak, followed with the pile ones and eluted with the retention volume of lower molecular weight range same as that of chitooligosaccharides was also found in each of the 3 samples, ignoring the protein removal or not. These results suggested that most of 14 C-chitosan was not to be digested in intestine. On the other hand, a small amount of 14 C-chitosan was likely to be absorbed directly or after degraded to small molecular compounds into blood, liver and other tissues, and then connected with the proteins. Perhaps it is these trace materials that were playing important roles in reduction of the bioavailability of radiostrontium in rats

  13. Thermal Degradation of Lead Monoxide Filled Polymer Composite Radiation Shields

    International Nuclear Information System (INIS)

    Harish, V.; Nagaiah, N.

    2011-01-01

    Lead monoxide filled Isophthalate resin particulate polymer composites were prepared with different filler concentrations and investigated for physical, thermal, mechanical and gamma radiation shielding characteristics. This paper discusses about the thermo gravimetric analysis of the composites done to understand their thermal properties especially the effect of filler concentration on the thermal stability and degradation rate of composites. Pristine polymer exhibits single stage degradation whereas filled composites exhibit two stage degradation processes. Further, the IDT values as well as degradation rates decrease with the increased filler content in the composite.

  14. Comparison of chitosan nanoparticles and chitosan hydrogels for vaccine delivery

    DEFF Research Database (Denmark)

    Gordon, Sarah; Saupe, Anne; McBurney, Warren

    2008-01-01

    In this work the potential of chitosan nanoparticles (CNP) and thermosensitive chitosan hydrogels as particulate and sustained release vaccine delivery systems was investigated. CNP and chitosan hydrogels were prepared, loaded with the model protein antigen ovalbumin (OVA) and characterised...... of the release of fluorescently-labelled OVA (FITC-OVA) from CNP and chitosan hydrogels in-vitro showed that approximately 50% of the total protein was released from CNP within a period of ten days; release of antigen from chitosan gel occurred in a more sustained manner, with ... released after 10 days. The slow release from gel formulations may be explained by the strong interactions of the protein with chitosan. While OVA-loaded CNP showed no significant immunogenicity, formulations of OVA in chitosan gel were able to stimulate both cell-mediated and humoral immunity in-vivo....

  15. Research and development on radiation processing in Sri Lanka

    International Nuclear Information System (INIS)

    Kulatunge, S.S.; Motha, L.; Sultanbawa, Y.; Malavipathirana, S.; Silva, A de; Nanayakkara, S.; Hewajulige, I.G.N.; Silva, K.R.C de

    2008-01-01

    Research on radiation processing of natural polymer such as polysaccharides of chitosan, cellulose, carrageenan has been carried out in Sri Lanka since the year 2004. The research group have been involving in development activities on application of chitin and chitosan for wound dressing, irradiated chitosan on shelf life extension of fruits such as papaya, banana, mangoes, radiation crosslinked super-absorbent hydrogel from sodium carboxymethyl cellulose by radiation processing. Hydrogels prepared with PVA/Carrageenan/Agar has been studied on guinea pigs to determine the wound healing effect. Irradiated chitosan powder and chitosan solution was studied in vitro and found chitosan solution (1%) directly subjected to irradiation dosages even at 5 kGy was highly effective in control of anthracnose causing organism of papaya. In vivo studies with irradiated 1% chitosan solution on Rathana and red lady variety of papaya shows better control of spoilage of papaya to a considerable extent. The government of Sri Lanka (Ministry of Science and Technology and Atomic Energy Authority) is in the process of establishing the first government owned Multipurpose Gamma Irradiation Facility and it will be helpful to transfer the output of R and D in radiation processing. (author)

  16. Accelerated degradation of the D2 protein of photosystem II under ultraviolet radiation

    International Nuclear Information System (INIS)

    Jansen, M.A.K.; Edelman, M.; Greenberg, B.M.; Gaba, V.

    1996-01-01

    The D2 protein of photosystem II is relatively stable in vivo under photosynthetic active radiation, but its degradation accelerates under UVB radiation. Little is known about accelerated D2 protein degradation. We characterized wavelength dependence and sensitivity toward photosystem II inhibitors. The in vivo D2 degradation spectrum resembles the pattern for the rapidly turning over D1 protein of photosystem II, with rates being maximal in the UVB region. We propose that D2 degradation, like D1 degradation, is activated by distinct photosensitizers in the UVB and visible regions of the spectrum. In both wavelength regions, photosystem II inhibitors that are known to be targeted to the D1 protein affect D2 degradation. This suggests that degradation of the two proteins is coupled, D2 degradation being influenced by events occurring at the Q B niche on the D1 protein. (Author)

  17. Chitosan and chemically modified chitosan beads for acid dyes sorption

    Institute of Scientific and Technical Information of China (English)

    AZLAN Kamari; WAN SAIME Wan Ngah; LAI KEN Liew

    2009-01-01

    The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and AB 25. It was shown that the adsorption capacities of chitosan were comparatively higher than chitosan-EGDE for both acid dyes. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3+ on chitosan. Langmuir isotherm model showed best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment.

  18. Effectiveness of Gamma Irradiated Chitosan for Fresh Meat Preservation

    International Nuclear Information System (INIS)

    Zahran, D.A.

    2015-01-01

    Chitosan is a food preservative of natural origin that has drawn the attention of scientists working in the field of radiation processing and natural polymer products development. The effectiveness of 1% chitosan (CS) and chitosan oligosaccharides (COS) (chitosan subjected to γ irradiation, 50 or 100 kGy) dipping to preserve fresh beef slices during refrigerated storage was investigated. The microbiological quality, lipid and color stability were evaluated. The results revealed that dipping in 1% CS, COS 50 and COS 100 significantly (Ρ< 0.05) improved the microbiological quality and reduced lipid oxidation in beef samples compared to the control samples. On day 7, control samples were considered rejected from the microbiological and lipid oxidation point of view. Dipping in 1% COS 100 significantly (p< 0.05) influenced color properties compared with the other groups. It could be concluded that dipping in 1% COS improved quality parameters of fresh beef and could be used in preservation.

  19. Radiation degradation of molasses pigment. 2. Molecular weight fraction

    International Nuclear Information System (INIS)

    Sawai, Teruko; Sekiguchi, Masayuki; Tanabe, Hiroko

    1996-01-01

    Water demand in Tokyo has increased rapidly. Because of the scarcity of water sources within the city, Tokyo is dependent on water from other prefectures. Recycling of municipal effluent is an effective means of coping with water shortage in Tokyo. We have studied the radiation treatment of waste water for recycling. The degradation of molasses pigments in waste water from yeast factory by radiation was investigated. The dialyzed molasses pigments and non-dialyzed samples in waste waters were compared in chromaticity, UV absorption, color different and COD. The dialysis and fractionation by permeable membrane were carried out with Seamless Cellulose tubing (Union Carbide Corporation) and spectra/Por membrane (Spectrum Medical Industries INC.) The TOC values decreased and the dark brown color faded with increasing dose. The high molecular weight components of molasses pigment were degraded to lower molecular weight substances and decomposed to carbon dioxide. The relationships between the value of chromaticity/TOC and molecular weight of molasses pigments were obtained by radiation. (author)

  20. Modification of chitosan membranes with nanosilica particles as polymer electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kusumastuti, Ella, E-mail: ella.kusuma@gmail.com; Siniwi, Widasari Trisna, E-mail: wsiniwi@gmail.com; Mahatmanti, F. Widhi; Jumaeri [Department of Chemistry, Faculty of Mathematics and Natural Sciences, State University of Semarang D6 Building 2" n" d floor, Sekaran Unnes Campus, Gunungpati, Semarang (Indonesia); Atmaja, Lukman; Widiastuti, Nurul [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Tenth November Institute of Technology Keputih ITS Campus, Sukolilo, Surabaya (Indonesia)

    2016-04-19

    Chitosan has been widely used as polymer matrix for Polymer Electrolyte Membrane (PEM) application replacing Nafion which has shortcomings in terms of high methanol permeability that degrades the performance of fuel cells. Chitosan membranes modification is performed by adding nanosilica to prevent methanol transport through the membrane. Nanosilica is synthesized by sol-gel method and the particle diameter is obtained by analysis using Breunner Emmet Teller (BET) that is 6.59 nm. Nanosilica is mixed with chitosan solution to obtain nanosilica-chitosan as polymer electrolyte membrane. The membranes are synthesized through phase inversion method with nanosilica composition including 0; 0.5; 1; 2; 3; 5; and 10% w/w of chitosan. Characterization of the membranes indicate that the results of water swelling, proton conductivity and methanol permeability of the membrane with 3% nanosilica respectively were 49.23%, 0.231 S/cm, and 5.43 x 10{sup −7} cm{sup 2}/s. Based on the results of membrane selectivity calculation, the optimum membrane is the composition of 3% nanosilica with value 5.91 x 105 S s cm{sup −3}. The results of functional groups analysis with FTIR showed that it was only physical interaction that occurred between chitosan and nanosilica since no significant changes found in peak around the wave number 1000-1250 cm{sup −-1}.

  1. Effect of radiation and alkylating agents on chromatin degradation in normal and malignant lymphoid cells

    International Nuclear Information System (INIS)

    Ryabchenko, N.I.; Yurashkova, V.; Ivannik, B.P.; Konov, A.V.; Drashil, V.

    1991-01-01

    Regularities of chromatin degradation in thymocytes and LS/BL tumor cells have been investigated. It has been shown that the rate of DNA degradation by Ca/Mg-dependent endonuclease in LS/BL tumor cells is 25 times lower than that in thymocytes, and radiation does not induce chormatin degradation. The alkylating agent TS 160 causes chromatin degradation in both LS/Bl cells and thymocytes. In contrast to radiation TS 160 inhibits the endogenous chromatin degradation by Ca/Mg-dependent endonuclease in thymocytes

  2. Radiation degradation of cellulose

    International Nuclear Information System (INIS)

    Leonhardt, J.; Arnold, G.; Baer, M.; Langguth, H.; Gey, M.; Huebert, S.

    1985-01-01

    The application of straw and other cellulose polymers as feedstuff for ruminants is limited by its low digestibility. During recent decades it was attempted to increase the digestibility of straw by several chemical and physical methods. In this work some results of the degradation of gamma and electron treated wheat straw are reported. Complex methods of treatment are taken into consideration. In vitro-experiments with radiation treated straw show that the digestibility can be increased from 20% up to about 80%. A high pressure liquid chromatography method was used to analyze the hydrolysates. The contents of certain species of carbohydrates in the hydrolysates in dependence on the applied dose are given. (author)

  3. Influence of Chitosan Treatment on Surrogate Serum Markers of Cholesterol Metabolism in Obese Subjects

    Directory of Open Access Journals (Sweden)

    Dieter Lütjohann

    2018-01-01

    Full Text Available Chitosan treatment results in significantly lower serum low density lipoprotein (LDL cholesterol concentrations. To assess the working mechanisms of chitosan, we measured serum surrogate markers of cholesterol absorption (campesterol, sitosterol, cholestanol, synthesis (lathosterol, lanosterol, desmosterol, and degradation to bile acids (7α-hydroxy-cholesterol, 27-hydroxy-cholesterol, corrected for cholesterol concentration (R_sterols. Over 12 weeks, 116 obese subjects (Body Mass Index, BMI 31.7, range 28.1–38.9 kg/m2 were studied under chitosan (n = 61 and placebo treatments (n = 55. The participants were briefly educated regarding improvement of nutrition quality and energy expenditure. Daily chitosan intake was 3200 mg. Serum LDL cholesterol concentration decreased significantly more (p = 0.0252 under chitosan (−8.67 ± 18.18 mg/dL, 5.6% than under placebo treatment (−1.00 ± 24.22 mg/dL, 0.9%. This reduction was not associated with the expected greater decreases in markers of cholesterol absorption under chitosan treatment. Also, increases in markers of cholesterol synthesis and bile acid synthesis under chitosan treatment were not any greater than under placebo treatment. In conclusion, a significant selective reduction of serum LDL cholesterol under chitosan treatment is neither associated with a reduction of serum surrogate markers of cholesterol absorption, nor with increases of markers for cholesterol and bile acid synthesis.

  4. Effect of chitosan addition and gamma radiation on polymeric blends of PVP and PVAL; Efeito da adicao de quitosana e da radiacao gama em blendas polimericas de PVP e PVAL

    Energy Technology Data Exchange (ETDEWEB)

    Terence, M.C.; Castro, P.J.; Miranda, L.F.; Faldini, S.B., E-mail: mauroterence@yahoo.com.b [Universidade Presbiteriana Mackenzie, Sao Paulo. SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    The objective of this project is the study of the effect of chitosan addition and the radiation with gamma rays. The polymeric blend usage is a recent development that expanded the applications of the polymers, due to the improvement of the properties of a single polymer. The PVP and PVAL were chosen because they present the main required characteristics to the formation of a hydrogel, such as water absorption and crosslinking, and the chitosan to improve the interaction between the hydrogel and the organism. The flexibility of the PVP was added with the mechanical resistance of the PVAL and the chitosan biocompatibility. With a defined concentration of PVP and PVAL, films of this blend was irradiated and also solutions with different concentrations of chitosan was prepared to obtain new films of this blend. After obtaining the films, some assays were realized to evaluate the mechanical properties. (author)

  5. Poly(vinyl pyrrolidone)-Chitosan implant for endoscopic treatment of vesicoureteral reflux

    International Nuclear Information System (INIS)

    Relleve, Lorna S.; Abad, Lucille V.; Aranilla, Charito T.; Dela Rosa, A.M.; Bolong, David T.; Bisnar, Carlo C.

    2008-01-01

    Radiation-crosslinked poly(vinyl pyrrolidone) (PVP)-Chitosan was prepared as a potential injectable implant for endoscopic treatment of vesicoureteral reflux (VUR). The physical and histological properties of PVP-Chitosan implant in comparison with the commercial dextranomer/hyaluronic acid copolymer (Deflux) have been evaluated in vivo by subcutaneous and abdominal injection in rats over a period of 6 months. The PVP-Chitosan implant was easily injected through 26-gauge needle. Monthly gross examination of the implanted sites showed no significant decrease in volume of implant and no local inflammatory reaction. Histological findings indicated no evidence of migration to the distant organs after 6 months of implantation. Results of this study indicated that PVP-Chitosan implant has properties of a good tissue augmenting substance such as stability, biocompatibility and non-migration but long-term studies are needed to evaluate its therapeutic efficiency. (author)

  6. Controlling of degradation effects in radiation processing of polymers

    International Nuclear Information System (INIS)

    2009-05-01

    The interest of Member States of the IAEA in introducing radiation technology into the polymer and plastics industry is growing. This publication summarizes a number of studies conducted in the framework of a coordinated research project (CRP) on controlling of degradation effects on polymers by radiation processing technologies. It reviews a variety of applications and details the most important results and achievements of the participating centres and laboratories during the course of the CRP. The publication is intended to be of use to scientists implementing the technology and managers of radiation processing facilities

  7. Evaluation of a collagen-chitosan hydrogel for potential use as a pro-angiogenic site for islet transplantation.

    Directory of Open Access Journals (Sweden)

    Joanne E McBane

    Full Text Available Islet transplantation to treat type 1 diabetes (T1D has shown varied long-term success, due in part to insufficient blood supply to maintain the islets. In the current study, collagen and collagen:chitosan (10:1 hydrogels, +/- circulating angiogenic cells (CACs, were compared for their ability to produce a pro-angiogenic environment in a streptozotocin-induced mouse model of T1D. Initial characterization showed that collagen-chitosan gels were mechanically stronger than the collagen gels (0.7 kPa vs. 0.4 kPa elastic modulus, respectively, had more cross-links (9.2 vs. 7.4/µm(2, and were degraded more slowly by collagenase. After gelation with CACs, live/dead staining showed greater CAC viability in the collagen-chitosan gels after 18 h compared to collagen (79% vs. 69%. In vivo, collagen-chitosan gels, subcutaneously implanted for up to 6 weeks in a T1D mouse, showed increased levels of pro-angiogenic cytokines over time. By 6 weeks, anti-islet cytokine levels were decreased in all matrix formulations ± CACs. The 6-week implants demonstrated increased expression of VCAM-1 in collagen-chitosan implants. Despite this, infiltrating vWF(+ and CXCR4(+ angiogenic cell numbers were not different between the implant types, which may be due to a delayed and reduced cytokine response in a T1D versus non-diabetic setting. The mechanical, degradation and cytokine data all suggest that the collagen-chitosan gel may be a suitable candidate for use as a pro-angiogenic ectopic islet transplant site.

  8. Antibacterial activity of irradiated and non-irradiated chitosan and chitosan derivatives against Escherichia coli growth

    International Nuclear Information System (INIS)

    Tg Ahbrizal Farizal Tg Ahmad; Norimah Yusof; Kamarudin Bahari; Kamaruddin Hashim

    2006-01-01

    Samples of chitosan and four chitosan derivatives [ionic chitosan, chitosan lactate, carboxymethyl chitosan (C) and carboxymethyl chitosan (L)] were studied for their antibacterial activities against Escherichia coli growth. Chitosan and chitosan derivatives were prepared at concentrations 20, 100, 1000, 10000 ppm and 250, 1000, 5000, 10000, 20000 ppm, respectively. Each of the samples was tested before and after irradiation with electron beam at 25 kGy. The turbidity of bacterial growth media was measured periodically at 0, 0.5, 1, 2, 4, 6 and 24 h after inoculation using the optical density method. The results indicated that non- irradiated chitosan inhibited E. coli growth at 20 and 100 ppm. Meanwhile, irradiated chitosan at 100 and 1000 ppm concentration inhibited E. coli growth. Both irradiated and non-irradiated ionic chitosan inhibited E. coli growth at all concentrations used. Chitosan lactate was found to inhibit E. coli at concentration as low as 5000 ppm for both irradiated and non-irradiated samples. E. coli growth was not inhibited by carboxymethyl chitosan (C) and carboxymethyl chitosan (L), before and after irradiation. The findings suggested that chitosan has greater antibacterial activity as compared to the chitosan derivative samples. (Author)

  9. On the mechanisms of the radiation-induced degradation of cellulosic substances

    Science.gov (United States)

    Tissot, Chanel; Grdanovska, Slavica; Barkatt, Aaron; Silverman, Joseph; Al-Sheikhly, Mohamad

    2013-03-01

    Much interest has been generated in utilizing ionizing radiation for the production of bio-fuels from cellulosic plant materials. It is well known that exposure of cellulose to ionizing radiation causes significant breakdown of the polysaccharide. Radiation-induced degradation of cellulose may reduce or replace ecologically hazardous chemical steps in addition to reducing the number of processing stages and decreasing energy consumption.

  10. Preparation of poly(vinyl alcohol)/chitosan/starch blends and studies on thermal and surface properties

    Science.gov (United States)

    Nasalapure, Anand V.; Chalannavar, Raju K.; Malabadi, Ravindra B.

    2018-05-01

    Biopolymers are abundantly available from its natural sources of extraction. Chitosan(CH) is one of the widely used natural polymer which is perspective natural polysaccharide. Natural polymer blend with synthetic polymer enhances property of the material such as polyvinyl alcohol (PVA). PVA is nontoxic degradable synthetic polymer and very good film forming polymer. In this study prepared hybrid based film by adding starch into Chitosan/PVA which slighlty increased the surface and thermal property of ternary blend film.

  11. The Use of Radiation-Induced Degradation in Controlling Molecular Weights of Polysaccharides : The Effect of Humidity

    International Nuclear Information System (INIS)

    Sen, M.

    2006-01-01

    Better understanding of chemistry of radiation-induced degradation is becoming of increasing importance on account of the utilization of polymeric materials in a variety of radiation environments as well as beneficial uses of degraded polymers. It is very well known that polysaccharides in dry form or in solution degrade when exposed to ionizing radiation. In this study degrading effect of radiation has been considered from the point of view of controlling the molecular weights of kappa- and iota-carrageenans and sodium alginate irradiated under varying environmental conditions. The humidity equilibrated polymer samples kept over saturated aqueous salt solutions of NaCl, NaNO 3 and MgCl 2 were irradiated in a Gammacell 220 at room temperature. The degradation was investigated in detail by a careful Gel Permeation Chromatographic analysis of their respective molecular weights before and after irradiation Alexander-Charlesby-Ross equation was used in determining their radiation-chemical yields. Degradation yield is the highest for dry irradiated kappa- (G(S) = 0.73) and iota-carrageenans (G(S) = 2.43) and with small amount of water taken up from surrounding humidity degradation becomes less pronounced and G(S) values show a decrease down to G(S) = 0.16 and 0.87 at 75 % relative humidity, respectively. At very high water contents degradation effect again becomes more effective. Sodium alginate has fount to be less sensitive to the effect of humidity. When there is small amount of water in the polysaccharide structure, it is unlikely to expect an indirect effect of radiation. The water located in between the polymer chains however can give enough mobility to kappa and iota karrageenans chains, plastifying effect, which may enhance the radical-radical combinations thus lowering the rate of degradation hence reducing G(S) values

  12. Hemostatic foam from radiation-modified carboxymethyl derivative of chitosan

    International Nuclear Information System (INIS)

    Barba, Bin Jeremiah D.; Aranilla, Charito T.; Vista, Jeanina Richelle M.; Relleve, Lorna S.; Abad, Lucille V.

    2015-01-01

    A hemostatic agent or hemostat is intended to accelerate the blood clotting process when applied to a bleeding surface, such as those in military and civilian wound trauma or in surgery. Natural polymers like chitosan (Ch) has been previously used as raw material in developing hemostats owing to their bioavailability and biocompatibility. Hydrogels were made from its carboxymethylated derivate (CMCh) and were crosslinked by gamma irradiation at a dose of 30 kGy. Further processing was done by salt leaching with sodium chloride and lyophilization to produce the foam hemostat. The final products were then radiation-sterilized at 25 kGy. The use of gamma radiation for both the crosslinking and sterilization process preserves the biocompatibility of the product unlike conventional methods that may require the use of harmful and non-biocompatible chemicals. The hemostatic efficacy of the designed foam hemostats was compared to the commercially available foam hemostat, GELFOAM Sterile Compressed Sponge by Pfizer. The results showed a significantly higher efficiency of the designed products using in vitro test to determine blood clotting index and platelet adhesion capacity. Characterization by gel fraction, swelling capacity and SEM imaging indicated a hydrophilic three-dimensional network which can be attributed for the thrombogenicity of the foams produced. The foam structure can act as a physical matrix for platelet adhesion forming the mechanical plug and at the same time, rapidly absorb water thereby locally increasing the concentration of platelets and physiological coagulation factors that will contribute to quick and efficient hemostasis. The designed products will provide the healthcare and military sector with a local alternative to the commercial products which are both expensive (USD 85 per piece) and not readily accessible in the Philippine market. Further animal efficacy and biocompatibility studies are recommended to supplement the positive in vitro

  13. Edible Film from Polyblend of Ginger Starch, Chitosan, and Sorbitol as Plasticizer

    Science.gov (United States)

    Sariningsih, N.; Putra, Y. P.; Pamungkas, W. P.; Kusumaningsih, T.

    2018-03-01

    Polyblend ginger starch/chitosan based edible film has been succesfully prepared and characterized. The purpose of this research was to produce edible film from polyblend of ginger starch, chitosan, and sorbitol as plasticizer. The resulted edible film were characterized by using FTIR, TGA and UTM. Edible film of ginger starch had OH vibration (3430 cm-1). Besides, edible film had elongation up to 15.63%. The thermal degradation of this material reached 208°C indicating high termal stability. The water uptake of the edible film was 42.85%. It concluded that edible film produce in this research has potential as a packaging.

  14. Effects of extraction parameters on physicochemical and functional characteristics of chitosan from Penaeus monodon shell

    Directory of Open Access Journals (Sweden)

    Jubril Olayinka Akolade

    2016-11-01

    Full Text Available Objective: To investigate the effect of extraction parameters with particular interest during the microwave deacetylation process on the characteristics of chitosan produced from Penaeus monodon (P. monodon sourced within the coastal region of Lagos, Nigeria for applications of controlled release systems for pharmaceutical industries. Methods: Chitosan was extracted from shrimp (P. monodon shell and evaluated as a controlled release system for curcumin. Effects of relevant processing parameters on physicochemical and functional characteristics of the extracted chitosan were assessed. The crude chitosan was purified and used to prepare controlled release formulations for curcumin via ionic gelation with tripolyphosphate. Results: Data from the study showed that increasing time and temperature during deproteinization significantly improved the removal of protein bound to the shell matrix. Also, the ratio of the weight of the deproteinized sample to the volume of HCl used for demineralization influenced the process. During microwave-assisted production of chitosan from chitin, increase in the concentration of the deacetylating medium significantly increased solubility, viscosity and degree of deacetylation, whereas increasing temperature and time during deacetylation of chitin degraded the biopolymer to give low molecular weight chitosan. Optimized extraction and purification process yielded absolutely soluble medium to low molecular weight chitosan. The encapsulation efficiency, loading capacity, percentage yield, release efficiencies in simulated gastric and intestinal fluids of curcumin loaded in the formulations of chitosan from P. monodon were compared favorably to encapsulation and release characteristics of the encapsulated curcumin in commercially available chitosan used as the reference. Conclusions: Valorization of shrimp waste into pharmaceutically graded medium molecular weight chitosan was achieved. The chitosan obtained can be used as

  15. Radiation degradation of pharmaceutical residues in water. Chloramphenicol

    International Nuclear Information System (INIS)

    Csay, T.; Racz, G.; Takacs, E.; Wojnarovits, L.

    2011-01-01

    Complete text of publication follows. Traditional wastewater treatment systems primarily rely upon physical, chemical and biological processes. The conventional techniques cannot efficiently remove badly biodegradable pollutants like pesticides, herbicides and drugs from influents. Leaving 'polluted' water flowing freely out to environment may cause unwanted and sometimes unpredictable effects. Degradation or removal of residual organic contaminations from wastewater is an important task both for science and engineering to preserve environment and drinking water. Ionizing radiation treatment of liquid wastes is one of the so called advanced oxidation processes (AOP) leading to decomposition of pharmaceuticals in aqueous solutions. The radiolysis of chloramphenicol (CPL) a broad spectrum antibiotic was investigated under different conditions. Steady-state gamma radiolysis were used to generate various reactive species ( · H, · OH and e aq - ). Reactions were followed by steady state and time resolved UV-Vis spectrometry. Several degradation products were separated and identified by LC-MS/MS. Mineralization was followed by measuring chemical oxygen demand (COD) and total organic carbon content (TOC). The change in toxicity was followed by Microtox, a luminescent bacteria test. Results indicate that ionizing radiation is very effective in degradation of CPL. After irradiating 0.1 mM CPL solutions with 5.0-7.5 kGy doses, no products could be observed indicating that irradiation resulted in complete mineralization.

  16. Biodegradability and Biocompatibility Study of Poly(Chitosan-g-lactic Acid Scaffolds

    Directory of Open Access Journals (Sweden)

    Zhe Zhang

    2012-03-01

    Full Text Available A biodegradable, biocompatible poly(chitosan-g-lactic acid (PCLA scaffold was prepared and evaluated in vitro and in vivo. The PCLA scaffold was obtained by grafting lactic acid (LA onto the amino groups on chitosan (CS without a catalyst. The PCLA scaffolds were characterized by Fourier Transform infrared spectroscopy (FT-IR and scanning electron microscopy (SEM. The biodegradabilty was determined by mass loss in vitro, and degradation in vivo as a function of feed ratio of LA/CS. Bone marrow mesenchymal stem cell (BMSC culture experiments and histological examination were performed to evaluate the PCLA scaffolds’ biocompatibility. The results indicated that PCLA was promising for tissue engineering application.

  17. Degradation of 4-Chloro phenol by gamma radiation of 137Cs and X-rays

    International Nuclear Information System (INIS)

    Gonzalez J, J. C.; Jimenez B, J.; Cejudo A, J.

    2010-01-01

    This paper presents results of radiolytic degradation of 4-chloro phenol in the presence of TiO 2 , Al 2 O 3 and SiO 2 , using different radiation sources than 60 Co, which is so common in this type of experiment. The radiation sources used were X-rays with energy of 100 keV and radiation from 137 Cs (662 keV). After irradiation with a dose of 50 c Gy X-ray and TiO 2 obtained a degradation of about 5%, no degradation was obtained with 137 Cs source and other oxides. This may be due to the fact that X-rays have a linear energy transfer greater value, and in the case of TiO 2 present a crystalline structure, whereas the other two oxides are amorphous. Both characteristics result in better formation of a reactive species that allows the degradation of the compound. (Author)

  18. Laccase-Based CLEAs: Chitosan as a Novel Cross-Linking Agent

    Directory of Open Access Journals (Sweden)

    Alexandre Arsenault

    2011-01-01

    Full Text Available Laccase from Coriolopsis Polyzona was insolubilized as cross-linked enzyme aggregates (CLEAs for the first time with chitosan as the cross-linking agent. Concentrations between 0.01 and 1.867 g/L of chitosan were used and between 0.05 and 600 mM of 1-ethyl-3-(3-dimethylaminopropylcarbodiimide hydrochloride. The laccase was precipitated using ammonium sulphate and cross-linked simultaneously. Specific activity and thermal stability of these biocatalysts were measured. Activities of up to 737 U/g were obtained when 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid (ABTS was used as a substrate. Moreover, the stability of these biocatalysts was improved with regards to thermal degradation compared to free laccase when exposed to denaturing conditions of high temperature and low pH. The CLEAs stability against chemical denaturants was also tested but no significant improvement was detected. The total amount of ABTS to be oxidized during thermal degradation by CLEAs and free laccase was calculated and the insolubilized enzymes were reported to oxidize more substrate than free laccase. The formation conditions were analyzed by response surface methodology in order to determine an optimal environment for the production of efficient laccase-based CLEAs using chitosan as the cross-linking agent. After 24 hours of formation at pH 3 and at 4°C without agitation, the CLEAs exhibit the best specific activity.

  19. Isocyanate-functionalized chitin and chitosan as gelling agents of castor oil.

    Science.gov (United States)

    Gallego, Rocío; Arteaga, Jesús F; Valencia, Concepción; Franco, José M

    2013-06-03

    The main objective of this work was the incorporation of reactive isocyanate groups into chitin and chitosan in order to effectively use the products as reactive thickening agents in castor oil. The resulting gel-like dispersions could be potentially used as biodegradable lubricating greases. Three different NCO-functionalized polymers were obtained: two of them by promoting the reaction of chitosan with 1,6-hexamethylene diisocyanate (HMDI), and the other by using chitin instead of chitosan. These polymers were characterized through 1H-NMR, FTIR and thermogravimetric analysis (TGA). Thermal and rheological behaviours of the oleogels prepared by dispersing these polymers in castor oil were studied by means of TGA and small-amplitude oscillatory shear (SAOS) measurements. The evolution and values of the linear viscoelasticity functions with frequency for -NCO-functionalized chitosan- and chitin-based oleogels are quite similar to those found for standard lubricating greases. In relation to long-term stability of these oleogels, no phase separation was observed and the values of viscoelastic functions increase significantly during the first seven days of ageing, and then remain almost constant. TGA analysis showed that the degradation temperature of the resulting oleogels is higher than that found for traditional lubricating greases.

  20. Effect of x-radiation on SERS spectra of chitosan adsorbed on silver nanoparticles with plasmon resonance

    International Nuclear Information System (INIS)

    Motevich, I.G.; Strekal', N.D.; Dul', M.V.; Ganchits, A.T.; Lagun, Yu.Ya.; Melamed, V.D.; Maskevich, S.A.

    2016-01-01

    Chitosan, a deacetylated product of the polysaccharide chitin, is a natural biopolyaminosaccharide obtained from various organisms. Raman and SERS spectra of irradiated and unirradiated chitosan, adsorbed on silver hydrosols, are presented. (authors)

  1. Graphite epoxy composite degradation by space radiation

    International Nuclear Information System (INIS)

    Taheri, M.; Sandquist, G.M.; Slaughter, D.M.; Bennion, J.

    1991-01-01

    The radiation environment in space is a critical consideration for successful operation in space. All manned space missions with a duration of more than a few days are subjected to elevated ionizing radiation exposures, which are a threat to both personnel and structures in space. The increasing demands for high-performance materials as structural components in the aerospace, aircraft, and defense industries have led to the development of materials such as graphite fiber-reinforced, epoxy resin matrix composites (Gr/Ep). These materials provide important advantages over conventional structural materials, such as ultrahigh specific strength, enhanced specific moduli, and better fatigue resistance. The fact that most advanced composite materials under cyclic fatigue loading evidence little or no observable crack growth prior to rapid fracture suggests that for fail-safe considerations of parts subject to catastrophic failure, a detailed evaluation of radiation damage from very energetic particle is crucial. The Gr/Ep components are believed to suffer severe degradation in space due to highly penetrating secondary radiation, mainly from neutrons and protons. Investigation into the performance and stability of Gr/Ep materials are planned

  2. Degradation of polylactic acid (Pla) at different doses of gamma radiation

    International Nuclear Information System (INIS)

    Castillo R, Y.

    2015-01-01

    The excessive use of polymers such as polyethylene (PET), polystyrene (Ps) and recently the polylactic acid (Pla) that take more than 20 years to degrade, have caused great pollution in the environment. In this study the effects of gamma radiation in the Pla to different doses were studied, in order to reduce the degradation time of this polymer. The changes in physico-chemical structure of Pla during radiation were studied by thermo-gravimetric/Mass analysis; differential scanning calorimetry; scanning electron microscopy; X-ray dispersive analysis; infrared spectroscopy; X-ray diffraction and mechanical tests of hardness, elasticity and deformation. With scanning electron microscopy, the morphology of the Pla surface unirradiated was observed, in which an apparently smooth surface was observed, after changes that had the Pla when irradiated also was observed, where the effects of radiation were observed in form of scratch, agglomeration and small fractures. By X-ray dispersive analysis was determined and verified the elemental chemical composition of the Pla; as expected the tests showed only carbon, oxygen and hydrogen. With thermo-gravimetric/Mass analysis the decomposition temperatures of Pla were determined, identifying that the degradation compounds are CO, CO 2 and CH 4 . With infrared spectrometry the major peaks of Pla were observed before and after being irradiated with increasing of radiation dose the intensity of the bands decreased. Also by X-ray diffraction was observed that the polymer is an amorphous material. The mechanical tests indicate that the values of each of the tests decrease significantly with increasing the radiation dose. (Author)

  3. Preparation of thermal-responsive chitosan-graft-N-isopropylacrylamide membranes via γ-ray irradiation

    International Nuclear Information System (INIS)

    Mu Qing; Fang Yue'e

    2006-01-01

    Poly(N-isopropylacrylamide) (PNIPAAm) has been attracting increasing attention because of its thermosensitivity. Many authors have studied the reaction of chitosan with NIPAAm, with most of the interest being focused on hydrogels. Few research programs, however, were about chitosan membranes grafted with NIPAAm monomer. In this study, a novel thermo-sensitive switching membrane was prepared by radiation-induced simultaneous grafting of NIPAAm onto chitosan membrane. Fourier transform infrared spectroscopy (FT-IR) was used to identify structure of the grafted membranes. Compared to FT-IR spectra of pristine chitosan, the new band at 1535 cm-1 in the grafted membrane was attributed to amide II of PNIPAAm. This indicated that NIPAAm was introduced onto the chitosan membrane. Surface morphology of the grafted membrane was different from the pristine chitosan membrane. The SEM images revealed cypress leaf-like structures adhered tightly to the grafted membrane surface, in comparison to smooth surface of the pristine chitosan membrane. Pure water flux measurements showed that the grafted membrane decreased with the increasing temperature, while water flux of pristine chitosan membrane was constant. It was found that the grafted membrane was sensitive to temperature. The effects of dose, dose rate and the concentration of NIPAAm on the grafting percentage were discussed. The graft yield increased with the monomer concentration and the absorbed dose. (authors)

  4. Effects of Polarization–Maintaining Fibre Degrading on Precision of Fibre Optic Gyroscopes in Radiation Environment

    International Nuclear Information System (INIS)

    Wen, Xiao; De-Wen, Liu; Yang, Liu; Xiao-Su, Yi; Lin, Cong

    2008-01-01

    In the space environment, the precision of fibre optic gyroscopes (FOGs) degrades because of space radiation. Photonic components of FOGs are affected by radiation, especially the polarization-maintaining (PM) fibre coil. In relation to the space radiation environment characteristic, we have carried out a series of radiation experiments on a PM fibre coil with 60 Co radiation source at different dose rates. Based on the experimental results, the formula between the PM-fibre loss and radiation dose rate is built, and the relation between the precision of FOG and radiation dose is obtained accordingly. The results strongly show that the precision of our FOG degrades owing to the attenuation of the polarization-maintaining fibre, which provides theoretical foundation for the radiation-resistant design of the FOG

  5. Weight Measurement Chitosan Molecule using GPC-MALLS

    International Nuclear Information System (INIS)

    Mohd Yusof Hamzah; Norhashidah Talip; Maznah Mahmud

    2011-01-01

    Research on basic characteristics and application of practical chitosan are need in order to understand their physical and chemical properties of this materials. One of the physico chemical properties that important for every polymers is absolute molecular weights. The important of this aspects has give big impacts on non colligative of the polymers, for example, viscosity, solubility and so on. Absolute weight molecular weights of each polymers can be measured by using GPC-MALLS. This device functioned as molecular size separator and molecular weight measurement by integration of the information such as sample concentration, light scattering index and sample reaction information using laser radiation irradiated from 18 angles.In this scope, we will discuss deeply on absolute weight molecular measurement of chitosan by using GPC-MALLS. (author)

  6. Radiation-induced degradation of organic pollutants in wastewater

    International Nuclear Information System (INIS)

    Bagyo, A.N.M.; Lindu, W.A.; Sadjirun, S.; Winarno, E.K.; Widayat, E.; Aryanti; Winarno, H.

    2001-01-01

    The degradation and decolouration of organic pollutants, i.e. dye stuffs and phenolic compounds, by gamma irradiation have been studied. First, samples from effluent of textile industry were taken to be irradiated at a certain condition. Irradiation was done after dissolving the samples five times with distilled water in laboratory scale, followed by upscaling those samples into 5 litre in volume. Irradiation was done at a dose of 0- 25 kGy, aerated and a dose rate of 5 kGy/h. The parameters examined were the change of absorption spectra. COD (Chemical Oxygen Demand), the percentage of the degradation, the change of pH and degradation product using HPLC. It was demonstrated that the dilution of sample enhanced the degradation and decreased the COD values. The degradation product of textile wastewater is mainly oxalic acid. Second, the effects of radiation on aerated phenolic compounds mixture, i.e. resorcinol, o-cresol and m- cresol were done. Individual phenol was studied followed by mixture of the phenolic compounds. Irradiation was done in aerated condition with doses of 0-10 kGy, dose rate of 5 kGy/h and pH range from 3 to 12. The initial concentration of resorcinol, o-cresol and w-cresol were 50 ppm and 60 ppm for phenolic compounds mixture, respectively. Parameters examined were absorption spectrum, pH, and degradation products. The uv-vis absorption of the solution were observed before and after irradiation. HPLC was used to determine the products of degradation. Degradation of resorcinol, w-cresol and o-cresol could be achieved at dose of 6 kGy at pH 9, while o-cresol in acid condition (pH 3). The degree of degradation for resorcinol, w-cresol and o-cresol at above conditions were 90%, 88% and 45%, respectively. Degradation of phenolic compound mixture occurred at a dose of 7.5 kGy and pH 9', at this condition almost 99% of phenolic compounds degraded. Oxalic acid was the main degradation product. (author)

  7. Study of the influence of ZnO addition on the properties of chitosan-banana starch bioplastics

    Science.gov (United States)

    Sapei, L.; Padmawijaya, K. S.; Sijayanti, O.; Wardhana, P. J.

    2017-07-01

    Plastics have been widely used in our daily life due to their relatively low cost and practical uses. However, plastics are hardly degraded and thus creating lots of environmental problems. Bioplastics have been developed in order to replace the conventional plastics since they are easily degraded and environmentally friendly. In this research, chitosan-banana starch bioplastics were made with the ratio of 70:30 in the presence of 30% glycerol as the plasticizer. ZnO with varying concentrations of 1, 3, and 5% were added into the biopolymer mixtures before casting in order to improve their mechanical properties. It turned out that 3% ZnO significantly increased the bioplastics tensile strength up to ~36MPa. Vice versa, elongation and swelling percentage were decreased as ZnO concentrations increased. Bioplastics prepared with 3% ZnO were degraded within relatively short time in 90 min. These chitosan-banana starch bioplastics reinforced by ZnO seems quite promising to substitute some commercial conventional plastics.

  8. Comparison of cadmium adsorption onto chitosan and epichlorohydrin crosslinked chitosan/eggshell composite

    Science.gov (United States)

    Rahmi; Marlina; Nisfayati

    2018-05-01

    The use of chitosan and epichlorohydrin crosslinked chitosan/eggshell composite for cadmium adsorption from water were investigated. The factors affecting adsorption such as pH and contact time were considered. The results showed that the optimum pH of adsorption was pH = 6.0 and the equilibrium time of adsorption was 40 min. The adsorption isotherm of Cd ions onto chitosan and composite were well fitted to Langmuir equation. The maximum adsorption capacity (fitting by Langmuir model) of chitosan and composite were 1.008 and 11.7647 mg/g, respectively. Adsorption performance of composite after regeneration was better than chitosan.

  9. Preparation of Chito-Oligomers by Hydrolysis of Chitosan in the Presence of Zeolite as Adsorbent

    Science.gov (United States)

    Ibrahim, Khalid A.; El-Eswed, Bassam I.; Abu-Sbeih, Khaleel A.; Arafat, Tawfeeq A.; Al Omari, Mahmoud M. H.; Darras, Fouad H.; Badwan, Adnan A.

    2016-01-01

    An increasing interest has recently been shown to use chitin/chitosan oligomers (chito-oligomers) in medicine and food fields because they are not only water-soluble, nontoxic, and biocompatible materials, but they also exhibit numerous biological properties, including antibacterial, antifungal, and antitumor activities, as well as immuno-enhancing effects on animals. Conventional depolymerization methods of chitosan to chito-oligomers are either chemical by acid-hydrolysis under harsh conditions or by enzymatic degradation. In this work, hydrolysis of chitosan to chito-oligomers has been achieved by applying adsorption-separation technique using diluted HCl in the presence of different types of zeolite as adsorbents. The chito-oligomers were retrieved from adsorbents and characterized by differential scanning calorimetry (DSC), liquid chromatography/mass spectroscopy (LC/MS), and ninhydrin test. PMID:27455287

  10. Degradation kinetics and mechanism of penicillin G in aqueous matrices by ionizing radiation

    Science.gov (United States)

    Chu, Libing; Zhuang, Shuting; Wang, Jianlong

    2018-04-01

    The gamma radiation induced-degradation of a β-lactam antibiotic, penicillin G was investigated in aqueous solution. Special attention was paid to the effects of the organic substances such as peptone and glucose on penicillin G degradation, which can be found in the wastewater of the factories producing antibiotics. Results showed that gamma radiation was effective to degrade and deactivate penicillin G in pure water. With the initial concentrations of 0.27 mM, 1.34 mM and 2.68 mM, a complete removal of penicillin G could be achieved at the adsorbed doses of 2.5 kGy, 10 kGy and 20 kGy, respectively. Penicilloic acid from the β-lactam ring cleavage and a series of fragment compounds such as thiazolidine and penicillic acid were identified during gamma irradiation-induced degradation of penicillin G. Addition of Fe2+ was efficient to enhance the mineralization. The TOC removal efficiency of penicillin G was 21.7% using gamma irradiation alone at 10 kGy, which increased to 56.4% with 1.0 mM Fe2+ addition. The gamma radiation-induced degradation of penicillin G was inhibited in the presence of peptone and glucose and the inhibitive effect increased with increasing their concentrations. The rate constant, k of the pseudo first-order kinetics decreased by 74% and 64% in the presence of 1.0 g/L of peptone and glucose, respectively, and by 96% and 89% in the presence of 10 g/L of peptone and glucose, respectively. The ratio of k/k0 was increased by 1.3 times with H2O2 addition and by 3 times with Fe2+ addition, in the presence of 10 g/L of glucose. Adding Fe2+ was effective to improve the ionizing radiation induced degradation of penicillin G antibiotic in the glucose-containing wastewater.

  11. Degradation of the insecticide ethyl parathion in different environmental matrices by gamma radiation from Cobalt-60

    International Nuclear Information System (INIS)

    Luchini, Luiz Carlos

    1995-01-01

    This work studies the use of gamma radiation from cobalt-60 to induce parathion degradation in different matrices, as well as, quantified GC-NPD and identified by GC-MS, the radiolysis resulting products. Results show that the insecticide was completely degraded in aqueous solution after treatment with 1.0 kGy dosis in a dosis rate of 3.12 kGy h -1 . In methanol, parathion was completely degraded only with 30 kGy at 3.12 kGy h -1 . The metabolites detected after radiolysis were the same formed by biological degradation, i.e, p-nitrophenol, p-aminophenol, paraoxon and aminoparathion. The gamma radiation also degraded paraoxon which is the most toxic metabolite of parathion. It was verified that, not only the total radiation, but also the dosis rate supplied to the aqueous solution had a significant effect on the insecticide degradation, and the formation of metabolites occurred in a selective way respecting the dosis and dosis rate. Otherwise, the gamma radiation did almost not degraded the parathion adsorbed in solid matrices as rice, moist and dry soil, even using dosis of 5,30 and 50 kGy, respectively. The parathion yield and the dosis of gamma radiation needed for 50% reduction of the insecticide initial concentration in aqueous solution were also calculated and presented. Thus, it was verified that irradiation of parathion besides to be an important instrument for environmental decontamination of this pesticide in aqueous matrix, it allows the production of parathion metabolites for ecotoxicological studies. (author)

  12. Radiation degradation of Congo Red in aqueous solution

    International Nuclear Information System (INIS)

    Ma Hongjuan; Wang Min; Yang Ruiyuan; Wang Wenfeng; Shen Zhongqun; Yao Side

    2006-01-01

    About one-half of the dyes used in textile industry are azo dyes, and as a consequence a lot of azo dyes are released into the environment with industrial wastewater. Because of complex structures of the dyes, biological, physical and chemical treatments of dye effluents are inefficient. In this study, radiation degradation of Congo Red in aqueous solutions was investigated in different reaction systems. Both pulsed radiolysis and laser flash photolysis experiments were carried out for better understandings of degradation mechanisms involved in the treatments. Congo Red solutions saturated by air, N 2 O, O 2 , N 2 O or N 2 and added with tert-butanol were irradiated to 0-14.8 kGy. The absorption spectra, degradation efficiency, TOC (total organic carbon) removal and pH changes of the solutions were investigated. The main radiolytic products from Congo Red samples irradiated in steady-state were determined by HPLC-MS. And probable reaction mechanisms were proposed. Effects of primary species from water radiolysis, such as e aq - , . OH and . O 2 . /HO 2 . on the degradation behavior of the dye were discussed. Below 5 kGy in γ-rays irradiation, the bleaching efficiency of Congo Red was (N 2 +tert-butanol) >O 2 >air>N 2 O>N 2 . Complete degradation of Congo Red was observed at 4.0, 5.5 and 10.2 kGy irradiation of the aqueous solutions saturated by N 2 with tert-butanol added, O 2 and N 2 O, respectively. With just oxidative or reductive species, highly conjugated part of Congo Red molecules could be destroyed. While oxidative species produced from water radiolysis could oxidize the Congo Red more effectively, making the dye to break into fatty acids and CO 2 finally. In the solution saturated with N 2 and air, the primary active species were both of oxidative and reductive and the highly conjugated part of Congo Red molecules could not be destroyed completely up to 14.8 kGy of γ-ray irradiation. It was more difficult to achieve high TOC removal in comparison with

  13. Oxidation-mediated chitosan as additives for creation of chitosan aerogels with diverse three-dimensional interconnected skeletons

    International Nuclear Information System (INIS)

    Zhang, Sizhao; Feng, Jian; Feng, Junzong; Jiang, Yonggang

    2017-01-01

    Highlights: • A new synthetic method for controlling morphology of chitosan aerogels is proposed. • Chitosan aerogels with nanoflake-like and nanofiber-like were prepared. • Textures of chitosan aerogels are strongly dependent upon the oxidation pattern. - Abstract: Naturally occurring polymer-based aerogels have myriad practical utilizations due to environmentally benign and fruitful resources. However, engineering morphology-controllable biomass aerogels still represents a great challenge. Here we present a facile solution to synthesize chitosan aerogels having distinguished textures by reacting oxidized chitosan with formaldehyde and chitosan sol. In more detail, chitosan was chemically oxidized using two types of oxidation agents such as ammonium persulphate (SPD) and sodium periodate (APS) to obtain corresponding oxidized chitosan, subsequently cross-linked with chitosan solution containing formaldehyde to harvest SPD-oxidized chitosan aerogels (SCAs) and APS-SPD-oxidized ones (ASCAs) after aging, solvent exchange and supercritical drying processes. We found that the morphologies of as-prepared chitosan aerogels are strongly dependent upon the oxidation pattern towards chitosan. The structural textures of SCAs and ASCAs appear nanoflake-like and nanofiber-like structures, which may be related to spatial freedom of active groups located in chitosan. Selected area electron diffraction analysis reveals that the crystalline properties of chitosan aerogels generally appear the serious deterioration comparing to raw chitosan owing to their interconnected skeletal structure formation. The occurrence of characteristic groups displays cross-linked chain construction by using chemical state measurements such as FT-IR and XPS. Further, a plausible mechanism for controlling morphology of chitosan aerogels is also established. This new family of method for creation of chitosan aerogels may open up a perspective for biomass aerogels with controllable textures.

  14. Oxidation-mediated chitosan as additives for creation of chitosan aerogels with diverse three-dimensional interconnected skeletons

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Sizhao, E-mail: bule-soul@hotmail.com; Feng, Jian, E-mail: fengj@nudt.edu.cn; Feng, Junzong; Jiang, Yonggang

    2017-02-28

    Highlights: • A new synthetic method for controlling morphology of chitosan aerogels is proposed. • Chitosan aerogels with nanoflake-like and nanofiber-like were prepared. • Textures of chitosan aerogels are strongly dependent upon the oxidation pattern. - Abstract: Naturally occurring polymer-based aerogels have myriad practical utilizations due to environmentally benign and fruitful resources. However, engineering morphology-controllable biomass aerogels still represents a great challenge. Here we present a facile solution to synthesize chitosan aerogels having distinguished textures by reacting oxidized chitosan with formaldehyde and chitosan sol. In more detail, chitosan was chemically oxidized using two types of oxidation agents such as ammonium persulphate (SPD) and sodium periodate (APS) to obtain corresponding oxidized chitosan, subsequently cross-linked with chitosan solution containing formaldehyde to harvest SPD-oxidized chitosan aerogels (SCAs) and APS-SPD-oxidized ones (ASCAs) after aging, solvent exchange and supercritical drying processes. We found that the morphologies of as-prepared chitosan aerogels are strongly dependent upon the oxidation pattern towards chitosan. The structural textures of SCAs and ASCAs appear nanoflake-like and nanofiber-like structures, which may be related to spatial freedom of active groups located in chitosan. Selected area electron diffraction analysis reveals that the crystalline properties of chitosan aerogels generally appear the serious deterioration comparing to raw chitosan owing to their interconnected skeletal structure formation. The occurrence of characteristic groups displays cross-linked chain construction by using chemical state measurements such as FT-IR and XPS. Further, a plausible mechanism for controlling morphology of chitosan aerogels is also established. This new family of method for creation of chitosan aerogels may open up a perspective for biomass aerogels with controllable textures.

  15. In vitro evaluation of electrospun chitosan mats crosslinked with genipin as guided tissue regeneration barrier membranes

    Science.gov (United States)

    Norowski, Peter Andrew, Jr.

    Guided tissue regeneration (GTR) is a surgical technique commonly used to exclude bacteria and soft tissues from bone graft sites in oral/maxillofacial bone graft sites by using a barrier membrane to maintain the graft contour and space. Current clinical barrier membrane materials based on expanded polytetrafluoroethylene (ePTFE) and bovine type 1 collagen are non-ideal and experience a number of disadvantages including membrane exposure, bacterial colonization/biofilm formation and premature degradation, all of which result in increased surgical intervention and poor bone regeneration. These materials do not actively participate in tissue regeneration, however bioactive materials, such as chitosan, may provide advantages such as the ability to stimulate wound healing and de novo bone formation. Our hypothesis is that electrospun chitosan GTR membranes will support cell attachment and growth but prevent cell infiltration/penetration of membrane, demonstrate in vitro degradation predictive of 4--6 month in vivo functionality, and will deliver antibiotics locally to prevent/inhibit periopathogenic complications. To test this hypothesis a series of chitosan membranes were electrospun, in the presence or absence of genipin, a natural crosslinking agent, at concentrations of 5 and 10 mM. These membranes were characterized by scanning electron microscopy, tensile testing, suture pullout testing, Fourier transform infrared spectroscopy, X-ray diffraction, and gel permeation chromatography, and in vitro biodegradation for diameter/morphology of fibers, membrane strengths, degree of crosslinking, crystallinity, molecular weight, and degradation kinetics, respectively. Cytocompability of membranes was evaluated in osteoblastic, fibroblastic and monocyte cultures. The activity of minocycline loaded and released from the membranes was determined in zone of inhibition tests using P. gingivalis microbe. The results demonstrated that genipin crosslinking extended the in vitro

  16. Tailoring the properties and functions of phosphate/silk/Ag/chitosan scaffolds

    International Nuclear Information System (INIS)

    Abdel-Fattah, Wafa I.; Sallam, Abdel Sattar M.; Diab, A.M.; Ali, Ghareib W.

    2015-01-01

    Two novel silk composites of phosphatic phases with nanosilver/chitosan having enhanced biocompatibility were achieved. Hydroxyapatite and octa calcium phosphates were synthesized in situ within silk fibroin/chitosan/nanosilver composites recently studied. Thermo-gravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) verified their thermal behavior. The structural aspects were characterized applying X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscope (FESEM) with EDAX. Additionally X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared spectroscopy (FTIR) were applied. Mercury porosimeter was used to verify the pore size distribution. The in vitro degradation was followed in D-MEM for 48 h in a cumulative manner for five successive periods. Biochemical analyses of Ca, P and total protein using relevant chemical kits and atomic absorption for silver were performed. ANOVA statistics was carried out. Phosphatic crystalline phases along with the presence of silk, chitosan and nano-silver were developed. The diameters of hydroxyapatite and octa calcium phosphate particles were ~ 8–17 nm and 15–22 nm respectively. Comparatively higher degradation of Octa composite possessing higher porosity proved in turn more osteoinduction with in situ apatitic development. - Highlights: • A bottom–up approach controlled the achieved in situ configurations. • The calculated (CI) XDR and (CI) FTIR for both phases are highly conformable. • Post-immersion trimodal pore system was achieved in OCP composite. • Silver nanoparticle inclusion expected to enhance composite bactericidal activity

  17. Utilization of natural polysaccharides by radiation in Korea

    International Nuclear Information System (INIS)

    Lee, Young Keun; Young Chang Nho

    2001-01-01

    Radiation can induce a chemical reaction to modify polymer under even solid conditions or in low temperatures. Radiation crosslinking can be easily adjusted and is easily reproducible by controlling the radiation dose. The finished product contains no residues of substances required to initiate the chemical crosslinking which can restrict the application possibilities. In these studies, hydrogels from a mixture of chitosan and polyvinyl alcohol (PVA)/Poly-N-vinylpyrrolidone (PVP) were made by 'freezing and thawing', or gamma-ray irradiation or two steps of 'freezing and thawing' and gamma-ray irradiation for wound dressing. Mechanical properties such as gelation, water absorptivity, and gel strength were examined to evaluate the hydrogels for wound dressing. The composition of PVA:PVP was 60:40, PVA/PVP: chitosan ratio was in the range 9:1 - 7:3, and the solid concentration of PVA/PVP/chitosan solution was 15wt%. Gamma irradiation doses of 25, 35,50, 60 and 70kGy were exposed to a mixture of PVA/PVP/chitosan to evaluate the effect of irradiation dose on the mechanical properties of hydrogels. Water-soluble chitosan was used in this experiment. The gelation of hydrogels was higher when two steps of 'freezing and thawing' and irradiation were used than when only 'freezing and thawing' was utilized. Gel content was influenced slightly by PVA/PVP: chitosan composition and irradiation dose, but swelling was influenced greatly by them. The swelling percent was much increased as the composition of chitosan in PVA/PVP/chitosan increased. (author)

  18. Airlift bioreactor containing chitosan-immobilized Sphingobium sp. P2 for treatment of lubricants in wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Khondee, Nichakorn; Tathong, Sitti [International Postgraduate Programs in Environmental Management, Graduate School, Chulalongkorn University, Bangkok (Thailand); Bioremediation Research Unit, Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); Pinyakong, Onruthai [Bioremediation Research Unit, Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); National Center of Excellence for Environmental and Hazardous Waste Management (NCE-EHWM), Chulalongkorn University, Bangkok (Thailand); Powtongsook, Sorawit [Center of Excellence for Marine Biotechnology (c/o Department of Marine Science, Chulalongkorn University), National Center for Genetic Engineering and Biotechnology, Pathum Thani (Thailand); Chatchupong, Thawach; Ruangchainikom, Chalermchai [Environmental Research and Management Department, PTT Research and Technology Institute, Ayutthaya (Thailand); Luepromchai, Ekawan, E-mail: ekawan.l@chula.ac.th [Bioremediation Research Unit, Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); National Center of Excellence for Environmental and Hazardous Waste Management (NCE-EHWM), Chulalongkorn University, Bangkok (Thailand)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer Sphingobium sp. P2 effectively degraded various lubricant samples. Black-Right-Pointing-Pointer Efficiency of Sphingobium sp. P2 increased after immobilization on chitosan. Black-Right-Pointing-Pointer High removal efficiency was due to both sorption and degradation processes. Black-Right-Pointing-Pointer The immobilized bacteria (4 g L{sup -1}) were applied in internal loop airlift bioreactor. Black-Right-Pointing-Pointer The bioreactor continuously removed lubricant from emulsified wastewater. - Abstract: An internal loop airlift bioreactor containing chitosan-immobilized Sphingobium sp. P2 was applied for the removal of automotive lubricants from emulsified wastewater. The chitosan-immobilized bacteria had higher lubricant removal efficiency than free and killed-immobilized cells because they were able to sorp and degrade the lubricants simultaneously. In a semi-continuous batch experiment, the immobilized bacteria were able to remove 80-90% of the 200 mg L{sup -1} total petroleum hydrocarbons (TPH) from both synthetic and carwash wastewater. The internal loop airlift bioreactor, containing 4 g L{sup -1} immobilized bacteria, was later designed and operated at 2.0 h HRT (hydraulic retention time) for over 70 days. At a steady state, the reactor continuously removed 85 {+-} 5% TPH and 73 {+-} 11% chemical oxygen demand (COD) from the carwash wastewater with 25-200 mg L{sup -1} amended lubricant. The internal loop airlift reactor's simple operation and high stability demonstrate its high potential for use in treating lubricants in emulsified wastewater from carwashes and other industries.

  19. Airlift bioreactor containing chitosan-immobilized Sphingobium sp. P2 for treatment of lubricants in wastewater

    International Nuclear Information System (INIS)

    Khondee, Nichakorn; Tathong, Sitti; Pinyakong, Onruthai; Powtongsook, Sorawit; Chatchupong, Thawach; Ruangchainikom, Chalermchai; Luepromchai, Ekawan

    2012-01-01

    Highlights: ► Sphingobium sp. P2 effectively degraded various lubricant samples. ► Efficiency of Sphingobium sp. P2 increased after immobilization on chitosan. ► High removal efficiency was due to both sorption and degradation processes. ► The immobilized bacteria (4 g L −1 ) were applied in internal loop airlift bioreactor. ► The bioreactor continuously removed lubricant from emulsified wastewater. - Abstract: An internal loop airlift bioreactor containing chitosan-immobilized Sphingobium sp. P2 was applied for the removal of automotive lubricants from emulsified wastewater. The chitosan-immobilized bacteria had higher lubricant removal efficiency than free and killed-immobilized cells because they were able to sorp and degrade the lubricants simultaneously. In a semi-continuous batch experiment, the immobilized bacteria were able to remove 80–90% of the 200 mg L −1 total petroleum hydrocarbons (TPH) from both synthetic and carwash wastewater. The internal loop airlift bioreactor, containing 4 g L −1 immobilized bacteria, was later designed and operated at 2.0 h HRT (hydraulic retention time) for over 70 days. At a steady state, the reactor continuously removed 85 ± 5% TPH and 73 ± 11% chemical oxygen demand (COD) from the carwash wastewater with 25–200 mg L −1 amended lubricant. The internal loop airlift reactor's simple operation and high stability demonstrate its high potential for use in treating lubricants in emulsified wastewater from carwashes and other industries.

  20. Impedance spectroscopy study of dehydrated chitosan and chitosan containing LiClO4

    International Nuclear Information System (INIS)

    Costa, M.M.; Terezo, A.J.; Matos, A.L.; Moura, W.A.; Giacometti, Jose A.; Sombra, A.S.B.

    2010-01-01

    Cast films of chitosan and chitosan containing LiClO 4 were characterized using Fourier transform infrared spectroscopy and the thermogravimetric technique. The electric properties of hydrated and dehydrated films were investigated with impedance spectroscopy in the frequency range from 0.1 Hz to 1 MHz, at temperatures varying from 30 to 110 o C. The frequency dependence of the impedance for dehydrated chitosan and chitosan containing LiClO 4 films indicated ionic conduction. Two relaxation peaks were evident on the imaginary curve of the electric modulus, which were assigned to ionic conduction. The peak at higher frequency was found for chitosan and chitosan containing LiClO 4 films. The peak at lower frequency was attributed to Li + conduction since it appeared only for the chitosan containing LiClO 4 . The peak frequency varied with the temperature according to an Arrhenius process with activation energies of circa of 0.6 and 0.45 eV, for H + and Li + conduction, respectively.

  1. Accelerated thermal and radiation-oxidation combined degradation of electric cable insulation materials

    International Nuclear Information System (INIS)

    Yagi, Toshiaki; Seguchi, Tadao; Yoshida, Kenzo

    1986-03-01

    For the development of accelerated testing methodology to estimate the life time of electric cable, which is installed in radiation field such as a nuclear reactor containment vessel, radiation and thermal combined degradation of cable insulation and jacketing materials was studied. The materials were two types of formulated polyethylene, ethylene-propylene rubber, Hypalon, and Neoprene. With Co-60 γ-rays the materials were irradiated up to 0.5 MGy under vacuum and in oxygen under pressure, then exposed to thermal aging at elevated temperature in oxygen. The degradation was investigated by the tensile test, gelfraction, and swelling measurements. The thermal degradation rate for each sample increases with increase of oxygen concentration, i.e. oxygen pressure, during the aging, and tends to saturate above 0.2 MPa of oxygen pressure. Then, the effects of irradiation and the temperature on the thermal degradation rate were investigated at the oxygen pressure of 0.2 MPa in the temperature range from 110 deg C to 150 deg C. For all of samples irradiated in oxygen, the following thermal degradation rate was accelerated by several times comparing with unirradiated samples, while the rate of thermal degradation for the sample except Neoprene irradiated under vacuum was nearly equal to that of unirradiated one. By the analysis of thermal degradation rate against temperature using Arrhenius equation, it was found that the activation energy tends to decrease for the samples irradiated in oxidation condition. (author)

  2. Quaternized chitosan/rectorite/AgNP nanocomposite catalyst for reduction of 4-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Yunzhi [State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Zeng, Xianjie [School of Business Administration, South China University of Technology, Guangzhou 510640 (China); Tan, Weirui [State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Jiwen, E-mail: holdit@126.com [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Liu, Shijie, E-mail: sjliu@163.com [State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); China Department of Paper and Bioprocess Engineering, State University of New York, College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210 (United States)

    2015-10-25

    This study investigated a one-step green fabrication of exfoliated quaternized chitosan/rectorite/AgNP nanocomposites under microwave radiation method. The nanocomposites were characterized by FT-IR, XRD, XPS and TEM. The results revealed that quaternized chitosan and rectorite acted as reducing and stabilizing agents, spherical AgNPs were synthesized greenly and rapidly, meanwhile the layers of rectorite were exfoliated, and when the ratio of quaternized chitosan, rectorite and silver nitrate was 100 mg: 10 mg: 2 mmol, the AgNP content reached the maximum of 2.73%. Then, the quaternized chitosan/rectorite/AgNP nanocomposite was fabricated as a film, which was used in the catalytic reduction from 4-nitrophenol to 4-aminophenol by NaBH{sub 4}. The film showed excellent catalytic efficiency with an activation energy of 29.76 kJ mol{sup −1} and outstanding reusable performance even after catalysis for 10 times. - Graphical abstract: Quaternized chitosan/rectorite/AgNP nanocomposite catalyst was prepared greenly in one pot and fabricated as a film, which showed excellent catalytic efficiency and reusable performance. - Highlights: • Quaternized chitosan and rectorite acted as reducing and stabilizing agents. • Spherical Ag NPs were synthesized greenly and rapidly. • AgNP dispersed well on the surface and the interlayer of exfoliated rectorite. • Quaternized chitosan/rectorite/AgNP nanocomposite was prepared as a film. • The film showed excellent catalytic efficiency and reusable performance.

  3. Materials Degradation in the Jovian Radiation Environment

    Science.gov (United States)

    Miloshevsky, Gennady; Caffrey, Jarvis A.; Jones, Jonathan E.; Zoladz, Thomas F.

    2017-01-01

    The radiation environment of Jupiter represents a significant hazard for Europa Lander deorbit stage components, and presents a significant potential mission risk. The radiolytic degradation of ammonium perchlorate (AP) oxidizer in solid propellants may affect its properties and performance. The Monte Carlo code MONSOL was used for modeling of laboratory experiments on the electron irradiation of propellant samples. An approach for flattening dose profiles along the depth of irradiated samples is proposed. Depth-dose distributions produced by Jovian electrons in multi-layer slabs of materials are calculated. It is found that the absorbed dose in a particular slab is significantly affected by backscattered electrons and photons from neighboring slabs. The dose and radiolytic decomposition of AP crystals are investigated and radiation-induced chemical yields and weight percent of radical products are reported.

  4. Heterogeneous photocatalytic degradation of p-toluenesulfonic acid using concentrated solar radiation in slurry photoreactor

    International Nuclear Information System (INIS)

    Kamble, Sanjay P.; Sawant, Sudhir B.; Pangarkar, Vishwas G.

    2007-01-01

    In this work, the photocatalytic degradation (PCD) of p-toluenesulfonic acid (p-TSA) in batch reactor using concentrated solar radiation was investigated. The effect of the various operating parameters such as initial concentration of substrate, catalyst loading, solution pH and types of ions on photocatalytic degradation has been studied in a batch reactor to derive the optimum conditions. The rate of photocatalytic degradation was found to be maximum at the self pH (pH 3.34) of p-TSA. It was also observed that in the presence of anions and cations, the rate of PCD decreases drastically. The kinetics of photocatalytic degradation of p-TSA was studied. The PCD of p-TSA was also carried at these optimized conditions in a bench scale slurry bubble column reactor using concentrated solar radiation

  5. Preparation and Characterization of Films Extruded of Polyethylene/Chitosan Modified with Poly(lactic acid

    Directory of Open Access Journals (Sweden)

    Jesús Manuel Quiroz-Castillo

    2014-12-01

    Full Text Available The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid was developed; then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young’s modulus and a decrease in the elongation at break; additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid, promoted by the compatibilizer.

  6. Preparation and Characterization of Films Extruded of Polyethylene/Chitosan Modified with Poly(lactic acid)

    Science.gov (United States)

    Quiroz-Castillo, Jesús Manuel; Rodríguez-Félix, Dora Evelia; Grijalva-Monteverde, Heriberto; Lizárraga-Laborín, Lauren Lucero; Castillo-Ortega, María Mónica; del Castillo-Castro, Teresa; Rodríguez-Félix, Francisco; Herrera-Franco, Pedro Jesús

    2014-01-01

    The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid) was developed; then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid) produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM) analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young’s modulus and a decrease in the elongation at break; additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid), promoted by the compatibilizer. PMID:28787928

  7. Chitosan-caffeic acid-genipin films presenting enhanced antioxidant activity and stability in acidic media.

    Science.gov (United States)

    Nunes, Cláudia; Maricato, Élia; Cunha, Ângela; Nunes, Alexandra; da Silva, José A Lopes; Coimbra, Manuel A

    2013-01-02

    The use of chitosan films has been limited due to their high degradability in aqueous acidic media. In order to produce chitosan films with high antioxidant activity and insoluble in acid solutions caffeic acid was grafted to chitosan by a radical mechanism using ammonium cerium (IV) nitrate (60 mM). Genipin was used as cross-linker. This methodology originated films with 80% higher antioxidant activity than the pristine film. Also, these films only lost 11% of their mass upon seven days immersion into an aqueous solution at pH 3.5 under stirring. The films surface wettability (contact angle 105°), mechanical properties (68 MPa of tensile strength and 4% of elongation at break), and thermal stability for temperatures lower than 300 °C were not significantly influenced by the covalent linkage of caffeic acid and genipin to chitosan. Due to their characteristics, mainly higher antioxidant activity and lower solubility, these are promising materials to be used as active films. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Radiation degradation in the mechanical properties of Polyetheretherketone–alumina composites

    International Nuclear Information System (INIS)

    Lawrence, Falix; Mallika, C.; Kamachi Mudali, U.; Natarajan, R.; Ponraju, D.; Seshadri, S.K.; Sampath Kumar, T.S.

    2012-01-01

    Polyetheretherketone (PEEK) is extensively employed in corrosive and radiation environments. To improve the radiation tolerance of PEEK in the presence of high energetic radiation, PEEK was reinforced with micron sized alumina powder (5–25% by weight) and PEEK–alumina composite sheets fabricated were irradiated to 10 MGy. Mechanical properties of the irradiated composites revealed significant reduction in the degradation of PEEK with addition of alumina as the polymer reinforced with ceramic additives is expected to increase the interface area of the constituents in the system resulting in an improvement in the performance of the reinforced material.

  9. Radiation-induced degradation of trichloroethylene and tetrachloroethylene in drinking water

    International Nuclear Information System (INIS)

    Gehringer, P.; Proksch, E.; Szinovatz, W.

    1984-10-01

    The γ-radiation degradation of trace amounts (70-440 ppb) of trichloroethylene and tetrachloroethylene in drinking water has been investigated. The doses necessary to reduce the pollutant concentration to 1 ppb are in the order of 1kGy. (Author)

  10. Iodine-125 Chitosan-Vitamin C complex. Preparation, characterization and application

    Energy Technology Data Exchange (ETDEWEB)

    Elbarbary, Ahmed M. [National Center for Radiation Research and Technology, Cairo (Egypt). Polymer Chemistry Dept.; Shafik, H.M.; Ebeid, N.H.; Ayoub, S.M. [Atomic Energy Authority, Cairo (Egypt). Hot Lab. Center; Othman, Sameh H. [Atomic Energy Authority, Cairo (Egypt). Nuclear Research Center

    2015-07-01

    In heterogeneous conditions, water soluble Chitosan-Vitamin C Complex (CSVC) is successfully synthesized via the ionic interaction between γ-degraded CS and VC. Chitosan (CS) of low molecular weight (MW) is prepared using γ-irradiation method. The coupling of CS and vitamin C (VC) is carried out by the chemical treatment of VC with the γ-degraded CS. The formation of CSVC complex instead of physical mixture is confirmed by FT-IR and UV spectrometry. Characterization by transmission electron microscope (TEM) and dynamic light scattering (DLS) shows the formation of a nanostructure in 40 nm range. The preparation of labeled CSVC was performed using chloramines-T oxidation method. The labeling feasibility of CSVC nanostructure by Iodine-125 ({sup 125}I) is investigated. The optimized conditions of labeling are thought to be 50 μg of oxidizing agent, pH 3, and one minute reaction time. The Biodistribution activity of {sup 125}I radiolabeled CSVC nanostructure ({sup 125}I-CSVC) is examined on a group of different ascites tumor bearing mice. Calculation of the biodistribution percentages shows that the tumor, liver, and kidney are the targeting organs of {sup 125}I-CSVC nanostructure.

  11. Iodine-125 Chitosan-Vitamin C complex. Preparation, characterization and application

    International Nuclear Information System (INIS)

    Elbarbary, Ahmed M.; Shafik, H.M.; Ebeid, N.H.; Ayoub, S.M.; Othman, Sameh H.

    2015-01-01

    In heterogeneous conditions, water soluble Chitosan-Vitamin C Complex (CSVC) is successfully synthesized via the ionic interaction between γ-degraded CS and VC. Chitosan (CS) of low molecular weight (MW) is prepared using γ-irradiation method. The coupling of CS and vitamin C (VC) is carried out by the chemical treatment of VC with the γ-degraded CS. The formation of CSVC complex instead of physical mixture is confirmed by FT-IR and UV spectrometry. Characterization by transmission electron microscope (TEM) and dynamic light scattering (DLS) shows the formation of a nanostructure in 40 nm range. The preparation of labeled CSVC was performed using chloramines-T oxidation method. The labeling feasibility of CSVC nanostructure by Iodine-125 ( 125 I) is investigated. The optimized conditions of labeling are thought to be 50 μg of oxidizing agent, pH 3, and one minute reaction time. The Biodistribution activity of 125 I radiolabeled CSVC nanostructure ( 125 I-CSVC) is examined on a group of different ascites tumor bearing mice. Calculation of the biodistribution percentages shows that the tumor, liver, and kidney are the targeting organs of 125 I-CSVC nanostructure.

  12. Autoclavable physically-crosslinked chitosan cryogel as a wound dressing.

    Science.gov (United States)

    Takei, Takayuki; Danjo, So; Sakoguchi, Shogo; Tanaka, Sadao; Yoshinaga, Takuma; Nishimata, Hiroto; Yoshida, Masahiro

    2018-04-01

    Moist wounds were known to heal more rapidly than dry wounds. Hydrogel wound dressings were suitable for the moist wound healing because of their hyperhydrous structure. Chitosan was a strong candidate as a base material for hydrogel wound dressings because the polymer had excellent biological properties that promoted wound healing. We previously developed physically-crosslinked chitosan cryogels, which were prepared solely by freeze-thawing of a chitosan-gluconic acid conjugate (CG) aqueous solution, for wound treatment. The CG cryogels were disinfected by immersing in 70% ethanol before applying to wounds in our previous study. In the present study, we examined the influence of autoclave sterilization (121°C, 20 min) on the characteristics of CG cryogel because complete sterilization was one of the fundamental requirements for medical devices. We found that optimum value of gluconic acid content of CG, defined as the number of the incorporated gluconic acid units per 100 glucosamine units of chitosan, was 11 for autoclaving. An increased crosslinking level of CG cryogel on autoclaving enhanced resistance of the gels to enzymatic degradation. Furthermore, the autoclaved CG cryogels retained favorable biological properties of the pre-autoclaved CG cryogels in that they showed the same hemostatic activity and efficacy in repairing full-thickness skin wounds as the pre-autoclaved CG cryogels. These results showed the great potential of autoclavable CG cryogels as a practical wound dressing. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  13. Preparation of Chito-Oligomers by Hydrolysis of Chitosan in the Presence of Zeolite as Adsorbent

    Directory of Open Access Journals (Sweden)

    Khalid A. Ibrahim

    2016-07-01

    Full Text Available An increasing interest has recently been shown to use chitin/chitosan oligomers (chito-oligomers in medicine and food fields because they are not only water-soluble, nontoxic, and biocompatible materials, but they also exhibit numerous biological properties, including antibacterial, antifungal, and antitumor activities, as well as immuno-enhancing effects on animals. Conventional depolymerization methods of chitosan to chito-oligomers are either chemical by acid-hydrolysis under harsh conditions or by enzymatic degradation. In this work, hydrolysis of chitosan to chito-oligomers has been achieved by applying adsorption-separation technique using diluted HCl in the presence of different types of zeolite as adsorbents. The chito-oligomers were retrieved from adsorbents and characterized by differential scanning calorimetry (DSC, liquid chromatography/mass spectroscopy (LC/MS, and ninhydrin test.

  14. Degradation of 4-Chloro phenol by gamma radiation of {sup 137}Cs and X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez J, J. C. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, Ex-Rancho La Virgen, 52140 Metepec, Estado de Mexico (Mexico); Jimenez B, J.; Cejudo A, J., E-mail: jaime.jimenez@inin.gob.m [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2010-07-01

    This paper presents results of radiolytic degradation of 4-chloro phenol in the presence of TiO{sub 2}, Al{sub 2}O{sub 3} and SiO{sub 2}, using different radiation sources than {sup 60}Co, which is so common in this type of experiment. The radiation sources used were X-rays with energy of 100 keV and radiation from {sup 137}Cs (662 keV). After irradiation with a dose of 50 c Gy X-ray and TiO{sub 2} obtained a degradation of about 5%, no degradation was obtained with {sup 137}Cs source and other oxides. This may be due to the fact that X-rays have a linear energy transfer greater value, and in the case of TiO{sub 2} present a crystalline structure, whereas the other two oxides are amorphous. Both characteristics result in better formation of a reactive species that allows the degradation of the compound. (Author)

  15. Study on radiation degradation of hydroxylamine derivatives. Pt.2: The qualitative and quantitative analysis of light hydrocarbons produced by radiation degradation of N, N-diethyl hydroxylamine

    International Nuclear Information System (INIS)

    Wang Jinhua; Bao Borong; Wu Minghong; Sun Xilian

    2004-01-01

    The qualitative and quantitative analysis of light hydrocarbons produced by radiation degradation of N,N-diethyl hydroxylamine are reported. These analyses are performed on the gas chromatography in which a porous layer open tubular column coated with aluminum oxide and a flame-ionization detector are used. When the doses are between 10 and 1000 kGy, the main hydrocarbons produced by radiation degradation of N,N-diethyl hydroxylamine are methane, ethane, ethene, propane and n-butane. The volume fraction of methane, ethane, n-butane and propane are increased with the increase of dose. The volume fraction of ethene is also increased with the increase of dose at first, however, when the absorbed dose is higher than 500 kGy. The volume fraction of ethene is decreased with the increase of dose

  16. Impact of molecular weight on the formation of electrosprayed chitosan microcapsules as delivery vehicles for bioactive compounds.

    Science.gov (United States)

    Gómez-Mascaraque, Laura G; Sanchez, Gloria; López-Rubio, Amparo

    2016-10-05

    The molecular weight of chitosan is one of its most determinant characteristics, which affects its processability and its performance as a biomaterial. However, information about the effect of this parameter on the formation of electrosprayed chitosan microcapsules is scarce. In this work, the impact of chitosan molecular weight on its electrosprayability was studied and correlated with its effect on the viscosity, surface tension and electrical conductivity of solutions. A Discriminant Function Analysis revealed that the morphology of the electrosprayed chitosan materials could be correctly predicted using these three parameters for almost 85% of the samples. The suitability of using electrosprayed chitosan capsules as carriers for bioactive agents was also assessed by loading them with a model active compound, (-)-epigallocatechin gallate (EGCG). This encapsulation, with an estimated efficiency of around 80% in terms of preserved antioxidant activity, showed the potential to prolong the antiviral activity of EGCG against murine norovirus via gradual bioactive release combined with its protection against degradation in simulated physiological conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Synthesis of N-oleyl O-sulfate chitosan from methyl oleate with O-sulfate chitosan as edible film material

    Science.gov (United States)

    Daniel; Sihaloho, O.; Saleh, C.; Magdaleni, A. R.

    2018-04-01

    The research on the synthesis of N-oleyl O-sulfate chitosan through sulfonation reaction on chitosan with ammonium sulfate and followed by amidation reaction using methyl oleate has been done. In this study, chitosan was chemically modified into N-oleyl O-sulfatechitosan as an edible film making material. N-oleyl O-sulfate chitosan was synthesized by reaction between methyl oleate and O-sulfate chitosan. Wherein the depleted chitosan of O-sulfate chitosan into O-sulfate chitosan was obtained by reaction of sulfonation between ammonium sulfate and chitosan aldimine. While chitosan aldimine was obtained through reaction between chitosan with acetaldehyde. The structure of N-oleyl O-sulfate chitosan was characterized by FT-IR analysis which showed vibration uptake of C-H sp3 group, S=O group, and carbonyl group C=O of the ester. The resulting of N-oleyl O-sulfate chitosan yielded a percentage of 93.52%. Hydrophilic-Lipophilic Balance (HLB) test results gave a value of 6.68. In the toxicity test results of N-oleyl O-sulfate chitosan obtained LC50 value of 3738.4732 ppm. In WVTR (Water Vapor Transmission Rate) test results for chitosan film was 407.625 gram/m2/24 hours and N-oleylO-sulfate chitosan film was 201.125 gram/m2/24 hours.

  18. Evaluation of Inulin Replacing Chitosan in a Polyurethane/Polysaccharide Material for Pb2+ Removal.

    Science.gov (United States)

    Hernández-Martínez, Angel Ramon; Molina, Gustavo A; Jiménez-Hernández, Luis Fernando; Oskam, Adrian Hendrik; Fonseca, Gerardo; Estevez, Miriam

    2017-11-29

    Downstream waste from industry and other industrial processes could increase concentration of heavy metals in water. These pollutants are commonly removed by adsorption because it is an effective and economical method. Previously, we reported adsorption capacity of a chitosan/polyurethane/titanium dioxide (TiO₂) composite for three ions in a dynamic wastewater system. There, increasing the chitosan concentration in composite increased the cation removal as well; however, for ratios higher than 50% of chitosan/TiO₂, the manufacturing cost increased significantly. In this work, we address the manufacturing cost problem by proposing a new formulation of the composite. Our hypothesis is that inulin could replace chitosan in the composite formulation, either wholly or in part. In this exploratory research, three blends were prepared with a polyurethane matrix using inulin or/and chitosan. Adsorption was evaluated using a colorimetric method and the Langmuir and Freundlich models. Fourier-transform infrared spectroscopy (FTIR) spectra, scanning electron microscopy (SEM) micrographs, differential scanning calorimetry and thermogravimetric analysis curves were obtained to characterize blends. Results indicate that blends are suitable for toxic materials removal (specifically lead II, Pb 2+ ). Material characterization indicates that polysaccharides were distributed in polyurethane's external part, thus improving adsorption. Thermal degradation of materials was found above 200 °C. Comparing the blends data, inulin could replace chitosan in part and thereby improve the cost efficiency and scalability of the production process of the polyurethane based-adsorbent. Further research with different inulin/chitosan ratios in the adsorbent and experiments with a dynamic system are justified.

  19. Evaluation of Inulin Replacing Chitosan in a Polyurethane/Polysaccharide Material for Pb2+ Removal

    Directory of Open Access Journals (Sweden)

    Angel Ramon Hernández-Martínez

    2017-11-01

    Full Text Available Downstream waste from industry and other industrial processes could increase concentration of heavy metals in water. These pollutants are commonly removed by adsorption because it is an effective and economical method. Previously, we reported adsorption capacity of a chitosan/polyurethane/titanium dioxide (TiO2 composite for three ions in a dynamic wastewater system. There, increasing the chitosan concentration in composite increased the cation removal as well; however, for ratios higher than 50% of chitosan/TiO2, the manufacturing cost increased significantly. In this work, we address the manufacturing cost problem by proposing a new formulation of the composite. Our hypothesis is that inulin could replace chitosan in the composite formulation, either wholly or in part. In this exploratory research, three blends were prepared with a polyurethane matrix using inulin or/and chitosan. Adsorption was evaluated using a colorimetric method and the Langmuir and Freundlich models. Fourier-transform infrared spectroscopy (FTIR spectra, scanning electron microscopy (SEM micrographs, differential scanning calorimetry and thermogravimetric analysis curves were obtained to characterize blends. Results indicate that blends are suitable for toxic materials removal (specifically lead II, Pb2+. Material characterization indicates that polysaccharides were distributed in polyurethane’s external part, thus improving adsorption. Thermal degradation of materials was found above 200 °C. Comparing the blends data, inulin could replace chitosan in part and thereby improve the cost efficiency and scalability of the production process of the polyurethane based-adsorbent. Further research with different inulin/chitosan ratios in the adsorbent and experiments with a dynamic system are justified.

  20. Influence of chitosan concentration on mechanical and barrier properties of corn starch/chitosan films.

    Science.gov (United States)

    Ren, Lili; Yan, Xiaoxia; Zhou, Jiang; Tong, Jin; Su, Xingguang

    2017-12-01

    The active packaging films based on corn starch and chitosan were prepared through mixing the starch solution and the chitosan solution (1:1) by casting. The aim of this work was to characterize and analyze the effects of the chitosan concentrations (0, 21, 41, 61 and 81wt% of starch) on physicochemical, mechanical and water vapor barrier properties as well as morphological characteristics of the corn starch/chitosan (CS/CH) films. Starch molecules and chitosan could interact through hydrogen bonding as confirmed from the shift of the main peaks to higher wavenumbers in FTIR and the reduction of crystallinity in XRD. Results showed that the incorporation of chitosan resulted in an increase in film solubility, total color differences, tensile strength and elongation at break and a decrease in Young's modulus and water vapor permeability (WVP). Elongation at break of the CS/CH films increased with increasing of chitosan concentration, and reached a maximum at 41 wt%, then declined at higher chitosan concentration. The WVP of CS/CH films increased with an increase of chitosan concentration and the same tendency observed for the moisture content. The results suggest that this biodegradable CS/CH films could potentially be used as active packaging films for food and pharmaceutical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Scanning electron microscopy and swelling test of shrimp shell chitosan and chitosan-RGD scaffolds

    Science.gov (United States)

    Mandacan, M. C.; Yuniastuti, M.; Amir, L. R.; Idrus, E.; Suniarti, D. F.

    2017-08-01

    Shrimp shell chitosan and chitosan-RGD scaffold membranes are produced to be biocompatible with tissue engineering. Nonetheless, their architectural properties have not yet been studied. Analyze the architectural properties of chitosan and chitosan-RGD scaffolds. Analyze pore count and size, interpore distance, and porosity (using SEM testing and ImageJ analysis) and water absorption (using a swelling test). The properties of the chitosan and chitosan-RGD scaffolds were as follows, respectively. The pore counts were 225 and 153; pore size, 171.4 μam and 180.2 μam interpore distance, 105.7 μam and 101.4 μam porosity, 22% and 10.2%; and water absorption, 9.1 mgH2O/mgScaffold and 19.3 mgH2O/mgScaffold. The shrimp shell chitosan-RGD membrane scaffold was found to have architectural properties that make it more conducive to use in tissue engineering.

  2. Transfection efficiency of chitosan and thiolated chitosan in retinal pigment epithelium cells: A comparative study

    Directory of Open Access Journals (Sweden)

    Ana V Oliveira

    2013-01-01

    Full Text Available Objective: Gene therapy relies on efficient vector for a therapeutic effect. Efficient non-viral vectors are sought as an alternative to viral vectors. Chitosan, a cationic polymer, has been studied for its gene delivery potential. In this work, disulfide bond containing groups were covalently added to chitosan to improve the transfection efficiency. These bonds can be cleaved by cytoplasmic glutathione, thus, releasing the DNA load more efficiently. Materials and Methods: Chitosan and thiolated chitosan nanoparticles (NPs were prepared in order to obtain a NH3 + :PO4− ratio of 5:1 and characterized for plasmid DNA complexation and release efficiency. Cytotoxicity and gene delivery studies were carried out on retinal pigment epithelial cells. Results: In this work, we show that chitosan was effectively modified to incorporate a disulfide bond. The transfection efficiency of chitosan and thiolated chitosan varied according to the cell line used, however, thiolation did not seem to significantly improve transfection efficiency. Conclusion: The apparent lack of improvement in transfection efficiency of the thiolated chitosan NPs is most likely due to its size increase and charge inversion relatively to chitosan. Therefore, for retinal cells, thiolated chitosan does not seem to constitute an efficient strategy for gene delivery.

  3. Preparation and characterisation of irradiated crab chitosan and New Zealand Arrow squid pen chitosan

    International Nuclear Information System (INIS)

    Shavandi, Amin; Bekhit, Adnan A.; Bekhit, Alaa El-Din A.; Sun, Zhifa; Ali, M. Azam

    2015-01-01

    The properties of chitosan from Arrow squid (Nototodarus sloanii) pen (CHS) and commercial crab shell (CHC) were investigated using FTIR, DSC, SEM and XRD before and after irradiation at the dose of 28 kGy in the presence or absence of 5% water. Also, the viscosity, deacetylation degree, water and oil holding capacities, colour and antimicrobial activities of the chitosan samples were determined. Irradiation decreased (P < 0.05) the viscosity of CHC from 0.21 to 0.03 Pa s and of CHS from 1.71 to 0.23 Pa s. The inclusion of water had no effect on the viscosity of irradiated chitosan. Irradiation did not affect the degree of deacetylation of CHC, but increased the deacetylation degree of CHS from 72.78 to 82.29% in samples with 5% water. Water and oil holding capacities of CHS (1197.30% and 873.3%, respectively) were higher (P < 0.05) than those found in CHC (340.70% and 264.40%, respectively). The water and oil holding capacities were decreased for both types of chitosan irradiation, but were not affected by the addition of water. Squid pen chitosan was whiter in colour (White Index = 90.06%) compared to CHC (White Index = 83.70%). Generally, the CHC samples (control and irradiated) exhibited better antibacterial activity compared to CHS, but the opposite was observed with antifungal activity. - Highlights: • Chitosan prepared from Arrow squid pens (Nototodarus sloanii). • Chitosan samples were gamma irradiated at 28 kGy. • Squid pen chitosan showed high fat and water uptake capacities compared to crab shell chitosan. • Gamma irradiation enhanced the DDA of squid pen chitosan but not crab shell chitosan.

  4. Genipin Cross-Linked Polymeric Alginate-Chitosan Microcapsules for Oral Delivery: In-Vitro Analysis

    Directory of Open Access Journals (Sweden)

    Hongmei Chen

    2009-01-01

    Full Text Available We have previously reported the preparation of the genipin cross-linked alginate-chitosan (GCAC microcapsules composed of an alginate core with a genipin cross-linked chitosan membrane. This paper is the further investigation on their structural and physical characteristics. Results showed that the GCAC microcapsules had a smooth and dense surface and a networked interior. Cross-linking by genipin substantially reduced swelling and physical disintegration of microcapsules induced by nongelling ions and calcium sequestrants. Strong resistance to mechanical shear forces and enzymatic degradation was observed. Furthermore, the GCAC membranes were permeable to bovine serum albumin and maintained a molecular weight cutoff at 70 KD, analogous to the widely studied alginate-chitosan, and alginate-poly-L-lysine-alginate microcapsules. The release features and the tolerance of the GCAC microcapsules in the stimulated gastrointestinal environment were also investigated. This GCAC microcapsule formulation offers significant potential as a delivery vehicle for many biomedical applications.

  5. Radiation cross-linked collagen/dextran dermal scaffolds: effects of dextran on cross-linking and degradation.

    Science.gov (United States)

    Zhang, Yaqing; Zhang, Xiangmei; Xu, Ling; Wei, Shicheng; Zhai, Maolin

    2015-01-01

    Ionizing radiation effectively cross-links collagen into network with enhanced anti-degradability and biocompatibility, while radiation-cross-linked collagen scaffold lacks flexibility, satisfactory surface appearance, and performs poor in cell penetration and ingrowth. To make the radiation-cross-linked collagen scaffold to serve as an ideal artificial dermis, dextran was incorporated into collagen. Scaffolds with the collagen/dextran (Col/Dex) ratios of 10/0, 7/3, and 5/5 were fabricated via (60)Co γ-irradiation cross-linking, followed by lyophilization. The morphology, microstructure, physicochemical, and biological properties were investigated. Compared with pure collagen, scaffolds with dextran demonstrated more porous appearance, enhanced hydrophilicity while the cross-linking density was lower with the consequence of larger pore size, higher water uptake, as well as reduced stiffness. Accelerated degradation was observed when dextran was incorporated in both the in vitro and in vivo assays, which led to earlier integration with cell and host tissue. The effect of dextran on degradation was ascribed to the decreased cross-linking density, looser microstructure, more porous and hydrophilic surface. Considering the better appearance, softness, moderate degradation rate due to controllable cross-linking degree and good biocompatibility as well, radiation-cross-linked collagen/dextran scaffolds are expected to serve as promising artificial dermal substitutes.

  6. Gelatin/chitosan biofilm: preparation and characterization

    International Nuclear Information System (INIS)

    Trindade, Luciane da C.; Nunes, Raquel A.; Diniz, Nadie K.S.; Braga, Carla R.C.; Silva, Suedina M. de Lima

    2011-01-01

    In this study, gelatin, chitosan and gelatin/chitosan bio films using the ratio of gelatin/chitosan (50/50) were prepared by casting method. The bio films prepared were characterized by X-ray diffraction, scanning electron microscopy and dissolution ratio. According to the results, the incorporation of chitosan into gelatin indicate the decrease of crystallinity of chitosan, a compact structure without large pores and that the dissolution of gelatin/chitosan film is little influenced by hot water than gelatin films. (author)

  7. Fabrication of chitosan microparticles loaded in chitosan and poly

    Indian Academy of Sciences (India)

    In recent decades, the use of microparticle-mediated drug delivery is widely applied in the field of biomedicalapplication. Here, we report the new dressing material with ciprofloxacin-loaded chitosan microparticle (CMP) impregnatedin chitosan (CH) and poly(vinyl alcohol) (PVA) scaffold for effective delivery of drug in a ...

  8. Collagen-chitosan scaffold - Lauric acid plasticizer for skin tissue engineering on burn cases

    Science.gov (United States)

    Widiyanti, Prihartini; Setyadi, Ewing Dian; Rudyardjo, Djony Izak

    2017-02-01

    The prevalence of burns in the world is more than 800 cases per one million people each year and this is the second highest cause of death due to trauma after traffic accident. Many studies are turning to skin substitute methods of tissue engineering. The purpose of this study is to determine the composition of the collagen, chitosan, and lauric acid scaffold, as well as knowing the results of the characterization of the scaffold. The synthesis of chitosan collagen lauric acid scaffold as a skin tissue was engineered using freeze dried method. Results from making of collagen chitosan lauric acid scaffold was characterized physically, biologically and mechanically by SEM, cytotoxicity, biodegradation, and tensile strength. From the morphology test, the result obtained is that pore diameter size ranges from 94.11 to 140.1 µm for samples A,B,C,D, which are in the range of normal pore size 63-150 µm, while sample E has value below the standard which is about 37.87 to 47.36 µm. From cytotoxicity assay, the result obtained is the percentage value of living cells between 20.11 to 21.51%. This value is below 50% the standard value of living cells. Incompatibility is made possible because of human error mainly the replication of washing process over the standard. Degradation testing obtained values of 19.44% - 40% by weight which are degraded during the 7 days of observation. Tensile test results obtained a range of values of 0.192 - 3.53 MPa. Only sample A (3.53 MPa) and B (1.935 MPa) meet the standard values of skin tissue scaffold that is 1-24 MPa. Based on the results of the characteristics of this study, composite chitosan collagen scaffold with lauric acid plasticizer has a potential candidate for skin tissue engineering for skin burns cases.

  9. Utilization of bio-resources by low energy electron beam

    International Nuclear Information System (INIS)

    Kume, Tamikazu

    2003-01-01

    Utilization of bio-resources by radiation has been investigated for recycling the natural resources and reducing the environmental pollution. Polysaccharides such as chitosan and sodium alginate were easily degraded by irradiation and induced various kinds of biological activities, i.g. anti-microbial activity, promotion of plant growth, suppression of heavy metal stress, phytoalexins induction. Radiation degraded chitosan was effective to enhance the growth of plants in tissue culture. It was demonstrated that the liquid sample irradiation system using low energy EB was effective for the preparation of degraded polysaccharides. Methylcellulose (MC) can be crosslinked under certain radiation condition as same as carboxymethylcellulose (CMC) and produced the biodegradable hydrogel for medical and agricultural use. Treatment of soybean seeds by low energy EB enhanced the growth and the number of rhizobia on the root. (author)

  10. Radiation-induced degradation of 4-chloroaniline in aqueous solution

    International Nuclear Information System (INIS)

    Sanchez, M.; Wolfger, H.; Getoff, N.

    2002-01-01

    The radiation-induced decomposition of 4-chloroaniline (4-ClA) was studied under steady-state conditions using aqueous solutions saturated with air, pure oxygen, N 2 O, argon and argon in the presence of t-Butanol. Using HPLC-method, the initial G-values of the substrate degradation as well as of a number of radiolytic products were determined. The formation of aminophenols, chlorophenols, aniline and phenol in addition to chloride, ammonia, formaldehyde and mixture of aldehydes as well as carboxylic acids was studied as a function of absorbed dose. Based on the experimental data, probable reaction mechanisms for the degradation of 4-ClA by γ-rays and the formation of the identified products are presented

  11. Radiation degradation of α-substituted acrylate polymers and copolymers

    International Nuclear Information System (INIS)

    Helbert, J.N.; Caplan, P.J.; Poindexter, E.H.

    1977-01-01

    Radiation degradation is observed in poly(methyl α-chloroacrylate), poly(methyl α-cyanoacrylate), and poly (α-chloroacrylonitrile) homopolymers and their respective MMA copolymers when γ-irradiated in vacuo. Polymer degradation susceptibilities are quantified in terms of G(scission radicals) and G(scission) -- G(crosslinks), measured by EPR and membrane osmometry, respectively; values by these two methods are compared. Higher G(rads) values ranging from 2 to 6 and [G(s) -- G(x)] values ranging from 2 to 11 are obtained for the substituted polymers and copolymers relative to the values for PMMA (1.6; 1.9), a standard e-beam positive resist, which suggests that these modified polymers are more sensitive e-beam resists than PMMA

  12. Characterization of bioactive chitosan and sulfated chitosan from Doryteuthis singhalensis (Ortmann, 1891).

    Science.gov (United States)

    Ramasamy, Pasiyappazham; Subhapradha, Namasivayam; Thinesh, Thangadurai; Selvin, Joseph; Selvan, Kanagaraj Muthamizh; Shanmugam, Vairamani; Shanmugam, Annaian

    2017-06-01

    Chitosan was extracted from the pen of squid Doryteuthis singhalensis and characterized using FT-IR, NMR, CHN, SEM and DSC analysis. Purified chitosan was sulfated with chlorosulfonic acid in N,N-dimethylformamide and the added sulfate group was confirmed with FT-IR analysis. The molecular weight and degree of deacetylation (DDA) of chitosan was found 226.6kDa and 83.76% respectively. Chitosan exhibited potent antioxidant activity evidenced by reducing power, chelating ability on ferrous ions and scavenging activity on DPPH, superoxide and hydroxyl radicals. The anticoagulant assay using activated partial thromboplastin time (APTT) and prothrombin time (PT) showed chitosan as a strong anticoagulant. The results of this study showed possibility of using D. singhalensis pen as a non-conventional source of natural antioxidants and anticoagulant which can be incorporated in functional food formulations. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Assessment of reinforced poly(ethylene glycol) chitosan hydrogels as dressings in a mouse skin wound defect model

    International Nuclear Information System (INIS)

    Chen, Szu-Hsien; Tsao, Ching-Ting; Chang, Chih-Hao; Lai, Yi-Ting; Wu, Ming-Fung; Chuang, Ching-Nan; Chou, Hung-Chia; Wang, Chih-Kuang; Hsieh, Kuo-Haung

    2013-01-01

    Wound dressings of chitosan are biocompatible, biodegradable, antibacterial and hemostatic biomaterials. However, applications for chitosan are limited due to its poor mechanical properties. Here, we conducted an in vivo mouse angiogenesis study on reinforced poly(ethylene glycol) (PEG)-chitosan (RPC) hydrogels. RPC hydrogels were formed by cross-linking chitosan with PEGs of different molecular weights at various PEG to chitosan ratios in our previous paper. These dressings can keep the wound moist, had good gas exchange capacity, and was capable of absorbing or removing the wound exudate. We examined the ability of these RPC hydrogels and neat chitosan to heal small cuts and full-thickness skin defects on the backs of male Balb/c mice. Histological examination revealed that chitosan suppressed the infiltration of inflammatory cells and accelerated fibroblast proliferation, while PEG enhanced epithelial migration. The RPC hydrogels promoted wound healing in the small cuts and full layer wounds. The optimal RPC hydrogel had a swelling ratio of 100% and a water vapor transmission rate (WVTR) of about 2000 g/m 2 /day. In addition, they possess good mechanical property and appropriate degradation rates. Thus, the optimal RPC hydrogel formulation functioned effectively as a wound dressing and promoted wound healing. Highlights: ► Mouse angiogenesis study on reinforced poly(ethylene glycol)-chitosan (RPC) ► Water vapor transmission rate of about 2000 g/m 2 /day is characteristic of RPC. ► RPC suppressed inflammatory cells and accelerated fibroblast proliferation. ► RPC composed of 1000-RP10C90 can be used as a biomaterial for wound dressing

  14. Assessment of reinforced poly(ethylene glycol) chitosan hydrogels as dressings in a mouse skin wound defect model

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Szu-Hsien [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Tsao, Ching-Ting [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Epithelial Biology Laboratory/Transgenic Mice Core-Laboratory, Department of Anatomy, Chang Gung University, Taoyuan 33302, Taiwan (China); Chang, Chih-Hao [Department of Orthopedics, National Taiwan University Hospital, Taiwan (China); National Taiwan University College of Medicine, No. 1, Jen-Ai Road, Taipei City 10018, Taiwan (China); Lai, Yi-Ting [Department of Chemical Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Wu, Ming-Fung [Animal Medicine Center, College of Medicine, National Taiwan University, No. 1, Jen-Ai Road, Taipei City 10018, Taiwan (China); Chuang, Ching-Nan [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Chou, Hung-Chia [Department of Chemical Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Wang, Chih-Kuang, E-mail: ckwang@kmu.edu.tw [Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Hsieh, Kuo-Haung, E-mail: khhsieh@ntu.edu.tw [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China)

    2013-07-01

    Wound dressings of chitosan are biocompatible, biodegradable, antibacterial and hemostatic biomaterials. However, applications for chitosan are limited due to its poor mechanical properties. Here, we conducted an in vivo mouse angiogenesis study on reinforced poly(ethylene glycol) (PEG)-chitosan (RPC) hydrogels. RPC hydrogels were formed by cross-linking chitosan with PEGs of different molecular weights at various PEG to chitosan ratios in our previous paper. These dressings can keep the wound moist, had good gas exchange capacity, and was capable of absorbing or removing the wound exudate. We examined the ability of these RPC hydrogels and neat chitosan to heal small cuts and full-thickness skin defects on the backs of male Balb/c mice. Histological examination revealed that chitosan suppressed the infiltration of inflammatory cells and accelerated fibroblast proliferation, while PEG enhanced epithelial migration. The RPC hydrogels promoted wound healing in the small cuts and full layer wounds. The optimal RPC hydrogel had a swelling ratio of 100% and a water vapor transmission rate (WVTR) of about 2000 g/m{sup 2}/day. In addition, they possess good mechanical property and appropriate degradation rates. Thus, the optimal RPC hydrogel formulation functioned effectively as a wound dressing and promoted wound healing. Highlights: ► Mouse angiogenesis study on reinforced poly(ethylene glycol)-chitosan (RPC) ► Water vapor transmission rate of about 2000 g/m{sup 2}/day is characteristic of RPC. ► RPC suppressed inflammatory cells and accelerated fibroblast proliferation. ► RPC composed of 1000-RP10C90 can be used as a biomaterial for wound dressing.

  15. Encapsulation of testosterone by chitosan nanoparticles.

    Science.gov (United States)

    Chanphai, P; Tajmir-Riahi, H A

    2017-05-01

    The loading of testosterone by chitosan nanoparticles was investigated, using multiple spectroscopic methods, thermodynamic analysis, TEM images and modeling. Thermodynamic parameters showed testosterone-chitosan bindings occur mainly via H-bonding and van der Waals contacts. As polymer size increased more stable steroid-chitosan conjugates formed and hydrophobic contact was also observed. The loading efficacy of testosterone-nanocarrier was 40-55% and increased as chitosan size increased. Testosterone encapsulation markedly alters chitosan morphology. Chitosan nanoparticles are capable of transporting testosterone in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Theory of electron degradation and yields of initial molecular species produced by ionizing radiation

    International Nuclear Information System (INIS)

    Inokuti, M.; Dillon, M.A.; Kimura, M.

    1987-01-01

    Ionizing radiations generate in matter a large number of energetic electrons, which in turn collide with molecules in matter, produce ions and excited states, and thereby degrade in energy. The description of the consequences of many collision processes to the electrons and to matter is the goal of the electron degradation theory. They summarize the current understanding of this topic, which is important as a basis of radiation chemistry and biology. In addition, they present an initial report of their new work, namely, a generalization of the Spencer-Fano theory to time-dependent cases

  17. Preparation and comparative characterization of keratin–chitosan and keratin–gelatin composite scaffolds for tissue engineering applications

    International Nuclear Information System (INIS)

    Balaji, S.; Kumar, Ramadhar; Sripriya, R.; Kakkar, Prachi; Ramesh, D. Vijaya; Reddy, P. Neela Kanta; Sehgal, P.K.

    2012-01-01

    We report fabrication of three dimensional scaffolds with well interconnected matrix of high porosity using keratin, chitosan and gelatin for tissue engineering and other biomedical applications. Scaffolds were fabricated using porous Keratin–Gelatin (KG), Keratin–Chitosan (KC) composites. The morphology of both KG and KC was investigated using SEM. The scaffolds showed high porosity with interconnected pores in the range of 20–100 μm. They were further tested by FTIR, DSC, CD, tensile strength measurement, water uptake and swelling behavior. In vitro cell adhesion and cell proliferation tests were carried out to study the biocompatibility behavior and their application as an artificial skin substitute. Both KG and KC composite scaffolds showed similar properties and patterns for cell proliferation. Due to rapid degradation of gelatin in KG, we found that it has limited application as compared to KC scaffold. We conclude that KC scaffold owing to its slow degradation and antibacterial properties would be a better substrate for tissue engineering and other biomedical application. Highlights: ► Extraction of reduced keratin from horn meal. ► Preparation of keratin–gelatin and keratin–chitosan composite scaffolds. ► Characterizations of the composite scaffolds. ► Comparative cytotoxicity analysis on NIH3T3 fibroblasts.

  18. An introduction to radiation induced degradation of biological molecules in aqueous solutions

    International Nuclear Information System (INIS)

    Lal, Manohar

    1991-01-01

    Radiation chemistry of aqueous systems is the chemistry of H, OH, e aq - , H 3 O + and H 2 O * formed when a solute in aqueous solutions is exposed to ionising radiation. The pulse radiolysis technique has helped in the production, the detection and understanding of the reactions of primary species with solutes. A great deal of data on radiation biochemical studies e.g. degradation of DNA, its constituents and their protection, radiation protection and sensitisation, generation of superoxide ion and their reactions has already been reported but a great deal still needs to be done for the understanding of radiation biology. (author). 12 refs

  19. Radiation processing of silk protein (Bilateral research cooperation OAEP and JAERI. December 1998 - December 2002)

    International Nuclear Information System (INIS)

    2003-01-01

    Thailand's production of silk, about 1,200 ton per year, also gives about 10% of silk waste which is expected to be recycled into new material (non-textile application) and to avoid environmental pollution. For this purpose, cooperative program 'radiation processing of silk protein' was conducted between OAEP (Thailand) and JAERI. Among the results already obtained are: radiation degradation of silk protein (fibroin) with gamma rays at 160 kGy, production of fine silk milled powder (<90 microns) by electron beam irradiation at 250-1000 kGy (dry method) using electron accelerator (1 MeV, 1 mA), use of antioxidant effect of silk protein on lipid peroxidation and antibacterial activity of irradiated silk protein powder, and wound dressing hydrogel mixed with silk protein and use of antibacterial activity of cross-linked silk protein/PVA hydrogel. Other topics of interest are gamma irradiation of anionic natural polymer solution for use as latex protein scavenger and gamma radiation degradation of chitosan for use as plant growth promoter and fungicide. (S. Ohno)

  20. Hyaluronic acid-coated chitosan nanoparticles: molecular weight-dependent effects on morphology and hyaluronic acid presentation.

    Science.gov (United States)

    Almalik, Abdulaziz; Donno, Roberto; Cadman, Christopher J; Cellesi, Francesco; Day, Philip J; Tirelli, Nicola

    2013-12-28

    Chitosan nanoparticles are popular carriers for the delivery of macromolecular payloads, e.g. nucleic acids. In this study, nanoparticles were prepared via complexation with triphosphate (TPP) anions and were successively coated with hyaluronic acid (HA). Key variables of the preparative process (e.g. chitosan and HA molecular weight) were optimised in view of the maximisation of loading with DNA, of the Zeta potential and of the dimensional stability, and the resulting particles showed excellent storage stability. We have focused on the influence of chitosan molecular weight on nanoparticle properties. Larger molecular weight increased their porosity (=decreased cross-link density), and this caused also larger dimensional changes in response to variations in osmotic pressure or upon drying. The dependency of nanoparticle porosity on chitosan molecular weight had a profound effect on the adsorption of HA on the nanoparticles; HA was apparently able to penetrate deeply into the more porous high molecular weight (684 kDa) chitosan nanoparticles, while it formed a corona around those composed of more densely cross-linked low molecular weight (25 kDa) chitosan. Atomic Force Microscopy (AFM) allowed not only to highlight the presence of this corona, but also to estimate its apparent thickness to about 20-30 nm (in a dry state). The different morphology has a significant effect on the way HA is presented to biomolecules, and this has specific relevance in relation to interactions with HA receptors (e.g. CD44) that influence kinetics and mechanism of nanoparticle uptake. Finally, it is worth to mention that chitosan molecular weight did not appear to greatly affect the efficiency of nanoparticle loading with DNA, but significantly influenced its chitosanase-triggered release, with high molecular chitosan nanoparticles seemingly more prone to degradation by this enzyme. © 2013.

  1. Chitosan-Coated Magnetic Nanoparticles with Low Chitosan Content Prepared in One-Step

    Directory of Open Access Journals (Sweden)

    Yolanda Osuna

    2012-01-01

    Full Text Available Chitosan-coated magnetic nanoparticles (CMNP were obtained at 50°C in a one-step method comprising coprecipitation in the presence of low chitosan content. CMNP showed high magnetization and superparamagnetism. They were composed of a core of 9.5 nm in average diameter and a very thin chitosan layer in accordance with electron microscopy measurements. The results from Fourier transform infrared spectrometry demonstrated that CMNP were obtained and those from thermogravimetric analysis allowed to determine that they were composed of 95 wt% of magnetic nanoparticles and 5 wt% of chitosan. 67% efficacy in the Pb+2 removal test indicated that only 60% of amino groups on CMNP surface bound to Pb, probably due to some degree of nanoparticle flocculation during the redispersion. The very low weight ratio chitosan to magnetic nanoparticles obtained in this study, 0.053, and the high yield of the precipitation reactions (≈97% are noticeable.

  2. Structure and properties of microcrystalline chitosan

    International Nuclear Information System (INIS)

    Pighinelli, Luciano; Guimaraes, Fernando Machado; Paz, Luan Rios; Zanin, Gabrielle Brehm; Kmiec, Marzena; Tedesco, Felipe Melleu; Reis, Victoria Oliva dos; Silva, Matheus Machado; Becker, Cristiane Miotto; Zehetmeyer, Gislene; Rasia, Gisele

    2016-01-01

    Full text: The microcrystalline chitosan is a modified form of chitosan; it has been elaborated from obtaining method of chitosan salts. It is characterized by special properties of the initial chitosan such as biocompatibility, bioactivity, non-toxic, biodegradability [1]. The objective of this study is to develop a different method to obtain the microcrystalline chitosan and the following characterization of the initial chitosan and MCCh. The material was characterized by FTIR, scanning of electron microscopy, SEM, nuclear magnetic resonance, NMR, and x-ray diffraction. The results indicate that the process to obtain MCCh, did not change the structure of the initial chitosan. The MCCh shows the same functional groups of the initial chitosan. The NMR results shows the acetylated and deacetylated groups. The morphology shows a homogeneous structure of surface. The X-ray diffraction shows the reduction of the crystallinity in the MCCh, indicating a bigger amorphous structure of the MCCh. The chitosan and its derivatives are polymers with excellent properties to be used in regenerative medicine because of ensure efficiency in healing process. This polysaccharide has a great potential to develop a new generation of biomaterials that can be used in regenerative medicine and tissue engineering [2]. References: [1]. LI, Q. et al. Applications and properties of chitosan. In: GOOSEN, M. F. A. (Ed.). Applications of chitin and chitosan. Basel: Technomic, 1997. p. 3-29; [2]. Luciano Pighinelli, Magdalena Kucharska, Dariuz Wawro. Preparation of Microcrystalline chitosan: (MCCh0/tricalcium phosphate complex with Hydroxyapatite in sponge and fibre from for hard tissue regeneration. (author)

  3. Structure and properties of microcrystalline chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Pighinelli, Luciano; Guimaraes, Fernando Machado; Paz, Luan Rios; Zanin, Gabrielle Brehm; Kmiec, Marzena; Tedesco, Felipe Melleu; Reis, Victoria Oliva dos; Silva, Matheus Machado, E-mail: lpighinelli@hotmail.com [Universidade Luterana, Sao Paulo, SP (Brazil); Becker, Cristiane Miotto; Zehetmeyer, Gislene; Rasia, Gisele [Centro Universitario SENAI CIMATEC, Salvador, BA (Brazil). Instituto de Engenharia de Materiais Polimericos

    2016-07-01

    Full text: The microcrystalline chitosan is a modified form of chitosan; it has been elaborated from obtaining method of chitosan salts. It is characterized by special properties of the initial chitosan such as biocompatibility, bioactivity, non-toxic, biodegradability [1]. The objective of this study is to develop a different method to obtain the microcrystalline chitosan and the following characterization of the initial chitosan and MCCh. The material was characterized by FTIR, scanning of electron microscopy, SEM, nuclear magnetic resonance, NMR, and x-ray diffraction. The results indicate that the process to obtain MCCh, did not change the structure of the initial chitosan. The MCCh shows the same functional groups of the initial chitosan. The NMR results shows the acetylated and deacetylated groups. The morphology shows a homogeneous structure of surface. The X-ray diffraction shows the reduction of the crystallinity in the MCCh, indicating a bigger amorphous structure of the MCCh. The chitosan and its derivatives are polymers with excellent properties to be used in regenerative medicine because of ensure efficiency in healing process. This polysaccharide has a great potential to develop a new generation of biomaterials that can be used in regenerative medicine and tissue engineering [2]. References: [1]. LI, Q. et al. Applications and properties of chitosan. In: GOOSEN, M. F. A. (Ed.). Applications of chitin and chitosan. Basel: Technomic, 1997. p. 3-29; [2]. Luciano Pighinelli, Magdalena Kucharska, Dariuz Wawro. Preparation of Microcrystalline chitosan: (MCCh0/tricalcium phosphate complex with Hydroxyapatite in sponge and fibre from for hard tissue regeneration. (author)

  4. In-vitro starch hydrolysis of chitosan incorporating whey protein and wheat starch composite gels

    Directory of Open Access Journals (Sweden)

    Natasha Yang

    2017-10-01

    Full Text Available The study examined the influence of chitosan, incorporated into whey protein and wheat starch thermo gels, on the in-vitro hydrolysis of the polysaccharide. Gels were subjected to the following external conditions containing α-amylase at constant incubation temperature of 37 °C: In the first procedure, they were immersed in phosphate buffer (0.05 M and maintained at pH 6.9 throughout the entire digestion. In the second instance, they were introduced into a salt solution, with pH and total volume adjusted at times in sync with the human gastrointestinal tract. Results indicate that low and medium molecular weight chitosan, in combination with whey protein, were effective at enhancing the protective barrier against starch degradation. Less maltose was liberated from gels containing medium molecular weight chitosan, as opposed to the low molecular weight counterpart, and results compare favorably with the outcome of the in-vitro digestion of binary whey protein and wheat starch composites. Keywords: Food science

  5. Pseudo-thermosetting chitosan hydrogels for biomedical application.

    Science.gov (United States)

    Berger, J; Reist, M; Chenite, A; Felt-Baeyens, O; Mayer, J M; Gurny, R

    2005-01-06

    To prepare transparent chitosan/beta-glycerophosphate (betaGP) pseudo-thermosetting hydrogels, the deacetylation degree (DD) of chitosan has been modified by reacetylation with acetic anhydride. Two methods (I and II) of reacetylation have been compared and have shown that the use of previously filtered chitosan, dilution of acetic anhydride and reduction of temperature in method II improves efficiency and reproducibility. Chitosans with DD ranging from 35.0 to 83.2% have been prepared according to method II under homogeneous and non-homogeneous reacetylation conditions and the turbidity of chitosan/betaGP hydrogels containing homogeneously or non-homogeneously reacetylated chitosan has been investigated. Turbidity is shown to be modulated by the DD of chitosan and by the homogeneity of the medium during reacetylation, which influences the distribution mode of the chitosan monomers. The preparation of transparent chitosan/betaGP hydrogels requires a homogeneously reacetylated chitosan with a DD between 35 and 50%.

  6. Influence of fiber upon the radiation degradation of fiber-reinforced plastics

    International Nuclear Information System (INIS)

    Udagawa, Akira

    1992-01-01

    Influences of fiber upon the radiation degradation of fiber-reinforced plastics were investigated by using 2 MeV electrons. Radiation resistances were evaluated from the three-point bending strength of the fiber laminates which used bisphenol A-type epoxy resin as a matrix. Carbon fiber laminates had higher radiation resistance values than the laminates made of glass fiber. Model laminates using polyethylene as a matrix were prepared in order to examine the differences between carbon fiber and glass fiber filler, the relation between gel fraction and absorbed dose was established. When the polyethylene was filled in the carbon fiber, forming the gel was strikingly delayed. This result suggests that radiation protective action existing in carbon fiber to matrix resin is the main cause of the higher radiation resistance of carbon fiber reinforced plastics. (author)

  7. Mechanical Behavior Optimization of Chitosan Extracted from Shrimp Shells as a Sustainable Material for Shopping Bags.

    Science.gov (United States)

    D'Angelo, Giacomo; Elhussieny, Amal; Faisal, Marwa; Fahim, I S; Everitt, Nicola M

    2018-05-22

    The use of biodegradable materials for shopping bag production, and other products made from plastics, has recently been an object of intense research-with the aim of reducing the environmental burdens given by conventional materials. Chitosan is a potential material because of its biocompatibility, degradability, and non-toxicity. It is a semi-natural biopolymeric material produced by the deacetylation of chitin, which is the second most abundant natural biopolymer (after cellulose). Chitin is found in the exoskeleton of insects, marine crustaceans, and the cell walls of certain fungi and algae. The raw materials most abundantly available are the shells of crab, shrimp, and prawn. Hence, in this study chitosan was selected as one of the main components of biodegradable materials used for shopping bag production. Firstly, chitin was extracted from shrimp shell waste and then converted to chitosan. The chitosan was next ground to a powder. Although, currently, polyethylene bags are prepared by blown extrusion, in this preliminary research the chitosan powder was dissolved in a solvent and the films were cast. Composite films with several fillers were used as a reinforcement at different dosages to optimize mechanical properties, which have been assessed using tensile tests. These results were compared with those of conventional polyethylene bags used in Egypt. Overall, the chitosan films were found to have a lower ductility but appeared to be strong enough to fulfill shopping bag functions. The addition of fillers, such as chitin whiskers and rice straw, enhanced the mechanical properties of chitosan films, while the addition of chitin worsened overall mechanical behavior.

  8. Mechanical Behavior Optimization of Chitosan Extracted from Shrimp Shells as a Sustainable Material for Shopping Bags

    Directory of Open Access Journals (Sweden)

    Giacomo D’Angelo

    2018-05-01

    Full Text Available The use of biodegradable materials for shopping bag production, and other products made from plastics, has recently been an object of intense research—with the aim of reducing the environmental burdens given by conventional materials. Chitosan is a potential material because of its biocompatibility, degradability, and non-toxicity. It is a semi-natural biopolymeric material produced by the deacetylation of chitin, which is the second most abundant natural biopolymer (after cellulose. Chitin is found in the exoskeleton of insects, marine crustaceans, and the cell walls of certain fungi and algae. The raw materials most abundantly available are the shells of crab, shrimp, and prawn. Hence, in this study chitosan was selected as one of the main components of biodegradable materials used for shopping bag production. Firstly, chitin was extracted from shrimp shell waste and then converted to chitosan. The chitosan was next ground to a powder. Although, currently, polyethylene bags are prepared by blown extrusion, in this preliminary research the chitosan powder was dissolved in a solvent and the films were cast. Composite films with several fillers were used as a reinforcement at different dosages to optimize mechanical properties, which have been assessed using tensile tests. These results were compared with those of conventional polyethylene bags used in Egypt. Overall, the chitosan films were found to have a lower ductility but appeared to be strong enough to fulfill shopping bag functions. The addition of fillers, such as chitin whiskers and rice straw, enhanced the mechanical properties of chitosan films, while the addition of chitin worsened overall mechanical behavior.

  9. The effect of chitosan and whey proteins-chitosan films on the growth of Penicillium expansum in apples.

    Science.gov (United States)

    Simonaitiene, Dovile; Brink, Ieva; Sipailiene, Ausra; Leskauskaite, Daiva

    2015-05-01

    Penicillium expansum causes a major post-harvest disease of apples. The aim of this study was to investigate the inhibition effect of chitosan and whey proteins-chitosan films containing different amounts of quince and cranberry juice against P. expansum on the simulation medium and on apples. The mechanical properties of films were also evaluated. The presence of cranberry and quince juice in the composition of chitosan and whey proteins-chitosan films caused a significant (P ≤ 0.05) increase in elasticity and decrease in tensile strength of films. Chitosan and whey proteins-chitosan films with quince and cranberry juice demonstrated a significant (P ≤ 0.05) inhibition effect against P. expansum growth on the simulated medium and apples. The presence of cranberry juice in the composition of chitosan and whey proteins-chitosan films resulted in a longer lag phase and a lower P. expansum growth rate on the simulation medium in comparison with films made with the addition of quince juice. These differences were not evident when experiment was conducted with apples. Addition of quince and cranberry juice to the chitosan and whey proteins-chitosan films as natural antifungal agents has some potential for prolonging the shelf life of apples. © 2014 Society of Chemical Industry.

  10. Intercalated chitosan/hydroxyapatite nanocomposites: Promising materials for bone tissue engineering applications.

    Science.gov (United States)

    Nazeer, Muhammad Anwaar; Yilgör, Emel; Yilgör, Iskender

    2017-11-01

    Preparation and characterization of chitosan/hydroxyapatite (CS/HA) nanocomposites displaying an intercalated structure is reported. Hydroxyapatite was synthesized through sol-gel process. Formic acid was introduced as a new solvent to obtain stable dispersions of nano-sized HA particles in polymer solution. CS/HA dispersions with HA contents of 5, 10 and 20% by weight were prepared. Self-assembling of HA nanoparticles during the drying of the solvent cast films led to the formation of homogeneous CS/HA nanocomposites. Composite films were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-rays (EDX) analysis, Fourier transform infrared (FTIR) spectroscopy, X-rays diffraction (XRD) analysis and thermogravimetric analysis (TGA). SEM and AFM confirmed the presence of uniformly distributed HA nanoparticles on the chitosan matrix surface. XRD patterns and cross-sectional SEM images showed the formation of layered nanocomposites. Complete degradation of chitosan matrix in TGA experiments, led to the formation of nanoporous 3D scaffolds containing hydroxyapatite, β-tricalcium phosphate and calcium pyrophosphate. CS/HA composites can be considered as promising materials for bone tissue engineering applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Deacetylation of Chitosan: Material Characterization and in vitro Evaluation via Albumin Adsorption and Pre-Osteoblastic Cell Cultures

    Directory of Open Access Journals (Sweden)

    Joel D. Bumgardner

    2011-08-01

    Full Text Available Degree of deacetylation (DDA and molecular weight (MW of chitosans are important to their physical and biological properties. In this study, two chitosans, HS (DDA = 73.3% and AT (DDA = 76.8%, were deacetylated with 45% sodium hydroxide under nitrogen atmosphere at 80 °C or 90 °C for up to 120 min, to obtain two series of chitosans. The polymers produced were characterized for MW by gel permeation chromatography, DDA by titration and UV-vis methods, and crystallinity, hydrophilicity and thermal stability by X-ray diffraction, water contact angle and differential scanning calorimetry respectively. Films, made by solution casting in dilute acetic acid at ambient conditions, were evaluated for biological activity by albumin adsorption and the attachment and growth of a pre-osteoblast cell line. Chitosans with between 80–93% DDA’s (based on titration were reproducibly obtained. Even though deacetylation under nitrogen was supposed to limit chain degradation during decetylation, MW decreased (by maximum of 37.4% of HS and 63.0% for AT with increasing deacetylation reaction time and temperature. Crystallinity and decomposition temperature increased and water contact angles decreased with processing to increase DDA. Significantly less albumin was absorbed on films made with 93% DDA chitosans as compared with the original materials and the AT chitosans absorbed less than the HS chitosans. The cells on higher DDA chitosan films grew faster than those on lower DDA films. In conclusion, processing conditions increased DDA and influenced physicochemical and biological properties. However, additional studies are needed to unambiguously determine the influence of DDA or MW on in vitro and in vivo performance of chitosan materials for bone/implant applications.

  12. Chitosan as a Biomaterial: Influence of Degree of Deacetylation on Its Physiochemical, Material and Biological Properties.

    Directory of Open Access Journals (Sweden)

    Leslie John Ray Foster

    Full Text Available Chitosan is a biomaterial with a range of current and potential biomedical applications. Manipulation of chitosan degree of deacetylation (DDA to achieve specific properties appears feasible, but studies investigating its influence on properties are often contradictory. With a view to the potential of chitosan in the regeneration of nerve tissue, the influence of DDA on the growth and health of olfactory ensheathing cells (OECs was investigated. There was a linear increase in OEC proliferation as the DDA increased from 72 to 85%. This correlated with linear increases in average surface roughness (0.62 to 0.78 μm and crystallinity (4.3 to 10.1% of the chitosan films. Mitochondrial activity and membrane integrity of OECs was significantly different for OECs cultivated on chitosan with DDAs below 75%, while those on films with DDAs up to 85% were similar to cells in asynchronous growth. Apoptotic indices and cell cycle analysis also suggested that chitosan films with DDAs below 75% were cytocompatible but induced cellular stress, while OECs grown on films fabricated from chitosan with DDAs above 75% showed no significant differences compared to those in asynchronous growth. Tensile strength and elongation to break varied with DDA from 32.3 to 45.3 MPa and 3.6 to 7.1% respectively. DDA had no significant influence on abiotic and biotic degradation profiles of the chitosan films which showed approximately 8 and 20% weight loss respectively. Finally, perceived patterns in property changes are subject to change based on potential variations in DDA analysis. NMR examination of the chitosan samples here revealed significant differences depending upon which peaks were selected for integration; 6 to 13% in DDA values within individual samples. Furthermore, differences between DDA values determined here and those reported by the commercial suppliers were significant and this may also be a source of concern when selecting commercial chitosans for

  13. Natural stimulus responsive scaffolds/cells for bone tissue engineering: influence of lysozyme upon scaffold degradation and osteogenic differentiation of cultured marrow stromal cells induced by CaP coatings.

    Science.gov (United States)

    Martins, Ana M; Pham, Quynh P; Malafaya, Patrícia B; Raphael, Robert M; Kasper, F Kurtis; Reis, Rui L; Mikos, Antonios G

    2009-08-01

    This work proposes the use of nonporous, smart, and stimulus responsive chitosan-based scaffolds for bone tissue engineering applications. The overall vision is to use biodegradable scaffolds based on chitosan and starch that present properties that will be regulated by bone regeneration, with the capability of gradual in situ pore formation. Biomimetic calcium phosphate (CaP) coatings were used as a strategy to incorporate lysozyme at the surface of chitosan-based materials with the main objective of controlling and tailoring their degradation profile as a function of immersion time. To confirm the concept, degradation tests with a lysozyme concentration similar to that incorporated into CaP chitosan-based scaffolds were used to study the degradation of the scaffolds and the formation of pores as a function of immersion time. Degradation studies with lysozyme (1.5 g/L) showed the formation of pores, indicating an increase of porosity ( approximately 5-55% up to 21 days) resulting in porous three-dimensional structures with interconnected pores. Additional studies investigated the influence of a CaP biomimetic coating on osteogenic differentiation of rat marrow stromal cells (MSCs) and showed enhanced differentiation of rat MSCs seeded on the CaP-coated chitosan-based scaffolds with lysozyme incorporated. At all culture times, CaP-coated chitosan-based scaffolds with incorporated lysozyme demonstrated greater osteogenic differentiation of MSCs, bone matrix production, and mineralization as demonstrated by calcium deposition measurements, compared with controls (uncoated scaffolds). The ability of these CaP-coated chitosan-based scaffolds with incorporated lysozyme to create an interconnected pore network in situ coupled with the demonstrated positive effect of these scaffolds upon osteogenic differentiation of MSCs and mineralized matrix production illustrates the strong potential of these scaffolds for application in bone tissue engineering strategies.

  14. Radiation degradation of molasses pigment. The fading color and product

    International Nuclear Information System (INIS)

    Sawai, Teruko; Sekiguchi, Masayuki; Tanabe, Hiroko; Sawai, Takeshi

    1993-01-01

    Water demand in Tokyo has increased rapidly. Because of the scarcity of water supply sources within the city, Tokyo is dependent on the water from other prefectures. Recycling of municipal effluent is an effective means of coping with water shortage in Tokyo. We have studied the radiation treatment of waste water for recycling. In this paper, the radiation decomposition methods for fading color of molasses pigment in the effluent from the sewage treatment plant and in the food industry wastwater were reported. The refractory organic substances (molasses pigment) in samples were degraded by gamma irradiation. The COD values decreased and the dark brown color faded with increasing dosage. The high molecular weight components of molasses pigment were degraded to lower molecular weight substances and were decomposed finally to carbon dioxide. The organic acids, such as formic acid, acetic acid, oxalic acid, citric acid and succinic acid were measured as intermediates of radiolytic decomposition. When we added hydrogen peroxide in samples to the gamma irradiation process, the dark brown color of molasses pigment faded with greater efficiency. (author)

  15. Degradation of poly(vinyl chloride) films by X-rays radiation

    International Nuclear Information System (INIS)

    Sbampato, M.E.; Kawano, Y.

    1984-01-01

    The degradation of pure poly(vinyl chloride) (PVC) films has been studied by X-rays radiation in vacuum. The films are transparent and become yellow with the exposure of radiation and this colour is enhanced with the time of irradiation. The infrared, ultraviolet and visible spectra changed in the irradiated material. The IR spectra show changes in itensities and band shifting, particularly in the region of C-Cl stretching vibrations indicating the occurrence of dehydrochlorination and a change in the conformation of the degraded PVC. The ultraviolet and visible spectra of irradiated films show a strong absorption band at 240 nm and many shoulders which are associated to dyenes, carbonyl and polyenes with few double bonds formed. The shoulder numbers increase in the spectra of samples kept for three months. This effect indicates that with irradiation, HCl is evolved resulting in the formation of polyenyl radicals, which propagate after irradiation. At the same time, should occur the reaction of these radicals with the atmospheric oxygen with formation of C=0 bonds. (Author) [pt

  16. Collagen-chitosan scaffold modified with Au and Ag nanoparticles: Synthesis and structure

    International Nuclear Information System (INIS)

    Rubina, M.S.; Kamitov, E.E.; Zubavichus, Ya. V.; Peters, G.S.; Naumkin, A.V.; Suzer, S.; Vasil’kov, A.Yu.

    2016-01-01

    Graphical abstract: - Highlights: • Biocompatible collagen-chitosan scaffolds were modified by Au and Ag nanoparticles via the metal-vapor synthesis. • Structural and morphological parameters of the nanocomposites were assessed using a set of modern instrumental techniques, including electron microscopy, X-ray diffraction, small-angle X-ray scattering, EXAFS, XPS. • Potential application of the nanocomposites are envisaged. - Abstract: Nowadays, the dermal biomimetic scaffolds are widely used in regenerative medicine. Collagen-chitosan scaffold one of these materials possesses antibacterial activity, good compatibility with living tissues and has been already used as a wound-healing material. In this article, collagen-chitosan scaffolds modified with Ag and Au nanoparticles have been synthesized using novel method - the metal-vapor synthesis. The nanocomposite materials are characterized by XPS, TEM, SEM and synchrotron radiation-based X-ray techniques. According to XRD data, the mean size of the nanoparticles (NPs) is 10.5 nm and 20.2 nm in Au-Collagen-Chitosan (Au-CollCh) and Ag-Collagen-Chitosan (Ag-CollCh) scaffolds, respectively in fair agreement with the TEM data. SAXS analysis of the composites reveals an asymmetric size distribution peaked at 10 nm for Au-CollCh and 25 nm for Ag-CollCh indicative of particle's aggregation. According to SEM data, the metal-carrying scaffolds have layered structure and the nanoparticles are rather uniformly distributed on the surface material. XPS data indicate that the metallic nanoparticles are in their unoxidized/neutral states and dominantly stabilized within the chitosan-rich domains.

  17. Collagen-chitosan scaffold modified with Au and Ag nanoparticles: Synthesis and structure

    Energy Technology Data Exchange (ETDEWEB)

    Rubina, M.S.; Kamitov, E.E. [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991 Russian Federation (Russian Federation); Zubavichus, Ya. V.; Peters, G.S. [National Research center «Kurchatov Institute», Moscow, 123182 Russian Federation (Russian Federation); Naumkin, A.V. [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991 Russian Federation (Russian Federation); Suzer, S. [Department of Chemistry, Bilkent University, Ankara, 06800 Turkey (Turkey); Vasil’kov, A.Yu., E-mail: alexandervasilkov@yandex.ru [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991 Russian Federation (Russian Federation)

    2016-03-15

    Graphical abstract: - Highlights: • Biocompatible collagen-chitosan scaffolds were modified by Au and Ag nanoparticles via the metal-vapor synthesis. • Structural and morphological parameters of the nanocomposites were assessed using a set of modern instrumental techniques, including electron microscopy, X-ray diffraction, small-angle X-ray scattering, EXAFS, XPS. • Potential application of the nanocomposites are envisaged. - Abstract: Nowadays, the dermal biomimetic scaffolds are widely used in regenerative medicine. Collagen-chitosan scaffold one of these materials possesses antibacterial activity, good compatibility with living tissues and has been already used as a wound-healing material. In this article, collagen-chitosan scaffolds modified with Ag and Au nanoparticles have been synthesized using novel method - the metal-vapor synthesis. The nanocomposite materials are characterized by XPS, TEM, SEM and synchrotron radiation-based X-ray techniques. According to XRD data, the mean size of the nanoparticles (NPs) is 10.5 nm and 20.2 nm in Au-Collagen-Chitosan (Au-CollCh) and Ag-Collagen-Chitosan (Ag-CollCh) scaffolds, respectively in fair agreement with the TEM data. SAXS analysis of the composites reveals an asymmetric size distribution peaked at 10 nm for Au-CollCh and 25 nm for Ag-CollCh indicative of particle's aggregation. According to SEM data, the metal-carrying scaffolds have layered structure and the nanoparticles are rather uniformly distributed on the surface material. XPS data indicate that the metallic nanoparticles are in their unoxidized/neutral states and dominantly stabilized within the chitosan-rich domains.

  18. Accelerated degradation by UV radiation of adhesive materials used in solar equipment

    International Nuclear Information System (INIS)

    Tilca, F.; Acosta, D; Barcena, H.; Suarez, H.; Cadena, C.; Bolzi, Claudio

    2003-01-01

    Several materials which are used as common adhesives in photovoltaic cells, were tested in order to study their stability. Accelerated degradation effects were produced using high radiation doses of UV-C and UV-b in a previously described camera at different times. The exposed and unexposed films were studied by transmittance, X-ray diffraction and infrared. The results are in agreement with complex degradation process at long exposition times, while transmittance doesn't change significantly. (author)

  19. Flow Cytometry Detection of Bacterial Cell Entrapment within the Chitosan Hydrogel and Antibacterial Property of Extracted Chitosan

    Directory of Open Access Journals (Sweden)

    Nafise Sadat Majidi

    2016-09-01

    Full Text Available Background:   Chitosan is unbranched polysaccharide composed of D-glucosamine and N-acetyl-D-glucosamine. Chitosan, derived from shrimp shell, has broad antimicrobial properties against Gram-negative, Gram-positive bacteria and fungi. Methods:  Chitosan was extracted from shrimp shell and studied for cell entrapment and anti-bacterial properties. The hydrogel chitosan was used as the beads for cell entrapment and chitosan beads were designed to deliver cells and nutrients. These data confirmed with flow cytometric analyses.                 Results:   Experimental results exhibited that internal diffusion through the chitosan matrix was the main mechanism for whole gelation by TPP (Tri-polyphosphate. The minimum inhibitory concentration (MIC for chitosan against Staphylococcus aureus and Escherichia coli was 16 and 32 μg/ml respectively. Conclusion:  Despite the antimicrobial properties of chitosan, trapped bacteria in the gel network were alive and were chelated indicating that their access to the outside was limited.

  20. Ellipsometric studies of synthetic albumin-binding chitosan-derivatives and selected blood plasma proteins

    Science.gov (United States)

    Sarkar, Sabyasachi

    This dissertation summarizes work on the synthesis of chitosan-derivatives and the development of ellipsometric methods to characterize materials of biological origin. Albumin-binding chitosan-derivatives were synthesized via addition reactions that involve amine groups naturally present in chitosan. These surfaces were shown to have an affinity towards human serum albumin via ELISA, UV spectroscopy and SDS PAGE. Modified surfaces were characterized with IR ellipsometry at various stages of their synthesis using appropriate optical models. It was found that spin cast chitosan films were anisotropic in nature. All optical models used for characterizing chitosan-derivatives were thus anisotropic. Chemical signal dependence on molecular structure and composition was illustrated via IR spectroscopic ellipsometry (IRSE). An anisotropic optical model of an ensemble of Lorentz oscillators were used to approximate material behavior. The presence of acetic acid in spin-cast non-neutralized chitosan samples was thus shown. IRSE application to biomaterials was also demonstrated by performing a step-wise chemical characterizations during synthesis stages. Protein adsorbed from single protein solutions on these modified surfaces was monitored by visible in-situ variable wavelength ellipsometry. Based on adsorption profiles obtained from single protein adsorption onto silicon surfaces, lumped parameter kinetic models were developed. These models were used to fit experimental data of immunoglobulin-G of different concentrations and approximate conformational changes in fibrinogen adsorption. Biomaterial characterization by ellipsometry was further extended to include characterization of individual protein solutions in the IR range. Proteins in an aqueous environment were characterized by attenuated total internal reflection (ATR) IR ellipsometry using a ZnSe prism. Parameterized dielectric functions were created for individual proteins using Lorentz oscillators. These

  1. Progress in radiation processing of polymers

    Science.gov (United States)

    Chmielewski, Andrzej G.; Haji-Saeid, Mohammad; Ahmed, Shamshad

    2005-07-01

    Modification in polymeric structure of plastic material can be brought either by conventional chemical means or by exposure to ionization radiation from ether radioactive sources or highly accelerated electrons. The prominent drawbacks of chemical cross-linking typically involve the generation of noxious fumes and by products of peroxide degradation. Both the irradiation sources have their merits and limitations. Increased utilization of electron beams for modification and enhancement of polymer materials has been in particular witnessed over the past 40 years. The paper highlights several recent cases of EB utilization to improve key properties of selected plastic products. In paper is provided a survey of radiation processing methods of industrial interest, encompassing technologies which are already commercially well established, through developments in the active R&D stage which show pronounced promise for future commercial use. Radiation cross-linking technologies discussed include: application in cable and wire, application in rubber tyres, radiation vulcanization of rubber latex, development of radiation crosslinked SiC fiber, polymer recycling, development of gamma compatible pp, hydrogels etc. Over the years, remarkable advancement has been achieved in radiation processing of natural polymers. Role of radiation in improving the processing of temperature of PCL for use as biodegradable polymer, in accelerated breakdown of cellulose into viscose and enhancement in yields of chitin/chitosan from sea-food waste, is described.

  2. Progress in radiation processing of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Chmielewski, Andrzej G. [International Atomic Energy Agency, Industrial Applications and Chemistry Section, Division of Physical and Chemical Sciences, Department of Nuclear Sciences and Applications, Wagramer Street 5, Vienna 1400 (Austria) and Department of Process and Chemical Engineering, Warsaw University of Technology, Warsaw (Poland)]. E-mail: a-g.chmielewski@iaea.org; Haji-Saeid, Mohammad [International Atomic Energy Agency, Industrial Applications and Chemistry Section, Division of Physical and Chemical Sciences, Department of Nuclear Sciences and Applications, Wagramer Street 5, Vienna 1400 (Austria); Ahmed, Shamshad [Applied Chemistry Laboratories, Pakistan Institute of Nuclear Science and Technology, P.O. Box Nilore, Islamabad (Pakistan)

    2005-07-01

    Modification in polymeric structure of plastic material can be brought either by conventional chemical means or by exposure to ionization radiation from ether radioactive sources or highly accelerated electrons. The prominent drawbacks of chemical cross-linking typically involve the generation of noxious fumes and by products of peroxide degradation. Both the irradiation sources have their merits and limitations. Increased utilization of electron beams for modification and enhancement of polymer materials has been in particular witnessed over the past 40 years. The paper highlights several recent cases of EB utilization to improve key properties of selected plastic products. In paper is provided a survey of radiation processing methods of industrial interest, encompassing technologies which are already commercially well established, through developments in the active R and D stage which show pronounced promise for future commercial use. Radiation cross-linking technologies discussed include: application in cable and wire, application in rubber tyres, radiation vulcanization of rubber latex, development of radiation crosslinked SiC fiber, polymer recycling, development of gamma compatible pp, hydrogels etc. Over the years, remarkable advancement has been achieved in radiation processing of natural polymers. Role of radiation in improving the processing of temperature of PCL for use as biodegradable polymer, in accelerated breakdown of cellulose into viscose and enhancement in yields of chitin/chitosan from sea-food waste, is described.

  3. Progress in radiation processing of polymers

    International Nuclear Information System (INIS)

    Chmielewski, Andrzej G.; Haji-Saeid, Mohammad; Ahmed, Shamshad

    2005-01-01

    Modification in polymeric structure of plastic material can be brought either by conventional chemical means or by exposure to ionization radiation from ether radioactive sources or highly accelerated electrons. The prominent drawbacks of chemical cross-linking typically involve the generation of noxious fumes and by products of peroxide degradation. Both the irradiation sources have their merits and limitations. Increased utilization of electron beams for modification and enhancement of polymer materials has been in particular witnessed over the past 40 years. The paper highlights several recent cases of EB utilization to improve key properties of selected plastic products. In paper is provided a survey of radiation processing methods of industrial interest, encompassing technologies which are already commercially well established, through developments in the active R and D stage which show pronounced promise for future commercial use. Radiation cross-linking technologies discussed include: application in cable and wire, application in rubber tyres, radiation vulcanization of rubber latex, development of radiation crosslinked SiC fiber, polymer recycling, development of gamma compatible pp, hydrogels etc. Over the years, remarkable advancement has been achieved in radiation processing of natural polymers. Role of radiation in improving the processing of temperature of PCL for use as biodegradable polymer, in accelerated breakdown of cellulose into viscose and enhancement in yields of chitin/chitosan from sea-food waste, is described

  4. Chitosan Modification and Pharmaceutical/Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Jiali Zhang

    2010-06-01

    Full Text Available Chitosan has received much attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine. Our recent efforts focused on the chemical and biological modification of chitosan in order to increase its solubility in aqueous solutions and absorbability in the in vivo system, thus for a better use of chitosan. This review summarizes chitosan modification and its pharmaceutical/biomedical applications based on our achievements as well as the domestic and overseas developments: (1 enzymatic preparation of low molecular weight chitosans/chitooligosaccharides with their hypocholesterolemic and immuno-modulating effects; (2 the effects of chitin, chitosan and their derivatives on blood hemostasis; and (3 synthesis of a non-toxic ion ligand—D-Glucosaminic acid from Oxidation of D-Glucosamine for cancer and diabetes therapy.

  5. Degradation of diazinon contaminated waters by ionizing radiation

    International Nuclear Information System (INIS)

    Basfar, A.A.; Mohamed, K.A.; Al-Abduly, A.J.; Al-Kuraiji, T.S.; Al-Shahrani, A.A.

    2007-01-01

    Study of degradation of diazinon pesticide by 60 Co gamma irradiation in a single aqueous solution was conducted on a laboratory scale and the effect of ionizing radiation on the removal efficiency of diazinon residues was investigated. Distilled water solutions at three different concentrations of targeted compound (i.e. 0.329, 1.643 and 3.286 μmol dm -3 ) were irradiated over the range 0.1-6 kGy. The initial concentration of contaminant and irradiation doses play a significant role in the rate of destruction; this was evident from the calculated decay constants of diazinon residue. Gamma radiolysis showed that the absorbed doses from 1.5 to 5.6 kGy at a dose rate of 4.79 kGy h -1 achieved 90% destruction for diazinon with initial concentrations over the range 0.329-3.286 μmol dm -3 . The radiolytic degradation by-products and their mass balances were qualitative determined with good confidence by using GC/quadrupole mass spectrometry (GC/MS) with EI + or CI in positive and negative ionization mode and diazinon degradation pathways were proposed. Additionally, the final products of irradiation were identified by ion chromatography (IC) to be acetic and formic acid

  6. Synthesis and characterization of Ag2S decorated chitosan nanocomposites and chitosan nanofibers for removal of lincosamides antibiotic.

    Science.gov (United States)

    Gupta, Vinod Kumar; Fakhri, Ali; Agarwal, Shilpi; Azad, Mona

    2017-10-01

    We report the synthesis of Ag 2 S-Chitosan nanocomposites and Ag 2 S-chitosan nanohybrids as performance adsorbents for Lincosamides such as Clindamycin antibiotic removal. Isotherms and kinetic studies were determined to understand the adsorption behavior both two adsorbent. At low adsorbent dose, removals are increased in the adsorption process, and performance is better with Ag 2 S-chitosan nanohybrids due to the special surface area increased. The average sizes and surface area of Ag 2 S-Chitosan nanocomposites and Ag 2 S-chitosan nanohybrids were found as 50nm, 70nm and 180.18, 238.24m 2 g -1 , respectively. In particular, Ag 2 S-Chitosan nanocomposites and Ag 2 S-chitosan nanohybrids show high maximum Clindamycin adsorption capacity (q max ) of 153.21, and 181.28mgg -1 , respectively. More strikingly, Ag 2 S-Chitosan nanocomposites and Ag 2 S-chitosan nanohybrids are also demonstrated to nearly completely remove Clindamycin from drinking water. The excellent adsorption performance along with their cost effective, convenient synthesis makes this range of adsorbents highly promising for commercial applications in drinking water and wastewater treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Interactions between chitosan and cells measured by AFM

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Sheng-Wen; Thien, Doan Van Hong; Ho, Ming-Hua [Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10617, Taiwan (China); Hsieh, Hsyue-Jen [Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Li, Chung-Hsing [Division of Orthodontics and Pediatric Dentistry, Department of Dentistry, Tri-Service General Hospital, Taipei, Taiwan (China); Hung, Chang-Hsiang [Department of Dentistry, Kinmen Hospital Department of Health, Taiwan (China); Li, Hsi-Hsin, E-mail: mhho@mail.ntust.edu.t [Deputy Superintendent, Kinmen Hospital Department of Health, Taiwan (China)

    2010-10-01

    Chitosan, a biocompatible material that has been widely used in bone tissue engineering, is believed to have a high affinity to osteoblastic cells. This research is the first to prove this hypothesis. By using atomic force microscopy (AFM) with a chitosan-modified cantilever, quantitative evaluation of the interforce between chitosan and cells was carried out. A chitosan tip functionalized with Arg-Gly-Asp (RGD) was also used to measure the interforce between RGD-chitosan and osteoblastic cells. This research concluded by examining cell adhesion and spreading of chitosan substrates as further characterization of the interactions between cells and chitosan. The force measured by AFM showed that the interforce between chitosan and osteoblasts was the highest (209 nN). The smallest adhesion force (61.8 nN) appeared between chitosan and muscle fibroblasts, which did not demonstrate any osteoblastic properties. This result proved that there was a significant interaction between chitosan and bone cells, and correlated with the observations of cell attachment and spreading. The technique developed in this research directly quantified the adhesion between chitosan and cells. This is the first study to demonstrate that specific interaction exists between chitosan and osteoblasts.

  8. Interactions between chitosan and cells measured by AFM

    International Nuclear Information System (INIS)

    Hsiao, Sheng-Wen; Thien, Doan Van Hong; Ho, Ming-Hua; Hsieh, Hsyue-Jen; Li, Chung-Hsing; Hung, Chang-Hsiang; Li, Hsi-Hsin

    2010-01-01

    Chitosan, a biocompatible material that has been widely used in bone tissue engineering, is believed to have a high affinity to osteoblastic cells. This research is the first to prove this hypothesis. By using atomic force microscopy (AFM) with a chitosan-modified cantilever, quantitative evaluation of the interforce between chitosan and cells was carried out. A chitosan tip functionalized with Arg-Gly-Asp (RGD) was also used to measure the interforce between RGD-chitosan and osteoblastic cells. This research concluded by examining cell adhesion and spreading of chitosan substrates as further characterization of the interactions between cells and chitosan. The force measured by AFM showed that the interforce between chitosan and osteoblasts was the highest (209 nN). The smallest adhesion force (61.8 nN) appeared between chitosan and muscle fibroblasts, which did not demonstrate any osteoblastic properties. This result proved that there was a significant interaction between chitosan and bone cells, and correlated with the observations of cell attachment and spreading. The technique developed in this research directly quantified the adhesion between chitosan and cells. This is the first study to demonstrate that specific interaction exists between chitosan and osteoblasts.

  9. Biopolymer molecular weight control by radiation treatment for functional property improvement

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Nguyen Duy; Diep, Tran Bang; Quynh, Tran Minh; Hung, Nguyen Manh [Vietnam Atomic Energy Commission, Institute for Nuclear Science and Techniques, Caugiay, Hanoi (Viet Nam); Nagasawa, Naotsugu; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-03-01

    Solid-state radiation treatment of chitosan an dose range of 30-100 kGy and of gelatin at dose range of 30-40 kGy significantly improved the water-stability of shrimp feed. In these dose ranges, the viscosity-average molecular weight (Mv) of bioadhesive was reduced from 552,000 to 250,000-130,000 and from 57,000 to 38,000-32,000 for chitosan and gelatin, respectively. Gelatin, which has been irradiated in liquid state, could not be used as bioadhesive due to the forming of higher macromolecules based on chaincrosslinks. Liquid-state radiation treatment, in comparison with solid-state irradiation at 100 kGy, required only dose of 4-6 kGy for similar MW and for the same optimal improvement of adhesive property. Radiation treatment with 60-100 kGy maximally enhanced the anti-microbial activity of chitosan. In addition, the optimal dose required for activity is depended on chitosan origin. Chitosan with initial MW of 830,000 required dose of 100 kGy to reduce to 120,000, while other kind of chitosan with initial MW of 550,000 required dose of 60-75 kGy to reduce to 170,000-150,000 for optimal enhancement. The antimicrobial activity is regulated by not only MW but also by its distribution. Irradiated chitosan that has largest width of MW distribution (Mw/Mn) may possesses highest antimicrobial activity. Result from fractionation by using centrifugal filter devices showed that fraction of 3-5 x 10{sup 4} has mainly contributed to the suppression of microbial growth. (author)

  10. Radiation-thermal degradation of PE and PVC: Mechanism of synergism and dose rate effects

    Science.gov (United States)

    Clough, Roger L.; Gillen, Kenneth T.

    Polyethylene insulation and polyvinyl chloride jacketing materials that had been in use in a nuclear application were recently found to be substantially deteriorated. The damage had occurred under conditions where both the total estimated dose (about 2.5 Mrad) and the operating temperatures (about 43°C average) seemed relatively moderate. These results prompted us to initiate a program to study polyvinyl chloride and polyethylene degradation under conditions of combined γ-radiation and elevated temperature environments. A number of interesting aging effects were observed, including 1) a striking synergism between radiation and temperature and 2) strong dose-rate dependent effects which occur over a wide range of dose rates. The aging effects are explained in terms of a chain branching degradation mechanism involving thermally induced breakdown of peroxides which are formed in reactions initiated by the radiation. Evidence for this mechanism is derived from infrared spectra, from sequential radiation-elevated temperature experiments including experiments under inert atmosphere, from activation energy estimates and from a new technique involving treatment of intact samples with PH 3 for chemical reduction of peroxides. The results of our studies raise significant doubts about the utility of earlier compilations which purportedly serve as radiation life expectancy guides by indicating "tolerable radiation doses" for a variety of polymers.

  11. Efficient gene delivery using chitosan-polyethylenimine hybrid systems

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hu-Lin; Kim, Tae-Hee; Kim, You-Kyoung; Park, In-Young; Cho, Chong-Su [Department of Agricultural Bioechnology, Seoul National University, Seoul 151-921 (Korea, Republic of); Cho, Myung-Haing [Laboratory of Toxicology, College of Veterinary Medicine, Seoul National University, Seoul 151-742 (Korea, Republic of)], E-mail: chocs@plaza.snu.ac.kr

    2008-06-01

    Chitosan and chitosan derivatives have been investigated as non-viral vectors because they have several advantages, such as biocompatibility, biodegradability, low cytotoxicity and low immunogenicity. However, low transfection efficiency and low cell specificity must be solved for their use in clinical trials. In this paper, chitosan-polyethylenimine (PEI) hybrid systems such as chitosan/PEI blend and chitosan-graft-PEI are described for efficient gene delivery because the PEI has high transfection efficiency owing to a proton sponge effect and chitosan has biocompatibility. Also, hepatocyte specificity of the galactosylated chitosan is explained after combination with PEI.

  12. Efficient gene delivery using chitosan-polyethylenimine hybrid systems

    International Nuclear Information System (INIS)

    Jiang, Hu-Lin; Kim, Tae-Hee; Kim, You-Kyoung; Park, In-Young; Cho, Chong-Su; Cho, Myung-Haing

    2008-01-01

    Chitosan and chitosan derivatives have been investigated as non-viral vectors because they have several advantages, such as biocompatibility, biodegradability, low cytotoxicity and low immunogenicity. However, low transfection efficiency and low cell specificity must be solved for their use in clinical trials. In this paper, chitosan-polyethylenimine (PEI) hybrid systems such as chitosan/PEI blend and chitosan-graft-PEI are described for efficient gene delivery because the PEI has high transfection efficiency owing to a proton sponge effect and chitosan has biocompatibility. Also, hepatocyte specificity of the galactosylated chitosan is explained after combination with PEI

  13. PVA/CM-chitosan/honey hydrogels prepared by using the combined technique of irradiation followed by freeze-thawing

    Science.gov (United States)

    Afshari, M. J.; Sheikh, N.; Afarideh, H.

    2015-08-01

    Hydrogels with three components, poly(vinyl alcohol) (PVA), carboxymethylate chitosan (CM-chitosan) and honey have been prepared by using radiation method and radiation followed by freeze-thawing cycles technique (combinational method). The solid concentration of the polymer solution is 15 wt% and the ratios of PVA/CM-chitosan/honey are 10/1.5/3.5, 10/2/3, 10/3/2, and 10/3.5/1.5. The applied irradiation doses are 25, 30 and 40 kGy. Various tests have been done to evaluate the hydrogel properties to produce materials to be used as wound dressing. The results show that combinational method improves the mechanical strength of hydrogels while it has no significant effect on the water evaporation rate of gels. The combinational method decreases the swelling of hydrogels significantly, albeit this parameter is still acceptable for wound dressing. Microbiological analyses show that the hydrogel prepared by both methods can protect the wound from Escherichia coli bacterial infection. The wound healing test shows the good performance of the gels in mice.

  14. Synthesis of fish scales gelatin-chitosan crosslinked films by gamma irradiation techniques

    International Nuclear Information System (INIS)

    Erizal; Perkasa, D.P.; Abbas, B.; Sulistioso, G.S.

    2013-01-01

    Gelatin is an important component of fish scales. Nowadays, attention has increased concerning the application of gelatin.The aim of this research was to improve the mechanical properties of gelatin produced from fish scales, which concurrently could increase the usefulness of fish scales. Gelatin (G) is prone to degrade or dissolve in water at room temperature, therefore to enhance its lifetime, it has to be modified with other compound such as chitosan. Chitosan (Cs) is a biodegradable polymer, which has biocompatibility and antibacterial properties. In this study, gelatin solution was mixed with chitosan solution in various ratios (G/Cs: 100/0, 75/25, 50/50, 25/75, 0/100), casted at room temperature to make composite films, then tested for the effectiveness of various gamma irradiation doses (10-40 kGy) for crosslinking of the two polymers. Chemical changes of the films were measured by FT-IR, gel fractions were determined by gravimetry, and mechanical properties were determined by tensile strength and elongation at break using universal testing machine. At optimum conditions ( 30 kGy and 75% Cs), the gel fraction, tensile strength, and elongation at break were higher leading to a stronger composite films as compared to the gelatin film. FTIR spectral analysis showed that gelatin and chitosan formed a crosslinked network. It was concluded that G-Cs films prepared by gamma irradiation have improved their mechanical properties than the gelatin itself. (author)

  15. Plasticized chitosan/polyolefin films produced by extrusion.

    Science.gov (United States)

    Matet, Marie; Heuzey, Marie-Claude; Ajji, Abdellah; Sarazin, Pierre

    2015-03-06

    Plasticized chitosan and polyethylene blends were produced through a single-pass extrusion process. Using a twin-screw extruder, chitosan plasticization was achieved in the presence of an acetic acid solution and glycerol, and directly mixed with metallocene polyethylene, mPE, to produce a masterbatch. Different dilutions of the masterbatch (2, 5 and 10 wt% of plasticized chitosan), in the presence of ethylene vinyl acetate, EVA, were subsequently achieved in single screw film extrusion. Very small plasticized chitosan domains (number average diameter <5 μm) were visible in the polymeric matrix. The resulting films presented a brown color and increasing haze with chitosan plasticized content. Mechanical properties of the mPE films were affected by the presence of plasticized chitosan, but improvement was observed as a result of some compatibility between mPE and chitosan in the presence of EVA. Finally the incorporation of plasticized chitosan affected mPE water vapor permeability while oxygen permeability remained constant. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Radiation effects on some polymeric materials and their utilization for possible practical applications

    International Nuclear Information System (INIS)

    Refaee, A.M.El.A.

    2008-01-01

    The present study divided into two parts. First part focused on the effect of the radiation on some naturally occurring polymers such as chitosan, sodium alginate and carboxymethylcellulose for controlling the degradation process of these polymers. These polymers of low molecular weights can be used as growth promoters for plants in the agriculture field. Second part focused on the radiation grafting of VAc/HEMA binary monomers onto PFA films using gamma irradiation was carried out to synthesize the graft copolymer membranes by direct method. The complexing ability with some selected transition metal ions such as Cu 2+ and Cr 3+ ions was investigated. These graft copolymer membranes can be used in the field of blood biocompatibility and in waste treatment of some heavy metals in the environmental industrial wastes

  17. Radiation effects on some polymeric materials and their utilization for possible practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Refaee, A M.El.A. [National Center for Radiation Research and Technology, Atomic Energy Authority, Cairo (Egypt)

    2008-07-01

    The present study divided into two parts. First part focused on the effect of the radiation on some naturally occurring polymers such as chitosan, sodium alginate and carboxymethylcellulose for controlling the degradation process of these polymers. These polymers of low molecular weights can be used as growth promoters for plants in the agriculture field. Second part focused on the radiation grafting of VAc/HEMA binary monomers onto PFA films using gamma irradiation was carried out to synthesize the graft copolymer membranes by direct method. The complexing ability with some selected transition metal ions such as Cu{sup 2+} and Cr{sup 3+} ions was investigated. These graft copolymer membranes can be used in the field of blood biocompatibility and in waste treatment of some heavy metals in the environmental industrial wastes.

  18. Enhancement of Curcumin Bioavailability Using Nanocellulose Reinforced Chitosan Hydrogel

    Directory of Open Access Journals (Sweden)

    Thennakoon M. Sampath Udeni Gunathilake

    2017-02-01

    Full Text Available A unique biodegradable, superporous, swellable and pH sensitive nanocellulose reinforced chitosan hydrogel with dynamic mechanical properties was prepared for oral administration of curcumin. Curcumin, a less water-soluble drug was used due to the fact that the fast swellable, superporous hydrogel could release a water-insoluble drug to a great extent. CO2 gas foaming was used to fabricate hydrogel as it eradicates using organic solvents. Field emission scanning electron microscope images revealed that the pore size significantly increased with the formation of widely interconnected porous structure in gas foamed hydrogels. The maximum compression of pure chitosan hydrogel was 25.9 ± 1 kPa and it increased to 38.4 ± 1 kPa with the introduction of 0.5% cellulose nanocrystals. In vitro degradation of hydrogels was found dependent on the swelling ratio and the amount of CNC of the hydrogel. All the hydrogels showed maximum swelling ratios greater than 300%. The 0.5% CNC-chitosan hydrogel showed the highest swelling ratio of 438% ± 11%. FTIR spectrum indicated that there is no interaction between drug and ingredients present in hydrogels. The drug release occurred in non-Fickian (anomalous manner in simulated gastric medium. The drug release profiles of hydrogels are consistent with the data obtained from the swelling studies. After gas foaming of the hydrogel, the drug loading efficiency increased from 41% ± 2.4% to 50% ± 2.0% and release increased from 0.74 to 1.06 mg/L. The drug release data showed good fitting to Ritger-Peppas model. Moreover, the results revealed that the drug maintained its chemical activity after in vitro release. According to the results of this study, CNC reinforced chitosan hydrogel can be suggested to improve the bioavailability of curcumin for the absorption from stomach and upper intestinal tract.

  19. Effects of Chitosan Alkali Pretreatment on the Preparation of Electrospun PCL/Chitosan Blend Nanofibrous Scaffolds for Tissue Engineering Application

    Directory of Open Access Journals (Sweden)

    Fatemeh Roozbahani

    2013-01-01

    Full Text Available Recently, nanofibrous scaffolds have been used in the field of biomedical engineering as wound dressings, tissue engineering scaffolds, and drug delivery applications. The electrospun nanofibrous scaffolds can be used as carriers for several types of drugs, genes, and growth factors. PCL is one of the most commonly applied synthetic polymers for medical use because of its biocompatibility and slow biodegradability. PCL is hydrophobic and has no cell recognition sites on its structure. Electrospinning of chitosan and PCL blend was investigated in formic acid/acetic acid as the solvent with different PCL/chitosan ratios. High viscosity of chitosan solutions makes difficulties in the electrospinning process. Strong hydrogen bonds in a 3D network in acidic condition prevent the movement of polymeric chains exposed to the electrical field. Consequently, the amount of chitosan in PCL/chitosan blend was limited and more challenging when the concentration of PCL increases. The treatment of chitosan in alkali condition under high temperature reduced its molecular weight. Longer treatment time further decreased the molecular weight of chitosan and hence its viscosity. Electrospinning of PCL/chitosan blend was possible at higher chitosan ratio, and SEM images showed a decrease in fiber diameter and narrower distribution with increase in the chitosan ratio.

  20. Chitosan/alginate based multilayers to control drug release from ophthalmic lens.

    Science.gov (United States)

    Silva, Diana; Pinto, Luís F V; Bozukova, Dimitriya; Santos, Luís F; Serro, Ana Paula; Saramago, Benilde

    2016-11-01

    In this study we investigated the possibility of using layer-by-layer deposition, based in natural polymers (chitosan and alginate), to control the release of different ophthalmic drugs from three types of lens materials: a silicone-based hydrogel recently proposed by our group as drug releasing soft contact lens (SCL) material and two commercially available materials: CI26Y for intraocular lens (IOLs) and Definitive 50 for SCLs. The optimised coating, consisting in one double layer of (alginate - CaCl2)/(chitosan+glyoxal) topped with a final alginate-CaCl2 layer to avoid chitosan degradation by tear fluid proteins, proved to have excellent features to control the release of the anti-inflammatory, diclofenac, while keeping or improving the physical properties of the lenses. The coating leads to a controlled release of diclofenac from SCL and IOL materials for, at least, one week. Due to its high hydrophilicity (water contact angle≈0) and biocompatibility, it should avoid the use of further surface treatments to enhance the useŕs comfort. However, the barrier effect of this coating is specific for diclofenac, giving evidence to the need of optimizing the chemical composition of the layers in view of the desired drug. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Characterization and electromechanical performance of cellulose–chitosan blend electro-active paper

    International Nuclear Information System (INIS)

    Cai Zhijiang; Kim, Jaehwan

    2008-01-01

    Cellulose-based electro-active paper (EAPap) has been reported as a smart material that has merits in terms of light weight, dry condition, biodegradability, sustainability, large displacement output and low actuation voltage. However, its actuator performance is very sensitive to humidity and degrades with time. To solve these drawbacks, we introduce an EAPap actuator made with cellulose and chitosan blend films. Cellulose–chitosan blend films were prepared by dissolving the polymers in trifluoroacetic acid as a co-solvent followed by spin-coating onto glass substrates. A bending EAPap actuator is made by depositing thin gold electrodes on both sides of the cellulose–chitosan films. Characteristics of these blend films are performed by FT-IR, XRD, TGA, SEM and a pull test. The electromechanical performance of the EAPap actuator is evaluated in terms of free bending displacement with respect to the actuation frequency, voltage, time variation and humidity levels. Results show that this chitosan–cellulose-based EAPap actuator is less sensitive to humidity: it shows a large bending displacement (about 4.1 mm) and long lifetime (more than 9 h) at room humidity conditions. It indicates that this chitosan–cellulose EAPap is promising for many biomimetic applications in the foreseeable future

  2. Chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol

    Directory of Open Access Journals (Sweden)

    Shete Amol S

    2012-12-01

    Full Text Available Abstract Background and the purpose of the study Carvedilol nonselective β-adrenoreceptor blocker, chemically (±-1-(Carbazol-4-yloxy-3-[[2-(o-methoxypHenoxy ethyl] amino]-2-propanol, slightly soluble in ethyl ether; and practically insoluble in water, gastric fluid (simulated, TS, pH 1.1, and intestinal fluid (simulated, TS without pancreatin, pH 7.5 Compounds with aqueous solubility less than 1% W/V often represents dissolution rate limited absorption. There is need to enhance the dissolution rate of carvedilol. The objective of our present investigation was to compare chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol. Methods The different formulations were prepared by different methods like solvent change approach to prepare hydrosols, solvent evaporation technique to form solid dispersions and cogrind mixtures. The prepared formulations were characterized in terms of saturation solubility, drug content, infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, powder X-ray diffraction (PXRD, electron microscopy, in vitro dissolution studies and stability studies. Results The practical yield in case of hydrosols was ranged from 59.76 to 92.32%. The drug content was found to uniform among the different batches of hydrosols, cogrind mixture and solid dispersions ranged from 98.24 to 99.89%. There was significant improvement in dissolution rate of carvedilol with chitosan chlorhdyrate as compare to chitosan and explanation to this behavior was found in the differences in the wetting, solubilities and swelling capacity of the chitosan and chitosan salts, chitosan chlorhydrate rapidly wet and dissolve upon its incorporation into the dissolution medium, whereas the chitosan base, less water soluble, would take more time to dissolve. Conclusion This technique is scalable and valuable in manufacturing process in future for enhancement of dissolution of poorly water soluble

  3. STIFFNESS MODIFICATION OF COTTON IN CHITOSAN TREATMENT

    Directory of Open Access Journals (Sweden)

    CAMPOS Juan

    2017-05-01

    Full Text Available Chitosan is a biopolymer obtained from chitin, and among their most important aspects highlights its applications in a lot of industrial sectors due to its intrinsic properties, especially in the textile sector. In the last years, chitosan is widely used in the cotton and wool finishing processes due to its bond between them and its properties as an antifungical and antimicrobial properties. In this paper three different molecular weight chitosan are used in the finishing process of cotton to evaluate its influence in the surface properties modification. In order to evaluate the effect of the treatment with chitosan, flexural stiffness test is performed in warp and weft direction, and then the total value is calculated. The cotton fabric is treated with 5 g/L of different types of chitosan in an impregnation bath. This study shows the extent of surface properties modification of the cotton provided by three types of chitosan treatment. The results show that all types of chitosan modify the cotton flexural rigidity properties but the one which modifies it in a relevant manner is chitosan originated from shrimps. Chitosan, textile, flexural stiffnes, chitin, cotton.

  4. Chitosan and its derivatives for application in mucoadhesive drug delivery systems

    OpenAIRE

    Ways, Twana Mohammed M.; Lau, Wing Man; Khutoryanskiy, Vitaliy V.

    2018-01-01

    Mucoadhesive drug delivery systems are desirable as they can increase the residence time of drugs at the site of absorption/action, provide sustained drug release and minimize the degradation of drugs in various body sites. Chitosan is a cationic polysaccharide that exhibits mucoadhesive properties and it has been widely used in the design of mucoadhesive dosage forms. However, its limited mucoadhesive strength and limited water-solubility at neutral and basic pHs are considered as two major ...

  5. Chitosan and Its Derivatives for Application in Mucoadhesive Drug Delivery Systems

    OpenAIRE

    Twana Mohammed M. Ways; Wing Man Lau; Vitaliy V. Khutoryanskiy

    2018-01-01

    Mucoadhesive drug delivery systems are desirable as they can increase the residence time of drugs at the site of absorption/action, provide sustained drug release and minimize the degradation of drugs in various body sites. Chitosan is a cationic polysaccharide that exhibits mucoadhesive properties and it has been widely used in the design of mucoadhesive dosage forms. However, its limited mucoadhesive strength and limited water-solubility at neutral and basic pHs are considered as two major ...

  6. Effect of Chitosan Properties on Immunoreactivity

    Science.gov (United States)

    Ravindranathan, Sruthi; Koppolu, Bhanu prasanth; Smith, Sean G.; Zaharoff, David A.

    2016-01-01

    Chitosan is a widely investigated biopolymer in drug and gene delivery, tissue engineering and vaccine development. However, the immune response to chitosan is not clearly understood due to contradicting results in literature regarding its immunoreactivity. Thus, in this study, we analyzed effects of various biochemical properties, namely degree of deacetylation (DDA), viscosity/polymer length and endotoxin levels, on immune responses by antigen presenting cells (APCs). Chitosan solutions from various sources were treated with mouse and human APCs (macrophages and/or dendritic cells) and the amount of tumor necrosis factor-α (TNF-α) released by the cells was used as an indicator of immunoreactivity. Our results indicate that only endotoxin content and not DDA or viscosity influenced chitosan-induced immune responses. Our data also indicate that low endotoxin chitosan (chitosan in preclinical studies in order for this valuable biomaterial to achieve widespread clinical application. PMID:27187416

  7. Combined environment aging effects: radiation-thermal degradation of polyvinylchloride and polyethylene

    International Nuclear Information System (INIS)

    Clough, R.L.; Gillen, K.T.

    1981-01-01

    Results are presented for a case of polymer aging in which powerful synergisms are found between radiation and temperature. This effect was observed with formulations of polyvinylchloride and polyethylene and occurred in simultaneous and sequential radiation-thermal experiments. Dose rate dependencies, which appear to be mechanistically related to the synergism, were also found. The evidence indicates that these aging effects are mediated by a thermally induced breakdown of peroxides initially formed by the radiation. Similar effects could be important to material degradation in a variety of other types of combined-stress environment. A new technique, which uses PH 3 treatment of intact polymer specimens to test for the importance of peroxides in the pathway that leads to changes in macroscopic tensile properties, is described

  8. The use of chitosan/PLA nano-fibers by emulsion eletrospinning for periodontal tissue engineering.

    Science.gov (United States)

    Shen, Renze; Xu, Weihong; Xue, Yanxiang; Chen, Luyuan; Ye, Haicheng; Zhong, Enyi; Ye, Zhanchao; Gao, Jie; Yan, Yurong

    2018-04-16

    In this study, nanofibrous scaffolds base on pure polylactic acid (PLA) and chitosan/PLA blends were fabricated by emulsion eletrospinning. By modulating their mechanical and biological properties, cell-compatible and biodegradable scaffolds were developed for periodontal bone regeneration. Pure PLA and different weight ratios of chitosan nano-particle/PLA nano-fibers were fabricated by emulsion eletrospinning. Scanning electron microscope (SEM) was performed to observe the morphology of nano-fibers. Mechanical properties of nano-fibers were tested by single fiber strength tester. Hydrophilic/hydrophobic nature of the nano-fibers was observed by stereomicroscope. In vitro degradation was also tested. Cells were seeded on nano-fibers scaffolds. Changes in cell adhesion, proliferation and osteogenic differentiation were tested by MTT assay and Alizarin Red S staining. Reverse transcription-polymerase chain reaction (RT-PCR) assay was used to evaluate the expression of (Toll-like receptor 4) TLR4, IL-6, IL-8, IL-1β, OPG, RUNX2 mRNA. It is shown that the mean diameter of nano-fibers is about 200 nm. The mean diameter of chitosan nano-particles is about 50 nm. The combination of chitosan nano-particles enhanced the mechanical properties of pure PLA nano-fibers. By adding a certain amount of chitosan nano-particles, it promoted cell adhesion. It also promoted the osteogenic differentiation of bone marrow stem cells (BMSCs) by elevating the expression of osteogenic marker genes such as BSP, Ocn, collagen I, and OPN and enhanced ECM mineralization. Nonetheless, it caused higher expression of inflammatory mediators and TLR4 of human periodontal ligament cells (hPDLCs). The combination of chitosan nano-particles enhanced the mechanical properties of pure PLA nano-fibers and increased its hydrophilicity. Pure PLA nano-fibers scaffold facilitated BMSCs proliferation. Adding an appropriate amount of chitosan nano-particles may promote its properties of cell proliferation

  9. Effectiveness of chitosan against wine-related microorganisms.

    Science.gov (United States)

    Bağder Elmaci, Simel; Gülgör, Gökşen; Tokatli, Mehmet; Erten, Hüseyin; İşci, Asli; Özçelik, Filiz

    2015-03-01

    The antimicrobial action of chitosan against wine related microorganisms, including Lactobacillus plantarum, Saccharomyces cerevisiae, Oeonococcus oeni, Lactobacillus hilgardii, Brettanomyces bruxellensis, Hanseniaspora uvarum and Zygosaccharomyces bailii was examined in laboratory media. In order to assess the potential applicability of chitosan as a microbial control agent for wine, the effect of chitosan, applied individually and/or in combination with sulphur dioxide (SO2), on the growth of microorganisms involved in various stages of winemaking and on the fermentative performance of S. cerevisiae was investigated. Of the seven wine-related microorganisms studied, S. cerevisiae exhibited the strongest resistance to antimicrobial action of chitosan in laboratory media with a minimum inhibitory concentration (MIC) greater than 2 g/L. L. hilgardii, O. oeni and B. bruxellensis were the most susceptible to chitosan since they were completely inactivated by chitosan at 0.2 g/L. The MIC of chitosan for L. plantarum, H. uvarum and Z. bailii was 2, 0.4 and 0.4 g/L, respectively. In wine experiments, it was found that chitosan had a retarding effect on alcoholic fermentation without significantly altering the viability and the fermentative performance of S. cerevisiae. With regard to non-Saccharomyces yeasts (H. uvarum and Z. bailii) involved in winemaking, the early deaths of these yeasts in mixed cultures with S. cerevisiae were not probably due to the antimicrobial action of chitosan but rather due to ethanol produced by the yeasts. The complex interactions between chitosan and wine ingredients as well as microbial interactions during wine fermentation considerably affect the efficacy of chitosan. It was concluded that chitosan was worthy of further investigation as an alternative or complementary preservative to SO2 in wine industry.

  10. Removal of Arsenic (V) from Aqueous Solutions Using Chitosan-Red Scoria and Chitosan-Pumice Blends.

    Science.gov (United States)

    Asere, Tsegaye Girma; Mincke, Stein; De Clercq, Jeriffa; Verbeken, Kim; Tessema, Dejene A; Fufa, Fekadu; Stevens, Christian V; Du Laing, Gijs

    2017-08-09

    In different regions across the globe, elevated arsenic contents in the groundwater constitute a major health problem. In this work, a biopolymer chitosan has been blended with volcanic rocks (red scoria and pumice) for arsenic (V) removal. The effect of three blending ratios of chitosan and volcanic rocks (1:2, 1:5 and 1:10) on arsenic removal has been studied. The optimal blending ratio was 1:5 (chitosan: volcanic rocks) with maximum adsorption capacity of 0.72 mg/g and 0.71 mg/g for chitosan: red scoria (Ch-Rs) and chitosan: pumice (Ch-Pu), respectively. The experimental adsorption data fitted well a Langmuir isotherm ( R ² > 0.99) and followed pseudo-second-order kinetics. The high stability of the materials and their high arsenic (V) removal efficiency (~93%) in a wide pH range (4 to 10) are useful for real field applications. Moreover, the blends could be regenerated using 0.05 M NaOH and used for several cycles without losing their original arsenic removal efficiency. The results of the study demonstrate that chitosan-volcanic rock blends should be further explored as a potential sustainable solution for removal of arsenic (V) from water.

  11. Chitosan based metallic nanocomposite scaffolds as antimicrobial wound dressings.

    Science.gov (United States)

    Mohandas, Annapoorna; Deepthi, S; Biswas, Raja; Jayakumar, R

    2018-09-01

    Chitosan based nanocomposite scaffolds have attracted wider applications in medicine, in the area of drug delivery, tissue engineering and wound healing. Chitosan matrix incorporated with nanometallic components has immense potential in the area of wound dressings due to its antimicrobial properties. This review focuses on the different combinations of Chitosan metal nanocomposites such as Chitosan/nAg, Chitosan/nAu, Chitosan/nCu, Chitosan/nZnO and Chitosan/nTiO 2 towards enhancement of healing or infection control with special reference to the antimicrobial mechanism of action and toxicity.

  12. Microencapsulation of norfloxacin in chitosan/chitosan oligosaccharides and its application in shrimp culture.

    Science.gov (United States)

    Lian, Ziru; Pan, Rong; Wang, Jiangtao

    2016-11-01

    Norfloxacin chitosan/chitosan oligosaccharide microcapsules (NCCM) were prepared by emulsion-chemical crosslinking method. The characteristics of obtained microcapsules were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy and release experiments. Cumulative release profile of norfloxacin from the chitosan microcapsules in natural seawater was measured and the controlled release of drugs was at a uniform rate in 48h. The chitosan microcapsules were applied onto the antibacterial study of the shrimp culture in natural seawater. It is observed that the seawater in the NCCM added groups was relatively clear and the biomass of Vibrio increased slowly in contrast to the control and norfloxacin groups. The inhibition rate of Vibrio in norfloxacin groups obvioursly decreased after the 5 th day, whereas, it remained high and stable during experiment period in NCCM groups. The results showed that the chitosan microcapsules as release materials have excellent antibacterial effects on Vibrio in the farming of Penaeus vannamei Boone. The controlled release could obviously reduce dosage of antibiotics and delivery times, and effectively improve the utilization rate of norfloxacin drugs for shrimps. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Surface grafted chitosan gels. Part I. Molecular insight into the formation of chitosan and poly(acrylic acid) multilayers

    DEFF Research Database (Denmark)

    Liu, Chao; Thormann, Esben; Claesson, Per M.

    2014-01-01

    Composite polyelectrolyte multilayers of chitosan and low molecular weight poly(acrylic acid) (PAA) have been assembled by sequential adsorption as a first step toward building a surface anchored chitosan gel. Silane chemistry was used to graft the first chitosan layer to prevent film detachment...... and decomposition. The assembly process is characterized by nonlinear growth behavior, with different adsorption kinetics for chitosan and PAA. In situ analysis of the multilayer by means of surface sensitive total internal reflection Raman (TIRR) spectroscopy, combined with target factor analysis of the spectra...... molecular weight chitosan shows a similar behavior, although to a much lower extent. Our data demonstrate that the charged monomeric units of chitosan are mainly compensated by carboxylate ions from PAA. Furthermore, the morphology and mechanical properties of the multilayers were investigated in situ using...

  14. Preparation of chitosan-collagen-alginate composite dressing and its promoting effects on wound healing.

    Science.gov (United States)

    Xie, Haixia; Chen, Xiuli; Shen, Xianrong; He, Ying; Chen, Wei; Luo, Qun; Ge, Weihong; Yuan, Weihong; Tang, Xue; Hou, Dengyong; Jiang, Dingwen; Wang, Qingrong; Liu, Yuming; Liu, Qiong; Li, Kexian

    2018-02-01

    The present study aimed to prepare a composite dressing composed of collagen, chitosan, and alginate, which may promote wound healing and prevent from seawater immersion. Chitosan-collagen-alginate (CCA) cushion was prepared by paintcoat and freeze-drying, and it was attached to a polyurethane to compose CCA composite dressing. The swelling, porosity, degradation, and mechanical properties of CCA cushion were evaluated. The effects on wound healing and seawater prevention of CCA composite dressing were tested by rat wound model. Preliminary biosecurity was tested by cytotoxicity and hemocompatibility. The results revealed that CCA cushion had good water absorption and mechanical properties. A higher wound healing ratio was observed in CCA composite dressing treated rats than in gauze or chitosan treated ones. On the fifth day, the healing rates of CCA composite dressing, gauze, and chitosan were 48.49%±1.07%, 28.02%±6.4%, and 38.97%±8.53%, respectively. More fibroblast and intact re-epithelialization were observed in histological images of CCA composite dressing treated rats, and the expressions of EGF, bFGF, TGF-β, and CD31 increased significantly. CCA composite dressing showed no significant cytotoxicity, and favorable hemocompatibility. These results suggested that CCA composite dressing could prevent against seawater immersion and promote wound healing while having a good biosecurity. Copyright © 2017. Published by Elsevier B.V.

  15. Physical Properties and Antibacterial Efficacy of Biodegradable Chitosan Films

    OpenAIRE

    中島, 照夫

    2009-01-01

    [Synopsis] Chitin, chitosan and quaternary chitosan films were prepared, and the physical properties and the antibacterial activities of chitosan and quaternary chitosan films were evaluated. The tensile strength of chitin films was 30~40% lower than that of chitosan films, but the crystallinity of chitin film was much higher than that of chitosan films. The crystallinity and orientation of crystallites were hardly affected by the four kinds of solvent chosen to cast chitosan films, but a de...

  16. pH-triggered chitosan nanogels via an ortho ester-based linkage for efficient chemotherapy.

    Science.gov (United States)

    Yang, Guanqing; Wang, Xin; Fu, Shengxiang; Tang, Rupei; Wang, Jun

    2017-09-15

    We report on new types of chitosan-based nanogels via an ortho ester-based linkage, used as drug carriers for efficient chemotherapy. First, we synthesized a novel diacrylamide containing ortho ester (OEAM) as an acid-labile cross-linker. Subsequently, methacrylated succinyl-chitosan (MASCS) was prepared and polymerized with OEAM at different molar ratios to give a series of pH-triggered MASCS nanogels. Doxorubicin (DOX) as a model anticancer drug was loaded into MASCS nanogels with a loading content of 16.5%. As expected, with the incorporation of ortho ester linkages, these nanogels showed pH-triggered degradation and drug release at acidic pH values. In vitro cellular uptake shows that the DOX-loaded nanogels could be preferentially internalized by two-dimensional (2D) cells and three-dimensional (3D) multicellular spheroids (MCs), resulting in higher inhibition of the proliferation of tumor cells. In vivo biodistribution and anti-tumor effect were determined in H22 tumor-bearing mice, and the results demonstrate that the acid-labile MASCS nanogels can significantly prolong the blood circulation time of DOX and improve the accumulation in tumor areas, leading to higher therapeutic efficacy. We designed new pH-triggered chitosan nanogels via an ortho ester-based cross-linker for efficient drug-loading and chemotherapy. These drug-loaded nanogels exhibit excellent pH-triggered drug release behavior due to the degradation of ortho ester linkages in mildly acidic environments. In vitro and in vivo results demonstrate that the nanogels could be efficiently internalized by 2D cells and 3D-MCs, improve drug concentration in solid tumors, and lead to higher therapeutic efficacy. To the best of our knowledge, this is the first report on using an ortho ester-based cross-linker to prepare pH-triggered chitosan nanogels as tumor carriers, which may provide a potential route for improved safety and to increase the therapeutic efficacy of anticancer therapy. Copyright © 2017

  17. Chitosan-crosslinked gels prepared by a simultaneously occurring reaction of radiation-induced polymerization and self-bridging of acrylic acid in aqueous solutions

    International Nuclear Information System (INIS)

    Elhag Ali, Amr; Hegazy, Elsayed Ahmed; Hendri, John; Katakai, Ryoichi; Maekawa, Yasunari; Kume, Tamikazu; Yoshida, Masaru

    2001-01-01

    Chitosan is one of the most interesting natural polymers, in addition to its biodegradability it shows wide biological properties such as antifibrolastic and antimicrobial activities, which verify its biomedical application. Novel Acrylic acid/Chitosan hydrogel was prepared by means of γ-irradiation as a clean source for initiation, and crosslinking. The nature of the AAc/CS gel and the effect of the presence of chitosan on the behavior of AAc were characterized. The effect of pH on the degree of swelling of different gels and time course swelling studies show the effect of presence of chitosan and its molecular weight on the swelling of the gels. DSC and TGA were used to study the effect of the presence of chitosan on the thermal behavior of PAAc. It was found that chitosan change thermal behavior of AAc. These results support our assumption for the formation of crosslinking between PAAc and CS chains via polyelectrolyte complex formation, attributed to the high affinity between CS and AAc, accompanied by homopolymerization and self-bridging. This crosslinking increase with CS molecular weight increasing and affect the thermal behavior of PAAc. (author)

  18. Green synthesis approach: extraction of chitosan from fungus mycelia.

    Science.gov (United States)

    Dhillon, Gurpreet Singh; Kaur, Surinder; Brar, Satinder Kaur; Verma, Mausam

    2013-12-01

    Chitosan, copolymer of glucosamine and N-acetyl glucosamine is mainly derived from chitin, which is present in cell walls of crustaceans and some other microorganisms, such as fungi. Chitosan is emerging as an important biopolymer having a broad range of applications in different fields. On a commercial scale, chitosan is mainly obtained from crustacean shells rather than from the fungal sources. The methods used for extraction of chitosan are laden with many disadvantages. Alternative options of producing chitosan from fungal biomass exist, in fact with superior physico-chemical properties. Researchers around the globe are attempting to commercialize chitosan production and extraction from fungal sources. Chitosan extracted from fungal sources has the potential to completely replace crustacean-derived chitosan. In this context, the present review discusses the potential of fungal biomass resulting from various biotechnological industries or grown on negative/low cost agricultural and industrial wastes and their by-products as an inexpensive source of chitosan. Biologically derived fungal chitosan offers promising advantages over the chitosan obtained from crustacean shells with respect to different physico-chemical attributes. The different aspects of fungal chitosan extraction methods and various parameters having an effect on the yield of chitosan are discussed in detail. This review also deals with essential attributes of chitosan for high value-added applications in different fields.

  19. Characterization of Radiation Fields for Assessing Concrete Degradation in Biological Shields of NPPs

    Science.gov (United States)

    Remec, Igor; Rosseel, Thomas M.; Field, Kevin G.; Pape, Yann Le

    2017-09-01

    Life extensions of nuclear power plants (NPPs) to 60 years of operation and the possibility of subsequent license renewal to 80 years have renewed interest in long-term material degradation in NPPs. Large irreplaceable sections of most nuclear generating stations are constructed from concrete, including safety-related structures such as biological shields and containment buildings; therefore, concrete degradation is being considered with particular focus on radiation-induced effects. Based on the projected neutron fluence values (E > 0.1 MeV) in the concrete biological shields of the US pressurized water reactor fleet and the currently available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database is desirable to ensure reliable risk assessment for extended operation of nuclear power plants.

  20. Immobilization of catalase on chitosan and amino acid- modified chitosan beads.

    Science.gov (United States)

    Başak, Esra; Aydemir, Tülin

    2013-08-01

    Bovine liver catalase was covalently immobilized onto amino acid-modified chitosan beads. The beads were characterized with SEM, FTIR, TGA and the effects of immobilization on optimum pH and temperature, thermostability, reusability were evaluated. Immobilized catalase showed the maximal enzyme activity at pH 7.0 at 30°C. The kinetic parameters, Km and Vmax, for immobilized catalase on alanine-chitosan beads and lysine-chitosan beads were estimated to be 25.67 mM, 27 mM and 201.39 μmol H2O2/min, 197.50 μmol H2O2/min, respectively. The activity of the immobilized catalase on Ala-CB and Lys-CB retained 40% of its high initial activity after 100 times of reuse.

  1. Scaffold of chitosan/poly(vinyl alcohol) blend chemically crosslinked by glutaraldehyde for tissue engineering applications;Constructos de blendas de quitosana/poli(alcool vinilico) reticulados quimicamente com glutaraldeido para aplicacao em engenharia de tecido

    Energy Technology Data Exchange (ETDEWEB)

    Costa Junior, Ezequiel de S., E-mail: escjr50@deii.cefetmg.b [Centro Federal de Educacao Tecnologica (DEM/CEFET/MG), Belo Horizonte, MG (Brazil). Dept. de Engenharia de Materiais; Laguardia-Nascimento, Mateus; Barbosa-Stancioli, Edel F. [Universidade Federal de Minas Gerais (ICB/UFMG), Belo Horizonte (Brazil). Inst. de Ciencias Biologicas. Dept. de Microbiologia; Mansur, Herman S., E-mail: hmansur@demet.ufmg.b [Universidade Federal de Minas Gerais (DEM/UFMG), Belo Horizonte (Brazil). Dept. de Engenharia Metalurgica

    2009-07-01

    Chitosan/PVA based films were chemically crosslinked by glutaraldehyde (GA) in order to achieve scaffolds for potential tissue engineering application. Both precursors and developed films were characterized by FTIR and XRD in order to determine the presence of chemicals groups and nanostructural order, respectively. The results have showed that the GA crosslinking have altered the crystallinity of the chitosan and the increase on the C=N bands and decreasing of NH{sub 2} bands suggest that Chitosan/GA crosslinking has preference to occur in the carbon 2 by Schiff's base. The mechanical properties, swelling behavior, degradation rate in vitro and cellular viability were compatible with the characteristic of an epithelial tissue. The material presented a toughness range from 1.4 to 34MJ/m3, swelling from 150% to 700% in 24h, degradation rate from 20% to 75% (wt%) in 24h and cellular viability in vitro above 60% compared to the cellular control. The developed scaffolds from the films have also showed swelling and degradation in vitro properties well-matched for biomedical applications in tissue engineering (author)

  2. In vitro assessment of three dimensional dense chitosan-based structures to be used as bioabsorbable implants.

    Science.gov (United States)

    Guitian Oliveira, Nuno; Sirgado, Tatiana; Reis, Luís; Pinto, Luís F V; da Silva, Cláudia Lobato; Ferreira, Frederico Castelo; Rodrigues, Alexandra

    2014-12-01

    Chitosan biocompatibility and biodegradability properties make this biopolymer promising for the development of advanced internal fixation devices for orthopedic applications. This work presents a detailed study on the production and characterization of three dimensional (3D) dense, non-porous, chitosan-based structures, with the ability to be processed in different shapes, and also with high strength and stiffness. Such features are crucial for the application of such 3D structures as bioabsorbable implantable devices. The influence of chitosan's molecular weight and the addition of one plasticizer (glycerol) on 3D dense chitosan-based products' biomechanical properties were explored. Several specimens were produced and in vitro studies were performed in order to assess the cytotoxicity of these specimens and their physical behavior throughout the enzymatic degradation experiments. The results point out that glycerol does not impact on cytotoxicity and has a high impact in improving mechanical properties, both elasticity and compressive strength. In addition, human mesenchymal stem/stromal cells (MSC) were used as an ex-vivo model to study cell adhesion and proliferation on these structures, showing promising results with fold increase values in total cell number similar to the ones obtained in standard cell culture flasks. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Colon-specific delivery of 5-aminosalicylic acid from chitosan-Ca-alginate microparticles.

    Science.gov (United States)

    Mladenovska, K; Raicki, R S; Janevik, E I; Ristoski, T; Pavlova, M J; Kavrakovski, Z; Dodov, M G; Goracinova, K

    2007-09-05

    Chitosan-Ca-alginate microparticles for colon-specific delivery and controlled release of 5-aminosalicylic acid after peroral administration were prepared using spray drying method followed by ionotropic gelation/polyelectrolyte complexation. Physicochemical characterization pointed to the negatively charged particles with spherical morphology having a mean diameter less than 9 microm. Chitosan was localized dominantly in the particle wall, while for alginate, a homogeneous distribution throughout the particles was observed. (1)H NMR, FTIR, X-ray and DSC studies indicated molecularly dispersed drug within the particles with preserved stability during microencapsulation and in simulated in vivo drug release conditions. In vitro drug release studies carried out in simulated in vivo conditions in respect to pH, enzymatic and salt content confirmed the potential of the particles to release the drug in a controlled manner. The diffusional exponents according to the general exponential release equation indicated anomalous (non-Fickian) transport in 5-ASA release controlled by a polymer relaxation, erosion and degradation. Biodistribution studies of [(131)I]-5-ASA loaded chitosan-Ca-alginate microparticles, carried out within 2 days after peroral administration to Wistar male rats in which TNBS colitis was induced, confirmed the dominant localization of 5-ASA in the colon with low systemic bioavailability.

  4. Effect of water-soluble P-chitosan and S-chitosan on human primary osteoblasts and giant cell tumor of bone stromal cells

    Energy Technology Data Exchange (ETDEWEB)

    Tang, T; Zhang, G; PY Lau, Carol; Zheng, L Z; Xie, X H; Wang, X L; Patrick, Y; Qin, L; Kumta, Shekhar M [Department of Orthopaedics and Traumatology, Chinese University of Hong Kong (Hong Kong); Wang, X H; He, K, E-mail: kumta@cuhk.edu.hk [Department of Mechanical Engineering, Institute of Bio-manufacturing Engineering, Tsinghua University, Beijing (China)

    2011-02-15

    Water-soluble phosphorylated chitosan (P-chitosan) and disodium (1 {yields} 4)-2-deoxy-2-sulfoamino-{beta}-D-glucopyranuronan (S-chitosan) are two chemically modified chitosans. In this study, we found that P-chitosan significantly promotes cell proliferation of both human primary osteoblasts (OBs) and the OB like stromal cell component of the giant cell tumor of bone (GCTB) cells at the concentration from 125 to 1000 {mu}g ml{sup -1} at all time points of 1, 3, 5 and 7 days after treatment. Further investigation of the osteogenic effect of the P-chitosan suggested that it regulates the levels of osteoclastogenic factors, receptor activator of nuclear factor kappa B ligand and osteoprotegerin expression. An interesting finding is that S-chitosan at lower concentration (100 {mu}g ml{sup -1}) stimulates cell proliferation while a higher dose (1000 {mu}g ml{sup -1}) of S-chitosan inhibits it. The inhibitory effect of S-chitosan on human primary GCT stromal cells was greater than that of OBs (p < 0.05). Taken together, our findings elucidated the osteogenic effect of P-chitosan and the varying effects of S-chitosan on the proliferation of human primary OBs and GCT stromal cells and provided us the rationale for the construction of novel bone repair biomaterials with the dual properties of bone induction and bone tumor inhibition.

  5. Investigation of 207 nm UV radiation for degradation of organic dye ...

    African Journals Online (AJOL)

    The photo-degradation of organic dye C.I. Acid Red 213 (AR-213) was achieved by 207 nm UV radiation emitted from a planar KrBr* excimer lamp without addition of oxidants at varying initial pH values. Precipitates were found to be generated when the irradiated solution of initial acid pH was adjusted to alkaline pH and ...

  6. Effect of glycerol and zinc oxide addition on antibacterial activity of biodegradable bioplastics from chitosan-kepok banana peel starch

    Science.gov (United States)

    Agustin, Y. E.; Padmawijaya, K. S.

    2017-07-01

    Bioplastic is a biopolymer plastic that can be degraded easily by microorganisms so it can be used as alternative replaced commercial plastic. This research aims to study the effects of additive (glycerol and zinc oxide) addition in the characteristic of antimicrobial activity and biodegradability bioplastic from chitosan and Kepok banana peel starch. In this research, bioplastics were synthesized by chitosan as the backbone and antimicrobial, Kepok banana peel starch as filler, glycerol as plasticizer, also ZnO as an amplifier. Bioplastics were characterized their antimicrobial activity using agar diffusion method (zone inhibition assay) and biodegradability test using microbe (EM4). The result showed the optimum composition of bioplastic is kitosan 4 - 30% starch - 5 mL glycerol - 5% ZnO gives the good antimicrobial activity towards gram positive and gram negative bacteria, and this bioplastic will be degraded within an hour and 12 min. Thus, this bioplastics may have potential to be use for food packaging by having biodegradable properties and also inhibit bacterial growth.

  7. The degradation of triazo dye Chlorantine Fast Green BLL in aqueous solutions by gamma radiation: Pt. 3

    International Nuclear Information System (INIS)

    El-Assy, N.B.

    1991-01-01

    The radiation degradation yield (G d values) of Chlorantine Fast Green BLL (CFGBLL), G d , i.e. the value of moles of dye molecules degraded per joule of energy absorbed, was measured in aerated, oxygen-and nitrogen-saturated aqueous solutions. The relatively low degradation yield indicates the absence of chain reactions and probably the poor efficiency and economics, in terms of the practical application of the radiation process. For applications in the radiation treatment of waste water, it is noted that in the presence of oxygen and at higher concentration of CFGBLL, the value of G d increases markedly, so that it may be practical to monitor the extent of sterilization of water. In addition the radiation processing of CFGBLL waste water may also become economically feasible. The specific bimolecular rate constant of the reaction of CFGBLL with the . OH was determined by studying the effect of ethanol concentration on G d using competition kinetics. Suggestions are made for the possible use of CFGBLL aqueous solution as a chemical dosimeter in the range of absorbed dose from 0.1 to 5 kGy. (author)

  8. Effect of Chitosan Properties on Immunoreactivity

    Directory of Open Access Journals (Sweden)

    Sruthi Ravindranathan

    2016-05-01

    Full Text Available Chitosan is a widely investigated biopolymer in drug and gene delivery, tissue engineering and vaccine development. However, the immune response to chitosan is not clearly understood due to contradicting results in literature regarding its immunoreactivity. Thus, in this study, we analyzed effects of various biochemical properties, namely degree of deacetylation (DDA, viscosity/polymer length and endotoxin levels, on immune responses by antigen presenting cells (APCs. Chitosan solutions from various sources were treated with mouse and human APCs (macrophages and/or dendritic cells and the amount of tumor necrosis factor-α (TNF-α released by the cells was used as an indicator of immunoreactivity. Our results indicate that only endotoxin content and not DDA or viscosity influenced chitosan-induced immune responses. Our data also indicate that low endotoxin chitosan (<0.01 EU/mg ranging from 20 to 600 cP and 80% to 97% DDA is essentially inert. This study emphasizes the need for more complete characterization and purification of chitosan in preclinical studies in order for this valuable biomaterial to achieve widespread clinical application.

  9. Fabrication and mechanical characterization of biodegradable and synthetic polymeric films: Effect of gamma radiation

    International Nuclear Information System (INIS)

    Akter, Nousin; Khan, Ruhul A.; Salmieri, Stephane; Sharmin, Nusrat; Dussault, Dominic; Lacroix, Monique

    2012-01-01

    Chitosan (1 wt%, in 2% aqueous acetic acid solution) and starch (1 wt%, in deionised water) were dissolved and mixed in different proportions (20–80 wt% chitosan) then films were prepared by casting. Tensile strength and elongation at break of the 50% chitosan containing starch-based films were found to be 47 MPa and 16%, respectively. It was revealed that with the increase of chitosan in starch, the values of TS improved significantly. Monomer, 2-butane diol-diacrylate (BDDA) was added into the film forming solutions (50% starch-based), then casted films. The BDDA containing films were irradiated under gamma radiation (5–25 kGy) and it was found that strength of the films improved significantly. On the other hand, synthetic petroleum-based polymeric films (polycaprolactone, polyethylene and polypropylene) were prepared by compression moulding. Mechanical and barrier properties of the films were evaluated. The gamma irradiated (25 kGy) films showed higher strength and better barrier properties. - Highlights: ► Chitosan and starch-based biodegradable films were prepared by casting. ► With the increase of chitosan in starch, the strength of the films improved significantly. ► Monomer, 2-Butane diol-diacrylate was grafted with the films by gamma radiation. ► Mechanical properties of synthetic polymeric films improved by gamma radiation. ► The irradiated polymer films showed better water vapor barrier properties.

  10. The effect of andiroba oil and chitosan concentration on the physical properties of chitosan emulsion film

    Directory of Open Access Journals (Sweden)

    Vanessa Tiemi Kimura

    Full Text Available Abstract Chitosan film is used as a dressing to heal burns. The physical and biological properties of the film can be modified by the addition of phytotherapic compounds. This work used the casting -solvent evaporation technique to prepare chitosan film containing andiroba oil (Carapa guianensis which has anti-inflammatory, antibiotic, and healing properties. The objective of this study was to determine the effect of the concentrations of chitosan and andiroba oil on the physical properties of chitosan films. The emulsion films were evaluated concerning the mechanical properties and fluid handling capacity. Additionally, scanning electron microscopy and thermal analysis were performed. The results showed that the barrier and mechanical properties were affected by the addition of andiroba oil, and these may be modulated as a function of the concentration of oil added to the film. The thermal analysis showed no evidence of chemical interactions between the oil and chitosan.

  11. In Vitro Evaluation of an Injectable Chitosan Gel for Sustained Local Delivery of BMP-2 for Osteoblastic Differentiation

    Science.gov (United States)

    2011-11-01

    In vitro cellular responses to scaffolds containing two microencapsulated growth factors. Biomaterials 2009;30:5215–5224. 16. Park KH, Kim H, Moon S...applications. Eur. J Pharm Biopharm 2004;57:19–34. 32. Ren D, Yi H, Wang W, Ma X. The enzymatic degradation and swelling properties of chitosan

  12. Radiation degradation adsorption treatment of some toxic dyes present in wastewater

    International Nuclear Information System (INIS)

    Dessouki, A.M.; Hegazy, E.A.; El-Kelesh, N.A.

    2000-01-01

    The degradation kinetics due to gamma irradiation of aqueous solutions of some organic pollutants (reactive yellow dye, acidic yellow Dye and fast yellow Dye) were investigated. A combined treatment of gamma irradiation and conventional methods was applied and is much more effective than either alone. Factors affecting the radiolysis of the pollutants such as concentration, irradiation dose, dose rate and ph of the solutions was studied. Radiochemical degradation yields were calculated to elucidate the mechanism of the degradation process. Also, the feasibility of using granular activated carbon (GAC), ion exchange resins (Merck I, III, Iv) for the removal of these pollutants from aqueous solution were studied. Synergistic treatment of the dye solutions by irradiation methods showed that the saturation of the dye solutions with nitrogen did not enhance the radiation degradation of the dyes, while addition of O 2 , H 2 O 2 or Na Ocl resulted in remarkable enhancement. Adsorption of the dyes into GAC and some ion-exchangers, showed that GAC has the highest adsorption capacity compared with ion-exchangers. Irradiation followed by adsorption resulted in the removal of these toxic pollutants from wastewater

  13. Radiation degradation adsorption treatment of some toxic dyes present in wastewater

    International Nuclear Information System (INIS)

    Al-Dousougi, A. M.; Hijarzi, A. A.; Al-Qalash, N. A. A.

    2002-01-01

    The degradation kinetics due to gamma irradiation of aqueous solutions of some organic pollutants (Reactive Yellow Dye, acidic yellow dye and fast yellow dye) were investigated. A combined treatment of gamma irradiation and conventional methods was applied and is much more effective than either alone. Factors affecting the radiolysis of the pollutants such as concentration, irradiation dose, dose rate, and pH of the solutions was studied. Radiochemical degradation yields were calculated to elucidate the mechanism of the degradation process. Also, the feasibility of using granular Activated carbon (GAC), ion exchange resins (Metck I, II, III, IV) for the removal of these pollutants from aqueous solutions were studied. Synergistic treatment of the dye solutions by irradiation methods showed that the saturation of the dye solutions with nitrogen did not enhance the radiation degradation of the dyes, while addition of O 2 , H 2 O 2 or NaOCI resulted in remarkable enhancement. Adsorption of the dyes onto GAC and some ion-exchangers, showed that GAC has the highest adsorption capacity compared with ion-exchangers. Irradiation followed by adsorption resulted in the removal of these toxic pollutants from wastewater. (author)

  14. Extraction and Characterization of Chitin and Chitosan from Blue Crab and Synthesis of Chitosan Cryogel Scaffolds

    Directory of Open Access Journals (Sweden)

    Nimet Bölgen

    2016-08-01

    Full Text Available Polymeric scaffolds produced by cryogelation technique have attracted increasing attention for tissue engineering applications. Cryogelation is a technique which enables to produce interconnected porous matrices from the frozen reaction mixtures of polymers or monomeric precursors. Chitosan is a biocompatible, biodegradable, nontoxic, antibacterial, antioxidant and antifungal natural polymer that is obtained by deacetylation of chitin, which is mostly found in the exoskeleton of many crustacean. In this study, chitin was isolated from the exoskeleton of blue crap (Callinectes sapidus using a chemical method. Callinectes sapidus samples were collected from a market, as a waste material after it has been consumed as food. Demineralization, deproteinization and decolorization steps were applied to the samples to obtain chitin. Chitosan was prepared from isolated chitin by deacetylation at high temperatures. The chemical compositon of crab shell, extracted chitin and chitosan were characterized with FTIR analyses. And also to determine the physicochemical and functional properties of the produced chitosan; solubility, water binding and fat binding analysis were performed. Chitosan cryogel scaffolds were prepared by crosslinking reaction at cryogenic conditions at constant amount of chitosan (1%, w/v with different ratios of glutaraldehyde (1, 3, and 6%, v/v as crosslinker. The chemical structure of the scaffolds were examined by FTIR. Also, the water uptake capacity of scaffolds have been determined. Collectively, the results suggested that the characterized chitosan cryogels can be potential scaffolds to be used in tissue engineering applications.

  15. Aging phenomena of chitosan and chitosan-diclofenac sodium system detected by low-frequency dielectric spectroscopy.

    Science.gov (United States)

    Bodek, K H; Bak, G W

    1999-09-01

    The use of natural polymers for design of dosage form has received considerable attention recently, especially from the safety point of view. Among these polymers, chitosan shows very interesting biological, chemical and physical properties which makes it possible to use chitosan for various pharmaceutical applications. Microcrystalline chitosan (MCCh) is a special multifunctional polymeric material existing in the form of either of gelatinous water dispersion or a powder. Thermal aging of chitosan and chitosan-diclofenac sodium mixture have been studied using low-frequency dielectric measurements. The aging was carried out by annealing in ambient atmosphere in the temperature range between 25 degrees C and 100 degrees C. The dielectric losses in the aged samples proved to decrease by about one order of magnitude. The additional measurements of molecular weight distribution and infrared absorption were also carried out for better understanding of nature of the ageing phenomena. Partial evacuation of water, cross-linking and improvement of structural order may be suggested to be a result of thermal aging of the investigated materials.

  16. Impact of salt form and molecular weight of chitosan on swelling and drug release from chitosan matrix tablets.

    Science.gov (United States)

    Huanbutta, Kampanart; Cheewatanakornkool, Kamonrak; Terada, Katsuhide; Nunthanid, Jurairat; Sriamornsak, Pornsak

    2013-08-14

    Magnetic resonance imaging (MRI) and gravimetric techniques were used to assess swelling and erosion behaviors of hydrophilic matrix tablets made of chitosan. The impact of salt form, molecular weight (MW) and dissolution medium on swelling behavior and drug (theophylline) release was studied. The matrix tablets made of chitosan glycolate (CGY) showed the greatest swelling in both acid and neutral media, compared to chitosan aspartate, chitosan glutamate and chitosan lactate. MRI illustrated that swelling region of CGY in both media was not different in the first 100 min but glassy region (dry core) in 0.1N HCl was less than in pH 6.8 buffer. The tablets prepared from chitosan with high MW swelled greater than those of low MW. Moreover, CGY can delay drug release in the acid condition due to thick swollen gel and low erosion rate. Therefore, CGY may be suitably applied as sustained drug release polymer or enteric coating material. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Collagen Structural Hierarchy and Susceptibility to Degradation by Ultraviolet Radiation.

    Science.gov (United States)

    Rabotyagova, Olena S; Cebe, Peggy; Kaplan, David L

    2008-12-01

    Collagen type I is the most abundant extracellular matrix protein in the human body, providing the basis for tissue structure and directing cellular functions. Collagen has complex structural hierarchy, organized at different length scales, including the characteristic triple helical feature. In the present study, the relationship between collagen structure (native vs. denatured) and sensitivity to UV radiation was assessed, with a focus on changes in primary structure, changes in conformation, microstructure and material properties. A brief review of free radical reactions involved in collagen degradation is also provided as a mechanistic basis for the changes observed in the study. Structural and functional changes in the collagens were related to the initial conformation (native vs. denatured) and the energy of irradiation. These changes were tracked using SDS-PAGE to assess molecular weight, Fourier transform infrared (FTIR) spectroscopy to study changes in the secondary structure, and atomic force microscopy (AFM) to characterize changes in mechanical properties. The results correlate differences in sensitivity to irradiation with initial collagen structural state: collagen in native conformation vs. heat-treated (denatured) collagen. Changes in collagen were found at all levels of the hierarchical structural organization. In general, the native collagen triple helix is most sensitive to UV-254nm radiation. The triple helix delays single chain degradation. The loss of the triple helix in collagen is accompanied by hydrogen abstraction through free radical mechanisms. The results received suggest that the effects of electromagnetic radiation on biologically relevant extracellular matrices (collagen in the present study) are important to assess in the context of the state of collagen structure. The results have implications in tissue remodeling, wound repair and disease progression.

  18. Chitosan/CNTs green nanocomposite membrane: Synthesis, swelling and polyaromatic hydrocarbons removal

    International Nuclear Information System (INIS)

    Bibi, Saira; Yasin, Tariq; Hassan, Safia; Riaz, Muhammad; Nawaz, Mohsan

    2015-01-01

    Carbon nanotubes (CNTs) were irradiated in air at 100 kGy under gamma radiations. The Raman spectroscopy of γ-treated CNTs showed distinctive changes in the absorption bands. The CNTs were mixed with blend of chitosan (Cs)/poly (vinyl alcohol) (PVA) and crosslinked with silane. The chemical reactions between the components affected the position and intensities of the infrared bands. Scanning electron micrograph of Cs/CNTs nanocomposite membrane showed the homogeneous dispersion of CNTs in the polymer matrix. The addition of CNTs lowered its swelling in water. Naphthalene (NAPH) was selected as a model compound and its removal was studied using HPLC technique. This membrane showed fast uptake of NAPH and 87% was removed from water within 30 min. The NAPH loaded membrane showed strong chemical interactions and cannot be desorbed. The fast uptake of PAHs and the green nature of this membrane made them suitable candidates for clean-up purposes. - Highlights: • Radiation modified CNTs and chitosan gave nanocomposite membranes. • This membrane showed hydrogel properties. • This membrane was used for the removal of naphthalene. • The green nature made them suitable candidates for clean-up purposes of PAH

  19. Amino Groups of Chitosan Are Crucial for Binding to a Family 32 Carbohydrate Binding Module of a Chitosanase from Paenibacillus elgii*

    Science.gov (United States)

    Das, Subha Narayan; Wagenknecht, Martin; Nareddy, Pavan Kumar; Bhuvanachandra, Bhoopal; Niddana, Ramana; Balamurugan, Rengarajan; Swamy, Musti J.; Moerschbacher, Bruno M.; Podile, Appa Rao

    2016-01-01

    We report here the role and mechanism of specificity of a family 32 carbohydrate binding module (CBM32) of a glycoside hydrolase family 8 chitosanase from Paenibacillus elgii (PeCsn). Both the activity and mode of action of PeCsn toward soluble chitosan polymers were not different with/without the CBM32 domain of P. elgii (PeCBM32). The decreased activity of PeCsn without PeCBM32 on chitosan powder suggested that PeCBM32 increases the relative concentration of enzyme on the substrate and thereby enhanced enzymatic activity. PeCBM32 specifically bound to polymeric and oligomeric chitosan and showed very weak binding to chitin and cellulose. In isothermal titration calorimetry, the binding stoichiometry of 2 and 1 for glucosamine monosaccharide (GlcN) and disaccharide (GlcN)2, respectively, was indicative of two binding sites in PeCBM32. A three-dimensional model-guided site-directed mutagenesis and the use of defined disaccharides varying in the pattern of acetylation suggested that the amino groups of chitosan and the polar residues Glu-16 and Glu-38 of PeCBM32 play a crucial role for the observed binding. The specificity of CBM32 has been further elucidated by a generated fusion protein PeCBM32-eGFP that binds to the chitosan exposing endophytic infection structures of Puccinia graminis f. sp. tritici. Phylogenetic analysis showed that CBM32s appended to chitosanases are highly conserved across different chitosanase families suggesting their role in chitosan recognition and degradation. We have identified and characterized a chitosan-specific CBM32 useful for in situ staining of chitosans in the fungal cell wall during plant-fungus interaction. PMID:27405759

  20. Effect of top electrode material on radiation-induced degradation of ferroelectric thin film structures

    Energy Technology Data Exchange (ETDEWEB)

    Brewer, Steven J.; Bassiri-Gharb, Nazanin [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Deng, Carmen Z.; Callaway, Connor P. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Paul, McKinley K. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Woodward Academy, College Park, Georgia 30337 (United States); Fisher, Kenzie J. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Riverwood International Charter School, Atlanta, Georgia 30328 (United States); Guerrier, Jonathon E.; Jones, Jacob L. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Rudy, Ryan Q.; Polcawich, Ronald G. [Army Research Laboratory, Adelphi, Maryland 20783 (United States); Glaser, Evan R.; Cress, Cory D. [Naval Research Laboratory, Washington, DC 20375 (United States)

    2016-07-14

    The effects of gamma irradiation on the dielectric and piezoelectric responses of Pb[Zr{sub 0.52}Ti{sub 0.48}]O{sub 3} (PZT) thin film stacks were investigated for structures with conductive oxide (IrO{sub 2}) and metallic (Pt) top electrodes. The samples showed, generally, degradation of various key dielectric, ferroelectric, and electromechanical responses when exposed to 2.5 Mrad (Si) {sup 60}Co gamma radiation. However, the low-field, relative dielectric permittivity, ε{sub r}, remained largely unaffected by irradiation in samples with both types of electrodes. Samples with Pt top electrodes showed substantial degradation of the remanent polarization and overall piezoelectric response, as well as pinching of the polarization hysteresis curves and creation of multiple peaks in the permittivity-electric field curves post irradiation. The samples with oxide electrodes, however, were largely impervious to the same radiation dose, with less than 5% change in any of the functional characteristics. The results suggest a radiation-induced change in the defect population or defect energy in PZT with metallic top electrodes, which substantially affects motion of internal interfaces such as domain walls. Additionally, the differences observed for stacks with different electrode materials implicate the ferroelectric–electrode interface as either the predominant source of radiation-induced effects (Pt electrodes) or the site of healing for radiation-induced defects (IrO{sub 2} electrodes).

  1. A study on radiation technological degradation of organic chloride wastewater-Exemplified by TCE and PCE

    Energy Technology Data Exchange (ETDEWEB)

    Huang, S.-K.; Hsieh, L.-L. [Institute of Radiological Science, Central Taiwan University of Science and Technology, No. 11, Buzih Lane, Beitun District, Taichung City 40601, Taiwan (China); Chen, C.-C. [Isotope Application Division, Institute of Nuclear Energy Research, Taiwan (China); Lee, P.-H. [Institute of Radiological Science, Central Taiwan University of Science and Technology, No. 11, Buzih Lane, Beitun District, Taichung City 40601, Taiwan (China); Hsieh, B.-T. [Institute of Radiological Science, Central Taiwan University of Science and Technology, No. 11, Buzih Lane, Beitun District, Taichung City 40601, Taiwan (China)], E-mail: bthsieh@ctust.edu.tw

    2009-07-15

    This paper describes the potential of using gamma radiation technology to degrade trichloroethylene (TCE) and perchloroethylene (PCE) wastewater. The experimental method is divided into two parts: (1) using the {gamma}-ray to irradiate the TCE and PCE solution, the dose-rate is 10 Gy/minute, the irradiation dosage is 0-2.5 kGy and (2) self-making the UV irradiation system, the tube specification is 254 nm and 6 W, and turning on 8 tubes at the same time to make the irradiation. The efficiency of degradation ratio for {gamma}-ray is better than UV in the range of 0.1-250 ppm; for example, as for the concentration of 0.1 ppm, when TCE is degraded to D{sub 90} and T{sub 90}, the {gamma}-ray only needed 46.7 Gy and took about 4.67 minutes, but UV needed to take about 28.1 minutes. The dose-concentration equations of TCE and PCE are: TCE: y=44.58+8.832x, R{sup 2}=0.999; and PCE: y=81.33+12.81x, R{sup 2}=0.997. We verified that the radiation technology is able to effectively degrade the organic chlorine wastewater without yielding the secondary pollution, and the TCE and PCE that degraded by using {gamma}-ray will be reached US-EPA and Taiwan Effluent Standard (5 ppb)

  2. A study on radiation technological degradation of organic chloride wastewater--exemplified by TCE and PCE.

    Science.gov (United States)

    Huang, Sheng-Kai; Hsieh, Ling-Ling; Chen, Chia-Chieh; Lee, Po-Hsiu; Hsieh, Bor-Tsung

    2009-01-01

    This paper describes the potential of using gamma radiation technology to degrade trichloroethylene (TCE) and perchloroethylene (PCE) wastewater. The experimental method is divided into two parts: (1) using the gamma-ray to irradiate the TCE and PCE solution, the dose-rate is 10Gy/minute, the irradiation dosage is 0-2.5kGy and (2) self-making the UV irradiation system, the tube specification is 254nm and 6W, and turning on 8 tubes at the same time to make the irradiation. The efficiency of degradation ratio for gamma-ray is better than UV in the range of 0.1-250ppm; for example, as for the concentration of 0.1ppm, when TCE is degraded to D(90) and T(90), the gamma-ray only needed 46.7Gy and took about 4.67 minutes, but UV needed to take about 28.1 minutes. The dose-concentration equations of TCE and PCE are: TCE: y=44.58+8.832x, R(2)=0.999; and PCE: y=81.33+12.81x, R(2)=0.997. We verified that the radiation technology is able to effectively degrade the organic chlorine wastewater without yielding the secondary pollution, and the TCE and PCE that degraded by using gamma-ray will be reached US-EPA and Taiwan Effluent Standard (5ppb).

  3. A study on radiation technological degradation of organic chloride wastewater-Exemplified by TCE and PCE

    International Nuclear Information System (INIS)

    Huang, S.-K.; Hsieh, L.-L.; Chen, C.-C.; Lee, P.-H.; Hsieh, B.-T.

    2009-01-01

    This paper describes the potential of using gamma radiation technology to degrade trichloroethylene (TCE) and perchloroethylene (PCE) wastewater. The experimental method is divided into two parts: (1) using the γ-ray to irradiate the TCE and PCE solution, the dose-rate is 10 Gy/minute, the irradiation dosage is 0-2.5 kGy and (2) self-making the UV irradiation system, the tube specification is 254 nm and 6 W, and turning on 8 tubes at the same time to make the irradiation. The efficiency of degradation ratio for γ-ray is better than UV in the range of 0.1-250 ppm; for example, as for the concentration of 0.1 ppm, when TCE is degraded to D 90 and T 90 , the γ-ray only needed 46.7 Gy and took about 4.67 minutes, but UV needed to take about 28.1 minutes. The dose-concentration equations of TCE and PCE are: TCE: y=44.58+8.832x, R 2 =0.999; and PCE: y=81.33+12.81x, R 2 =0.997. We verified that the radiation technology is able to effectively degrade the organic chlorine wastewater without yielding the secondary pollution, and the TCE and PCE that degraded by using γ-ray will be reached US-EPA and Taiwan Effluent Standard (5 ppb).

  4. Application of irradiated chitosan for fruit preservation

    Energy Technology Data Exchange (ETDEWEB)

    Lan, K.N. [Post-harvest Technology Institute, 4, Ngo Quyen-Ha Noi (Viet Nam); Lam, N.D. [Ha Noi Radiation Center, VAEC, 5T-160, Nghiado, Tuliem, Ha Noi (Viet Nam); Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Preliminary test of mango (Mangifera indica) preservation by irradiated chitosan coating has been investigated. The coating by using irradiated chitosan in 1.5% solution has extended the shelf life of mango from 7 to 15 days. At the 15th day mango coated by irradiated chitosan has been keeping good color, natural ripening, without spoilage, weight loss 10%, whereas the mango without coating was spoiled completely and the coating of fruit with unirradiated chitosan inhibited the ripening. (author)

  5. Application of irradiated chitosan for fruit preservation

    International Nuclear Information System (INIS)

    Lan, K.N.; Lam, N.D.; Kume, Tamikazu

    2000-01-01

    Preliminary test of mango (Mangifera indica) preservation by irradiated chitosan coating has been investigated. The coating by using irradiated chitosan in 1.5% solution has extended the shelf life of mango from 7 to 15 days. At the 15th day mango coated by irradiated chitosan has been keeping good color, natural ripening, without spoilage, weight loss 10%, whereas the mango without coating was spoiled completely and the coating of fruit with unirradiated chitosan inhibited the ripening. (author)

  6. Radiation induced electrical degradation in crystalline Al2O3: a bulk effect

    International Nuclear Information System (INIS)

    Zong Xiangfu; Chen, Y.; Evans, B.D.; Gonzalez, R.; Sellers, C.H.

    1995-01-01

    Kesternich et al. and Jung et al. have recently raised serious questions as to whether past investigations of permanent radiation induced electrical degradation (RIED) of ceramics were actually monitoring bulk effects, as claimed. Their evidence to the contrary appears compelling. The present investigation provides evidence that bulk damage does exist and is in the form of dislocations. Discussions are focussed on some aspects of the controversy between evidence for RIED, as reported in the past, and evidence for radiation enhanced surface contaminations. ((orig.))

  7. Chitosan-nanosilica hybrid materials: Preparation and properties

    International Nuclear Information System (INIS)

    Podust, T.V.; Kulik, T.V.; Palyanytsya, B.B.; Gun’ko, V.M.; Tóth, A.; Mikhalovska, L.; Menyhárd, A.; László, K.

    2014-01-01

    Highlights: • Hybrid chitosan-nanosilica materials were synthesized using an adsorption modification method. • The chitosan adsorption capacity is higher on the silica/titania and silica/alumina than on the fumed silica. • Nanosilicas undergo structural and textural alterations due to modification by chitosan. • The more severe chitosan thermodestruction occurs on the silica/titania and silica/alumina surfaces than on the plain silica surface. - Abstract: The research focuses on the synthesis of novel organic–inorganic hybrid materials based on polysaccharide chitosan and nanosilicas (SiO 2 , TiO 2 /SiO 2 and Al 2 O 3 /SiO 2 ). The chitosan modified nanooxides were obtained by the equilibrium adsorption method. The chitosan adsorption capacities of silica/titania and silica/alumina are higher than of the plain silica due to the additional active sites present on the surfaces of the mixed oxides. The hybrid materials were characterized by low-temperature nitrogen adsorption/desorption, photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), thermogravimetry (TG/DTG) and temperature-programmed desorption with mass spectrometry control (TPD MS) methods. The chitosan treatment only modestly influences the surface area S BET of the nanooxides but the rearrangement of the secondary and tertiary structures (aggregates and agglomerates) results in an enhancement of the mesoporosity and affects the size of the aggregates. The more severe thermodestruction of the polysaccharide desorbing from the modified mixed silicas indicates a stronger interaction between the chitosan and the mixed oxides compared to the silanol groups of the plain silica surface

  8. Chitosan-nanosilica hybrid materials: Preparation and properties

    Energy Technology Data Exchange (ETDEWEB)

    Podust, T.V., E-mail: tania_list@yahoo.com [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164 (Ukraine); Kulik, T.V., E-mail: tanyakulyk@i.ua [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164 (Ukraine); Palyanytsya, B.B.; Gun’ko, V.M. [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164 (Ukraine); Tóth, A. [Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Mikhalovska, L. [School of Pharmacy and Biomolecular Sciences, University of Brighton, Lewes Road, Brighton BN2 4GJ (United Kingdom); Menyhárd, A. [Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Institute of Materials Science and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences (Hungary); László, K. [Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics, H-1521 Budapest (Hungary)

    2014-11-30

    Highlights: • Hybrid chitosan-nanosilica materials were synthesized using an adsorption modification method. • The chitosan adsorption capacity is higher on the silica/titania and silica/alumina than on the fumed silica. • Nanosilicas undergo structural and textural alterations due to modification by chitosan. • The more severe chitosan thermodestruction occurs on the silica/titania and silica/alumina surfaces than on the plain silica surface. - Abstract: The research focuses on the synthesis of novel organic–inorganic hybrid materials based on polysaccharide chitosan and nanosilicas (SiO{sub 2}, TiO{sub 2}/SiO{sub 2} and Al{sub 2}O{sub 3}/SiO{sub 2}). The chitosan modified nanooxides were obtained by the equilibrium adsorption method. The chitosan adsorption capacities of silica/titania and silica/alumina are higher than of the plain silica due to the additional active sites present on the surfaces of the mixed oxides. The hybrid materials were characterized by low-temperature nitrogen adsorption/desorption, photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), thermogravimetry (TG/DTG) and temperature-programmed desorption with mass spectrometry control (TPD MS) methods. The chitosan treatment only modestly influences the surface area S{sub BET} of the nanooxides but the rearrangement of the secondary and tertiary structures (aggregates and agglomerates) results in an enhancement of the mesoporosity and affects the size of the aggregates. The more severe thermodestruction of the polysaccharide desorbing from the modified mixed silicas indicates a stronger interaction between the chitosan and the mixed oxides compared to the silanol groups of the plain silica surface.

  9. Radiation degradation of biological waste (aflatoxins) produced in food laboratory

    International Nuclear Information System (INIS)

    Rogovschi, Vladimir Dias

    2009-01-01

    Many filamentous fungi can produce secondary metabolites, called mycotoxins, which can be found in food and agricultural products. One of the main genera of myco toxigenic fungi related to the food chain is the Aspergillus spp. There are over 400 mycotoxins described in the literature, the most common the aflatoxins B1, B2, G1 and G2. The mycotoxins are commonly found in foods and are considered one of the most dangerous contaminants. The aflatoxin B1 is classified in group one by the International Agency of Research on Cancer. Aflatoxins resisting for more than one hour in autoclave making it necessary to other means of degradation of these toxins. This work aimed to observe the effects of gamma radiation of 60 Co and electron beams in the degradation of aflatoxins and compare the damage caused on the morphology of the Aspergillus flavus. The fungus was grown on potato dextrose agar (PDA) for 10 days and was subsequently transferred to coconut agar medium, and maintained for 14 days at 25 degree C. After this step the coconut agar was ground to become a homogeneous pasty and was irradiated with doses of 2.5, 5.0, 10 and 20 kGy. The samples used in scanning electron microscopy were irradiated with doses of 0, 2.5, 5.0, 10 and 20 kGy with sources of 60 Co and electron beams. Irradiation with electron accelerator showed a slightly higher degradation to gamma radiation, reducing 29.93 %, 34.50 %, 52.63 % and 72.30 % for doses of 2.5, 5.0, 10 and 20 kGy, respectively. The Scanning Electron Microscopy showed that doses of 2.5 to 10 kGy did not cause damage to the fungus, but with a dose of 20 kGy it can be observed fungal damage to structures. (author)

  10. Regioselective Sequential Modification of Chitosan via Azide-Alkyne Click Reaction: Synthesis, Characterization, and Antimicrobial Activity of Chitosan Derivatives and Nanoparticles

    Science.gov (United States)

    Sarwar, Atif; Katas, Haliza; Samsudin, Siti Noradila; Zin, Noraziah Mohamad

    2015-01-01

    Recently, the attention of researchers has been drawn toward the synthesis of chitosan derivatives and their nanoparticles with enhanced antimicrobial activities. In this study, chitosan derivatives with different azides and alkyne groups were synthesized using click chemistry, and these were further transformed into nanoparticles by using the ionotropic gelation method. A series of chitosan derivatives was successfully synthesized by regioselective modification of chitosan via an azide-alkyne click reaction. The amino moieties of chitosan were protected during derivatization by pthaloylation and subsequently unblocked at the end to restore their functionality. Nanoparticles of synthesized derivatives were fabricated by ionic gelation to form complexes of polyanionic penta-sodium tripolyphosphate (TPP) and cationic chitosan derivatives. Particle size analysis showed that nanoparticle size ranged from 181.03 ± 12.73 nm to 236.50 ± 14.32 nm and had narrow polydispersity index and positive surface charge. The derivatives and corresponding nanoparticles were evaluated in vitro for antibacterial and antifungal activities against three gram-positive and gram-negative bacteria and three fungal strains, respectively. The minimum inhibitory concentration (MIC) of all derivatives ranged from 31.3 to 250 µg/mL for bacteria and 188 to1500 µg/mL for fungi and was lower than that of native chitosan. The nanoparticles with MIC ranging from 1.56 to 25 µg/mLfor bacteria and 94 to 750 µg/mL for fungi exhibited higher activity than the chitosan derivatives. Chitosan O-(1-methylbenzene) triazolyl carbamate and chitosan O-(1-methyl phenyl sulfide) triazolyl carbamate were the most active against the tested bacterial and fungal strains. The hemolytic assay on erythrocytes and cell viability test on two different cell lines (Chinese hamster lung fibroblast cells V79 and Human hepatic cell line WRL68) demonstrated the safety; suggesting that these derivatives could be used in future

  11. New sizing agents and flocculants derived from chitosan

    International Nuclear Information System (INIS)

    Hebeish, A.; Higay, A.; El-Shafei, A.

    2005-01-01

    Novel approaches for development of new textile sizing agents and flocculants were undertaken. One of these approaches is based on acid hydrolysis of chitosan and the other involves its carboxy methylation. Characterization of the hydrolyzed chitosan was performed through monitoring nitrogen content and apparent viscosity, while carboxymethyl chitosan was analyzed for degree of substitution (DS) along with apparent viscosity. Factors affecting both hydrolysis and carboxy methylation were investigated. The nitrogen content and apparent viscosity of chitosan decrease variably by increasing HCl concentration as well as time and temperature of hydrolysis. On the other hand, the DS of carboxymethyl chitosan increases by increasing the concentration of both sodium hydroxide and monochloroacetic acid and similarly increases by prolonging the duration and raising the temperature of carboxy methylation; in contrast with apparent viscosity which is inversely related to these parameters. Aqueous solutions of hydrolyzed chitosan or carboxymethyl chitosan were applied to light cotton fabric with a view to envision the technical feasibility of such water soluble chitosan for textile sizing. The size add-on on the light fabric is directly related to the concentration of the hydrolyzed or carboxymethyl chitosan in the sizing solution and so does the apparent viscosity of the latter. Hundred percent size removals could be achieved with the hydrolyzed chitosan irrespective or the size solution concentration provided that the latter is not less than 8%. Different situation is encountered with carboxymethyl chitosan where the percent size removal increase from 81% to 95% by increasing its concentration in the sizing solution from 5 % to 15%. Drying the sized fabric at 80 degree C for 5 minutes or 120 degree C for 3 minutes has practically no effect on percent size removal. The same holds true for heat treatment of the sized fabric at higher temperatures (up to 160 degree C) for longer

  12. Preparations, properties and applications of chitosan based nanofibers fabricated by electrospinning

    Directory of Open Access Journals (Sweden)

    2011-04-01

    Full Text Available Chitosan is soluble in most acids. The protonation of the amino groups on the chitosan backbone inhibits the electrospinnability of pure chitosan. Recently, electrospinning of nanofibers based on chitosan has been widely researched and numerous nanofibers containing chitosan have been prepared by decreasing the number of the free amino groups of chitosan as the nanofibiers have enormous possibilities for better utilization in various areas. This article reviews the preparations and properties of the nanofibers which were electrospun from pure chitosan, blends of chitosan and synthetic polymers, blends of chitosan and protein, chitosan derivatives, as well as blends of chitosan and inorganic nanoparticles, respectively. The applications of the nanofibers containing chitosan such as enzyme immobilization, filtration, wound dressing, tissue engineering, drug delivery and catalysis are also summarized in detail.

  13. Adsorption of crude oil from aqueous solution by hydrogel of chitosan based polyacrylamide prepared by radiation induced graft polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Sokker, H.H., E-mail: hesham_sokkre@yahoo.com [Jazan University, Faculty of Science (Saudi Arabia); National Center for Radiation Research and Technology, Polymer Chemistry Department, P.O. Box 29, Cairo (Egypt); El-Sawy, Naeem M. [National Center for Radiation Research and Technology, Polymer Chemistry Department, P.O. Box 29, Cairo (Egypt); Hassan, M.A. [Scib Company of Paints, Cairo (Egypt); El-Anadouli, Bahgat E. [Chemistry Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)

    2011-06-15

    The adsorption of crude oil (initial concentration 0.5-30 g/L) from aqueous solution using hydrogel of chitosan based polyacrylamide (PAM) prepared by radiation induced graft polymerization has been investigated. The prepared hydrogel was characterized by FTIR and SEM micrographs. The experiments were carried out as a function of different initial concentrations of oil residue, acrylamide concentration, contact time and pH to determine the optimum condition for the adsorption of residue oil from aqueous solution and sea water. The results obtained showed that the hydrogel prepared at concentration of 40% acrylamide (AAm) and at a radiation dose of 5 kGy has high removal efficiency of crude oil 2.3 g/g at pH 3. Equilibrium studies have been carried out to determine the capacity of the hydrogel for adsorption of crude oil, Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms and isotherms constants. Equilibrium data were found to fit very well with both Freundlich and Langmuir models. Also the adsorption of oil onto the hydrogel behaves as a pseudo-second-order kinetic models rather than the pseudo-first-order kinetic model.

  14. Maillard reaction products from chitosan-xylan ionic liquid solution.

    Science.gov (United States)

    Luo, Yuqiong; Ling, Yunzhi; Wang, Xiaoying; Han, Yang; Zeng, Xianjie; Sun, Runcang

    2013-10-15

    A facile method is reported to prepare Maillard reaction products (MRPs) from chitosan and xylan in co-solvent ionic liquid. UV absorbance and fluorescence changes were regarded as indicators of the occurrence of Maillard reaction. FT-IR, NMR, XRD and TG were used to investigate the structure of chitosan-xylan conjugate. The results revealed that when chitosan reacted with xylan in ionic liquid, the hydrogen bonds in chitosan were destroyed, the facts resulted in the formation of chitosan-xylan MRPs. Moreover, when the mass ratio of chitosan to xylan was 1:1, the Maillard reaction proceeded easily. In addition, relatively high antioxidant property was also noted for the chitosan-xylan conjugate with mass ratio 1:1. So the obtained chitosan-xylan MRP is a promising antioxidant agent for food industry. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Chitosan: A potential biopolymer for wound management.

    Science.gov (United States)

    Bano, Ijaz; Arshad, Muhammad; Yasin, Tariq; Ghauri, Muhammad Afzal; Younus, Muhammad

    2017-09-01

    It has been seen that slow healing and non-healing wounds conditions are treatable but still challenging to humans. Wound dressing usually seeks for biocompatible and biodegradable recipe. Natural polysaccharides like chitosan have been examined for its antimicrobial and healing properties on the basis of its variation in molecular weight and degree of deacetylation. Chitosan adopts some vital characteristics for treatment of various kinds of wounds which include its bonding nature, antifungal, bactericidal and permeability to oxygen. Chitosan therefore has been modified into various forms for the treatment of wounds and burns. The purpose of this review article is to understand the exploitation of chitosan and its derivatives as wound dressings. This article will also provide a concise insight on the properties of chitosan necessary for skin healing and regeneration, particularly highlighting the emerging role of chitosan films as next generation skin substitutes for the treatment of full thickness wounds. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Molecular interactions in gelatin/chitosan composite films.

    Science.gov (United States)

    Qiao, Congde; Ma, Xianguang; Zhang, Jianlong; Yao, Jinshui

    2017-11-15

    Gelatin and chitosan were mixed at different mass ratios in solution forms, and the rheological properties of these film-forming solutions, upon cooling, were studied. The results indicate that the significant interactions between gelatin and chitosan promote the formation of multiple complexes, reflected by an increase in the storage modulus of gelatin solution. Furthermore, these molecular interactions hinder the formation of gelatin networks, consequently decreasing the storage modulus of polymer gels. Both hydrogen bonds and electrostatic interactions are formed between gelatin and chitosan, as evidenced by the shift of the amide-II bands of polymers. X-ray patterns of composite films indicate that the contents of triple helices decrease with increasing chitosan content. Only one glass transition temperature (T g ) was observed in composite films with different composition ratios, and it decreases gradually with an increase in chitosan proportion, indicating that gelatin and chitosan have good miscibility and form a wide range of blends. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Suppression of Zn stress on barley by irradiated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, N.; Mitomo, H. [Gunma Univ., Faculty of Engineering, Department of Biological and Chemical Engineering, Kiryu, Gunma (Japan); Ha, P.T.L. [Nuclear Research Institute, Dalat (Viet Nam); Watanabe, S.; Ito, T.; Takeshita, H.; Yoshii, F.; Kume, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Chitosan was irradiated up to 1000 kGy in solid state. Irradiation of chitosan caused the reduction of molecular weight. The molecular weight of the chitosan reduced from ca. 4 x 10{sup 5} to ca. 6 x 10{sup 3} by irradiation at 1000 kGy. For the barley growth promotion, irradiated chitosan showed the significant effect and 1000 kGy irradiated chitosan improved 20% of growth. Using the positron emitting tracer imaging system (PETIS), the effect of chitosan on uptake and transportation of {sup 62}Zn in barley were investigated. It was found that the transportation of Zn from root to shoot and the damage of plant by Zn were suppressed with irradiated chitosan. (author)

  18. Chitosan Fibers Modified with HAp/β–TCP Nanoparticles

    Directory of Open Access Journals (Sweden)

    Dariusz Wawro

    2011-10-01

    Full Text Available This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp, tricalcium phosphate (β-TCP, and HAp/β-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis and nanoparticles of tricalcium phosphate (β-TCP and hydroxyapatite (HAp suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/β-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0 wt% acetic acid. The properties of the spinning solutions were examined. Chitosan fibers modified with nanoparticles of HAp/β-TCP were characterized by a level of tenacity and calcium content one hundred times higher than that of regular chitosan fibers.

  19. Suppression of Zn stress on barley by irradiated chitosan

    International Nuclear Information System (INIS)

    Nagasawa, N.; Mitomo, H.; Ha, P.T.L.; Watanabe, S.; Ito, T.; Takeshita, H.; Yoshii, F.; Kume, T.

    2001-01-01

    Chitosan was irradiated up to 1000 kGy in solid state. Irradiation of chitosan caused the reduction of molecular weight. The molecular weight of the chitosan reduced from ca. 4 x 10 5 to ca. 6 x 10 3 by irradiation at 1000 kGy. For the barley growth promotion, irradiated chitosan showed the significant effect and 1000 kGy irradiated chitosan improved 20% of growth. Using the positron emitting tracer imaging system (PETIS), the effect of chitosan on uptake and transportation of 62 Zn in barley were investigated. It was found that the transportation of Zn from root to shoot and the damage of plant by Zn were suppressed with irradiated chitosan. (author)

  20. Electrochemical and Thermal Studies of Prepared Conducting Chitosan Biopolymer Film

    International Nuclear Information System (INIS)

    Hlaing Hlaing Oo; Kyaw Naing; Kyaw Myo Naing; Tin Tin Aye; Nyunt Wynn

    2005-09-01

    In this paper, chitosan based conducting bipolymer films were prepared by casting and solvent evaporating technique. All prepared chitosan films were of pale yellow colour, transparent, and smooth. Sulphuric acid was chosen as the cross-linking agent. It enhanced conduction pathway in cross-linked chitosan films. Mechanical properties, solid-state, and thermal behavior of prepared chitosan fimls were studied by means of a material testing machine, powder X-ray diffractometry (XRD), thermogravimetric analysis (TG-DTG), and differential scanning calorimetry (DSC). By the XRD diffraction pattern, high molecular weight of chitosan product indicates the semi-crystalline nature, but the prepared chitosan film and doped chitosan film indicate significantly lower in crystallinity prove which of the amorphous characteristics. In addition, DSC thermogram of pure chitosan film exhibited exothermic peak around at 300 C, indicating polymer decomposition of chitosan molecules in chitosan films. Furthermore, these DSC thermograms clearly showed that while pure chitosan film display exothermal decomposition, the doped chitosan films mainly endothermic characteristics. The ionic conductivity of doped chitosan films were in the order of 10 to 10 S cm , which is in the range of semi-conductor. These results showed that cross-linked chitoson films may be used as polymer electrolyte film to fabricate solid state electrochemical cells

  1. Evaluation of Radiation Processed Polymers as Materials for Agricultural Purposes. Chapter 8

    Energy Technology Data Exchange (ETDEWEB)

    El-Rehim, H. Abd [Atomic Energy Authority, Cairo (Egypt)

    2014-07-15

    The use of ionizing radiation in the development of natural and synthetic polymers for agricultural purposes has proven to be successful. Polysaccharides such as chitosan and sodium alginate are easily degraded through ionizing radiation which is considered to be a safe, clean, and an environment-friendly method. As a result, different kinds of biologically active fragments possessing growth promotion properties for plant performance and antimicrobial activities against pathogenic microorganisms for food preservation were obtained. Several factors such as preparation conditions, quality of the new materials, safety of the materials especially where the environment is concerned, and economic feasibility and production cost have been studied in its aim to commercialize the products. The required dose for degradation of soluble polysaccharide is relatively low when compared with that of solid polysaccharides. From the economic point of view, the choice to degrade polysaccharide with the use of viscous polysaccharide solutions containing 0.5–1 wt% oxidizing agent such as H{sub 2}O{sub 2} is necessary to decrease the dose required for degradation in the range of 20–30 kGy. Average molecular weights (MW) as well as molecular weights distributions were accurately determined by using different techniques like gel permeation chromatography (GPC) and viscometer. Large scale field studies of degraded polysaccharide materials as a growth promoter or an elicitor for different crops like wheat, faba bean, zea maze, and other vegetables and fruits (e.g. tomato, hot pepper, and banana crops) have been carried out. It was found that the treatment with low MW alginate of plants such as wheat increased its productivity by 25–30%, improved the quality of the crop, and enhanced the capability of wheat seeds to be used for long-term cultivation. The use of irradiated polysaccharides in stimulating defense reactions against some diseases in some plants was studied. Sodium alginates

  2. Radiation degradation of silk

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Kazushige; Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Silk fibroin powder was prepared from irradiated silk fibroin fiber by means of only physical treatment. Silk fibroin fiber irradiated with an accelerated electron beam in the dose range of 250 - 1000 kGy was pulverized by using a ball mill. Unirradiated silk fibroin fiber was not pulverized at all. But the more irradiation was increased, the more the conversion efficiency from fiber to powder was increased. The conversion efficiency of silk fibroin fiber irradiated 1000 kGy in oxygen was 94%. Silk fibroin powder shows remarkable solubility, which dissolved 57% into water of ambient temperature. It is a very interesting phenomenon that silk fibroin which did not treat with chemicals gets solubility only being pulverized. In order to study mechanism of solubilization of silk fibroin powder, amino acid component of soluble part of silk fibroin powder was analyzed. The more irradiation dose up, the more glycine or alanine degraded, but degradation fraction reached bounds about 50%. Other amino acids were degraded only 20% even at the maximum. To consider crystal construction of silk fibroin, it is suggested that irradiation on silk fibroin fiber selectively degrades glycine and alanine in amorphous region, which makes it possible to pulverize and to dissolve silk fibroin powder. (author)

  3. Chitosan dan Aplikasi Klinisnya Sebagai Biomaterial

    Directory of Open Access Journals (Sweden)

    Bambang Irawan

    2015-10-01

    Full Text Available The development of new materials with both organic and inorganic structures is of great interest to obtain special material properties. Chitosan [2-amino-2-deoxy-D-glucan] can be obtained by N-deacetylation of chitin. Chitin is the second most abundant biopolymer in nature and the supporting material of crustaceans, insects, fungi etc. Chitosan is unique polysaccharide and has been widely used in various biomedical application due to its biocompatibility, low toxicity, biodegradability, non-immunogenic and non-carcinogenic character. In the past few years, chitosan and some of its modifications have been reported for use in biomedical applications such as artificial skin, wound dressing, anticoagulant, suture, drug delivery, vaccine carrier and dietary fibers. Recently, the use of chitosan and its derivatives has received much attention as temporary scaffolding to promotie mineralization or stimulate endochodral ossification. This article aims to give a broad overview of chitosan and its clinical applications as biomaterial.

  4. X-ray diffraction studies of chitosan acetate-based polymer electrolytes

    International Nuclear Information System (INIS)

    Osman, Z.; Ibrahim, Z.A.; Abdul Kariem Arof

    2002-01-01

    Chitosan is the product when partially deacetylated chitin dissolves in dilute acetic acid. This paper presents the x-ray diffraction patterns of chitosan acetate, plasticised chitosan acetate and plasticised-salted chitosan acetate films. The results show that the chitosan acetate based polymer electrolyte films are not completely amorphous but it is partially crystalline. X-ray diffraction study also confirms the occurrence of the complexation between chitosan and the salt and the interaction between salt and plasticizer. The salt-chitosan interaction is clearly justified by infrared spectroscopy. (Author)

  5. Determination of the Optimum Conditions for Production of Chitosan Nanoparticles

    Directory of Open Access Journals (Sweden)

    A. Dustgani

    2007-12-01

    Full Text Available Bioedegradable nanoparticles are intensively investigated for their potential applications in drug delivery systems. Being a biocompatible and biodegradable polymer, chitosan holds great promise for use in this area. This investigation was concerned with determination and optimization of the effective parameters involved in the production of chitosan nanoparticles using ionic gelation method. Studied variables were concentration and pH of the chitosan solution, the ratio of chitosan to sodium tripolyphosphate therein and the molecular weight of chitosan. For this purpose, Taguchistatistical method was used for design of experiments in three levels. The size of chitosan nanoparticle was determined using laser light scattering. The experimental results showed that concentration of chitosan solution was the most important parameter and chitosan molecular weight the least effective parameter. The optimum conditions for preparation of nanoparticles were found to be 1 mg/mL chitosan solution with pH=5, chitosan to sodium tripolyphosphate ratio of 3 and chitosan molecular weight of 200,000 daltons. The average nanoparticle size at optimum conditions was found to be about 150 nm.

  6. Modified Chitosan Nanoparticle by Radiation Synthesis: An Approach to Drug Delivery and Bio-Based Additive for Biomedical Applications

    International Nuclear Information System (INIS)

    Pasanphan, W.; Rimdusit, P.; Rattanawongwiboon, T.; Choofong, S.

    2010-01-01

    Self-assembly chitosan nanoparticle (CsNP) has been synthesized via radiolytic methodology using gamma irradiation. The systematic condition in preparation was studied. Chitosan nanoparticle was modified using hydrophobic core of deoxycholic acid (DC) and stearyl methacrylate (SMA) and the hydrophilic shell of polyethylene glycol monomethacrylate (PEG). The hydrophobic/hydrophilic CsNP was prepared for drug carrier molecule. The SMA-CsNP was also conjugated with pyperidine, hindered amine light stabilizer function, to achieve a bio-based additive for biomedical plastic. (author)

  7. Modified Chitosan Nanoparticle by Radiation Synthesis: An Approach to Drug Delivery and Bio-Based Additive for Biomedical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Pasanphan, W.; Rimdusit, P.; Rattanawongwiboon, T.; Choofong, S., E-mail: sciwvm@ku.ac.th, E-mail: pwanvimol@yahoo.com [Kasetsart University, Faculty of Science, Department of Applied Radiation and Isotopes, 50 Phahonyothin Road, Chatuchak, Bangkok 1090 (Thailand)

    2010-07-01

    Self-assembly chitosan nanoparticle (CsNP) has been synthesized via radiolytic methodology using gamma irradiation. The systematic condition in preparation was studied. Chitosan nanoparticle was modified using hydrophobic core of deoxycholic acid (DC) and stearyl methacrylate (SMA) and the hydrophilic shell of polyethylene glycol monomethacrylate (PEG). The hydrophobic/hydrophilic CsNP was prepared for drug carrier molecule. The SMA-CsNP was also conjugated with pyperidine, hindered amine light stabilizer function, to achieve a bio-based additive for biomedical plastic. (author)

  8. Chitosan Based Self-Assembled Nanoparticles in Drug Delivery

    Directory of Open Access Journals (Sweden)

    Javier Pérez Quiñones

    2018-02-01

    Full Text Available Chitosan is a cationic polysaccharide that is usually obtained by alkaline deacetylation of chitin poly(N-acetylglucosamine. It is biocompatible, biodegradable, mucoadhesive, and non-toxic. These excellent biological properties make chitosan a good candidate for a platform in developing drug delivery systems having improved biodistribution, increased specificity and sensitivity, and reduced pharmacological toxicity. In particular, chitosan nanoparticles are found to be appropriate for non-invasive routes of drug administration: oral, nasal, pulmonary and ocular routes. These applications are facilitated by the absorption-enhancing effect of chitosan. Many procedures for obtaining chitosan nanoparticles have been proposed. Particularly, the introduction of hydrophobic moieties into chitosan molecules by grafting to generate a hydrophobic-hydrophilic balance promoting self-assembly is a current and appealing approach. The grafting agent can be a hydrophobic moiety forming micelles that can entrap lipophilic drugs or it can be the drug itself. Another suitable way to generate self-assembled chitosan nanoparticles is through the formation of polyelectrolyte complexes with polyanions. This paper reviews the main approaches for preparing chitosan nanoparticles by self-assembly through both procedures, and illustrates the state of the art of their application in drug delivery.

  9. Preparation, characteristics and assessment of a novel gelatin-chitosan sponge scaffold as skin tissue engineering material.

    Science.gov (United States)

    Han, Fei; Dong, Yang; Su, Zhen; Yin, Ran; Song, Aihua; Li, Sanming

    2014-12-10

    In order to develop a skin tissue engineering material for wound dressing application, a novel gelatin-chitosan sponge scaffold was designed and studied. The effect of chitosan and gelatin ratio on the morphology, pore size, porosity, water uptake capacity, water retention capacity and the degradation behavior were evaluated. Biocompatibility was investigated by both MTT method and AO/EB staining method. Antibacterial assessment and in vivo pharmacodynamic was also studied to evaluate the potential for wound healing. Results showed the sponge scaffold have uniform porous structure with pore size range between 120 and 140 μm, high porosity (>90%), high water uptake capacity (>1500%), high water retention capacity (>400%), and degradation percent in 28 days between 38.3 and 53.9%. Biocompatibility results showed that the activity of cells could not be affected by the nature of the sponge and it was suitable for cell adhesion and proliferation for 21 days. In vivo evaluation indicated that the sponge scaffold could offer effective support and attachment to cells for skin wound healing. In conclusion, the developed sponge scaffold was a potential skin tissue engineering material with appropriate physical properties and good biocompatibility. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Degradation studies on plasticized PVC films submited to gamma radiation

    Directory of Open Access Journals (Sweden)

    Vinhas Glória Maria

    2003-01-01

    Full Text Available Poly (vinyl chloride, PVC, is a rigid polymer and for several of its applications must be compounded with plasticizing agents. The plasticizers minimize the dipolar interactions, which exist between the polymer's chains, promoting their mobility. In this work we studied the properties of PVC/plasticizer systems submitted to different doses of gamma radiation. We have used four commercial plasticizers amongt them di(2-ethylhexyl phthalate, DEHP, which is present in a great number of commercial applications. The PVC/plasticizer systems have been studied as films made by the solvent evaporation technique. Irradiated and non-irradiated films have been characterized by viscosimetric analysis, mechanical essays and infrared spectroscopy. The results have shown that the rigid, non plasticized, PVC film presented the greatest degradation index, while among the plasticized films the one which presented the larger degradation index due to chain scission was the DEHP plasticized PVC.

  11. Degradation studies on plasticised PVC films submitted to gamma radiation

    International Nuclear Information System (INIS)

    Vinhas, Gloria Maria; Souto-Maior, Rosa Maria; Lapa, Camila Maria; Almeida, Yeda Medeiros Bastos de

    2003-01-01

    Poly (vinyl chloride), PVC, is a rigid polymer and for several of its applications must be compounded with plasticizing agents. The plasticizers minimize the dipolar interactions, which exist between the polymer's chains, promoting their mobility. In this work we studied the properties of PVC/plasticizer systems submitted to different doses of gamma radiation. We have used four commercial plasticizers among them di(2-ethylhexyl) phthalate, DEHP, which is present in a great number of commercial applications. The PVC/plasticizer systems have been studied as films made by the solvent evaporation technique. Irradiated and non-irradiated films have been characterized by viscosimetric analysis, mechanical essays and infrared spectroscopy. The results have shown that the rigid, non plasticized, PVC film presented the greatest degradation index, while among the plasticised films the one which presented the larger degradation index due to chain scission was the DEHP plasticised PVC. (author)

  12. Formulation, characterization, and expression of a recombinant MOMP Chlamydia trachomatis DNA vaccine encapsulated in chitosan nanoparticles

    Directory of Open Access Journals (Sweden)

    Cambridge CD

    2013-05-01

    Full Text Available Chino D Cambridge, Shree R Singh, Alain B Waffo, Stacie J Fairley, Vida A DennisCenter for NanoBiotechnology Research (CNBR, Alabama State University, Montgomery, AL, USAAbstract: Chlamydia trachomatis is a bacterial sexually transmitted infection affecting millions of people worldwide. Previous vaccination attempts have employed the recombinant major outer membrane protein (MOMP of C. trachomatis nonetheless, with limited success, perhaps, due to stability, degradation, and delivery issues. In this study we cloned C. trachomatis recombinant MOMP DNA (DMOMP and encapsulated it in chitosan nanoparticles (DMCNP using the complex coacervation technique. Physiochemical characterizations of DMCNP included transmission and scanning electron microcopy, Fourier transform infrared and ultraviolet-visible spectroscopy, and zeta potential. Encapsulated DMOMP was 167–250 nm, with a uniform spherical shape and homogenous morphology, and an encapsulation efficiency > 90%. A slow release pattern of encapsulated DMOMP, especially in acidic solution, was observed over 7 days. The zeta potential of DMCNP was ~8.80 mV, which indicated that it was highly stable. Toxicity studies of DMCNP (25–400 µg/mL to Cos-7 cells using the MTT assay revealed minimal toxicity over 24–72 hours with >90% viable cells. Ultra-violet visible (UV-vis spectra indicated encapsulated DMOMP protection by chitosan, whereas agarose gel electrophoresis verified its protection from enzymatic degradation. Expression of MOMP protein in DMCNP-transfected Cos-7 cells was demonstrated via Western blotting and immunofluorescence microscopy. Significantly, intramuscular injection of BALB/c mice with DMCNP confirmed the delivery of encapsulated DMOMP, and expression of the MOMP gene transcript in thigh muscles and spleens. Our data show that encapsulation of DMOMP in biodegradable chitosan nanoparticles imparts stability and protection from enzymatic digestion, and enhances delivery and

  13. Degree of Acetylization Chitosan Gonggong Snail Shells

    Science.gov (United States)

    Horiza, H.; Iskandar, I.; Aldo, N.

    2018-04-01

    Chitosan is a polysaccharide obtained from the deacetylation of chitin, which is generally derived from crustacean animal waste and animal skins other sea. One marine animals that have compounds that can be processed chitin chitosan is derived from the snail Gonggong marine waters of Riau Islands province. The purpose of this study was to determine the degree of chitosan from the shells of snails asetilisasi Gonggong. This research is an experimental research laboratory. The results of this study indicate that the degree of chitosan shell snail deasetilisasi Gonggong is 70.27%.

  14. Novel Profluorescent Nitroxides for Monitoring Alkyl Radical Reactions During Radiation Degradation

    International Nuclear Information System (INIS)

    George, G.

    2006-01-01

    Hindered amine stabilizers (HAS) are effective at retarding the photo-oxidative and high energy radiation degradation of PP and in certain circumstances, also thermo-oxidative degradation. The effectiveness of HAS as retarders of oxidation relies on the oxidation of the N-C bond by polymer hydroperoxide, ROOH, to form the nitroxyl group -NO which is the scavenger of polymer alkyl radicals, R. This reaction, which produces the alkoxy amine: -NO-R, must be competitive with the reaction of R with oxygen (which gives the chain-carrying peroxy radical, RO 2 ) if this stabilization mechanism is to be important in the inhibition of radiation-induced oxidative degradation of polyolefins by HAS. The rate of this reaction is high and in solution the rate coefficient is from 1 to 9x10 8 l mol - 1 s - 1. The efficient radical trapping by nitroxides has been widely employed in spin-trapping studies by electron spin resonance (esr) spectroscopy]. In addition to the hindered piperidine structure of commercial HAS, more rigid aromatic systems have been studied that are more stable to oxidative degradation and are more efficient at scavenging alkyl radicals. One such family is the iso-indoline nitroxide system, TMDBIO, shown below which, as it contains the phenanthrene fluorophore, is termed phenanthrene nitroxide. This nitroxide only becomes fluorescent when it reacts with alkyl radicals or is reduced and is termed profluorescent. TMDBIO has a vanishingly small fluorescence quantum yield (φ∼10 - 4) due to the enhanced intersystem crossing from the first excited singlet state to the ground state due to electron exchange interactions of the nitroxyl radical. When the nitroxide traps an alkyl radical, R, the resulting alkoxy amine is fluorescent (φ∼10 - 1) and the emission intensity is a measure of the number of reactions that have occurred. This property may be exploited by using quantitative fluorescence spectroscopy to follow the reaction of the nitroxide with alkyl radicals

  15. Chitosan pretreatment for cotton dyeing with black tea

    Science.gov (United States)

    Campos, J.; Díaz-García, P.; Montava, I.; Bonet-Aracil, M.; Bou-Belda, E.

    2017-10-01

    Chitosan is used in a wide range of applications due to its intrinsic properties. Chitosan is a biopolymer obtained from chitin and among their most important aspects highlights its bonding with cotton and its antibacterial properties. In this study two different molecular weight chitosan are used in the dyeing process of cotton with black tea to evaluate its influence. In order to evaluate the effect of the pretreatment with chitosan, DSC and reflection spectrophotometer analysis are performed. The curing temperature is evaluated by the DSC analysis of cotton fabric treated with 15 g/L of chitosan, whilst the enhancement of the dyeing is evaluated by the colorimetric coordinates and the K/S value obtained spectrophotometrically. This study shows the extent of improvement of the pretreatment with chitosan in dyeing with natural products as black tea.

  16. Cobalt-60 gamma radiation effects on degradation of pesticides used in stored rice and beans

    International Nuclear Information System (INIS)

    Groppo, Gerson A.

    1988-02-01

    The present work, carried out at CENA, an agriculture nuclear energy center - University of Sao Paulo - Brazil, investigates the Cobalt-60 gamma radiation effects on insecticides applied to stored rice and beans. The radiation dose applied - 200 Gy - to the stored rice and beans treated with insecticides was not sufficient to cause a noticeable chemical degradation through insect mortality. (author). 31 refs., 23 tabs

  17. Novel bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate: Fabrication, characterisation and evaluation of biocompatibility

    International Nuclear Information System (INIS)

    Chen, Yirong; Zhou, Yilin; Yang, Shenyu; Li, Jiao Jiao; Li, Xue; Ma, Yunfei; Hou, Yilong; Jiang, Nan; Xu, Changpeng; Zhang, Sheng; Zeng, Rong; Tu, Mei; Yu, Bin

    2016-01-01

    Calcium sulfate is in routine clinical use as a bone substitute, offering the benefits of biodegradability, biocompatibility and a long history of use in bone repair. The osteoconductive properties of calcium sulfate may be further improved by doping with strontium ions. Nevertheless, the high degradation rate of calcium sulfate may impede bone healing as substantial material degradation may occur before the healing process is complete. The purpose of this study is to develop a novel composite bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate in the form of microcapsules, which can promote osteogenesis while matching the natural rate of bone healing. The developed microcapsules exhibited controlled degradation that facilitated the sustained release of strontium ions. In vitro testing showed that the microcapsules had minimal cytotoxicity and ability to inhibit bacterial growth. In vivo testing in a mouse model showed the absence of genetic toxicity and low inflammatory potential of the microcapsules. The novel microcapsules developed in this study demonstrated suitable degradation characteristics for bone repair as well as favourable in vitro and in vivo behaviour, and hold promise for use as an alternative bone substitute in orthopaedic surgery. - Highlights: • Chitosan + Sr-doped α-calcium sulfate hemihydrate microcapsules were synthesised. • The novel composite microcapsules had potential application as a bone substitute. • The microcapsules showed controlled degradation and release of strontium ions. • The microcapsules showed in vitro biocompatibility by cytotoxicity test. • The microcapsules showed in vivo biocompatibility in a mouse model.

  18. Novel bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate: Fabrication, characterisation and evaluation of biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yirong; Zhou, Yilin [Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Yang, Shenyu [Department of Materials Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Li, Jiao Jiao [Biomaterials and Tissue Engineering Research Unit, School of AMME, University of Sydney, Sydney, NSW 2006 (Australia); Li, Xue; Ma, Yunfei; Hou, Yilong; Jiang, Nan; Xu, Changpeng; Zhang, Sheng [Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Zeng, Rong [Department of Materials Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Tu, Mei, E-mail: tumei@jnu.edu.cn [Department of Materials Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Yu, Bin, E-mail: yubinol@163.com [Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China)

    2016-09-01

    Calcium sulfate is in routine clinical use as a bone substitute, offering the benefits of biodegradability, biocompatibility and a long history of use in bone repair. The osteoconductive properties of calcium sulfate may be further improved by doping with strontium ions. Nevertheless, the high degradation rate of calcium sulfate may impede bone healing as substantial material degradation may occur before the healing process is complete. The purpose of this study is to develop a novel composite bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate in the form of microcapsules, which can promote osteogenesis while matching the natural rate of bone healing. The developed microcapsules exhibited controlled degradation that facilitated the sustained release of strontium ions. In vitro testing showed that the microcapsules had minimal cytotoxicity and ability to inhibit bacterial growth. In vivo testing in a mouse model showed the absence of genetic toxicity and low inflammatory potential of the microcapsules. The novel microcapsules developed in this study demonstrated suitable degradation characteristics for bone repair as well as favourable in vitro and in vivo behaviour, and hold promise for use as an alternative bone substitute in orthopaedic surgery. - Highlights: • Chitosan + Sr-doped α-calcium sulfate hemihydrate microcapsules were synthesised. • The novel composite microcapsules had potential application as a bone substitute. • The microcapsules showed controlled degradation and release of strontium ions. • The microcapsules showed in vitro biocompatibility by cytotoxicity test. • The microcapsules showed in vivo biocompatibility in a mouse model.

  19. Humidity detection using chitosan film based sensor

    Science.gov (United States)

    Nasution, T. I.; Nainggolan, I.; Dalimunthe, D.; Balyan, M.; Cuana, R.; Khanifah, S.

    2018-02-01

    A humidity sensor made of the natural polymer chitosan has been successfully fabricated in the film form by a solution casting method. Humidity testing was performed by placing a chitosan film sensor in a cooling machine room, model KT-2000 Ahu. The testing results showed that the output voltage values of chitosan film sensor increased with the increase in humidity percentage. For the increase in humidity percentage from 30 to 90% showed that the output voltage of chitosan film sensor increased from 32.19 to 138.75 mV. It was also found that the sensor evidenced good repeatability and stability during the testing. Therefore, chitosan has a great potential to be used as new sensing material for the humidity detection of which was cheaper and environmentally friendly.

  20. Degradation of persistent organochlorine pollutants by gamma-radiation and the possible use for waste water treatment

    International Nuclear Information System (INIS)

    Vollner, L.; Rohleder, H.; Korte, F.

    1975-01-01

    Some organochlorine pesticides, polychlorinated biphenyls and related chemicals have become ubiquitous pollutants by their persistence and are common contaminants in waste waters. Since gamma-radiation represents a possible treatment for decontamination, radiation yield and degradation chemistry were investigated. The pattern of hexane extractable compounds obtained from acetone-water and from pure water solutions are not very different when compared by GC-analysis. Dechlorination and dehydrochlorination were found to be the most important mechanisms of the first attack. The complete destruction of chlorine pesticides and of other chlorinated hydrocarbons (as PCBs) at the ppm-level demand considerable radiation doses. G-values for dieldrin and its hexane extractable degradation products are 1 x 10 -3 in deionized water and 3.6 x 10 -5 in twice-distilled water. G-values for aldrin, lindane, chlordane and PCBs are in the same order of magnitude. (orig./HK) [de

  1. An Investigation of Chitosan for Sorption of Radionuclides

    Science.gov (United States)

    2012-06-05

    Valenta et al. found that hydrogels made of EDTA-chitsoan were resistant to bacterial growth [88]. Nishi et al. found that alka- line earth metals...reviews of chitosan deriva- tives have been recently published [8, 21, 75, 89]. 10 Table 2.1: Select applications of chitosan. From [72, 75]. Agriculture ...pharmaceuticals 2.1.3 Chitosan applications Chitosan has found applications in a wide range of fields, including agriculture , water treatment, biomedical

  2. Effects of sulfate chitosan derivatives on nonalcoholic fatty liver disease

    Science.gov (United States)

    Yu, Mingming; Wang, Yuanhong; Jiang, Tingfu; Lv, Zhihua

    2014-06-01

    Sulfate chitosan derivatives have good solubility and therapeutic effect on the cell model of NAFLD. The aim of this study was to examine the therapeutic effect of sulfate chitosan derivatives on NAFLD. The male Wistar rats were orally fed high fat emulsion and received sulfate chitosan derivatives for 5 weeks to determine the pre-treatment effect of sulfate chitosan derivatives on NAFLD. To evaluate the therapeutic effect of sulfate chitosan derivatives on NAFLD, the rats were orally fed with high concentration emulsion for 5 weeks, followed by sulfate chitosan derivatives for 3 weeks. Histological analysis and biomedical assays showed that sulfate chitosan derivatives can dramatically prevent the development of hepatic steatosis in hepatocyte cells. In animal studies, pre-treatment and treatment with sulfate chitosan derivatives significantly protected against hepatic steatohepatitis induced by high fat diet according to histological analysis. Furthermore, increased TC, ALT, MDA, and LEP in NAFLD were significantly ameliorated by pre-treatment and treatment with sulfate chitosan derivatives. Furthermore, increased TG, AST, and TNF-α in NAFLD were significantly ameliorated by treatment with sulfate chitosan derivatives. Sulfate chitosan derivatives have good pre-treatment and therapeutic effect on NAFLD.

  3. Effect of chitosan coatings on postharvest green asparagus quality.

    Science.gov (United States)

    Qiu, Miao; Jiang, Hengjun; Ren, Gerui; Huang, Jianying; Wang, Xiangyang

    2013-02-15

    Fresh postharvest green asparagus rapidly deteriorate due to its high respiration rate. The main benefits of edible active coatings are their edible characteristics, biodegradability and increase in food safety. In this study, the quality of the edible coatings based on 0.50%, 0.25% high-molecular weight chitosan (H-chitosan), and 0.50%, 0.25% low-molecular weight chitosan (L-chitosan) on postharvest green asparagus was investigated. On the basis of the results obtained, 0.25% H-chitosan and 0.50% L-chitosan treatments ensured lower color variation, less weight loss and less ascorbic acid, decrease presenting better quality of asparagus than other concentrations of chitosan treatments and the control during the cold storage, and prolonging a shelf life of postharvest green asparagus. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Effect Of GAMMA-Irradiation On Production And Characteristics Of Chitosan Produced From Crustacean Waste By Using Some Bacterial Strains

    International Nuclear Information System (INIS)

    INAS ISMAIL MAHMOUD RAAFAT

    2015-01-01

    The main study focused on separation of chitin from crustacean waste (shrimp shell) using some proteolytic bacterial isolates. After that, chitosan was obtained by deactylation and its characteristics were studied using some characterizing tools. The produced chitosan was degraded to different molecular weights and evaluated as an antibacterial agent. Seventy bacterial isolates were obtained from different sources (soil, plant roots and shrimp shell waste) and tested for their ability to produce proteolytic enzymes. One isolate was selected, due its high proteolytic activity and ability to grow using shrimp as carbon and nitrogen source on shrimp shell agar medium and identified as Bacillus subtilis NA12 by 16S-rRNA gene sequences with a high degree of similarity (99 %) as a gene bank database. Factors affecting deproteinization (DP) and demineralization (DM) efficiency of shrimp shell waste (SSW) (carbon source and its optimal concentration, shrimp shell waste concentration, inoculum size and fermentation time) were studied. The most efficient DP (92.40 %) and DM (81.37 %) of SSW by B. subtilis NA12 were sucrose 10 % (w/v) and inoculum size 15 % (v/v 35 x 108 CFU/ml ) to ferment shrimp shell waste 5 % (w/v) for 6 days of fermentation time. The effect of γ-irradiation on the performance of selected bacterial strain was studied to maximize chitin yield. Box-Behnken design using response surface methodology was employed to establish the relationship between the previous variables, implied that the model was highly significant. It was found that a sucrose concentration of 5 % (w/v), SSW of 12.5 % (w/v), inoculum size of 10 % (v/v) and fermentation time of 7 days; had a predicted value of DP of 97.65 % whereas the actual experiment gave 96.37 %. The predicted value of DM was 82.94 % whereas the actual experiment gave 82.19 %. Chitosan polymer was successfully prepared by the deacetylation reaction from fermented shrimp shell waste (SSW) by Bacillus subtilis NA12

  5. Interaction between chitosan and its related enzymes: A review.

    Science.gov (United States)

    Shinya, Shoko; Fukamizo, Tamo

    2017-11-01

    Chitosan-related enzymes including chitosanases, exo-β-glucosaminidases, and enzymes having chitosan-binding modules recognize ligands through electrostatic interactions between the acidic amino acids in proteins and amino groups of chitosan polysaccharides. However, in GH8 chitosanases, several aromatic residues are also involved in substrate recognition through stacking interactions, and these enzymes consequently hydrolyze β-1,4-glucan as well as chitosan. The binding grooves of these chitosanases are extended and opened at both ends of the grooves, so that the enzymes can clamp a long chitosan polysaccharide. The association/dissociation of positively charged glucosamine residues to/from the binding pocket of a GH2 exo-β-glucosaminidase controls the p K a of the catalytic acid, thereby maintaining the high catalytic potency of the enzyme. In contrast to chitosanases, chitosan-binding modules only accommodate a couple of glucosamine residues, predominantly recognizing the non-reducing end glucosamine residue of chitosan by electrostatic interactions and a hydrogen-bonding network. These structural findings on chitosan-related enzymes may contribute to future applications for the efficient conversion of the chitin/chitosan biomass. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. β-Chitin and chitosan from squid gladius: Biological activities of chitosan and its application as clarifying agent for apple juice.

    Science.gov (United States)

    Abdelmalek, Baha Eddine; Sila, Assaâd; Haddar, Anissa; Bougatef, Ali; Ayadi, Mohamed Ali

    2017-11-01

    Chitin is the second most abundant polysaccharide in biomass after cellulose and the term chitosan usually refers to a family of polymers obtained after chitin deacetylation. The aim of this work was the preparation and the characterization of chitin and chitosan from the gladius (pen) of the European squid (Loligo vulgaris). A high level of deproteinization (more than 80%) was recorded using Alcalase ® with an enzyme/protein ratio of 10U/mg. The demineralization of the gladius was completely achieved within 8h at room temperature in HCl. 13 C NMR, FTIR, and XRD diffractograms of prepared chitin and chitosan were taken and then degree of deacetylation of chitosan was calculated using 13 C CP/MAS-NMR Spectroscopic. Further, in vitro antioxidant capacity of chitosan was evaluated on 1,1-diphenyl-2-picrylhydrazyl method (IC 50 =3.2mgmL -1 ) and the β-carotene bleaching assay (IC 50 =3.3mgmL -1 ). Antimicrobial activity was also investigated and assays indicated that prepared chitosan exhibited marked inhibitory activity against all microbial strains tested. Additionally, chitosan was tested such as clarifying agent for apple juice and showed powerful clarification capability, without affecting nutritional value. Furthermore, the results suggested that prepared chitosan could be used as alternative additive in pharmaceutical preparations and food industry. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Product analysis for polyethylene degradation by radiation and thermal ageing

    International Nuclear Information System (INIS)

    Sugimoto, Masaki; Shimada, Akihiko; Kudoh, Hisaaki; Tamura, Kiyotoshi; Seguchi, Tadao

    2013-01-01

    The oxidation products in crosslinked polyethylene for cable insulation formed during thermal and radiation ageing were analyzed by FTIR-ATR. The products were composed of carboxylic acid, carboxylic ester, and carboxylic anhydride for all ageing conditions. The relative yields of carboxylic ester and carboxylic anhydride increased with an increase of temperature for radiation and thermal ageing. The carboxylic acid was the primary oxidation product and the ester and anhydride were secondary products formed by the thermally induced reactions of the carboxylic acids. The carboxylic acid could be produced by chain scission at any temperature followed by the oxidation of the free radicals formed in the polyethylene. The results of the analysis led to formulation of a new oxidation mechanism which was different from the chain reactions via peroxy radicals and peroxides. - Highlights: ► Products analysis of polyethylene degradation by radiation and thermal ageing. ► Components of carbonyl compounds produced in polyethylene by thermal and radiation oxidation were determined by FTIR. ► Carbonyl compounds comprised carboxylic acid, carboxylic ester, and carboxylic anhydride. ► Carboxylic acid was the primary oxidation product of chain scission at any oxidation temperature. ► Carboxylic ester and carboxylic anhydride are secondary products formed from carboxylic acid at higher temperature.

  8. Poly(acrylonitrile)chitosan composite membranes for urease immobilization.

    Science.gov (United States)

    Gabrovska, Katya; Georgieva, Aneliya; Godjevargova, Tzonka; Stoilova, Olya; Manolova, Nevena

    2007-05-10

    (Poly)acrylonitrile/chitosan (PANCHI) composite membranes were prepared. The chitosan layer was deposited on the surface as well as on the pore walls of the base membrane. This resulted in the reduction of the pore size of the membrane and in an increase of their hydrophilicity. The pore structure of PAN and PANCHI membranes were determined by TEM and SEM analyses. It was found that the average size of the pore under a selective layer base PAN membrane is 7 microm, while the membrane coated with 0.25% chitosan shows a reduced pore size--small or equal to 5 microm and with 0.35% chitosan--about 4 microm. The amounts of the functional groups, the degree of hydrophilicity and transport characteristics of PAN/Chitosan composite membranes were determined. Urease was covalently immobilized onto all kinds of PAN/chitosan composite membranes using glutaraldehyde. Both the amount of bound protein and relative activity of immobilized urease were measured. The highest activity (94%) was measured for urease bound to PANCHI2 membranes (0.25% chitosan). The basic characteristics (pH(opt), pH(stability), T(opt), T(stability), heat inactivation and storage stability) of immobilized urease were determined. The obtained results show that the poly(acrylonitrile)chitosan composite membranes are suitable for enzyme immobilization.

  9. Emerging Chitosan-Based Films for Food Packaging Applications.

    Science.gov (United States)

    Wang, Hongxia; Qian, Jun; Ding, Fuyuan

    2018-01-17

    Recent years have witnessed great developments in biobased polymer packaging films for the serious environmental problems caused by the petroleum-based nonbiodegradable packaging materials. Chitosan is one of the most abundant biopolymers after cellulose. Chitosan-based materials have been widely applied in various fields for their biological and physical properties of biocompatibility, biodegradability, antimicrobial ability, and easy film forming ability. Different chitosan-based films have been fabricated and applied in the field of food packaging. Most of the review papers related to chitosan-based films are focusing on antibacterial food packaging films. Along with the advances in the nanotechnology and polymer science, numerous strategies, for instance direct casting, coating, dipping, layer-by-layer assembly, and extrusion, have been employed to prepare chitosan-based films with multiple functionalities. The emerging food packaging applications of chitosan-based films as antibacterial films, barrier films, and sensing films have achieved great developments. This article comprehensively reviews recent advances in the preparation and application of engineered chitosan-based films in food packaging fields.

  10. Functionalities of chitosan conjugated with stearic acid and gallic acid and application of the modified chitosan in stabilizing labile aroma compounds in an oil-in-water emulsion.

    Science.gov (United States)

    Yang, Tsung-Shi; Liu, Tai-Ti; Lin, I-Hwa

    2017-08-01

    The aims of this research were to conjugate chitosan (CT) with stearic acid (SA) and gallic acid (GA), and apply the modified chitosan to stabilize labile aroma compounds such as allyl isothiocyanate (AITC) and limonene in oil-in-water emulsions. Generally, the antioxidant activity of CT-SA-GA increased as the GA content in the conjugate increased. In most assays, GA had a lower IC 50 value than that of CT-SA-GA; however, CT-SA-GA exhibited better performance than GA in the Fe 2+ -chelating activity. In accelerated tests (heating or illumination) for evaluating the chemical stability of AITC and limonene during storage, CT-SA and CT-SA-GA were used to prepare AITC and limonene O/W emulsions, respectively. Tween 80 and Span 80 (T-S-80), an emulsifier mixture, were used as a control in both emulsions for comparison. The results show that CT-SA or CT-SA-GA could protect AITC or limonene from degradation or oxidation more effectively than T-S-80. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Lipase entrapment in PVA/Chitosan biodegradable film for reactor coatings

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Karla A. [Departamento de Bioquímica e Biologia Molecular, Laboratório de Química de Proteínas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970, Goiânia, GO (Brazil); Lopes, Flavio Marques [Departamento de Bioquímica e Biologia Molecular, Laboratório de Química de Proteínas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970, Goiânia, GO (Brazil); Unidade Universitária de Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, Anápolis, GO (Brazil); Yamashita, Fabio [Departamento de Tecnologia de Alimentos e Medicamentos, Laboratório de Tecnologia, Universidade Estadual de Londrina, Cx. Postal 6001, CEP 86051-990, Londrina, PR (Brazil); Fernandes, Kátia Flávia, E-mail: katia@icb.ufg.br [Departamento de Bioquímica e Biologia Molecular, Laboratório de Química de Proteínas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970, Goiânia, GO (Brazil)

    2013-04-01

    This study reports the development and characterization of novel biodegradable film, based on chitosan and polyvinyl alcohol containing lipase entrapped. The films showed a thickness of 70.4 and 79 μm to PVA/Chitosan and PVA/Chitosan/Lipase, respectively. The entrapment of lipase in PVA/Chitosan film resulted in increasing of 69.4% tensile strength (TS), and 52.4% of elongation. SEM images showed the formation of a continuous film, without pores or cracks. The lipase entrapment efficiency was estimated in 92% and the films were repeatedly used for 25 hydrolytic cycles, maintaining 62% of initial activity. The PVA/Chitosan/Lipase film was used for olive oil hydrolysis of high performance. These results indicate that PVA/Chitosan/Lipase is a promising material for biotechnology applications such as triacylglycerol hydrolysis and biodiesel production. - Highlights: ► Development and characterization of PVA/Chitosan biodegradable film ► Lipase immobilization onto PVA/Chitosan film ► PVA/Chitosan/Lipase film for reactor coating ► Olive oil hydrolysis using PVA/Chitosan/Lipase film.

  12. Lipase entrapment in PVA/Chitosan biodegradable film for reactor coatings

    International Nuclear Information System (INIS)

    Batista, Karla A.; Lopes, Flavio Marques; Yamashita, Fabio; Fernandes, Kátia Flávia

    2013-01-01

    This study reports the development and characterization of novel biodegradable film, based on chitosan and polyvinyl alcohol containing lipase entrapped. The films showed a thickness of 70.4 and 79 μm to PVA/Chitosan and PVA/Chitosan/Lipase, respectively. The entrapment of lipase in PVA/Chitosan film resulted in increasing of 69.4% tensile strength (TS), and 52.4% of elongation. SEM images showed the formation of a continuous film, without pores or cracks. The lipase entrapment efficiency was estimated in 92% and the films were repeatedly used for 25 hydrolytic cycles, maintaining 62% of initial activity. The PVA/Chitosan/Lipase film was used for olive oil hydrolysis of high performance. These results indicate that PVA/Chitosan/Lipase is a promising material for biotechnology applications such as triacylglycerol hydrolysis and biodiesel production. - Highlights: ► Development and characterization of PVA/Chitosan biodegradable film ► Lipase immobilization onto PVA/Chitosan film ► PVA/Chitosan/Lipase film for reactor coating ► Olive oil hydrolysis using PVA/Chitosan/Lipase film

  13. Grape Preservation Using Chitosan Combined with β-Cyclodextrin

    Directory of Open Access Journals (Sweden)

    Yu Youwei

    2013-01-01

    Full Text Available The effect of 1% chitosan combined with 2% β-cyclodextrin to the preservation of fresh grapes under ambient temperature was investigated. The results indicated that the hydrogen bond formed between the hydroxyl group of β-cyclodextrin and the amidogen or hydroxyl group of chitosan and the crystal form of chitosan was also changed when cyclodextrin was doped into chitosan coating. The compound coating could prolong the shelf life of grapes, maintain lower respiration rate and higher activities of superoxide dismutase, peroxidase, and catalase during storage time, and restrain weight loss and malonaldehyde content increase. Coating grapes with chitosan + β-cyclodextrin was a good method in postharvested grape preservation.

  14. Nuclear Radiation Degradation Study on HD Camera Based on CMOS Image Sensor at Different Dose Rates.

    Science.gov (United States)

    Wang, Congzheng; Hu, Song; Gao, Chunming; Feng, Chang

    2018-02-08

    In this work, we irradiated a high-definition (HD) industrial camera based on a commercial-off-the-shelf (COTS) CMOS image sensor (CIS) with Cobalt-60 gamma-rays. All components of the camera under test were fabricated without radiation hardening, except for the lens. The irradiation experiments of the HD camera under biased conditions were carried out at 1.0, 10.0, 20.0, 50.0 and 100.0 Gy/h. During the experiment, we found that the tested camera showed a remarkable degradation after irradiation and differed in the dose rates. With the increase of dose rate, the same target images become brighter. Under the same dose rate, the radiation effect in bright area is lower than that in dark area. Under different dose rates, the higher the dose rate is, the worse the radiation effect will be in both bright and dark areas. And the standard deviations of bright and dark areas become greater. Furthermore, through the progressive degradation analysis of the captured image, experimental results demonstrate that the attenuation of signal to noise ratio (SNR) versus radiation time is not obvious at the same dose rate, and the degradation is more and more serious with increasing dose rate. Additionally, the decrease rate of SNR at 20.0, 50.0 and 100.0 Gy/h is far greater than that at 1.0 and 10.0 Gy/h. Even so, we confirm that the HD industrial camera is still working at 10.0 Gy/h during the 8 h of measurements, with a moderate decrease of the SNR (5 dB). The work is valuable and can provide suggestion for camera users in the radiation field.

  15. Adhesion and viability of two enterococcal strains on covalently grafted chitosan and chitosan/kappa-carrageenan multilayers

    NARCIS (Netherlands)

    Bratskaya, S.; Marinin, D.; Simon, F.; Synytska, A.; Zschoche, S.; Busscher, H. J.; Jager, D.; van der Mei, H. C.

    Chitosans are natural aminopolysaccharides, whose low cytotoxicity suggests their potential use for nonadhesive, antibacterial coatings on biomaterials implant surfaces. Here, the antiadhesive behavior and ability to kill bacteria upon adhesion ("contact killing") of chitosan coatings were evaluated

  16. The study analysis of degradation product of Tributyl Phosphate by Gamma radiation and influence in extraction process

    International Nuclear Information System (INIS)

    Damunir; Didiek Herhady, R; Busron-Masduki; Ashar-Waskito; Armanu

    1996-01-01

    The analysis study of degradation product of TBP by gamma radiation using Co-60 Irradiator Irvasena was done. The investigation stressed on analysis and the relation of degradation product of TBP and extraction process. TBP-dodecane 30 % irradiated by radiation doses 1.172x10 3 rad, 1.155x10 5 rad, 1.125x10 7 and 1.155x10 9 rad. The analysis of degradation product of TBP mainly of MBP and DBP were determined in the mixture media of 5 ml isopropyl alcohol, 5 ml ethylene glycol, 5 ml acetone and 15 ml alcohol with potentiometric titration using NaOH 0.1 N in the alcohol solution, at potential condition of 500 mV and potential derivative 500 mV. The experiment shows that the gamma radiation doses 1.125x10 7 rad result 0.125 ± 0.049 mg MBP/ml solvent and 1.556 ± 0.084 mg DBP/ml solvent and radiation doses 1.115x10 9 rad result 26.135 ± 0.114 mg MBP/ml solvent and 62.454 ± 1.107 mg DBP/ml solvent, MBP dan DBP un detectable for radiation doses 1.172x10 3 rad and 1.055x10 5 rad. The result of MBP and DBP analysis compare to Tachehiko Ishihara and Erich Zimmer, using potentiometric titration method for MBP and DBP analysis was reliable addition and none addition. The TBP-dodecane solvent was irradiation by radiation doses 10 7 rad or greater than, is suggested to treat the solvent by regeneration so that doesn't disturbance extraction

  17. Effect of degree of deacetylation of chitosan on adsorption capacity and reusability of chitosan/polyvinyl alcohol/TiO2 nano composite.

    Science.gov (United States)

    Habiba, Umma; Joo, Tan Chin; Siddique, Tawsif A; Salleh, Areisman; Ang, Bee Chin; Afifi, Amalina M

    2017-11-01

    The chitosan/polyvinyl alcohol/TiO 2 composite was synthesized. Two different degrees of deacetylation of chitosan were prepared by hydrolysis to compare the effectiveness of them. The composite was analyzed via field emission scanning electron microscopy, Fourier transform infrared, X-ray diffraction, thermal gravimetric analysis, weight loss test and adsorption study. The FTIR and XRD results proved the interaction among chitosan, PVA and TiO 2 without any chemical reaction. It was found that, chitosan with higher degree of deacetylation has better stability. Furthermore, it also showed that higher DD of chitosan required less time to reach equilibrium for methyl orange. The adsorption followed the pseudo-second-order kinetic model. The Langmuir and Freundlich isotherm models were fitted well for isotherm study. Adsorption capacity was higher for the composite containing chitosan with higher DD. The dye removal rate was independent of the dye's initial concentration. The adsorption capacity was increased with temperature and it was found from reusability test that the composite containing chitosan with higher DD is more reusable. It was notable that adsorption capacity was even after 15 runs. Therefore, chitosan/PVA/TiO 2 composite can be a very useful material for dye removal. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. In vivo immuno-reactivity analysis of the porous three-dimensional chitosan/SiO2 and chitosan/SiO2 /hydroxyapatite hybrids.

    Science.gov (United States)

    Guo, Mengxia; Dong, Yifan; Xiao, Jiangwei; Gu, Ruicai; Ding, Maochao; Huang, Tao; Li, Junhua; Zhao, Naru; Liao, Hua

    2018-05-01

    Inorganic/organic hybrid silica-chitosan (CS) scaffolds have promising potential for bone defect repair, due to the controllable mechanical properties, degradation behavior, and scaffold morphology. However, the precise in vivo immuno-reactivity of silica-CS hybrids with various compositions is still poorly defined. In this study, we fabricated the three-dimensional (3D) interconnected porous chitosan-silica (CS/SiO 2 ) and chitosan-silica-hydroxyapatite (CS/SiO 2 /HA) hybrids, through sol-gel process and 3D plotting skill, followed by the naturally or freeze drying separately. Scanning electron microscopy demonstrated the hybrids possessed the uniform geometric structure, while, transmission electron microscopy displayed nanoscale silica, or HA nanoparticles dispersed homogeneously in the CS matrix, or CS/silica hybrids. After intramuscular implantation, CS/SiO 2 and CS/SiO 2 /HA hybrids triggered a local and limited monocyte/macrophage infiltration and myofiber degeneration. Naturally dried CS/SiO 2 hybrid provoked a more severe inflammation than the freeze-dried ones. Dendritic cells were attracted to invade into the implants embedded-muscle, but not be activated to prime the adaptive immunity, because the absence of cytotoxic T cells and B cells in muscle received the implants. Fluorescence-activated cell sorting (FACS) analysis indicated the implanted hybrids were incapable to initiate splenocytes activation. Plasma complement C3 enzyme linked immunosorbent assay (ELISA) assay showed the hybrids induced C3 levels increase in early implanting phase, and the subsequent striking decrease. Thus, the present results suggest that, in vivo, 3D plotted porous CS/SiO 2 and CS/SiO 2 /HA hybrids are relatively biocompatible in vivo, which initiate a localized inflammatory procedure, instead of a systematic immune response. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1223-1235, 2018. © 2018 Wiley Periodicals, Inc.

  19. 3D chitosan-gelatin-chondroitin porous scaffold improves osteogenic differentiation of mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Machado, C B [Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil); Ventura, J M G [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Lemos, A F [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Ferreira, J M F [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Leite, M F [Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil); Goes, A M [Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil)

    2007-06-01

    A porous 3D scaffold was developed to support and enhance the differentiation process of mesenchymal stem cells (MSC) into osteoblasts in vitro. The 3D scaffold was made with chitosan, gelatin and chondroitin and it was crosslinked by EDAC. The scaffold physicochemical properties were evaluated. SEM revealed the high porosity and interconnection of pores in the scaffold; rheological measurements show that the scaffold exhibits a characteristic behavior of strong gels. The elastic modulus found in compressive tests of the crosslinked scaffold was about 50 times higher than the non-crosslinked one. After 21 days, the 3D matrix submitted to hydrolytic degradation loses above 40% of its weight. MSC were collected from rat bone marrow and seeded in chitosan-gelatin-chondroitin 3D scaffolds and in 2D culture plates as well. MSC were differentiated into osteoblasts for 21 days. Cell proliferation and alkaline phosphatase activity were followed weekly during the osteogenic process. The osteogenic differentiation of MSC was improved in 3D culture as shown by MTT assay and alkaline phosphatase activity. On the 21st day, bone markers, osteopontin and osteocalcin, were detected by the PCR analysis. This study shows that the chitosan-gelatin-chondroitin 3D structure provides a good environment for the osteogenic process and enhances cellular proliferation.

  20. 3D chitosan-gelatin-chondroitin porous scaffold improves osteogenic differentiation of mesenchymal stem cells.

    Science.gov (United States)

    Machado, C B; Ventura, J M G; Lemos, A F; Ferreira, J M F; Leite, M F; Goes, A M

    2007-06-01

    A porous 3D scaffold was developed to support and enhance the differentiation process of mesenchymal stem cells (MSC) into osteoblasts in vitro. The 3D scaffold was made with chitosan, gelatin and chondroitin and it was crosslinked by EDAC. The scaffold physicochemical properties were evaluated. SEM revealed the high porosity and interconnection of pores in the scaffold; rheological measurements show that the scaffold exhibits a characteristic behavior of strong gels. The elastic modulus found in compressive tests of the crosslinked scaffold was about 50 times higher than the non-crosslinked one. After 21 days, the 3D matrix submitted to hydrolytic degradation loses above 40% of its weight. MSC were collected from rat bone marrow and seeded in chitosan-gelatin-chondroitin 3D scaffolds and in 2D culture plates as well. MSC were differentiated into osteoblasts for 21 days. Cell proliferation and alkaline phosphatase activity were followed weekly during the osteogenic process. The osteogenic differentiation of MSC was improved in 3D culture as shown by MTT assay and alkaline phosphatase activity. On the 21st day, bone markers, osteopontin and osteocalcin, were detected by the PCR analysis. This study shows that the chitosan-gelatin-chondroitin 3D structure provides a good environment for the osteogenic process and enhances cellular proliferation.

  1. 3D chitosan-gelatin-chondroitin porous scaffold improves osteogenic differentiation of mesenchymal stem cells

    International Nuclear Information System (INIS)

    Machado, C B; Ventura, J M G; Lemos, A F; Ferreira, J M F; Leite, M F; Goes, A M

    2007-01-01

    A porous 3D scaffold was developed to support and enhance the differentiation process of mesenchymal stem cells (MSC) into osteoblasts in vitro. The 3D scaffold was made with chitosan, gelatin and chondroitin and it was crosslinked by EDAC. The scaffold physicochemical properties were evaluated. SEM revealed the high porosity and interconnection of pores in the scaffold; rheological measurements show that the scaffold exhibits a characteristic behavior of strong gels. The elastic modulus found in compressive tests of the crosslinked scaffold was about 50 times higher than the non-crosslinked one. After 21 days, the 3D matrix submitted to hydrolytic degradation loses above 40% of its weight. MSC were collected from rat bone marrow and seeded in chitosan-gelatin-chondroitin 3D scaffolds and in 2D culture plates as well. MSC were differentiated into osteoblasts for 21 days. Cell proliferation and alkaline phosphatase activity were followed weekly during the osteogenic process. The osteogenic differentiation of MSC was improved in 3D culture as shown by MTT assay and alkaline phosphatase activity. On the 21st day, bone markers, osteopontin and osteocalcin, were detected by the PCR analysis. This study shows that the chitosan-gelatin-chondroitin 3D structure provides a good environment for the osteogenic process and enhances cellular proliferation

  2. Radiation processing of polysaccharide derivatives

    International Nuclear Information System (INIS)

    Yoshii, Fumio

    2004-01-01

    Carboxymethylcellulose (CMC), carboxymethylstarch (CMS), carboxymethylchitin (CM-chitin) and carboxymethylchitosan (CM-chitosan) form gels when irradiated at paste-like condition. Bedsore prevention mat filled up CMC hydrogel crosslinked by irradiation at paste-like condition was practical applied as a health care products. It was found that CM-chitosan hydrogels have anti-microbial activity and effective as absorbents to remove metal ions. When crosslinked gel sheets of CM-chitin and CM-chitosan were immersed in copper (II) aqueous solution, absorption of Cu (II) were 161 mg/g and 172 mg/g, respectively. Radiation crosslinking of cellulose derivative such as hydroxypropyl methylcellulose phthalate, (HPMCP) kneaded with aqueous alkali solution and methanol was achieved with EB-irradiation at paste-like condition. The HPMCP gel absorbed organic solvents such as chloroform and pyridine. (author)

  3. Effect of moisture and chitosan layered silicate on morphology and properties of chitosan/layered silicates films

    International Nuclear Information System (INIS)

    Silva, J.R.M.B. da; Santos, B.F.F. dos; Leite, I.F.

    2014-01-01

    Thin chitosan films have been for some time an object of practical assessments. However, to obtain biopolymers capable of competing with common polymers a significant improvement in their properties is required. Currently, the technology of obtaining polymer/layered silicates nanocomposites has proven to be a good alternative. This work aims to evaluate the effect of chitosan content (CS) and layered silicates (AN) on the morphology and properties of chitosan/ layered silicate films. CS/AN bionanocomposites were prepared by the intercalation by solution in the proportion 1:1 and 5:1. Then were characterized by infrared spectroscopy (FTIR), diffraction (XRD) and X-ray thermogravimetry (TG). It is expected from the acquisition of films, based on different levels of chitosan and layered silicates, choose the best composition to serve as a matrix for packaging drugs and thus be used for future research. (author)

  4. nanocomposites chitosan /clay for electrochemical sensors

    International Nuclear Information System (INIS)

    Braga, Carla R. Costa; Melo, Frank M. Araujo de; Costa, Gilmara M. Silva; Silva, Suedina M. Lima

    2009-01-01

    This study was performed to obtain films of nanocomposites chitosan/bentonite and chitosan/montmorillonite intercalation by the technique of solution in the proportions of 5:1 and 10:1. The nanocomposites were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and the nanocomposites Chitosan/montmorillonite also were characterized by thermogravimetric analysis (TG). The results indicated that the feasibility of obtaining films of nanocomposites exfoliate. Among the suggested applications for films developed in this study includes them use for electrochemical sensors. (author)

  5. Functional Comparison for Lipid Metabolism and Intestinal and Fecal Microflora Enzyme Activities between Low Molecular Weight Chitosan and Chitosan Oligosaccharide in High-Fat-Diet-Fed Rats.

    Science.gov (United States)

    Chiu, Chen-Yuan; Feng, Shih-An; Liu, Shing-Hwa; Chiang, Meng-Tsan

    2017-07-24

    The present study investigated and compared the regulatory effects on the lipid-related metabolism and intestinal disaccharidase/fecal bacterial enzyme activities between low molecular weight chitosan and chitosan oligosaccharide in high-fat-diet-fed rats. Diet supplementation of low molecular weight chitosan showed greater efficiency than chitosan oligosaccharide in suppressing the increased weights in body and in liver and adipose tissues of high-fat-diet-fed rats. Supplementation of low molecular weight chitosan also showed a greater improvement than chitosan oligosaccharide in imbalance of plasma, hepatic, and fecal lipid profiles, and intestinal disaccharidase activities in high-fat-diet-fed rats. Moreover, both low molecular weight chitosan and chitosan oligosaccharide significantly decreased the fecal microflora mucinase and β-glucuronidase activities in high-fat-diet-fed rats. These results suggest that low molecular weight chitosan exerts a greater positive improvement than chitosan oligosaccharide in lipid metabolism and intestinal disaccharidase activity in high-fat-diet-induced obese rats.

  6. Use of the montmorillonite as crosslink agents for chitosan

    International Nuclear Information System (INIS)

    Barbosa, Rossemberg C.; Lima, Rosemary S. Cunha; Braga, Carla R. Costa; Fook, Marcus V. Lia; Silva, Suedina M. Lima

    2009-01-01

    The montmorillonite (the main constituent of bentonite) has been the most commonly used inorganic load in the formation of nanocomposites chitosan / layered silicate. To evaluate its effect as an agent for the reticulation of chitosan, a sodium montmorillonite, Cloisite Na + , supplied by Southern Clay Products, Texas, USA, was used. For the reticulation of chitosan dispersions of chitosan / Cloisite Na + were prepared in different proportions and the obtained films characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TG). The results indicated that the Cloisite Na + was for efficient and the reticulation of the chitosan and can be used in place of sulfuric acid, which is one of the most common reticulants for chitosan. (author)

  7. Enhancement of Antibacterial activity of Chitosan by gamma irradiation

    International Nuclear Information System (INIS)

    Bashandy, A.S.; Ibrahim, H.M.M.

    2006-01-01

    The antibacterial activity of irradiated and non-irradiated chitosan against E.coli, S.aureus, Salmonella, Strep. fecalis,Closteridium and P. aerugenosa was studied. Up to 1.25 mg/l, chitosan hardly suppressed the growth of all the strains while 3 mg/l of chitosan clearly inhibited the growth of all the studied strains. Therefore, the concentration of 3 mg/l of chitosan in the medium was adopted in this study. Irradiation at 100 KGy under dry conditions was effective in increasing the activity of chitosan and the growth of bacterial strains which was completely inhibited. It was also found that the addition of chitosan to dressing membranes present good barrier properties against microbes especially that irradiated at 100 KGy

  8. Degradation of chlorpyrifos by ionizing radiation

    International Nuclear Information System (INIS)

    Mori, M.N.; Oikawa, H.; Sampa, M.H.O.; Duarte, C.L.

    2006-01-01

    Chlorpyrifos is an organophosphate pesticide commercialized since 1965 and it is now one of the top five commercial insecticides. It is registered for use in over 900 different pesticide formulations in the world. Chlorpyrifos poisoning usually affects many organs of the body, such as the central and peripheral nervous system, eyes, respiratory system, and the digestive tract. Depending on the pesticide formulation and type of application, chlorpyrifos residues may be detectable in water, soil, and on the surfaces from months to years. This paper presents preliminary studies of the removal of chlorpyrifos by exposition to ionizing radiation, to be applied in pesticide container decontamination. Samples containing various concentrations of chlorpyrifos in acetonitrile were irradiated with absorbed doses varying from 5 to 50 kGy, using a 60 Co gamma-source with 5,000 Ci activity (Gamma cell type). The chemical analysis of the chlorpyrifos and the by-products resulted from the radiolytic degradation were made using a gas chromatography associated to mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GCFID). (author)

  9. Study of the separation of fluoroquinolones using HPLC: Application to the study of their degradation by gamma radiation

    International Nuclear Information System (INIS)

    Ben Saad, Latifa

    2013-01-01

    A method of high performance liquid chromatography (HPLC) in reverse phase was developed for the separation of a mixture of five fluoroquinolones (lomefloxacin, ciprofloxacin, levofloxacin, enoxacin and enrofloxacin). The optimum operating conditions are: the wavelength of detection is fixed at 282nm DAD detector, the stationary phase consists of silica type X scratched Terra RP-18 (250mm x 4, 6 mm, 5μm) and the mobile phase consisted of acetonitrile and phosphate buffer (0.02 M) (20: 80 v: v), pH equal to flow rate of 1ml/M/Xin 3etde. This optimized method was applied to analyze the solutions of different concentrations of each fluoroquinolone (100 and 20 ppm) after irradiation with doses of gamma radiation (5 and 25 kGry). The study of the effect of such radiation on fluoroquinolones shows that with a dose of 5 kGry these radiations allow complete degradation of these active ingredients at a concentration of 20 ppm and the appearance of other degradation products. But a dose of 5 kGry is insufficient to degrade the active ingredients (100ppm).

  10. Thiolated chitosans: useful excipients for oral drug delivery.

    Science.gov (United States)

    Werle, Martin; Bernkop-Schnürch, Andreas

    2008-03-01

    To improve the bioavailability of orally administered drugs, formulations based on polymers are of great interest for pharmaceutical technologists. Thiolated chitosans are multifunctional polymers that exhibit improved mucoadhesive, cohesive and permeation-enhancing as well as efflux-pump-inhibitory properties. They can be synthesized by derivatization of the primary amino groups of chitosan with coupling reagents bearing thiol functions. Various data gained in-vitro as well as in-vivo studies clearly demonstrate the potential of thiolated chitosans for oral drug delivery. Within the current review, the synthesis and characterization of thiolated chitosans so far developed is summarized. Features of thiolated chitosans important for oral drug delivery are discussed as well. Moreover, different formulation approaches, such as matrix tablets and micro-/nanoparticles, as well as the applicability of thiolated chitosans for the oral delivery of various substance classes including peptides and efflux pump substrates, are highlighted.

  11. Synthesize and Characterization of Hydroxypropyl-N-octanealkyl Chitosan Ramification

    Science.gov (United States)

    Tan, Fu-neng

    2018-03-01

    A new type of amphiphilic ramification, hydroxypropyl-N-octanealkyl chitosan was prepared from chitosan via hydrophilic group and hydrophobic group were introduced. We could protect the amino group of chitosan via the reaction of chitosan and benzaldehyde could get Schiff base structure. Structures of the products were characterized with FT-IR, elemental analysis, themogrammetry (TG) analysis and X-ray diffraction. The degree of substitution of hydrophobic group was studied by elemental analysis. The result showed this chitosan ramification was soluble, biocompatible, biodegradable and nontoxic.

  12. Rapidly photo-cross-linkable chitosan hydrogel for peripheral neurosurgeries.

    Science.gov (United States)

    Rickett, Todd A; Amoozgar, Zohreh; Tuchek, Chad A; Park, Joonyoung; Yeo, Yoon; Shi, Riyi

    2011-01-10

    Restoring continuity to severed peripheral nerves is crucial to regeneration and enables functional recovery. However, the two most common agents for coaptation, sutures and fibrin glues, have drawbacks such as inflammation, pathogenesis, and dehiscence. Chitosan-based adhesives are a promising alternative, reported to have good cytocompatibility and favorable immunogenicity. A photo-cross-linkable hydrogel based on chitosan is proposed as a new adhesive for peripheral nerve anastomosis. Two Az-chitosans were synthesized by conjugating 4-azidobenzoic acid with low (LMW, 15 kDa) and high (HMW, 50-190 kDa) molecular weight chitosans. These solutions formed a hydrogel in less than 1 min under UV light. The LMW Az-chitosan was more tightly cross-linked than the HMW variant, undergoing significantly less swelling and possessing a higher rheological storage modulus, and both Az-chitosan gels were stiffer than commercial fibrin glue. Severed nerves repaired by Az-chitosan adhesives tolerated longitudinal forces comparable or superior to fibrin glue. Adhesive exposure to intact nerves and neural cell culture showed both Az-chitosans to be nontoxic in the acute (minutes) and chronic (days) time frames. These results demonstrate that Az-chitosan hydrogels are cytocompatible and mechanically suitable for use as bioadhesives in peripheral neurosurgeries.

  13. Poly(D,L-Lactide-Co-Glycolide) Tubes With Multifilament Chitosan Yarn or Chitosan Sponge Core in Nerve Regeneration.

    Science.gov (United States)

    Wlaszczuk, Adam; Marcol, Wiesław; Kucharska, Magdalena; Wawro, Dariusz; Palen, Piotr; Lewin-Kowalik, Joanna

    2016-11-01

    The influence of different kinds of nerve guidance conduits on regeneration of totally transected rat sciatic nerves through a 7-mm gap was examined. Five different types of conduits made of chitosan and poly(D,L-lactide-co-glycolide) (PLGA) were constructed and tested in vivo. We divided 50 animals into equal groups of 10, with a different type of conduit implanted in each group: chitosan sponge core with an average molecular mass of polymer (Mv) of 287 kDa with 7 channels in a PLGA sleeve, chitosan sponge core with an Mv of 423 kDa with 7 channels in a PLGA sleeve, chitosan sponge core (Mv, 423 kDa) with 13 channels in a PLGA sleeve, chitosan multifilament yarn in a PLGA sleeve, and a PLGA sleeve only. Seven weeks after the operation, we examined the distance covered by regenerating nerve fibers, growing of nerves into the conduit's core, and intensity and type of inflammatory reaction in the conduit, as well as autotomy behavior (reflecting neuropathic pain intensity) in the animals. Two types of conduits were allowing nerve outgrowth through the gap with minor autotomy and minor inflammatory reactions. These were the conduits with chitosan multifilament yarn in a PLGA sleeve and the conduits with 13-channel microcrystalline chitosan sponge in a PLGA sleeve. The type of chitosan used to build the nerve guidance conduit influences the intensity and character of inflammatory reaction present during nerve regeneration, which in turn affects the distance crossed by regenerating nerve fibers, growing of the nerve fibers into the conduit's core, and the intensity of autotomy in the animals. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Preparation and characterization of composites based on the blends of collagen, chitosan and hyaluronic acid with nano-hydroxyapatite.

    Science.gov (United States)

    Sionkowska, Alina; Kaczmarek, Beata

    2017-09-01

    3D porous composites based on the blend of chitosan, collagen and hyaluronic acid with the addition of nano-hydroxyapatite were prepared. SEM images for the composites were made and the structure was assessed. Mechanical properties were studied using a Zwick&Roell Testing Mashine. In addition, the porosity and density of composites were measured. The concentration of calcium ions released from the material was detected by the complexometric titration method. The results showed that in 3D porous sponge based on the blend of chitosan, collagen and hyaluronic acid, inorganic particles of nanohydroxyapatite can be incorporated, as well as that the properties of 3D composites depend on the material composition. Mechanical parameters and thermal stability of ternary biopolymeric blends were improved by the addition of hydroxyapatite. Moreover, the porosity of ternary materials was higher than in materials based on pure chitosan or collagen. All composites were characterized by a porous structure with interconnected pores. Calcium ions can be released from the composite during its degradation in water. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Chitosan derivatives with antimicrobial, antitumour and antioxidant activities--a review.

    Science.gov (United States)

    Jarmila, Vinsová; Vavríková, Eva

    2011-01-01

    Chitosan is a linear polysaccharide with a good biodegradability, biocompatibility, and no toxicity, which provide it with huge potential for future development. The chitosan molecule appears to be a suitable polymeric complex for many biomedical applications. This review gathers current findings on the antibacterial, antifungal, antitumour and antioxidant activities of chitosan derivatives and concurs with our previous review presenting data collected up to 2008. Antibacterial activity is based on molecular weight, the degree of deacetylation, the type of substitutents, which can be cationic or easily form cations, and the type of bacterium. In general, high molecular weight chitosan cannot pass through cell membranes and forms a film that protects cells against nutrient transport through the microbial cell membrane. Low molecular weight chitosan derivatives are water soluble and can better incorporate the active molecule into the cell. Gram-negative bacteria, often represented by Escherichia coli, have an anionic bacterial surface on which cationic chitosan derivatives interact electrostatically. Thus, many chitosan conjugates have cationic components such as ammonium, pyridinium or piperazinium substituents introduced into their molecules to increase their positive charge. Gram-positive bacteria like Staphylococcus aureus are inhibited by the binding of lower molecular weight chitosan derivatives to DNA or RNA. Chitosan nanoparticles exhibit an increase in loading capacity and efficacy. Antitumour active compounds such as doxorubicin, paclitaxel, docetaxel and norcantharidin are used as drug carriers. It is evident that chitosan, with its low molecular weight, is a useful carrier for molecular drugs requiring targeted delivery. The antioxidant scavenging activity of chitosan has been established by the strong hydrogen-donating ability of chitosan. The low molecular weight and greater degree of quarternization have a positive influence on the antioxidant activity

  16. Phytase-mediated enzymatic mineralization of chitosan-enriched hydrogels

    DEFF Research Database (Denmark)

    Lišková, Jana; Douglas, Timothy E.L.; Wijnants, Robbe

    2018-01-01

    Hydrogels mineralized with calcium phosphate (CaP) are increasingly popular bone regeneration biomaterials. Mineralization can be achieved by phosphatase enzyme incorporation and incubation in calcium glycerophosphate (CaGP). Gellan gum (GG) hydrogels containing the enzyme phytase and chitosan...... oligomer were mineralized in CaGP solution and characterized with human osteoblast-like MG63 cells and adipose tissue-derived stem cells (ADSC). Phytase induced CaP formation. Chitosan concentration determined mineralization extent and hydrogel mechanical reinforcement. Phytase-induced mineralization...... promoted MG63 adhesion and proliferation, especially in the presence of chitosan, and was non-toxic to MG63 cells (with and without chitosan). ADSC adhesion and proliferation were poor without mineralization. Chitosan did not affect ADSC osteogenic differentiation....

  17. Synthesis of (2-pyridyl)-Acetyl Chitosan and Its Antioxidant Activity

    International Nuclear Information System (INIS)

    Li, Rongchun

    2011-01-01

    In this paper, chloracetyl chitosan (CACTS) was prepared at first. In the molecules of CACTS, there are active chlorine groups, which can take part in other reactions. Thus, number of chitosan derivatives will be obtained after chlorine is substituted. Choosing pyridine as the active group, a novel water-soluble chitosan derivative, (2-pyridyl)-acetyl chitosan (PACTS) was obtained and its antioxidant activity against hydroxyl radicals and superoxide radicals was assessed. The results indicated that PACTS had better antioxidant activity than that of chitosan, carboxymethyl chitosan (CMCTS), hydroxypropyl chitosan (HPCTS), and Vitamin C. And the IC 50 values against hydroxyl radicals and superoxide radicals were 0.31 mg/mL and 0.21 mg/mL, respectively

  18. Preparation and characterization of magnetic chitosan particles for hyperthermia application

    International Nuclear Information System (INIS)

    Park, Ji-Ho; Im, Ki-Hyeong; Lee, Se-Ho; Kim, Dong-Hyun; Lee, Doug-Youn; Lee, Yong-Keun; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2005-01-01

    The size and shape of magnetic chitosan particles were found to be dependent on both the barium ferrite/chitosan (BF/C) ratio and viscosity of a chitosan solution. The saturation magnetization of magnetic chitosan particles varied directly with the BF/C ratio, while coercivity remained almost constant. Notably, incorporated chitosan was shown to exert substantial activity with regard to low cytotoxicity and high heating rate

  19. Overview of the Activities on Radiation Processing of Polymeric Materials in Bangladesh. Chapter 4

    Energy Technology Data Exchange (ETDEWEB)

    Haque, M.; Dafader, N. C.; Sultana, S.; Mollah, M. Z.I. [Nuclear and Radiation Chemistry Division, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Savar, Dhaka (Bangladesh); Mandal, M. M.A. [Crop Physiology Division, Bangladesh Institute of Nuclear Agriculture, BAU Campus, Mymensingh (Bangladesh)

    2014-07-15

    Natural polymers processed through radiation are used in agriculture, health care, and environmental protection. The process of chitosan extraction from prawn/shrimp shells has been established. The method used in determining the molecular weight of chitosan had previously been standardized during the harmonization program of protocol for molecular weight determination organized by IAEA in cooperation with Poland and UK during which Bangladesh was a participant. Increased yield of several crops over the control was achieved using chitosan as plant growth promoter: up to 13% for rice when chitosan with 50 ppm concentration was applied two times, up to 56% for summer tomato when chitosan with a concentration of 75 ppm was sprayed one time, up to 30% for mungbean when 50 ppm chitosan was applied two times, and up to 24% for maize when 100 ppm chitosan was applied three times. Field tests covering three seasons to confirm any increase in the yield of tomato and maize are still being conducted. Funding from the CRP helped carry out these activities to a great extent. Through the IAEA TC project, radiation processing laboratories were enhanced with new equipment, chemicals/monomers/polymers, and the capability of staff members was improved through additional training, expert assistance and scientific visits. One PhD student and several MSc students were able to complete their theses and had them published. Super Water Absorbent (SWA) hydrogel was prepared using 5%Acrylamide blended with 3% carboxymethyl cellulose (CMC) and irradiating at 25 kGy. It was applied on tomato plants as soil conditioner and positive results were obtained. Government funding aided in the establishment of a pilot plant that eventually became a full-fledged institute for radiation processing. (author)

  20. Rheological study of chitosan in solution

    International Nuclear Information System (INIS)

    Silva, Italo Guimaraes Medeiros da; Alves, Keila dos Santos; Balaban, Rosangela de Carvalho

    2009-01-01

    Chitosan is an abundant biopolymer with remarkable physicochemical and biological properties, usually employed in a wide range of applications. It acts as a cationic polyelectrolyte in aqueous acid solutions, leading to unique characteristics. In this work, chitosan was characterized by 1 H NMR and its rheological behavior were studied as function of chitosan sample, shear rate, polymer concentration, ionic strength, time and temperature. In order to calculate rheological parameters and to understand the macromolecular dynamic in solution, the Otswald-de Waele model was fitted. (author)

  1. Chitosan in Mucoadhesive Drug Delivery: Focus on Local Vaginal Therapy

    Directory of Open Access Journals (Sweden)

    Toril Andersen

    2015-01-01

    Full Text Available Mucoadhesive drug therapy destined for localized drug treatment is gaining increasing importance in today’s drug development. Chitosan, due to its known biodegradability, bioadhesiveness and excellent safety profile offers means to improve mucosal drug therapy. We have used chitosan as mucoadhesive polymer to develop liposomes able to ensure prolonged residence time at vaginal site. Two types of mucoadhesive liposomes, namely the chitosan-coated liposomes and chitosan-containing liposomes, where chitosan is both embedded and surface-available, were made of soy phosphatidylcholine with entrapped fluorescence markers of two molecular weights, FITC-dextran 4000 and 20,000, respectively. Both liposomal types were characterized for their size distribution, zeta potential, entrapment efficiency and the in vitro release profile, and compared to plain liposomes. The proof of chitosan being both surface-available as well as embedded into the liposomes in the chitosan-containing liposomes was found. The capability of the surface-available chitosan to interact with the model porcine mucin was confirmed for both chitosan-containing and chitosan-coated liposomes implying potential mucoadhesive behavior. Chitosan-containing liposomes were shown to be superior in respect to the simplicity of preparation, FITC-dextran load, mucoadhesiveness and in vitro release and are expected to ensure prolonged residence time on the vaginal mucosa providing localized sustained release of entrapped model substances.

  2. Chitosan-thioglycolic acid as a versatile antimicrobial agent.

    Science.gov (United States)

    Geisberger, Georg; Gyenge, Emina Besic; Hinger, Doris; Käch, Andres; Maake, Caroline; Patzke, Greta R

    2013-04-08

    As functionalized chitosans hold great potential for the development of effective and broad-spectrum antibiotics, representative chitosan derivatives were tested for antimicrobial activity in neutral media: trimethyl chitosan (TMC), carboxy-methyl chitosan (CMC), and chitosan-thioglycolic acid (TGA; medium molecular weight: MMW-TGA; low molecular weight: LMW-TGA). Colony forming assays indicated that LMW-TGA displayed superior antimicrobial activity over the other derivatives tested: a 30 min incubation killed 100% Streptococcus sobrinus (Gram-positive bacteria) and reduced colony counts by 99.99% in Neisseria subflava (Gram-negative bacteria) and 99.97% in Candida albicans (fungi). To elucidate LMW-TGA effects at the cellular level, microscopic studies were performed. Use of fluorescein isothiocyanate (FITC)-labeled chitosan derivates in confocal microscopy showed that LMW-TGA attaches to microbial cell walls, while transmission electron microscopy indicated that this derivative severely affects cell wall integrity and intracellular ultrastructure in all species tested. We therefore propose LMW-TGA as a promising and effective broad-band antimicrobial compound.

  3. Degrees of chitosan deacetylation from white shrimp shell waste as dental biomaterials

    Directory of Open Access Journals (Sweden)

    Sularsih Sularsih

    2012-03-01

    Full Text Available Background: Chitosan is biomaterial improved for various dentistry applications because it is biocompatible, degradable, nontoxic, and not carcinogenic. The main parameter affecting the characteristics of chitosan is deacetylation degree. Purpose: This study is aimed to determine the degree of deacetylated of chitosan derived from white shrimp shell waste used as dental biomaterial. Methods: White shrimp shells were crushed into powder. Next, deproteination process was conducted with 3.5% NaOH solution, demineralized with 1N HCl solution, and then depigmented with 90% acetone solution into chitin powder. Deacetylation process was then conducted by soaking the chitin powder in 50% NaOH solution for 6 h at 65° C to produce white powder of chitosan. Afterwards, deacetylation degree test was conducted by using Fourier Transform Infrared Spectrophotometer (FTIR to calculate the ratio of the absorption bands between the absorbance peak of amide group about 1655 cm–1 and the absorbance peak of hydroxyl group about 3450 cm–1. Results: The result of the deacetylation degree test on the chitosan powder derived from white shrimp shell waste was high, about 85.165%, and had the eligible form, solubility, and pH. Conclusion: It can be concluded that the deacetylation degree of chitosan from white shrimp shells could reach 85.165%.Latar belakang: Kitosan merupakan biomaterial yang dikembangkan untuk berbagai aplikasi kedokteran gigi karena biokompatibel, dapat didegradasi, tidak toksik dan tidak karsinogenik. Parameter utama yang mempengaruhi karakteristik kitosan adalah derajat deasetilasi. Tujuan: Tujuan dari penelitian ini adalah mengetahui derajat deasetilasi kitosan dari limbah kulit udang putih sebagai biomaterial kedokteran gigi. Metode: Kulit udang putih dihaluskan menjadi serbuk. Setelah itu dilakukan proses deproteinasi dengan larutan NaOH 3,5%, demineralisasi dengan larutan HCl 1N, depigmentasi dengan larutan aseton 90% sehingga menjadi serbuk

  4. Probing cellular behaviors through nanopatterned chitosan membranes

    International Nuclear Information System (INIS)

    Yang, Chung-Yao; Sung, Chun-Yen; Shuai, Hung-Hsun; Cheng, Chao-Min; Yeh, J Andrew

    2013-01-01

    This paper describes a high-throughput method for developing physically modified chitosan membranes to probe the cellular behavior of MDCK epithelial cells and HIG-82 fibroblasts adhered onto these modified membranes. To prepare chitosan membranes with micro/nanoscaled features, we have demonstrated an easy-to-handle, facile approach that could be easily integrated with IC-based manufacturing processes with mass production potential. These physically modified chitosan membranes were observed by scanning electron microscopy to gain a better understanding of chitosan membrane surface morphology. After MDCK cells and HIG-82 fibroblasts were cultured on these modified chitosan membranes for various culture durations (i.e. 1, 2, 4, 12 and 24 h), they were investigated to decipher cellular behavior. We found that both cells preferred to adhere onto a flat surface rather than on a nanopatterned surface. However, most (> 80%) of the MDCK cells showed rounded morphology and would suspend in the cultured medium instead of adhering onto the planar surface of negatively nanopatterned chitosan membranes. This means different cell types (e.g. fibroblasts versus epithelia) showed distinct capabilities/preferences of adherence for materials of varying surface roughness. We also showed that chitosan membranes could be re-used at least nine times without significant contamination and would provide us consistency for probing cell–material interactions by permitting reuse of the same substrate. We believe these results would provide us better insight into cellular behavior, specifically, microscopic properties and characteristics of cells grown under unique, nanopatterned cell-interface conditions. (paper)

  5. Properties of Chitosan-Laminated Collagen Film

    Directory of Open Access Journals (Sweden)

    Vera Lazić

    2012-01-01

    Full Text Available The objective of this study is to determine physical, mechanical and barrier properties of chitosan-laminated collagen film. Commercial collagen film, which is used for making collagen casings for dry fermented sausage production, was laminated with chitosan film layer in order to improve the collagen film barrier properties. Different volumes of oregano essential oil per 100 mL of filmogenic solution were added to chitosan film layer: 0, 0.2, 0.4, 0.6 and 0.8 mL to optimize water vapour barrier properties. Chitosan layer with 0.6 or 0.8 % of oregano essential oil lowered the water vapour transmission rate to (1.85±0.10·10–6 and (1.78±0.03·10–6 g/(m2·s·Pa respectively, compared to collagen film ((2.51±0.05·10–6 g/(m2·s·Pa. However, chitosan-laminated collagen film did not show improved mechanical properties compared to the collagen one. Tensile strength decreased from (54.0±3.8 MPa of the uncoated collagen film to (36.3±4.0 MPa when the film was laminated with 0.8 % oregano essential oil chitosan layer. Elongation at break values of laminated films did not differ from those of collagen film ((18.4±2.7 %. Oxygen barrier properties were considerably improved by lamination. Oxygen permeability of collagen film was (1806.8±628.0·10–14 cm3/(m·s·Pa and values of laminated films were below 35·10–14 cm3/(m·s·Pa. Regarding film appearance and colour, lamination with chitosan reduced lightness (L and yellowness (+b of collagen film, while film redness (+a increased. These changes were not visible to the naked eye.

  6. Photocrosslinkable chitosan as a biological adhesive.

    Science.gov (United States)

    Ono, K; Saito, Y; Yura, H; Ishikawa, K; Kurita, A; Akaike, T; Ishihara, M

    2000-02-01

    A photocrosslinkable chitosan to which both azide and lactose moieties were introduced (Az-CH-LA) was prepared as a biological adhesive for soft tissues and its effectiveness was compared with that of fibrin glue. Introduction of the lactose moieties resulted in a much more water-soluble chitosan at neutral pH. Application of ultraviolet light (UV) irradiation to photocrosslinkable Az-CH-LA produced an insoluble hydrogel within 60 s. This hydrogel firmly adhered two pieces of sliced ham with each other, depending upon the Az-CH-LA concentration. The binding strength of the chitosan hydrogel prepared from 30-50 mg/mL of Az-CH-LA was similar to that of fibrin glue. Compared to the fibrin glue, the chitosan hydrogel more effectively sealed air leakage from pinholes on isolated small intestine and aorta and from incisions on isolated trachea. Neither Az-CH-LA nor its hydrogel showed any cytotoxicity in cell culture tests of human skin fibroblasts, coronary endothelial cells, and smooth muscle cells. Furthermore, all mice studied survived for at least 1 month after implantation of 200 microL of photocrosslinked chitosan gel and intraperitoneal administration of up to 1 mL of 30 mg/mL of Az-CH-LA solution. These results suggest that the photocrosslinkable chitosan developed here has the potential of serving as a new tissue adhesive in medical use. Copyright 2000 John Wiley & Sons, Inc.

  7. Vitamin D-fortified chitosan films from mushroom waste

    Science.gov (United States)

    Brown mushroom (Agaricus bisporus) stalk bases from mushroom waste were treated with UV-B light to rapidly increase vitamin D2 content. Chitin was also recovered from this waste and converted into chitosan by N-deacetylation. FTIR spectra showed that the mushroom chitosan were similar to chitosan fr...

  8. Nuclear Radiation Degradation Study on HD Camera Based on CMOS Image Sensor at Different Dose Rates

    Directory of Open Access Journals (Sweden)

    Congzheng Wang

    2018-02-01

    Full Text Available In this work, we irradiated a high-definition (HD industrial camera based on a commercial-off-the-shelf (COTS CMOS image sensor (CIS with Cobalt-60 gamma-rays. All components of the camera under test were fabricated without radiation hardening, except for the lens. The irradiation experiments of the HD camera under biased conditions were carried out at 1.0, 10.0, 20.0, 50.0 and 100.0 Gy/h. During the experiment, we found that the tested camera showed a remarkable degradation after irradiation and differed in the dose rates. With the increase of dose rate, the same target images become brighter. Under the same dose rate, the radiation effect in bright area is lower than that in dark area. Under different dose rates, the higher the dose rate is, the worse the radiation effect will be in both bright and dark areas. And the standard deviations of bright and dark areas become greater. Furthermore, through the progressive degradation analysis of the captured image, experimental results demonstrate that the attenuation of signal to noise ratio (SNR versus radiation time is not obvious at the same dose rate, and the degradation is more and more serious with increasing dose rate. Additionally, the decrease rate of SNR at 20.0, 50.0 and 100.0 Gy/h is far greater than that at 1.0 and 10.0 Gy/h. Even so, we confirm that the HD industrial camera is still working at 10.0 Gy/h during the 8 h of measurements, with a moderate decrease of the SNR (5 dB. The work is valuable and can provide suggestion for camera users in the radiation field.

  9. Controlling chitosan-based encapsulation for protein and vaccine delivery

    Science.gov (United States)

    Koppolu, Bhanu prasanth; Smith, Sean G.; Ravindranathan, Sruthi; Jayanthi, Srinivas; Kumar, Thallapuranam K.S.; Zaharoff, David A.

    2014-01-01

    Chitosan-based nano/microencapsulation is under increasing investigation for the delivery of drugs, biologics and vaccines. Despite widespread interest, the literature lacks a defined methodology to control chitosan particle size and drug/protein release kinetics. In this study, the effects of precipitation-coacervation formulation parameters on chitosan particle size, protein encapsulation efficiency and protein release were investigated. Chitosan particle sizes, which ranged from 300 nm to 3 μm, were influenced by chitosan concentration, chitosan molecular weight and addition rate of precipitant salt. The composition of precipitant salt played a significant role in particle formation with upper Hofmeister series salts containing strongly hydrated anions yielding particles with a low polydispersity index (PDI) while weaker anions resulted in aggregated particles with high PDIs. Sonication power had minimal effect on mean particle size, however, it significantly reduced polydispersity. Protein loading efficiencies in chitosan nano/microparticles, which ranged from 14.3% to 99.2%, was inversely related to the hydration strength of precipitant salts, protein molecular weight and directly related to the concentration and molecular weight of chitosan. Protein release rates increased with particle size and were generally inversely related to protein molecular weight. This study demonstrates that chitosan nano/microparticles with high protein loading efficiencies can be engineered with well-defined sizes and controllable release kinetics through manipulation of specific formulation parameters. PMID:24560459

  10. Surface modification of protein enhances encapsulation in chitosan nanoparticles

    Science.gov (United States)

    Koyani, Rina D.; Andrade, Mariana; Quester, Katrin; Gaytán, Paul; Huerta-Saquero, Alejandro; Vazquez-Duhalt, Rafael

    2018-04-01

    Chitosan nanoparticles have a huge potential as nanocarriers for environmental and biomedical purposes. Protein encapsulation in nano-sized chitosan provides protection against inactivation, proteolysis, and other alterations due to environmental conditions, as well as the possibility to be targeted to specific tissues by ligand functionalization. In this work, we demonstrate that the chemical modification of the protein surface enhances the protein loading in chitosan nanocarriers. Encapsulation of green fluorescent protein and the cytochrome P450 was studied. The increase of electrostatic interactions between the free amino groups of chitosan and the increased number of free carboxylic groups in the protein surface enhance the protein loading, protein retention, and, thus, the enzymatic activity of chitosan nanoparticles. The chemical modification of protein surface with malonic acid moieties reduced drastically the protein isoelectric point increasing the protein interaction with the polycationic biomaterial and chitosan. The chemical modification of protein does not alter the morphology of chitosan nanoparticles that showed an average diameter of 18 nm, spheroidal in shape, and smooth surfaced. The strategy of chemical modification of protein surface, shown here, is a simple and efficient technique to enhance the protein loading in chitosan nanoparticles. This technique could be used for other nanoparticles based on polycationic or polyanionic materials. The increase of protein loading improves, doubtless, the performance of protein-loaded chitosan nanoparticles for biotechnological and biomedical applications.

  11. Chitosan: collagen sponges. In vitro mineralization

    International Nuclear Information System (INIS)

    Martins, Virginia da C.A.; Silva, Gustavo M.; Plepis, Ana Maria G.

    2011-01-01

    The regeneration of bone tissue is a problem that affects many people and scaffolds for bone tissue growth has been widely studied. The aim of this study was the in vitro mineralization of chitosan, chitosan:native collagen and chitosan:anionic collagen sponges. The sponges were obtained by lyophilization and mineralization was made by soaking the sponges in alternating solutions containing Ca 2+ and PO 4 3- . The mineralization was confirmed by infrared spectroscopy, energy dispersive X-ray and X-ray diffraction observing the formation of phosphate salts, possibly a carbonated hydroxyapatite since Ca/P=1.80. The degree of mineralization was obtained by thermogravimetry calculating the amount of residue at 750 deg C. The chitosan:anionic collagen sponge showed the highest degree of mineralization probably due to the fact that anionic collagen provides additional sites for interaction with the inorganic phase. (author)

  12. SOLID-STATE FERMENTATIVE PRODUCTION AND BIOACTIVITY OF FUNGAL CHITOSAN

    Directory of Open Access Journals (Sweden)

    Barry Aigbodion Omogbai

    2013-10-01

    Full Text Available Chitosan production was investigated using a laboratory-scale solid substrate fermentation (SSF technique with four species of fungi: Penicillium expansum, Aspergillus niger, Rhizopus oryzae and Fusarium moniliforme.The peak growth for the organisms was after 16 days. Aspergillus niger had the highest growth with a maximal dry cell biomass of 15.8g/kg after 16 days cultivation on corn straw under solid substrate fermentation. This was closely followed by Rhizopus oryzae (14.6g/kg, Penicillium expansum (13.8g/kg and Fusarium moniliforme (10.6g/kg respectively. The fungus Rhizopus oryzae had the highest chitosan production with a maximum of 8.57g/kg in 16 days under solid substrate fermentation (SSF with a medium containing corn straw. Aspergillus niger showed a modest chitosan yield of 6.8g/kg. Penicillium expansum and Fusarium moniliforme had low chitosan yields of 4.31g/kg and 3.1g/kg respectively. The degree of deacetylation of fungal chitosans ranged between 75.3-91.5% with a viscosity of 3.6-7.2 centipoises (Cp.Chitosan extracted from Rhizopus oryzae was found to have antibacterial activity on some bacterial isolates. At a concentration of 50mg/L, Rhizopus oryzae chitosan paralleled crab chitosan in susceptibility testing against some food-borne bacterial pathogens. Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and Bacillus subtilis showed inhibition rates of 83.2%, 67.9%, 63.8% and 62.4% respectively in response to 50mg/l Rhizopus oryzae chitosan in 24 h. The rate of inhibition (% increased with increase in chitosan concentration.

  13. Chitosan-based nanocarriers for antimalarials

    Science.gov (United States)

    Dreve, Simina; Kacso, Iren; Popa, Adriana; Raita, Oana; Bende, A.; Borodi, Gh.; Bratu, I.

    2012-02-01

    The objective of this research was to synthesize and characterize chitosan-based liquid and solid materials with unique absorptive and mechanical properties as carriers for quinine - one of the most used antimalarial drug. The use of chitosan (CTS) as base in polyelectrolyte complex systems, to prepare solid release systems as sponges is presented. The preparation by double emulsification of CTS hydrogels carrying quinine as anti-malarial drug is reported. The concentration of quinine in the CTS hydrogel was 0.08 mmol. Chitosan - drug loaded hydrogel was used to generate solid sponges by freeze-drying at -610°C and 0.09 atm. Structural investigations of the solid formulations were done by Fourier-transformed infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-VIS), spectrofluorimetry, differential scanning calorimetry (DSC) and X-ray diffractometry. The results indicated that the drug molecule is forming temporary chelates in CTS hydrogels and sponges. Electron paramagnetic resonance (EPR) demonstrates the presence of free radicals in a wide range and the antioxidant activity for chitosan - drug supramolecular cross-linked assemblies.

  14. Electrophoretic deposition of composite hydroxyapatite-chitosan coatings

    International Nuclear Information System (INIS)

    Pang Xin; Zhitomirsky, Igor

    2007-01-01

    Cathodic electrophoretic deposition has been utilized for the fabrication of composite hydroxyapatite-chitosan coatings on 316L stainless steel substrates. The addition of chitosan to the hydroxyapatite suspensions promoted the electrophoretic deposition of the hydroxyapatite nanoparticles and resulted in the formation of composite coatings. The obtained coatings were investigated by X-ray diffraction, thermogravimetric and differential thermal analysis, scanning and transmission electron microscopy, potentiodynamic polarization measurements, and electrochemical impedance spectroscopy. It was shown that the deposit composition can be changed by a variation of the chitosan or hydroxyapatite concentration in the solutions. Experimental conditions were developed for the fabrication of hydroxyapatite-chitosan nanocomposites containing 40.9-89.8 wt.% hydroxyapatite. The method enabled the formation of adherent and uniform coatings of thicknesses up to 60 μm. X-ray studies revealed that the preferred orientation of the hydroxyapatite nanoparticles in the chitosan matrix increases with decreasing hydroxyapatite content in the composite coatings. The obtained coatings provided the corrosion protection for the 316L stainless steel substrates

  15. Chitosan magnetic nanoparticles for drug delivery systems.

    Science.gov (United States)

    Assa, Farnaz; Jafarizadeh-Malmiri, Hoda; Ajamein, Hossein; Vaghari, Hamideh; Anarjan, Navideh; Ahmadi, Omid; Berenjian, Aydin

    2017-06-01

    The potential of magnetic nanoparticles (MNPs) in drug delivery systems (DDSs) is mainly related to its magnetic core and surface coating. These coatings can eliminate or minimize their aggregation under physiological conditions. Also, they can provide functional groups for bioconjugation to anticancer drugs and/or targeted ligands. Chitosan, as a derivative of chitin, is an attractive natural biopolymer from renewable resources with the presence of reactive amino and hydroxyl functional groups in its structure. Chitosan nanoparticles (NPs), due to their huge surface to volume ratio as compared to the chitosan in its bulk form, have outstanding physico-chemical, antimicrobial and biological properties. These unique properties make chitosan NPs a promising biopolymer for the application of DDSs. In this review, the current state and challenges for the application magnetic chitosan NPs in drug delivery systems were investigated. The present review also revisits the limitations and commercial impediments to provide insight for future works.

  16. Chitosan/bentonite bionanocomposites: morphology and mechanical behavior

    International Nuclear Information System (INIS)

    Braga, C.R.C.; Melo, F.M.A. de; Vitorino, I.F.; Fook, M.V.L.; Silva, S.M.L.

    2010-01-01

    This study chitosan/bentonite bionanocomposite films were prepared by solution intercalation process, seeking to investigate the effect of the chitosan/bentonite ratio (5/1 e 10/1) on the morphology and mechanical behavior of the bionanocomposites. It was used as nanophase, Argel sodium bentonite (AN), was provided by Bentonit Uniao Nordeste-BUN (Campina Grande, Brazil) and as biopolymer matrix the chitosan of low molecular weight and degree of deacetylation of 86,7% was supplied by Polymar (Fortaleza, Brazil). The bionanocomposites was investigated by X-ray diffraction and tensile properties. According to the results, the morphology and the mechanical behavior of the bionanocomposite was affected by the ratio of chitosan/bentonite. The chitosan/bentonite ratio (5/1 and 10/1) indicated the formation of an intercalated nanostructure and of the predominantly exfoliated nanostructure, respectively. And the considerable increases in the resistance to the traction were observed mainly for the bionanocomposite with predominantly exfoliated morphology. (author)

  17. Preparation of gold/carboxymethyl chitosan nanoparticles by radiation technique for application as an antioxidant

    International Nuclear Information System (INIS)

    Le Quang Luan; Nguyen Thanh Long; Nguyen Hai Nam; Do Thi Phuong Linh

    2015-01-01

    Gold nanoparticles (AuNPs) with the sizes of 5.2, 6.7 and 7.3 nm have been synthesised by γ-irradiation of Au 3+ solutions with the corresponding concentrations of 0.25, 0.5 and 1.0 mM using carboxylmethyl chitosan as stabiliser. The optical characteristics and particle sizes of AuNPs have been determined by UV-Vis spectra and TEM images respectively. The antioxidant activity of AuNPs has been investigated at the concentrations of 0.025 mM and 0.5 mM using ABTS scavenging activity. The results have shown that the higher concentration of AuNPs displays the stronger antioxidant activity and the faster reaction time. The highest antioxidant activity has been found at the concentration of 0.375 mM within 2-3 minutes. The antioxidant activity of AuNPs increases by the increase of reaction time and is higher than that of ascorbic acid. Thus, gold/carboxymethyl chitosan nanoparticles prepared by γ-irradiation method can be potentially utilised for the production of antioxidant products in pharmaceutics, functional foods and cosmetics. (author)

  18. Amphiphilic chitosan derivatives as carrier agents for rotenone

    Science.gov (United States)

    Kamari, Azlan; Aljafree, Nurul Farhana Ahmad

    2017-08-01

    In the present study, the feasibility of amphiphilic chitosan derivatives, namely oleoyl carboxymethyl chitosan (OCMCs), N,N-dimethylhexadecyl carboxymethyl chitosan (DCMCs) and deoxycholic acid carboxymethyl chitosan (DACMCs) as carrier agents for rotenone in water-insoluble pesticide formulations was investigated. Fourier Transform Infrared (FTIR) Spectrometer, CHN-O Elemental Analyser (CHN-O) and Transmission Electron Microscope (TEM) were used to characterise amphiphilic chitosan derivatives. The critical micelle concentration (CMC) of amphiphilic chitosan derivatives was determined using a Fluorescence Spectrometer. A High Performance Liquid Chromatography (HPLC) was used to determine the ability of OCMCs, DCMCs and DACMCs to load and release rotenone in an in vitro system. Based on TEM analysis, results have shown that amphiphilic chitosan derivatives formed self-assembly and exhibited spherical shape. The CMC values determined for OCMCs, DCMCs and DACMCs were 0.093, 0.098 and 0.468 mg/mL, respectively. The encapsulation efficiency (EE) values for the materials were more than 97.0%, meanwhile the loading capacity (LC) values were greater than 0.90%. OCMCs, DCMCs and DACMCs micelles exhibited an excellent ability to control the release of rotenone, of which 90.0% of rotenone was released within 40 to 52 h. In conclusion, OCMCs, DCMCs and DACMCs possess several key features to act as effective carrier agents for rotenone. Overall, amphiphilic chitosan derivatives produced in this study were successfully increased the solubility of rotenone by 49.0 times higher than free rotenone.

  19. Peritoneal macrophages mediated delivery of chitosan/siRNA nanoparticle to the lesion site in a murine radiation-induced fibrosis model

    DEFF Research Database (Denmark)

    Nawroth, Isabel; Alsner, Jan; Deleuran, B.W.

    2013-01-01

    of chitosan/siRNA nanoparticles directed towards silencing TNF alpha in local macrophage populations, but the mechanism for the therapeutic effect at the lesion site remains unclear. Methods. Using the same murine RIF model we utilized an optical imaging technique and fluorescence microscopy to investigate...... the uptake of chitosan/fluorescently labeled siRNA nanoparticles by peritoneal macrophages and their subsequent migration to the inflamed tissue in the RIF model. Results. We observed strong accumulation of the fluorescent signal in the lesion site of the irradiated leg up to 24 hours using the optical...... imaging system. We further confirm by immunohistochemical staining that Cy3 labeled siRNA resides in macrophages of the irradiated leg. Conclusion. We provide a proof-of-concept for host macrophage trafficking towards the inflamed region in a murine RIF model, which thereby suggests that the chitosan...

  20. Explanation of enhanced mechanical degradation rate for radiation- aged polyolefins as the aging temperature is decreased

    International Nuclear Information System (INIS)

    Gillen, K.T.; Clough, R.L.; Wise, J.; Malone, M.G.

    1994-01-01

    Degradation rates are normally increased by increasing the responsible environmental stresses. We describe results for a semi-crystalline, crosslinked polyolefin material that contradicts this assumption. In particular, under combined radiation plus thermal environments, this material mechanically degrades much faster at room temperature than it does at elevated temperatures. The probable explanation for this phenomenon relates to the importance on mechanical properties of the tie molecules connecting crystalline and amorphous regions. Partial melting and reforming/ reorganization of crystallites occurs throughout the crystalline melting region (at least room temperature up to 126 C), with the rate of such processes increasing with an increase in temperature. At low temperatures, this process is sufficiently slow such that a large percentage of the radiation-damaged tie molecules will still connect the amorphous and crystalline regions at the end of aging, leading to rapid reductions in tensile properties. At higher temperatures, the enhanced annealing rate will lead, during the aging, to the establishment of new, undamaged tie molecules connecting crystalline and amorphous regions. This healing process will reduce the degradation rate. Evidence in support of this model is presented

  1. Fabrication and evaluation of a sustained-release chitosan-based scaffold embedded with PLGA microspheres.

    Science.gov (United States)

    Song, Kedong; Liu, Yingchao; Macedo, Hugo M; Jiang, Lili; Li, Chao; Mei, Guanyu; Liu, Tianqing

    2013-04-01

    Nutrient depletion within three-dimensional (3D) scaffolds is one of the major hurdles in the use of this technology to grow cells for applications in tissue engineering. In order to help in addressing it, we herein propose to use the controlled release of encapsulated nutrients within polymer microspheres into chitosan-based 3D scaffolds, wherein the microspheres are embedded. This method has allowed maintaining a stable concentration of nutrients within the scaffolds over the long term. The polymer microspheres were prepared using multiple emulsions (w/o/w), in which bovine serum albumin (BSA) and poly (lactic-co-glycolic) acid (PLGA) were regarded as the protein pattern and the exoperidium material, respectively. These were then mixed with a chitosan solution in order to form the scaffolds by cryo-desiccation. The release of BSA, entrapped within the embedded microspheres, was monitored with time using a BCA kit. The morphology and structure of the PLGA microspheres containing BSA before and after embedding within the scaffold were observed under a scanning electron microscope (SEM). These had a round shape with diameters in the range of 27-55 μm, whereas the chitosan-based scaffolds had a uniform porous structure with the microspheres uniformly dispersed within their 3D structure and without any morphological change. In addition, the porosity, water absorption and degradation rate at 37 °C in an aqueous environment of 1% chitosan-based scaffolds were (92.99±2.51) %, (89.66±0.66) % and (73.77±3.21) %, respectively. The studies of BSA release from the embedded microspheres have shown a sustained and cumulative tendency with little initial burst, with (20.24±0.83) % of the initial amount released after 168 h (an average rate of 0.12%/h). The protein concentration within the chitosan-based scaffolds after 168 h was found to be (11.44±1.81)×10(-2) mg/mL. This novel chitosan-based scaffold embedded with PLGA microspheres has proven to be a promising technique

  2. Protein-adsorption and Ca-phosphate formation on chitosan-bioactive glass composite coatings

    Science.gov (United States)

    Wagener, V.; Boccaccini, A. R.; Virtanen, S.

    2017-09-01

    In the last years, chitosan-bioactive glass (BG) composites have been developed and investigated as bioactive coatings for orthopedic applications. The increase of bioactivity occurs due to the stimulation of calcium-phosphate/hydroxyapatite formation on the surface while the coating is degrading. In the present work, protein adsorption and its influence on calcium-phosphate precipitation was studied for the first time on such composite coatings. The experiments involved coating of 316L stainless steel substrates with chitosan (Ch) and chitosan-bioactive glass (Ch-BG) and immersion of the coated samples in two different bovine serum albumin (BSA) containing solutions, namely DI H2O (with pH adjusted to about 7.2 with diluted NaOH) and simulated body fluid (SBF). In order to investigate the influence of protein adsorption on calcium-phosphate precipitation, samples were also immersed in DI H2O and in SBF without BSA. Samples were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Surface analysis revealed that adsorption of BSA takes place on all studied samples and that protein adsorption is influenced by the presence of Ca2+ and PO43- ions. Bioactivity in the form of hydroxyapatite pre-stage formation is significantly increased on Ch-BG composite coating as compared with bare stainless steel surface. However, calcium-phosphate precipitation in SBF is reduced by the presence of BSA.

  3. Progress of research on the adsorption of chitosan and its derivatives to uranium

    International Nuclear Information System (INIS)

    Wang Caixia; Liu Yunhai; Hua Rong; Pang Cui; Wang Yong

    2010-01-01

    This paper has summarized the study on the adsorption of chitosan and its derivatives to uranium in recent years at home and abroad. It was found that the derivatives can be serine-type chitosan, methyl phosphoric acid modified chitosan, 3,4-dihydroxy benzoic acid-type chitosan, chitosan with 3,4-dihydroxybenzoic acid moiety, chitosan resin possessing a phenylarsonic acid moiety, quadrol modified chitosan, chitosan modified with molecular imprinting technique, polyacrylamide hydrogel, chitosan-coated perlite and so on. The application vista of chitosan and its derivatives to Absorpt uranium in water has been prospected. (authors)

  4. Study of sorption properties of nickel on chitosan; Studium sorpcnych vlastnosti niklu na chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Pivarciova, L; Rosskopfova, O; Galambos, M [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Katedra jadrovej chemie, 84215 Bratislava (Slovakia)

    2012-04-25

    Sorption of nickel on the selected sorbent was studied by a batch method. The effect of contact time and pH to reach sorption equilibrium was studied. During sorption of Ni{sup 2+} ions there proceed predominantly ion-exchange reactions on its surface. Time to reach sorption equilibrium of nickel on chitosan was 14 hours. Sorption percentage after 14 hours reached a value of 84 %. Solutions with starting pH value between 3.9 and 8.1 were used for sorption of nickel. A sorption of nickel on chitosan was > 97% in monitored interval of pH after 24 hours of contact . At an initial pH from 3.9 to 6.4 was the final pH 6.6 due to protonisation of amino groups. A pH value was 6.4 after sorption of 7.1. Sorption of nickel is reduced by increasing of concentrations of Ni{sup 2+} ions in the solution. Langmuir isotherm was used for interpretation of nickel sorption on chitosan. A maximum sorption capacity for chitosan was 2,67 {center_dot} 10{sup -3} mol/g{sup -}1. (authors)

  5. Photochemical degradation of the carbapenem antibiotics imipenem and meropenem in aqueous solutions under solar radiation.

    Science.gov (United States)

    Reina, Alejandro Cabrera; Martínez-Piernas, Ana B; Bertakis, Yannis; Brebou, Christina; Xekoukoulotakis, Nikolaos P; Agüera, Ana; Sánchez Pérez, José Antonio

    2018-01-01

    This paper deals with the photochemical fate of two representative carbapenem antibiotics, namely imipenem and meropenem, in aqueous solutions under solar radiation. The analytical method employed for the determination of the target compounds in various aqueous matrices, such as ultrapure water, municipal wastewater treatment plant effluents, and river water, at environmentally relevant concentrations, was liquid chromatography coupled with hybrid triple quadrupole-linear ion trap-mass spectrometry. The absorption spectra of both compounds were measured in aqueous solutions at pH values from 6 to 8, and both compounds showed a rather strong absorption band centered at about 300 nm, while their molar absorption coefficient was in the order from 9 × 10 3 -10 4  L mol -1  cm -1 . The kinetics of the photochemical degradation of the target compounds was studied in aqueous solutions under natural solar radiation in a solar reactor with compound parabolic collectors. It was found that the photochemical degradation of both compounds at environmentally relevant concentrations follows first order kinetics and the quantum yield was in the order of 10 -3  mol einsten -1 . Several parameters were studied, such as solution pH, the presence of nitrate ions and humic acids, and the effect of water matrix. In all cases, it was found that the presence of various organic and inorganic constituents in the aqueous matrices do not contribute significantly, either positively or negatively, to the photochemical degradation of both compounds under natural solar radiation. In a final set of photolysis experiments, the effect of the level of irradiance was studied under simulated solar radiation and it was found that the quantum yield for the direct photodegradation of both compounds remained practically constant by changing the incident solar irradiance from 28 to 50 W m -2 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. EFFECT OF PLASTICIZERS ON MECHANICAL PROPERTIES OF EDIBLE FILM FROM JANENG STARCH – CHITOSAN

    Directory of Open Access Journals (Sweden)

    Narlis Juandi

    2016-10-01

    Full Text Available The interest in the development of edible and biodegradable films has increased because it is every day more evident that non degradable are doing much damage to the environment. In this research, edible films were based on blends of janeng starch in different proportions, added of palm oil or glycerol, which were used as plasticizers. The objective was to study the effect of two different plasticizers, palm oil and glycerol of edible film from janeng starch–chitosan on the mechanical properties and FTIR spectra. Increasing concentration of glycerol as plasticizer resulted tend to increased tensile strength and elongation at break. The tensile strength and elongation at break values for palm oil is higher than glycerol as plasticizer at the same concentration. FTIR spectra show the process of making edible film from janeng starch–chitosan with palm oil or glycerol as plasticizers are physically mixing in the presence of hydrogen interactions between chains.

  7. Aerogels from Chitosan Solutions in Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Gonzalo Santos-López

    2017-12-01

    Full Text Available Chitosan aerogels conjugates the characteristics of nanostructured porous materials, i.e., extended specific surface area and nano scale porosity, with the remarkable functional properties of chitosan. Aerogels were obtained from solutions of chitosan in ionic liquids (ILs, 1-butyl-3-methylimidazolium acetate (BMIMAc, and 1-ethyl-3-methyl-imidazolium acetate (EMIMAc, in order to observe the effect of the solvent in the structural characteristics of this type of materials. The process of elaboration of aerogels comprised the formation of physical gels through anti-solvent vapor diffusion, liquid phase exchange, and supercritical CO2 drying. The aerogels maintained the chemical identity of chitosan according to Fourier transform infrared spectrophotometer (FT-IR spectroscopy, indicating the presence of their characteristic functional groups. The internal structure of the obtained aerogels appears as porous aggregated networks in microscopy images. The obtained materials have specific surface areas over 350 m2/g and can be considered mesoporous. According to swelling experiments, the chitosan aerogels could absorb between three and six times their weight of water. However, the swelling and diffusion coefficient decreased at higher temperatures. The structural characteristics of chitosan aerogels that are obtained from ionic liquids are distinctive and could be related to solvation dynamic at the initial state.

  8. Metal Complexation with Chitosan and its Grafted Copolymer

    International Nuclear Information System (INIS)

    Abo-Hussen, A.A.; Elkholy, S.S.; Elsabee, M.Z.

    2005-01-01

    The adsorption of M (II); Co (II), Ni (If), Cu (II), Zn (II) and Cd (II) from aqueous solutions by chitosan flakes and beads have been studied. The maximum up-take of M (II) ions on chitosan beads was greater than on flakes. Batch adsorption experiments were carried out as a function of ph, agitation period and initial concentration of the metal ions. A ph of 6.0 was found to be optimum for M (II) adsorption on chitosan flakes and beads. The uptake of the ions was determined from the changes in its concentration, as measured by ultraviolet and visible spectroscopy. The metal ions uptake of chitosan grafted with vinyl pyridine (VP) is higher than that of the chitosan. The experimental data of the adsorption equilibrium from M (II)-solutions correlated well with the Langmuir and Freundlich equations. Several spectroscopic methods have been used to study the formation of the polymer/metal cation complex. The cation coordination is accompanied by proton displacement off the polymer or by fixation of a hydroxide ion in aqueous solutions. The largest ionic displacement is observed with Cu (II) and Zn (II) demonstrating the largest affinity of chitosan for these ions. The FT-IR spectral of the complexes show that both the amino and hydroxyl groups of chitosan participated in the chelation process. The ESR spectra of Cu-complex show an absorption at gi 2.06, g// = 2.23, A// x 10-4 (cm-1) = 160 and G = 3.8 indicating the formation of square planar structure. The adsorption of M (II) ions followed the sequence Cu (II) > Zn (II) > Cd (II) > Ni (II) > Co (II), this order seems to be independent on the size and the physical form of chitosan. SEM shows small membranous structure on the surface of chitosan flakes as compared to Cu (Il)- chitosan complex. EDTA was used for the desorption studies

  9. Structural coloration of chitosan coated cellulose fabrics by electrostatic self-assembled poly (styrene-methyl methacrylate-acrylic acid) photonic crystals.

    Science.gov (United States)

    Yavuz, Gönül; Zille, Andrea; Seventekin, Necdet; Souto, Antonio P

    2018-08-01

    The structural coloration of a chitosan-coated woven cotton fabric obtained by glutaraldehyde-stabilized deposition of electrostatic self-assembled monodisperse and spherically uniform (250 nm) poly (styrene-methyl methacrylate-acrylic acid) photonic crystal nanospheres (P(St-MMA-AA)) was investigated. Bright iridescent coatings displaying different colors in function of the viewing angle were obtained. The SEM, diffuse reflectance spectroscopy, TGA, DSC and FTIR analyses confirm the presence of structural color and the glutaraldehyde and chitosan ability to provide durable chemical bonding between cotton fabric and photonic crystal (PCs) coating with the highest degradation temperature and the lowest enthalpy. The coatings are characterized by a mixture of face-centered cubic and hexagonal close-packed arrays alternating random packing regions. For the first time a cost-efficient structural coloration with high washing and light fastness using self-assembled P(St-MMA-AA) photonic crystals was successfully developed onto woven cotton fabric using chitosan and/or glutaraldehyde as stabilizing agent opening new strategies for the development of dye-free coloration of textiles. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Degradation of Methyl Orange and Congo Red dyes by using TiO2 nanoparticles activated by the solar and the solar-like radiation.

    Science.gov (United States)

    Ljubas, Davor; Smoljanić, Goran; Juretić, Hrvoje

    2015-09-15

    In this study we used TiO2 nanoparticles as semiconductor photocatalysts for the degradation of Methyl Orange (MO) and Congo Red (CR) dyes in an aqueous solution. Since TiO2 particles become photocatalytically active by UV radiation, two sources of UV-A radiation were used - natural solar radiation which contains 3-5% UV-A and artificial, solar-like radiation, created by using a lamp. The optimal doses of TiO2 of 500 mg/L for the CR and 1500 mg/L for the MO degradation were determined in experiments with the lamp and were also used in degradation experiments with natural solar light. The efficiency of each process was determined by measuring the absorbance at two visible wavelengths, 466 nm for MO and 498 nm for CR, and the total organic carbon (TOC), i.e. decolorization and mineralization, respectively. In both cases, considerable potential for the degradation of CR and MO was observed - total decolorization of the solution was achieved within 30-60 min, while the TOC removal was in the range 60-90%. CR and MO solutions irradiated without TiO2 nanoparticles showed no observable changes in either decolorization or mineralization. Three different commercially available TiO2 nanoparticles were used: pure-phase anatase, pure-phase rutile, and mixed-phase preparation named Degussa P25. In terms of degradation kinetics, P25 TiO2 exhibited a photocatalytic activity superior to that of pure-phase anatase or rutile. The electric energy consumption per gram of removed TOC was determined. For nearly the same degradation effect, the consumption in the natural solar radiation experiment was more than 60 times lower than in the artificial solar-like radiation experiment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Effect of chitosan coating on the characteristics of DPPC liposomes

    Directory of Open Access Journals (Sweden)

    Mohsen M. Mady

    2010-07-01

    Full Text Available Because it is both biocompatible and biodegradable, chitosan has been used to provide a protective capsule in new drug formulations. The present work reports on investigations into some of the physicochemical properties of chitosan-coated liposomes, including drug release rate, transmission electron microscopy (TEM, zeta potential and turbidity measurement. It was found that chitosan increases liposome stability during drug release. The coating of DPPC liposomes with a chitosan layer was confirmed by electron microscopy and the zeta potential of liposomes. The coating of liposomes by chitosan resulted in a marginal increase in the size of the liposomes, adding a layer of (92 ± 27.1 nm. The liposomal zeta potential was found to be increasingly positive as chitosan concentration increased from 0.1% to 0.3% (w/v, before stabilising at a relatively constant value. Turbidity studies revealed that the coating of DPPC liposomes with chitosan did not significantly modify the main phase transition temperature of DPPC at examined chitosan concentrations. The appropriate combination of liposomal and chitosan characteristics may produce liposomes with specific, prolonged and controlled release.

  12. Hydrophobization and antimicrobial activity of chitosan and paper-based packaging material.

    Science.gov (United States)

    Bordenave, Nicolas; Grelier, Stephane; Coma, Veronique

    2010-01-11

    This study reports the elaboration of water-resistant, antimicrobial, chitosan and paper-based materials as environmentally friendly food packaging materials. Two types of papers were coated with chitosan-palmitic acid emulsions or with a blend of chitosan and O,O'-dipalmitoylchitosan (DPCT). Micromorphology studies showed that inclusion of hydrophobic compounds into the chitosan matrix was enhanced by grafting them onto chitosan and that this led to their penetration of the paper's core. Compared to chitosan-coated papers, the coating of chitosan-palmitic emulsion kept vapor-barrier properties unchanged (239 and 170 g.m(-2).d(-1) versus 241 and 161 g.m(-2).d(-1)), while the coating of chitosan-DPCT emulsion dramatically deteriorated them (441 and 442 g.m(-2).d(-1)). However, contact angle measurements (110-120 degrees after 1 min) and penetration dynamics analysis showed that both strategies improved liquid-water resistance of the materials. Kit-test showed that all hydrophobized chitosan-coated papers kept good grease barrier properties (degree of resistance 6-8/12). Finally, all chitosan-coated materials exhibited over 98% inhibition on Salmonella Typhimurium and Listeria monocytogenes .

  13. Solid state synthesis of chitosan and its unsaturated derivatives for laser microfabrication of 3D scaffolds

    Science.gov (United States)

    Akopova, T. A.; Demina, T. S.; Bagratashvili, V. N.; Bardakova, K. N.; Novikov, M. M.; Selezneva, I. I.; Istomin, A. V.; Svidchenko, E. A.; Cherkaev, G. V.; Surin, N. M.; Timashev, P. S.

    2015-07-01

    Chitosans with various degrees of deacetylation and molecular weights and their allyl substituted derivatives were obtained through a solvent-free reaction under shear deformation in an extruder. Structure and physical-chemical analysis of the samples were carried out using nuclear magnetic resonance (NMR), ultraviolet (UV) and infrared radiation (IR) spectroscopy. Photosensitive materials based on the synthesized polymers were successfully used for microfabrication of 3D well-defined architectonic structures by laser stereolithography. Study on the metabolic activity of NCTC L929 cultured in the presence of the cured chitosan extracts indicates that the engineered biomaterials could support adhesion, spreading and growth of adherent-dependent cells, and thus could be considered as biocompatible scaffolds.

  14. Solid state synthesis of chitosan and its unsaturated derivatives for laser microfabrication of 3D scaffolds

    International Nuclear Information System (INIS)

    Akopova, T A; Demina, T S; Istomin, A V; Svidchenko, E A; Cherkaev, G V; Surin, N M; Bagratashvili, V N; Bardakova, K N; Novikov, M M; Selezneva, I I; Timashev, P S

    2015-01-01

    Chitosans with various degrees of deacetylation and molecular weights and their allyl substituted derivatives were obtained through a solvent-free reaction under shear deformation in an extruder. Structure and physical-chemical analysis of the samples were carried out using nuclear magnetic resonance (NMR), ultraviolet (UV) and infrared radiation (IR) spectroscopy. Photosensitive materials based on the synthesized polymers were successfully used for microfabrication of 3D well-defined architectonic structures by laser stereolithography. Study on the metabolic activity of NCTC L929 cultured in the presence of the cured chitosan extracts indicates that the engineered biomaterials could support adhesion, spreading and growth of adherent-dependent cells, and thus could be considered as biocompatible scaffolds. (paper)

  15. Chitosan composite hydrogels reinforced with natural clay nanotubes.

    Science.gov (United States)

    Huang, Biao; Liu, Mingxian; Zhou, Changren

    2017-11-01

    Here, chitosan composites hydrogels were prepared by addition of halloysite nanotubes (HNTs) in the chitosan KOH/LiOH/urea solution. The raw chitosan and chitosan/HNTs composite hydrogels were obtained by heat treatment at 60°C for 8h and then regeneration in ethanol solution. The viscosity of the composite solution is increased with HNTs content. The Fourier transform infrared spectroscopy (FT-IR) shows that the hydrogen bonds interactions exist between the HNTs and the chitosan. X-ray diffraction (XRD) results show that the crystal structure of HNT is not changed in the composite hydrogels. The compressive property test and storage modulus determination show that the mechanical properties and anti-deformation ability of the composite hydrogel significantly increase owing to the reinforcing effect of HNTs. The composites hydrogel with 66.7% HNTs can undergo 7 times compression cycles without breaking with compressive strength of 0.71MPa at 70% deformation, while pure chitosan hydrogel is broken after bearing 5 compression cycles with compressive strength of 0.14MPa and a maximum deformation of 59%. A porous structure with pore size of 100-500μm is found in the composite hydrogels by scanning electron microscopy (SEM), and the pore size and the swelling ratio in NaCl solution decrease by the addition of HNTs and the immersing of ethanol. Chitosan/HNTs composite hydrogels show low cytotoxicity towards MC3T3-E1 cells. Also, the composite hydrogels show a maximum drug entrapment efficiency of 45.7% for doxorubicin (DOX) which is much higher than that of pure chitosan hydrogel (27.5%). All the results illustrate that the chitosan/HNTs composite hydrogels show promising applications as biomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Physicochemical Characterization of Biopolymer Chitosan Extracted from Shrimp Shells

    Directory of Open Access Journals (Sweden)

    Nezamaddin Mengelizadeh

    2015-02-01

    Full Text Available Chitosan is a deacetylated derivative of chitin, which is a naturally abundant mucopolysaccharide, supporting the matter of crustaceans, insects, and fungi. Because of its unique properties, such as non-toxicity, biodegradability, and biocompatibility, chitosan has a wide range of applications in various fields. The objective of the present work is to extract the polymer chitosan from Persian Gulf shrimp shells. In order to determine the physicochemical characteristics of the extracted chitosan, degree of deacetylation, molecular weight, water and fat binding capacities extraction rate, and apparent viscosity were measured using a variety of techniques including viscometry, weight measurement method and Fourier transform infrared spectroscopy (FTIR. The results of the study of the physicochemical properties, molecular weight (6.7×105 Da, degree of deacetylation (57%, ash content as well as yield (0.5% of the prepared chitosan indicated that shrimp processing wastes (shrimp shells are a good source of chitosan. The water binding capacity (521% and fat binding capacity (327% of the prepared chitosan are in good agreement with the other studies. The elemental analysis showed the C, H and N contents of 35.92%, 7.02%, and 8.66%, respectively. In this study, the antimicrobial activity of chitosan was evaluated against Staphylococcus aureus and Escherichia coli. The results indicated the high potential of chitosan as an antibacterial agent. Moreover, the results of the study indicated that shrimp shells are a rich source of chitin as 25.21% of the shell’s dry weight.

  17. Preparation of mono-dispersed silver nanoparticles assisted by chitosan-g-poly(ε-caprolactone) micelles and their antimicrobial application

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Chunhua [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhang, Huan [State Key Laboratory of Bioreactor Engineering, New World Biotechnology Institute, East China University of Science and Technology, Shanghai 200237 (China); Lang, Meidong, E-mail: mdlang@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2014-05-01

    Graphical abstract: - Highlights: • Chemical modification of chitosan were conducted after phthaloyl protection of amino groups. • Silver nanoparticles were prepared in the presence of chitosan-based copolymer micelles. • The optimal time scale and weight ratios of silver to micelles were monitored by UV–vis spectrometer. - Abstract: Amphiphilic chitosan-graft-poly(ε-caprolactone) (CS-g-PCLs) copolymers were synthesized by a homogeneous coupling method and characterized by {sup 1}H NMR, FTIR and ninhydrin assay. The graft copolymers were subsequently self-assembled into micelles, which were measured by DLS and TEM. The particle size of the micelles decreased as the segment grafting fraction was increased. Thereafter, silver nanoparticles were prepared in the presence of chitosan-based micelles under UV irradiation. The molar ratio and radiation time of silver to micelles were optimized with process monitored via UV–vis spectrophotometer. DLS and TEM were used to illustrate the particle structure and size while XRD patterns were applied to characterize the crystal structures of polymer-assisted silver nanoparticles. Films impregnated with silver nanoparticles were conducted with results of strong antimicrobial activities against Escherichia coli and Staphylococcus aureus as model Gram-negative and positive bacteria.

  18. Preparation of mono-dispersed silver nanoparticles assisted by chitosan-g-poly(ε-caprolactone) micelles and their antimicrobial application

    International Nuclear Information System (INIS)

    Gu, Chunhua; Zhang, Huan; Lang, Meidong

    2014-01-01

    Graphical abstract: - Highlights: • Chemical modification of chitosan were conducted after phthaloyl protection of amino groups. • Silver nanoparticles were prepared in the presence of chitosan-based copolymer micelles. • The optimal time scale and weight ratios of silver to micelles were monitored by UV–vis spectrometer. - Abstract: Amphiphilic chitosan-graft-poly(ε-caprolactone) (CS-g-PCLs) copolymers were synthesized by a homogeneous coupling method and characterized by 1 H NMR, FTIR and ninhydrin assay. The graft copolymers were subsequently self-assembled into micelles, which were measured by DLS and TEM. The particle size of the micelles decreased as the segment grafting fraction was increased. Thereafter, silver nanoparticles were prepared in the presence of chitosan-based micelles under UV irradiation. The molar ratio and radiation time of silver to micelles were optimized with process monitored via UV–vis spectrophotometer. DLS and TEM were used to illustrate the particle structure and size while XRD patterns were applied to characterize the crystal structures of polymer-assisted silver nanoparticles. Films impregnated with silver nanoparticles were conducted with results of strong antimicrobial activities against Escherichia coli and Staphylococcus aureus as model Gram-negative and positive bacteria

  19. Studies on electrospun nylon-6/chitosan complex nanofiber interactions

    International Nuclear Information System (INIS)

    Zhang Haitao; Li Shubai; Branford White, Christopher J.; Ning Xin; Nie Huali; Zhu Limin

    2009-01-01

    Composite membranes of nylon-6/chitosan nanofibers with different weight ratio of nylon-6 to chitosan were fabricated successfully using electrospinning. Morphologies of the nanofibers were investigated by scanning electron microscopy (SEM) and the intermolecular interactions of the nylon-6/chitosan complex were evaluated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) as well as mechanical testing. We found that morphology and diameter of the nanofibers were influenced by the concentration of the solution and weight ratio of the blending component materials. Furthermore FT-IR analyses on interactions between components demonstrated an IR band frequency shift that appeared to be dependent on the amount of chitosan in the complex. Observations from XRD and DSC suggested that a new fraction of γ phase crystals appeared and increased with the increasing content of chitosan in blends, this indicated that intermolecular interactions occurred between nylon-6 and chitosan. Results from performance data in mechanical showed that intermolecular interactions varied with varying chitosan content in the fibers. It was concluded that a new composite product was created and the stability of this system was attributed to strong new interactions such as hydrogen bond formation between the nylon-6 polymers and chitosan structures.

  20. Recent advances in chitosan-based nanoparticulate pulmonary drug delivery

    Science.gov (United States)

    Islam, Nazrul; Ferro, Vito

    2016-07-01

    The advent of biodegradable polymer-encapsulated drug nanoparticles has made the pulmonary route of administration an exciting area of drug delivery research. Chitosan, a natural biodegradable and biocompatible polysaccharide has received enormous attention as a carrier for drug delivery. Recently, nanoparticles of chitosan (CS) and its synthetic derivatives have been investigated for the encapsulation and delivery of many drugs with improved targeting and controlled release. Herein, recent advances in the preparation and use of micro-/nanoparticles of chitosan and its derivatives for pulmonary delivery of various therapeutic agents (drugs, genes, vaccines) are reviewed. Although chitosan has wide applications in terms of formulations and routes of drug delivery, this review is focused on pulmonary delivery of drug-encapsulated nanoparticles of chitosan and its derivatives. In addition, the controversial toxicological effects of chitosan nanoparticles for lung delivery will also be discussed.