Beaded Fiber Mats of PVA Containing Unsaturated Heteropoly Salt

Institute of Scientific and Technical Information of China (English)

Guo Cheng YANG; Yan PAN; Jian GONG; Chang Lu SHAO; Shang Bin WEN; Chen SHAO; Lun Yu QU

2004-01-01

Poly(vinyl alcohol) (PVA) fiber mats containing unsaturated heteropoly salt was prepared for the first time. IR, X-ray diffraction and SEM photographs characterized the beaded fiber mats.The viscoelasticity and the conductivity of the solution were the key factors that influence the formation of the beaded fiber mats.

Biosorption of americium by alginate beads

International Nuclear Information System (INIS)

Borba, Tania Regina de; Marumo, Julio Takehiro; Goes, Marcos Maciel de; Ferreira, Rafael Vicente de Padua; Sakata, Solange Kazumi

2009-01-01

The use of biotechnology to remove heavy metals from wastes plays great potential in treatment of radioactive wastes and therefore the aim of this study was to evaluate the biosorption of americium by alginate beads. Biosorption has been defined as the property of certain biomolecules to bind and remove selected ions or other molecules from aqueous solutions. The calcium alginate beads as biosorbent were prepared and analyzed for americium uptaking. The experiments were performed in different solution activity concentrations, pH and exposure time. The results suggest that biosorption process is more efficient at pH 4 and for 75, 150, 300 Bq/mL and 120 minutes were necessary to remove almost 100% of the americium-241 from the solution. (author)

Growth and morphology of thermophilic dairy starters in alginate beads.

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Lamboley, Laurence; St-Gelais, Daniel; Champagne, Claude P; Lamoureux, Maryse

2003-06-01

The aim of this research was to produce concentrated biomasses of thermophilic lactic starters using immobilized cell technology (ICT). Fermentations were carried out in milk using pH control with cells microentrapped in alginate beads. In the ICT fermentations, beads represented 17% of the weight. Some assays were carried out with free cells without pH control, in order to compare the ICT populations with those of classical starters. With Streptococcus thermophilus, overall populations in the fermentor were similar, but maximum bead population for (8.2 x 10(9) cfu/g beads) was 13 times higher than that obtained in a traditional starter (4.9 x 10(8) cfu/ml). For both Lactobacillus helveticus strains studied, immobilized-cell populations were about 3 x 10(9) cfu/g beads. Production of immobilized Lb. bulgaricus 210R strain was not possible, since no increases in viable counts occurred in beads. Therefore, production of concentrated cell suspension in alginate beads was more effective for S. thermophilus. Photomicrographs of cells in alginate beads demonstrated that, while the morphology of S. thermophilus remained unchanged during the ICT fermentation, immobilized cells of Lb. helveticus appeared wider. In addition, cells of Lb. bulgaricus were curved and elongated. These morphological changes would also impair the growth of immobilized lactobacilli.

Fabrication of large size alginate beads for three-dimensional cell-cluster culture

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Zhang, Zhengtao; Ruan, Meilin; Liu, Hongni; Cao, Yiping; He, Rongxiang

2017-08-01

We fabricated large size alginate beads using a simple microfluidic device under a co-axial injection regime. This device was made by PDMS casting with a mold formed by small diameter metal and polytetrafluorothylene tubes. Droplets of 2% sodium alginate were generated in soybean oil through the device and then cross-linked in a 2% CaCl2 solution, which was mixed tween80 with at a concentration of 0.4 to 40% (w/v). Our results showed that the morphology of the produced alginate beads strongly depends on the tween80 concentration. With the increase of concentration of tween80, the shape of the alginate beads varied from semi-spherical to tailed-spherical, due to the decrease of interface tension between oil and cross-link solution. To access the biocompatibility of the approach, MCF-7 cells were cultured with the alginate beads, showing the formation of cancer cells clusters which might be useful for future studies.

Investigation the influence of dietary fiber on the rheological properties of alginate beads

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Z. Manev

2015-03-01

Full Text Available Abstract. During the current investigation experiments for the preparation of alginate beads with aqueous solutions of sodium alginate, calcium lactate or calcium dichloride and dietary fiber in different concentrations: inulin with varying degrees of polymerization, wheat bran and amidated apple pectin were carried out. The sodium alginate solutions were at constant concentration 3%, while calcium salts in 7% were applied for bead formation. It was proven that the rupture force of alginate beads was always higher than the pure model system regardless of the chemical structure of dietary fibers used. In the result of the carried research the dependence at a certain concentration was established at which the rupture force and deformation of the beads increased gradually.

High surface area mesoporous activated carbon-alginate beads for efficient removal of methylene blue.

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Nasrullah, Asma; Bhat, A H; Naeem, Abdul; Isa, Mohamed Hasnain; Danish, Mohammed

2018-02-01

High surface area mesoporous activated carbon-alginate (AC-alginate) beads were successfully synthesized by entrapping activated carbon powder derived from Mangosteen fruit peel into calcium-alginate beads for methylene blue (MB) removal from aqueous solution. The structure and surface characteristics of AC-alginate beads were analyzed using Fourier transform infra-red (FTIR) spectroscopy, scanning electron microscopy (SEM) and surface area analysis (S BET ), while thermal properties were tested using thermogravimetric analysis (TGA). The effect of AC-alginate dose, pH of solution, contact time, initial concentration of MB solution and temperature on MB removal was elucidated. The results showed that the maximum adsorption capacity of 230mg/g was achieved for 100mg/L of MB solution at pH 9.5 and temperature 25°C. Furthermore, the adsorption of MB on AC-alginate beads followed well pseudo-second order equation and equilibrium adsorption data were better fitted by the Freundlich isotherm model. The findings reveal the feasibility of AC-alginate beads composite to be used as a potential and low cost adsorbent for removal of cationic dyes. Copyright © 2017 Elsevier B.V. All rights reserved.

Drug Release Profile from Calcium-Induced Alginate-Phosphate Composite Gel Beads

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Yoshifumi Murata

2009-01-01

Full Text Available Calcium-induced alginate-phosphate composite gel beads were prepared, and model drug release profiles were investigated in vitro. The formation of calcium phosphate in the alginate gel matrix was observed and did not affect the rheological properties of the hydrogel beads. X-ray diffraction patterns showed that the calcium phosphate does not exist in crystalline form in the matrix. The initial release amount and release rate of a water-soluble drug, diclofenac, from the alginate gel beads could be controlled by modifying the composition of the matrix with calcium phosphate. In contrast, the release profile was not affected by the modification for hydrocortisone, a drug only slightly soluble in water.

Biosorption of strontium ions from aqueous solution using Ca-alginate biopolymer beads

International Nuclear Information System (INIS)

Goek, C.; Aytas, S.; Gerstmann, U.

2009-01-01

Biosorption of strontium ions from aqueous solution onto calcium alginate biopolymer beads was investigated in a batch system. Ca-alginate biopolymer beads were prepared from Na-alginate via cross-linking with divalent calcium ions according to the egg box model. Optimum biosorption conditions were determined as a function of initial solution pH, initial Sr concentration, contact time, biomass dosage and temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of Sr ions by Ca-alginate biopolymer beads. The thermodynamic parameters (ΔH, ΔS, ΔG) for Sr sorption onto biosorbent were also determined from the temperature dependence. The results indicate that this biosorbent has a good potential for removal of Sr ions from dilute aqueous solution.

Stability of alginate-titanium dioxide based photocatalyst beads for water treatment application under UV irradiation

OpenAIRE

WENG HOONG LAM

2017-01-01

Immobilizing TiO2 photocatalyst in alginate beads has been considered to be a green approach for the separation and recycling of the photocatalyst in UV water treatment. However, the feasibility of using alginate beads in industry is largely dependent on their photo-stability during operation. This study aimed to provide a better understanding on the degradation of alginate/TiO2 beads under UV irradiation and to improve beads stability. The beads stability can be improved by increasing the al...

Development of sodium alginate/PVA antibacterial nanofibers by the incorporation of essential oils

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Rafiq, M.; Hussain, T.; Abid, S.; Nazir, A.; Masood, R.

2018-03-01

Electrospinning is a well known method for the manufacturing of nanoscale fibers. Electrospun nanofibers have higher surface area to volume ratio and can be used for the incorporation of different materials. Essential oils are well known for their antimicrobial and healing properties since ancient times. The main objective of this study was to develop antibacterial nanofibers by the incorporation of essential oils in sodium alginate/PVA solution. Sodium alginate and PVA have excellent biocompatible properties which are the base of their use in wound care applications. Three different essential oils (cinnamon, clove, and lavender) at three different concentrations (0.5, 1 and 1.5%) were used to optimize the fiber forming conditions during electrospinning and then the desired antibacterial properties were evaluated. Addition of oils in PVA/SA solutions increased the viscosity but reduced the surface tension and conductivity as compared to pure PVA/sodium alginate solution. FTIR Spectra of composite fibers verified the successful incorporation of essential oils in nanofibers through electrospinning. All oil containing samples showed good antibacterial properties against staphylococcus aureus which make them a good replacement of antibiotics. Cinnamon oil loaded nanofibers showed the best results among selected oils regarding the antibacterial properties. Nanofibers with 1.5% cinnamon oil exhibited highest zone of inhabitation of 2.7 cm. Nanofibrous coated cotton gauze showed higher liquid absorptions as compared to simple cotton gauze and potential to be used as wound dressings for its improved liquid absorption and antibacterial activity.

Characterisation of bare and tannase-loaded calcium alginate beads by microscopic, thermogravimetric, FTIR and XRD analyses.

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Larosa, Claudio; Salerno, Marco; de Lima, Juliana Silva; Merijs Meri, Remo; da Silva, Milena Fernandes; de Carvalho, Luiz Bezerra; Converti, Attilio

2018-08-01

Incorporating enzymes into calcium alginate beads is an effective method to immobilise them and to preserve, at the same time, their catalytic activity. Sodium alginate was mixed with Aspergillus ficuum tannase in aqueous solution, and tannase-loaded calcium alginate beads were prepared using a simple droplet-based microfluidic system. Extensive experimental analysis was carried out to characterise the samples. Microscopic imaging revealed morphological differences between the surfaces of bare alginate matrix and tannase-loaded alginate beads. Thermal analysis allowed assessing the hydration contents of alginate and revealed the presence of tannase entrapped in the loaded beads, which was confirmed by vibrational spectroscopy. X-ray diffraction allowed us to conclude that alginate of tannase-loaded beads is not crystalline, which would make them suitable as carriers for possible controlled release. Moreover, they could be used in food applications to improve tea quality or clarify juices. Copyright © 2018 Elsevier B.V. All rights reserved.

Improvement of removal characteristics for uranium by immobilization of diphosil powder into alginate bead

International Nuclear Information System (INIS)

Kim, K. J.; Kang, I. S.; Lee, Y. H.; Son, J. S.; Hong, K. P.

2003-01-01

Chemical wastes containing small amounts of uranium can not be disposed of them as industrial wastes. Especially for the removal of uranium, In this study, the method of immobilizing Diphosil powder within alginate beads is adopted to make a bead from powdered resin. Sodium alginate bead itself showed a capability to uptake uranium to above 60%, but the value was decreased to below 30% after equilibrium. The rate of uranium adsorption increased with increasing content of Diphosil in sodium alginate bead. Diphosil resin itself showed very fast uptake of uranium from early stages, and then the rates were leveled off. Diphosil bead showed a improved capability to uptake uranium considering Diphosil content in the bead, and a considerable potential for further applications of a continuous process by using a bead form of Diphosil

Development of liposomes entrapped in alginate beads for the treatment of colorectal cancer.

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Bansal, Divya; Gulbake, Arvind; Tiwari, Jyoti; Jain, Sanjay K

2016-01-01

Folic Acid conjugated liposomes encapsulating Oxaliplatin (L-OHP) were entrapped in alginate beads and further coated with Eudragit-S-100 for effective delivery to colon tumors. Liposomes were prepared by cast film method and folic acid was coupled on the surface of liposomes. They were further entrapped in alginate beads which were Eudragit coated for degradation in the colonic region. The prepared beads were characterized for shape and surface morphology, percentage entrapment efficiency and drug release studies. The in vitro drug release was investigated using a USP dissolution paddle type apparatus in different simulated gastrointestinal fluids. In vivo studies of the beads containing free drug, folic acid coupled and uncoupled liposomes bearing L-OHP was administered orally at the dose of 10mg L-OHP/kg body weight to tumor bearing NUDE/SCID mice. γ-Scintigraphic study showed that Eudragit coated alginate beads entered into the colon of Balb/c mice between 4.20 and 4.50h after oral administration. In vivo data showed that folic acid coupled liposomes entrapped in alginate beads delivered 2.82 ± 0.58 and 21.52 ± 2.76 μg L-OHP/g tissues in the colon and tumor after 12h, reflecting its targeting potential to colon and tumor. The results clearly demonstrate that Eudragit coated calcium alginate beads bearing folic acid coupled liposome can be used as a prospective carrier for drug delivery to colon specific tumor. Copyright © 2015 Elsevier B.V. All rights reserved.

Controlled antiseptic release by alginate polymer films and beads.

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Liakos, Ioannis; Rizzello, Loris; Bayer, Ilker S; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

2013-01-30

Biodegradable polymeric materials based on blending aqueous dispersions of natural polymer sodium alginate (NaAlg) and povidone iodine (PVPI) complex, which allow controlled antiseptic release, are presented. The developed materials are either free standing NaAlg films or Ca(2+)-cross-linked alginate beads, which properly combined with PVPI demonstrate antibacterial and antifungal activity, suitable for therapeutic applications, such as wound dressing. Glycerol was used as the plasticizing agent. Film morphology was studied by optical and atomic force microscopy. It was found that PVPI complex forms well dispersed circular micro-domains within the NaAlg matrix. The beads were fabricated by drop-wise immersion of NaAlg/PVPI/glycerol solutions into aqueous calcium chloride solutions to form calcium alginate beads encapsulating PVPI solution (CaAlg/PVPI). Controlled release of PVPI was possible when the composite films and beads were brought into direct contact with water or with moist media. Bactericidal and fungicidal properties of the materials were tested against Escherichia coli bacteria and Candida albicans fungi. The results indicated very efficient antibacterial and antifungal activity within 48 h. Controlled release of PVPI into open wounds is highly desired in clinical applications to avoid toxic doses of iodine absorption by the wound. A wide variety of applications are envisioned such as external and internal wound dressings with controlled antiseptic release, hygienic and protective packaging films for medical devices, and polymer beads as water disinfectants. Copyright © 2012 Elsevier Ltd. All rights reserved.

Evaluation of the Effect of Psyllium on the Viability of Lactobacillus Acidophilus in Alginate-Polyl Lysine Beads.

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Esmaeilzadeh, Jaleh; Nazemiyeh, Hossein; Maghsoodi, Maryam; Lotfipour, Farzaneh

2016-09-01

Purpose: Psylliumseeds are used in traditional herbal medicine to treat various disorders. Moreover, as a soluble fiber, psyllium has potential to stimulate bacterial growth in digestive system. We aimed to substitute alkali-extractable polysaccharides of psyllium for alginate in beads with second coat of poly-l-lysine to coat Lactobacillus acidophilus. Methods: Beads were prepared using extrusion technique. Poly-l-lysine as second coat was incorporated on optimum alginate/psyllium beads using immersion technique. Beads were characterized in terms of size, encapsulation efficiency, integrity and bacterial survival in harsh conditions. Results: Beads with narrow size distribution ranging from 1.85 ± 0.05 to 2.40 ± 0.18 mm with encapsulation efficiency higher than 96% were achieved. Psyllium concentrations in beads did not produce constant trend in bead sizes. Surface topography by SEM showed that substitution of psyllium enhanced integrity of obtained beads. Psyllium successfully protected the bacteria against acidic condition and lyophilization equal to alginate in the beads. Better survivability with beads of alginate/psyllium-poly-l-lysine was achieved with around 2 log rise in bacterial count in acid condition compared to the corresponding single coat beads. Conclusion: Alginate/psyllium (1:2) beads with narrow size distribution and high encapsulation efficiency of the bacteria have been achieved. Presence of psyllium produced a much smoother and integrated surface texture for the beads with sufficient protection of the bacteria against acidic condition as much as alginate. Considering the health benefits of psyllium and its prebiotic activity, psyllium can be beneficially replaced in part for alginate in probiotic coating.

Development of a novel colorimetric sensor based on alginate beads for monitoring rainbow trout spoilage.

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Majdinasab, Marjan; Hosseini, Seyed Mohammad Hashem; Sepidname, Marziyeh; Negahdarifar, Manizheh; Li, Peiwu

2018-05-01

Alginate is a non-toxic, renewable, and linear copolymer obtained from the brown algae Laminaria digitata that can be easily shaped into beads. Its good gel forming properties have made it useful for entrapping food and pharmaceutical ingredients. In this study, alginate beads were used in a novel application as a colorimetric sensor in food intelligent packaging. Colorimetric sensor was developed through entrapping red cabbage extract as a pH indicator in alginate beads. The pH indicator beads were used in rainbow trout packaging for monitoring fillets spoilage. Color change of beads during fish storage was measured using the CIELab method. The alginate bead colorimetric sensor is validated by measuring total volatile basic nitrogen (TVB-N) levels and microbial populations in fish samples. Moreover, peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were evaluated during storage. Results indicated that increasing the bacterial population during storage and production of proteolytic enzymes resulted in protein degradation, accumulation of volatile amine compounds, increase in the pH and finally color change of alginate beads. The values of TVB-N, pH, PV and TBARS increased with time of storage. The results of TVB-N and microbial growth were in accordance with color change of beads and CIELab data. Therefore, the proposed system enjoys a high sensitivity to pH variations and is capable of monitoring the spoilage of fish or other protein-rich products through its wide range of color changes. The alginate beads containing the red cabbage extract can, thus, be used as a low-cost colorimetric sensor for intelligent packaging applications.

l-Arginine grafted alginate hydrogel beads: A novel pH-sensitive system for specific protein delivery

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Mohamed S. Mohy Eldin

2015-05-01

Full Text Available Novel pH-sensitive hydrogels based on l-arginine grafted alginate (Arg-g-Alg hydrogel beads were synthesized and utilized as a new carrier for protein delivery (BSA in specific pH media. l-arginine was grafted onto the polysaccharide backbone of virgin alginate via amine functions. Evidences of grafting of alginate were extracted from FT-IR and thermal analysis, while the morphological structure of Arg-g-Alg hydrogel beads was investigated by SEM photographs. Factors affecting on the grafting process e.g. l-arginine concentration, reaction time, reaction temperature, reaction pH, and crosslinking conditions, have been studied. Whereas, grafting efficiency of each factor was evaluated. Grafting of alginate has improved both thermal and morphological properties of Arg-g-Alg hydrogel beads. The swelling behavior of Arg-g-Alg beads was determined as a function of pH and compared with virgin calcium alginate beads. The cumulative in vitro release profiles of BSA loaded beads were studied at different pHs for simulating the physiological environments of the gastrointestinal tract. The amount of BSA released from neat alginate beads at pH 2 was almost 15% after 5 h, while the Arg-g-Alg beads at the same conditions were clearly higher than 45%, then it increased to 90% at pH 7.2. Accordingly, grafting of alginate has improved its release profile behavior particularly in acidic media. The preliminary results clearly suggested that the Arg-g-Alg hydrogel may be a potential candidate for polymeric carrier for oral delivery of protein or drugs.

Monoolein-alginate beads as a platform to promote adenosine cutaneous localization and wound healing.

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Ng, Wing Y; Migotto, Amanda; Ferreira, Thamyres Soares; Lopes, Luciana B

2017-09-01

Alginate beads containing the polar lipid monoolein were developed as a strategy to manage wet wounds by providing improved uptake of excess exudate while releasing adenosine locally for promotion of healing. To obtain monoolein-containing beads, the lipid was mixed with almond oil (2:1w/w), and emulsified within the alginate aqueous dispersion, followed by ionotropic gelation in CaCl 2 solution. Compared to alginate-only, monoolein-alginate systems were 1.44-fold larger, their swelling ability was 1.40-fold higher and adenosine cumulative release was approximately 1.30-fold lower (at 24h). Monoolein-alginate beads were considered safe for topical application as demonstrated by the absence of changes on the viability of reconstructed skin equivalents compared to PBS. Smaller amounts of adenosine were delivered by the beads into and across damaged porcine skin (created by an incisional wound) compared to the drug aqueous solution, and cutaneous localization was favored. More specifically, the beads increased the viable skin layer/receptor phase delivery ratio by approximately 4-fold at 12h post-application. Considering the wide range of adenosine physiological effects and the importance of skin localization for its use in wound healing, these results demonstrate the potential of monoolein-containing beads for localized drug delivery and management of wet wounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Cell proliferation on PVA/sodium alginate and PVA/poly(γ-glutamic acid) electrospun fiber.

Science.gov (United States)

Yang, Jen Ming; Yang, Jhe Hao; Tsou, Shu Chun; Ding, Chian Hua; Hsu, Chih Chin; Yang, Kai Chiang; Yang, Chun Chen; Chen, Ko Shao; Chen, Szi Wen; Wang, Jong Shyan

2016-09-01

To overcome the obstacles of easy dissolution of PVA nanofibers without crosslinking treatment and the poor electrospinnability of the PVA cross-linked nanofibers via electrospinning process, the PVA based electrospun hydrogel nanofibers are prepared with post-crosslinking method. To expect the electrospun hydrogel fibers might be a promising scaffold for cell culture and tissue engineering applications, the evaluation of cell proliferation on the post-crosslinking electrospun fibers is conducted in this study. At beginning, poly(vinyl alcohol) (PVA), PVA/sodium alginate (PVASA) and PVA/poly(γ-glutamic acid) (PVAPGA) electrospun fibers were prepared by electrospinning method. The electrospun PVA, PVASA and PVAPGA nanofibers were treated with post-cross-linking method with glutaraldehyde (Glu) as crosslinking agent. These electrospun fibers were characterized with thermogravimetry analysis (TGA) and their morphologies were observed with a scanning electron microscope (SEM). To support the evaluation and explanation of cell growth on the fiber, the study of 3T3 mouse fibroblast cell growth on the surface of pure PVA, SA, and PGA thin films is conducted. The proliferation of 3T3 on the electrospun fiber surface of PVA, PVASA, and PVAPGA was evaluated by seeding 3T3 fibroblast cells on these crosslinked electrospun fibers. The cell viability on electrospun fibers was conducted with water-soluble tetrazolium salt-1 assay (Cell Proliferation Reagent WST-1). The morphology of the cells on the fibers was also observed with SEM. The results of WST-1 assay revealed that 3T3 cells cultured on different electrospun fibers had similar viability, and the cell viability increased with time for all electrospun fibers. From the morphology of the cells on electrospun fibers, it is found that 3T3 cells attached on all electrospun fiber after 1day seeded. Cell-cell communication was noticed on day 3 for all electrospun fibers. Extracellular matrix (ECM) productions were found and

Swelling Studies and in vitro Release of Acemetacin and BSA from Alginate Gel Beads Crosslinked with Ca2+ or Ba2+

Institute of Scientific and Technical Information of China (English)

YUAN Pei; JIA Yuntao; ZHANG Liangke; ZHANG Jingqing; HU Wenjing; WANG Chengyuan

2012-01-01

The aim of the present work was to investigate the swelling behavior and the in vitro release of acemetacin and bovine serum albumin from alginate gel beads crosslinked with Ca2+ or Ba2+.The release profiles suggested that the extent of swelling of the alginate beads played an important role in the release of drug.Small drugs are mainly released via diffusion through the alginate gel matrix.Compared with small drugs,large molecule drugs are difficult to diffuse through the pores of the matrix bead until the beads swell to a certain extent to provide enough large pores.The Ba2+ crosslinked alginate beads showed slower release rate compared with the Ca2+ crosslinked alginate beads,whether loaded the large molecules or small drugs.In conclusion,the Ba2+ crosslinked alginate beads are considered more suitable than Ca2+ crosslinked alginate beads for using as a sustained release vehicle especially for large molecule drugs.

Optimization of Enzyme Co-Immobilization with Sodium Alginate and Glutaraldehyde-Activated Chitosan Beads.

Science.gov (United States)

Gür, Sinem Diken; İdil, Neslihan; Aksöz, Nilüfer

2018-02-01

In this study, two different materials-alginate and glutaraldehyde-activated chitosan beads-were used for the co-immobilization of α-amylase, protease, and pectinase. Firstly, optimization of multienzyme immobilization with Na alginate beads was carried out. Optimum Na alginate and CaCl 2 concentration were found to be 2.5% and 0.1 M, respectively, and optimal enzyme loading ratio was determined as 2:1:0.02 for pectinase, protease, and α-amylase, respectively. Next, the immobilization of multiple enzymes on glutaraldehyde-activated chitosan beads was optimized (3% chitosan concentration, 0.25% glutaraldehyde with 3 h of activation and 3 h of coupling time). While co-immobilization was successfully performed with both materials, the specific activities of enzymes were found to be higher for the enzymes co-immobilized with glutaraldehyde-activated chitosan beads. In this process, glutaraldehyde was acting as a spacer arm. SEM and FTIR were used for the characterization of activated chitosan beads. Moreover, pectinase and α-amylase enzymes immobilized with chitosan beads were also found to have higher activity than their free forms. Three different enzymes were co-immobilized with these two materials for the first time in this study.

Adsorption of ochratoxin A from grape juice by yeast cells immobilised in calcium alginate beads.

Science.gov (United States)

Farbo, Maria Grazia; Urgeghe, Pietro Paolo; Fiori, Stefano; Marceddu, Salvatore; Jaoua, Samir; Migheli, Quirico

2016-01-18

Grape juice can be easily contaminated with ochratoxin A (OTA), one of the known mycotoxins with the greatest public health significance. Among the different approaches to decontaminate juice from this mycotoxin, microbiological methods proved efficient, inexpensive and safe, particularly the use of yeast or yeast products. To ascertain whether immobilisation of the yeast biomass would lead to successful decontamination, alginate beads encapsulating Candida intermedia yeast cells were used in our experiments to evaluate their OTA-biosorption efficacy. Magnetic calcium alginate beads were also prepared by adding magnetite in the formulation to allow fast removal from the aqueous solution with a magnet. Calcium alginate beads were added to commercial grape juice spiked with 20 μg/kg OTA and after 48 h of incubation a significant reduction (>80%), of the total OTA content was achieved, while in the subsequent phases (72-120 h) OTA was slowly released into the grape juice by alginate beads. Biosorption properties of alginate-yeast beads were tested in a prototype bioreactor consisting in a glass chromatography column packed with beads, where juice amended with OTA was slowly flowed downstream. The adoption of an interconnected scaled-up bioreactor as an efficient and safe tool to remove traces of OTA from liquid matrices is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Piroxicam loaded alginate beads obtained by prilling/microwave tandem technique: morphology and drug release.

Science.gov (United States)

Aquino, Rita P; Auriemma, Giulia; d'Amore, Matteo; D'Ursi, Anna Maria; Mencherini, Teresa; Del Gaudio, Pasquale

2012-07-01

This paper presents a tandem technique, based on the combination of prilling and microwave (MW) assisted treatments, to produce biodegradable alginate carriers of piroxicam with different drug controlled release behaviours. Results showed that alginate/piroxicam beads demonstrated high encapsulation efficiency and very narrow dimensional distribution. Beads dried by MW retained shape and size distribution of the hydrated particles while drying rate was strongly increased compared to convective drying processes. Moreover, different MW irradiation regimes promoted interactions between the drug and alginate matrix, affected drug polymorphism as well as inner and surface matrix structure leading to different piroxicam release profiles. High level MW irradiation led to beads with highly porous and swellable matrix able to release piroxicam in few minutes in the intestine while convective drying produced gastro-resistant beads that exhibit sustained piroxicam release (total release in 5.5h) in intestinal environment. On these results the tandem technique prilling/MW irradiation appears to be promising to obtain alginate carrier with tailored NSAIDs release depending on drug characteristics and MW irradiation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Electro-spray of high viscous liquids for producing mono-sized spherical alginate beads

Institute of Scientific and Technical Information of China (English)

Hamid Moghadam; Mohsen Samimi; Abdolreza Samimi; Mohamad Khorram

2008-01-01

Alginate beads, often used for controlled release of enzymes and drugs, are usually produced by spraying sodium alginate liquid into a gelling agent using mechanical vibration nozzle or air jet. In this work an alternative method of electro-spray was employed to form droplets with desired size from a highly viscous sodium alginate solution using constant DC voltage. The droplets were then cured in a calcium chloride solution. The main objective was to produce mono-sized beads from such a highly viscous and non-Newtonian liquid (1000-5000 mPa s). The effects of nozzle diameter, flow rate and concentration of liquid on the size of the beads were investigated. Among the parameters studied, voltage had a pronounced effect on the size of beads as compared to flow rate zzle diameter and concentration of alginate liquid. The size of beads was reduced to a minimum value with increasing the voltage in the range of 0-10 kV. At the early stages of voltage increase (I.e. Up to about 4 kV), the rate of size reduction was relatively low, while the dripping mode dominated. However, in the middle part of the range of applied voltage, where the rate of size reduction was high (I.e. About 4-7 kV), an unstable transition occurred between dripping and jetting. At the end part of the range (I.e. 7-10 kV) jet mode of spray was observed. Increasing the height of fall of the droplets was found to improve the sphericity of the beads, because of the increased time of flight for the droplets. This was especially identifiable at higher concentrations of the alginate liquid (I.e. 3 w/v%)

Synthesis and characterization of chitosan impregnated calcium alginate beads for removal of uranium from aquatic stream

International Nuclear Information System (INIS)

Singhal, R.K.; Basu, H.; Manisha, V.; Reddy, A.V.R.; Sawant, Manjiri; Kamane, Suman

2015-01-01

The present study was conducted to study the feasibility of chitosan impregnated calcium alginate beads (Cal-Alg-Chi) to sorb the excess uranium from the aquatic stream. Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). The optimal composition of calcium alginate chitosan beads is 4 % (wt/vol) alginate gel having 5% loading of chitosan. The nature and morphology of pure and uranium sorbed calcium alginate chitosan beads were characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), and attenuated total reflectance Fourier transform infrared spectroscopy (ATRFTIR). The results of batch sorption experiments suggest that Cal-Alg-Chi beads are very effective for removal of uranium in the pH range of 2.0-5.0 and sorption is more than 80 % in the concentration range of 1-100 mgL -1

Alginate and Algal-Based Beads for the Sorption of Metal Cations: Cu(II and Pb(II

Directory of Open Access Journals (Sweden)

Shengye Wang

2016-09-01

Full Text Available Alginate and algal-biomass (Laminaria digitata beads were prepared by homogeneous Ca ionotropic gelation. In addition, glutaraldehyde-crosslinked poly (ethyleneimine (PEI was incorporated into algal beads. The three sorbents were characterized by scanning electron microscopy (SEM coupled with energy dispersive X-ray analysis (EDX: the sorption occurs in the whole mass of the sorbents. Sorption experiments were conducted to evaluate the impact of pH, sorption isotherms, and uptake kinetics. A special attention was paid to the effect of drying (air-drying vs. freeze-drying on the mass transfer properties. For alginate, freeze drying is required for maintaining the porosity of the hydrogel, while for algal-based sorbents the swelling of the material minimizes the impact of the drying procedure. The maximum sorption capacities observed from experiments were 415, 296 and 218 mg Pb g−1 and 112, 77 and 67 mg Cu g−1 for alginate, algal and algal/PEI beads respectively. Though the sorption capacities of algal-beads decreased slightly (compared to alginate beads, the greener and cheaper one-pot synthesis of algal beads makes this sorbent more competitive for environmental applications. PEI in algal beads decreases the sorption properties in the case of the sorption of metal cations under selected experimental conditions.

Effect of SiO2, PVA and glycerol concentrations on chemical and mechanical properties of alginate-based films.

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Yang, Manli; Shi, Jinsheng; Xia, Yanzhi

2018-02-01

Sodium alginate (SA)/polyvinyl alcohol (PVA)/SiO 2 nanocomposite films were prepared by in situ polymerization through solution casting and solvent evaporation. The effect of different SA/PVA ratios, SiO 2 , and glycerol content on the mechanical properties, water content, water solubility, and water vapor permeability were studied. The nanocomposite films were characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and thermal stability (thermogravimetric analysis/differential thermogravimetry) analyses. The nanocomposites showed the highest values of mechanical properties, such as SA/PVA ratio, SiO 2 , and glycerol content was 7:3, 6wt.%, and 0.25g/g SA, respectively. The tensile strength and elongation at break (E%) of the nanocomposites increased by 525.7% and 90.7%, respectively, compared with those of the pure alginate film. The Fourier transform infrared spectra showed a new SiOC band formed in the SA/PVA/SiO 2 nanocomposite film. The scanning electron microscopy image revealed good adhesion between SiO 2 and SA/PVA matrix. After the incorporation of PVA and SiO 2 , the water resistance of the SA/PVA/SiO 2 nanocomposite film was markedly improved. Transparency decreased with increasing PVA content but was enhanced by adding SiO 2 . Copyright © 2017. Published by Elsevier B.V.

Electro-Fenton decolourisation of dyes in an airlift continuous reactor using iron alginate beads.

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Iglesias, O; Rosales, E; Pazos, M; Sanromán, M A

2013-04-01

In this study, electro-Fenton dye degradation was performed in an airlift continuous reactor configuration by harnessing the catalytic activity of Fe alginate gel beads. Electro-Fenton experiments were carried out in an airlift reactor with a working volume of 1.5 L, air flow of 1.5 L/min and 115 g of Fe alginate gel beads. An electric field was applied by two graphite bars connected to a direct current power supply with a constant potential drop. In this study, Lissamine Green B and Reactive Black 5 were selected as model dyes. Fe alginate gel beads can be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process, as they are more efficient than the conventional electrochemical techniques. At optimal working conditions (3 V and pH 2), the continuous process was performed. For both dyes, the degree of decolourisation increases when the residence time augments. Taking into account hydrodynamic and kinetic behaviour, a model to describe the reactor profile was obtained, and the standard deviation between experimental and theoretical data was lower than 6%. The results indicate the suitability of the electro-Fenton technique to oxidise polluted effluents in the presence of Fe alginate gel beads. Moreover, the operation is possible in a continuous airlift reactor, due to the entrapment of iron in the alginate matrix.

Ionic liquid as a potential solvent for preparation of collagen-alginate-hydroxyapatite beads as bone filler.

Science.gov (United States)

Iqbal, Bushra; Sarfaraz, Zenab; Muhammad, Nawshad; Ahmad, Pervaiz; Iqbal, Jibran; Khan, Zia Ul Haq; Gonfa, Girma; Iqbal, Farasat; Jamal, Arshad; Rahim, Abdur

2018-07-01

In this study, collagen/alginate/hydroxyapatite beads having different proportions were prepared as bone fillers for the restoration of osteological defects. Ionic liquid was used to dissolve the collagen and subsequently the solution was mixed with sodium alginate solution. Hydroxyapatite was added in different proportions, with the rationale to enhance mechanical as well as biological properties. The prepared solutions were given characteristic bead shapes by dropwise addition into calcium chloride solution. The prepared beads were characterized using FTIR, XRD, TGA and SEM analysis. Microhardness testing was used to evaluate the mechanical properties. The prepared beads were investigated for water adsorption behavior to ascertain its ability for body fluid uptake and adjusted accordingly to the bone cavity. Drug loading and subsequently the antibacterial activity was investigated for the prepared beads. The biocompatibility was assessed using the hemolysis testing and cell proliferation assay. The prepared collagen-alginate-HA beads, having biocompatibility and good mechanical properties, have showed an option of promising biologically active bone fillers for bone regeneration.

Fabrication of highly porous keratin sponges by freeze-drying in the presence of calcium alginate beads

International Nuclear Information System (INIS)

Hamasaki, Shinichi; Tachibana, Akira; Tada, Daisuke; Yamauchi, Kiyoshi; Tanabe, Toshizumi

2008-01-01

Novel fabrication method of highly porous and flexible keratin sponges was developed by combining a particulate-leaching method and a freeze-drying method. Reduced keratin aqueous solution was mixed with dried calcium alginate beads and was lyophilized to give keratin/calcium alginate complex, which was subsequently treated with EDTA solution to leach out calcium alginate beads. The resultant keratin sponge was flexible enough to handle even in dried state because of its quite high porosity (98.9 ± 0.1%), which was brought about by the large and small pores formed by the elimination of calcium alginate beads and water. The sponge supported the attachment and the proliferation of mouse fibroblast cells. Thus, the keratin sponge given by the present fabrication method afforded one alternative as a cell scaffold for tissue engineering

Combined effects of adsorption and photocatalysis by hybrid TiO2/ZnO-calcium alginate beads for the removal of copper

Institute of Scientific and Technical Information of China (English)

Devagi Kanakaraju; Shantini Ravichandar; Ying Chin Lim

2017-01-01

The use of nanosized titanium dioxide (TiO2) and zinc oxide (ZnO) in the suspension form during treatment makes the recovering and recycling of photocatalysts difficult.Hence,supported photocatalysts are preferred for practical water treatment applications.This study was conducted to investigate the efficiency of calcium alginate (CaAlg) beads that were immobilized with hybrid photocatalysts,TiO2/ZnO to form TiO2/ZnO-CaAlg.Theseimmobilized beads,with three different mass ratios of TiO2:ZnO (1∶1,1∶2,and 2∶1) were used to remove Cu(Ⅱ) in aqueous solutions in the presence of ultraviolet light.These beads were subjected to three cycles of photocatalytic treatment with different initial Cu(Ⅱ) concentrations (10-80 ppm).EDX spectra have confirmed the inclusion of Ti and Zn on the surface of the CaAlg beads.Meanwhile,the surface morphology of the beads as determined using SEM,has indicated differences of before and after the photocatalytic treatment of Cu(Ⅱ).Among all three,the equivalent mass ratio TiO2/ZnO-CaAlg beads have shown the best performance in removing Cu(Ⅱ) during all three recycling experiments.Those TiO2/ZnO-CaAlg beads have also shown consistent removal of Cu,ranging from 7.14-62.0 ppm (first cycle) for initial concentrations of 10-80 ppm.In comparison,bare CaAlg was only able to remove 6.9-48 ppm of similar initial Cu concentrations.Thus,the potential use of TiO2/ZnO-CaAlg beads as environmentally friendly composite material can be further extended for heavy metal removal from contaminated water.

Simultaneous detection and removal of radioisotopes with modified alginate beads containing an azo-based probe using RGB coordinates

International Nuclear Information System (INIS)

Jo, Ara; Jang, Geunseok; Namgung, Ho; Kim, Choongho; Kim, Daigeun; Kim, Yujun; Kim, Jongho; Lee, Taek Seung

2015-01-01

Highlights: • Modified alginate with azo-based probe (ABO) was synthesized by a reaction between sodium alginate and azo-based probe (BO2). • BO2 was found to be a good probe molecule for radioisotopes using colorimetric analysis. • Detection of Co 2+ and Sr 2+ was mainly carried out via interaction between BO2 and metal ions. • Simultaneous removal of radioisotopes was assessed by the ion-exchange of carboxylate groups in sodium alginate. • The alginate beads with dual functions of detection and removal of metal ions are successfully accomplished. - Abstract: We prepared alginate beads that were modified with an azo-based probe molecule to monitor simultaneously the removal (by alginate) and probing (by the azo-probe molecule) of radioisotopes such as cobalt, strontium, and cesium ions. As an azo-probe molecule, Basic Orange 2 (BO2) was immobilized to the alginate bead. The BO2 in aqueous solution exhibited a slight red shift in absorption with a change in color from orange to dark orange upon addition of cobalt and strontium ions. In contrast, the color of BO2 did not change upon exposure to cesium ions. Thus, the covalently embedded BO2 in alginate beads could adsorb cobalt and strontium ions resulting in recognizable color change of the beads, which was induced by the formation of a complex between BO2 and metal ions. The color changes of the beads in the presence of metal ions were determined quantitatively using RGB color coordinate values. In addition to effectively removing metal ions, the colorimetric coordinate method provides a convenient and simple sensing technique for naked-eye metal ion detection.

Novel biochar-impregnated calcium alginate beads with improved water holding and nutrient retention properties.

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Wang, Bing; Gao, Bin; Zimmerman, Andrew R; Zheng, Yulin; Lyu, Honghong

2018-03-01

Drought conditions and nutrients loss have serious impacts on soil quality as well as crop yields in agroecosystems. New techniques are needed to carry out effective soil water and nutrient conservation and fertilizer application tools. Here, calcium alginate (CA) beads impregnated with ball-milled biochar (BMB) were investigated as a new type of water/nutrients retention agent. Both CA and Ca-alginate/ball milled biochar composite (CA-BMB) beads showed high kinetic swelling ratios in KNO 3 solution and low kinetic swelling ratios in water, indicating that CA-BMB beads have the potential to retain mineral nitrogen and nutrients by ion exchange. Pseudo-second-order kinetic model well-described the swelling kinetics of both beads in KNO 3 solution. Over a range of temperatures, the characteristics of dehydration suggested that impregnation with BMB improved the water holding capacity and postponed the dehydration time of Ca-alginate. The cumulative swelling and release characteristics of water, K + , and NO 3 - indicated that CA-BMB beads have great potential as a soil amendment to improve its nutrient retention and water holding capacity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Magnetic nanoparticle-loaded alginate beads for local micro-actuation of in vitro tissue constructs.

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Alshehri, Awatef M; Wilson, Otto C; Dahal, Bishnu; Philip, John; Luo, Xiaolong; Raub, Christopher B

2017-11-01

Magnetic nanoparticles (MNPs) self-align and transduce magnetic force, two properties which lead to promising applications in cell and tissue engineering. However, the toxicity of MNPs to cells which uptake them is a major impediment to applications in engineered tissue constructs. To address this problem, MNPs were embedded in millimeter-scale alginate beads, coated with glutaraldehyde cross-linked chitosan, and loaded in acellular and MDA-MB-231 cancer cell-seeded collagen hydrogels, providing local micro-actuation under an external magnetic field. Brightfield microscopy was used to assess nanoparticle diffusion from the bead. Phase contrast microscopy and digital image correlation were used to track collagen matrix displacement and estimate intratissue strain under magnetic actuation. Coating the magnetic alginate beads with glutaraldehyde-chitosan prevents bulk diffusion of nanoparticles into the surrounding microenvironment. Further, the beads exert force on the surrounding collagen gel and cells, resulting in intratissue strains of 0-10% tunable with bead dimensions, collagen density, and distance from the bead. Cells seeded adjacent to the embedded beads are subjected to strain gradients without loss of cell viability over two days culture. This study describes a simple way to fabricate crosslinked magnetic alginate beads to load in a collagen tissue construct without direct exposure of the construct to nanoparticles. The findings are significant to in vitro studies of mechanobiology in enabling precise control over dynamic mechanical loading of tissue constructs. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultra-structural changes and expression of chondrogenic and hypertrophic genes during chondrogenic differentiation of mesenchymal stromal cells in alginate beads

Directory of Open Access Journals (Sweden)

Havva Dashtdar

2016-03-01

Full Text Available Chondrogenic differentiation of mesenchymal stromal cells (MSCs in the form of pellet culture and encapsulation in alginate beads has been widely used as conventional model for in vitro chondrogenesis. However, comparative characterization between differentiation, hypertrophic markers, cell adhesion molecule and ultrastructural changes during alginate and pellet culture has not been described. Hence, the present study was conducted comparing MSCs cultured in pellet and alginate beads with monolayer culture. qPCR was performed to assess the expression of chondrogenic, hypertrophic, and cell adhesion molecule genes, whereas transmission electron microscopy (TEM was used to assess the ultrastructural changes. In addition, immunocytochemistry for Collagen type II and aggrecan and glycosaminoglycan (GAG analysis were performed. Our results indicate that pellet and alginate bead cultures were necessary for chondrogenic differentiation of MSC. It also indicates that cultures using alginate bead demonstrated significantly higher (p < 0.05 chondrogenic but lower hypertrophic (p < 0.05 gene expressions as compared with pellet cultures. N-cadherin and N-CAM1 expression were up-regulated in second and third weeks of culture and were comparable between the alginate bead and pellet culture groups, respectively. TEM images demonstrated ultrastructural changes resembling cell death in pellet cultures. Our results indicate that using alginate beads, MSCs express higher chondrogenic but lower hypertrophic gene expression. Enhanced production of extracellular matrix and cell adhesion molecules was also observed in this group. These findings suggest that alginate bead culture may serve as a superior chondrogenic model, whereas pellet culture is more appropriate as a hypertrophic model of chondrogenesis.

Development of pH-sensitive tamarind seed polysaccharide-alginate composite beads for controlled diclofenac sodium delivery using response surface methodology.

Science.gov (United States)

Nayak, Amit Kumar; Pal, Dilipkumar

2011-11-01

The present study deals with the development of novel pH-sensitive tamarind seed polysaccharide (TSP)-alginate composite beads for controlled diclofenac sodium delivery using response surface methodology by full 3(2) factorial design. The effect of polymer-blend ratio (sodium alginate:TSP) and cross-linker (CaCl(2)) concentration on the drug encapsulation efficiency (DEE, %) and drug release from diclofenac sodium loaded TSP-alginate composite beads prepared by ionotropic gelation was optimized. The observed responses were coincided well with the predicted values by the experimental design. The DEE (%) of these beads containing diclofenac sodium was within the range between 72.23±2.14 and 97.32±4.03% with sustained in vitro drug release (69.08±2.36-96.07±3.54% in 10 h). The in vitro drug release from TSP-alginate composite beads containing diclofenac sodium was followed by controlled-release pattern (zero-order kinetics) with case-II transport mechanism. Particle size range of these beads was 0.71±0.03-1.33±0.04 mm. The swelling and degradation of the developed beads were influenced by different pH of the test medium. The FTIR and NMR analyses confirmed the compatibility of the diclofenac sodium with TSP and sodium alginate used to prepare the diclofenac sodium loaded TSP-alginate composite beads. The newly developed TSP-alginate composite beads are suitable for controlled delivery of diclofenac sodium for prolonged period. Copyright © 2011 Elsevier B.V. All rights reserved.

Determination of diffusion coefficients and diffusion characteristics for chlorferon and diethylthiophosphate in Ca-alginate gel beads.

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Ha, Jiyeon; Engler, Cady R; Lee, Seung Jae

2008-07-01

Diffusion characteristics of chlorferon and diethylthiophosphate (DETP) in Ca-alginate gel beads were studied to assist in designing and operating bioreactor systems. Diffusion coefficients for chlorferon and DETP in Ca-alginate gel beads determined at conditions suitable for biodegradation studies were 2.70 x 10(-11) m(2)/s and 4.28 x 10(-11) m(2)/s, respectively. Diffusivities of chlorferon and DETP were influenced by several factors, including viscosity of the bulk solution, agitation speed, and the concentrations of diffusing substrate and immobilized cells. Diffusion coefficients increased with increasing agitation speed, probably due to poor mixing at low speed and some attrition of beads at high speeds. Diffusion coefficients also increased with decreasing substrate concentration. Increased cell concentration in the gel beads caused lower diffusivity. Theoretical models to predict diffusivities as a function of cell weight fraction overestimated the effective diffusivities for both chlorferon and DETP, but linear relations between effective diffusivity and cell weight fraction were derived from experimental data. Calcium-alginate gel beads with radii of 1.65-1.70 mm used in this study were not subject to diffusional limitations: external mass transfer resistances were negligible based on Biot number calculations and effectiveness factors indicated that internal mass transfer resistance was negligible. Therefore, the degradation rates of chlorferon and DETP inside Ca-alginate gel beads were reaction-limited. (c) 2007 Wiley Periodicals, Inc.

In vitro evaluation of chitosan coated- and uncoated-calcium alginate beads containing methyl salicylate-lactose physical mixture.

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Tamilvanan, S; Karmegam, S

2012-01-01

Methyl salicylate-lactose physical mixture (1:1 and 1:1.5 ratios) was incorporated into calcium alginate beads by a coacervation method involving an ionotropic gelation/polyelectrolyte complexation approach. This study aims to determine the influence of chitosan coating over the beads on drug entrapment efficiency (DEE) and release characteristics in artificial saliva compared to that of the uncoated beads. Changes in formulation parameters (gelation time, concentrations of Ca(2+) and alginate) resulted in decrease in DEE of chitosan-uncoated beads (p methyl salicylate-lactose physical mixture.

Effects of gelling bath on the physical properties of alginate gel beads and the biological characteristics of entrapped HepG2 cells.

Science.gov (United States)

Sun, Dongsheng; Liu, Yang; Wu, Hao; Ren, Ying; Ma, Xiaojun; Wu, Huijian; Sun, Guangwei

2018-03-01

Optimizing alginate gel beads is necessary to support the survival, proliferation, and function of entrapped hepatocytes. In this study, gelling bath was modified by decreasing calcium ion concentration and increasing sodium ion concentration. Alginate gel beads (using 36% G sodium alginate) prepared in the modified gelling bath had more homogeneous structure and better mass transfer properties compared with the traditional gelling bath that contains only calcium ions. Moreover, alginate gel beads generated in the modified gelling bath could significantly promote the HepG2 cell proliferation and the growth of cell spheroids, and maintain the albumin secretion ability similar to alginate gel beads prepared in the traditional gelling bath with only calcium ions. The mass transfer properties and cell proliferation were similar in ALG beads with different M/G ratio (36% G and 55% G) generated in the modified gelling bath, whereas they were significantly increased compared with alginate gel beads (55% G) in traditional gelling bath. These results indicated that adjusting the gelling bath was a simple and convenient method to enhance the mass transfer properties of alginate gel beads for 3D hepatocyte culture, which might provide more hepatocytes for the bioartificial liver support system. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

Antibacterial and wound healing properties of chitosan/poly(vinyl alcohol)/zinc oxide beads (CS/PVA/ZnO).

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Gutha, Yuvaraja; Pathak, Janak L; Zhang, Weijiang; Zhang, Yaping; Jiao, Xu

2017-10-01

Treatment against bacterial infection is crucial for wound healing. Development of cost-effective antibacterial agent with wound healing properties is still in high demand. In this study we aimed to design chitosan/poly(vinyl alcohol)/zinc oxide (CS/PVA/ZnO) beads as novel antibacterial agent with wound healing properties. CS/PVA/ZnO beads were synthesized, and characterized by using XRD, FTIR, SEM, and TEM analysis. Pure chitosan exhibits two peaks at 2θ=10 and 20 and the CS/PVA polymer matrix exhibit the peaks at 2θ=19.7° and another of low intensity at 2θ=11.5°. Pure ZnO shows the characteristic peaks at (100), (002), (101), (102), (110), (103), (200), and (112) that were in good agreement with wurtzite ore having hexagonal lattice structure. The antibacterial activity of CS/PVA/ZnO against Escherichia coli, and Staphylococcus aureus were evaluated with the zone of inhibition method. Antibacterial activity of CS/PVA/ZnO was higher than that of chitosan (CS) and poly(vinyl alcohol (PVA). Hemocompatibility and biocompatibility of CS/PVA/ZnO were tested in in vitro. Wound healing properties of CS/PVA/ZnO were tested in mice skin wound. CS/PVA/ZnO showed strong antimicrobial, wound healing effect, hemocompatibility and biocompatibility. Hence the results strongly support the possibility of using this novel CS/PVA/ZnO material for the anti bacterial and wound healing application. Copyright © 2017 Elsevier B.V. All rights reserved.

A comparative histological study of alginate beads as a promising controlled release delivery for mefenamic acid.

Science.gov (United States)

Sevgi, Ferhan; Kaynarsoy, Buket; Ozyazici, Mine; Pekcetin, Cetin; Ozyurt, Dogan

2008-01-01

The new mefenamic acid-alginate bead formulation prepared by ionotropic gelation method using 3 x 2(2) factorial design has shown adequate controlled release properties in vitro. In the present study, the irritation effects of mefenamic acid (MA), a prominent non-steroidal anti-inflammatory (NSAI) drug, were evaluated on rat gastric and duodenal mucosa when suspended in 0.5% (w/v) sodiumcarboxymethylcellulose (NaCMC) solution and loaded in alginate beads. Wistar albino rats weighing 200 +/- 50 g were used during in vivo animal studies. In this work, biodegradable controlled release MA beads and free MA were evaluated according to the degree of gastric or duodenal damage following oral administration in rats. The gastric and duodenal mucosa was examined for any haemorrhagic changes. Formulation code A10 showing both Case II transport and zero order drug release and t(50) % value of 5.22 h was chosen for in vivo animal studies. For in vivo trials, free MA (100 mgkg(-1)), blank and MA (100 mgkg(-1)) loaded alginate beads (formulation code A10) were suspended in 0.5% (w/v) NaCMC solution and each group was given to six rats orally by gavage. NaCMC solution was used as a control in experimental studies. In vivo data showed that the administration of MA in alginate beads prevented the gastric lesions.

Formulation optimization and evaluation of jackfruit seed starch-alginate mucoadhesive beads of metformin HCl.

Science.gov (United States)

Nayak, Amit Kumar; Pal, Dilipkumar

2013-08-01

The present study deals with the formulation optimization of jackfruit (Artocarpus heterophyllus Lam., family: Moraceae) seed starch (JFSS)-alginate mucoadhesive beads containing metformin HCl through ionotropic gelation using 3(2) factorial design. The effect of sodium alginate to JFSS ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release at 10h (R10h, %) was optimized. The optimized beads containing metformin HCl showed DEE of 97.48±3.92%, R10h of 65.70±2.22%, and mean diameter of 1.16±0.11mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads were influenced by pH of the test medium. The optimized beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier B.V. All rights reserved.

Zero-valent iron nanoparticles embedded into reduced graphene oxide-alginate beads for efficient chromium (VI) removal.

Science.gov (United States)

Lv, Xiaoshu; Zhang, Yuling; Fu, Wenyang; Cao, Jiazhen; Zhang, Jiao; Ma, Hanbo; Jiang, Guangming

2017-11-15

Zero-valent iron nanoparticles (Fe 0 NPs) technologies are often challenged by poor dispersibility, chemical instability to oxidation, and mobility during processing, storage and use. This work reports a facile approach to synthesize Fe 0 NPs embedded reduced graphene oxide-alginate beads (Fe@GA beads) via the immobilization of pre-synthesized Fe 0 NPs into graphene oxide modified alginate gel followed by a modelling and in-situ reduction process. The structure/composition characterization of the beads finds that the graphene sheets and the Fe 0 NPs (a shape of ellipsoid and a size of beads. We demonstrate that these Fe@GA beads show a robust performance in aqueous Cr(VI) removal. With a optimized Fe and alginate content, Fe@GA bead can achieve a high Cr(VI) removal efficiency and an excellent mechanical strength. The initial Cr(VI) concentration, ionic strength, temperature and especially solution pH are all critical factors to control the Fe@GA beads performance in Cr(VI) removal. Fitness of the pseudo second-order adsorption model with data suggests adsorption is the rate-controlling step, and both Langmuir and Freundlich adsorption isotherm are suitable to describe the removal behavior. The possible Cr(VI) removal path by Fe@GA beads is put forward, and the synergistic effect in this ternary system implies the potentials of Fe@GA beads in pollutant removal from water body. Copyright © 2017 Elsevier Inc. All rights reserved.

Continuous removal and recovery of lead by alginate beads, free ...

African Journals Online (AJOL)

This study examines the possibility of using Chlorella vulgaris cells in repeated lead adsorption/desorption cycles. Alginate beads and immobilized with algal cells were more effective and suitable than free cells. Consistently high lead removal (>90%) and recovery (about 100%) were achieved. Lead adsorption was mainly ...

Alginate/cellulose beads as supports for slow release of nutrient

Energy Technology Data Exchange (ETDEWEB)

Matos, Mailson de; Mattos, Bruno Dufau, E-mail: mailsondematos@gmail.com [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Magalhaes, Washington [Empresa Brasileira de Pesquisa Agropecuaria (EMBRAPA), Londrina, PR (Brazil)

2016-07-01

Full text: A total of 9 billion inhabitants is estimated by 2050, which will put a heavy pressure towards an increased cereal yield of at least 40% [1]. The smart systems for nutrient delivery could be used to increase the cropland productivity and biodegradable supports are especially needed to decrease the bio-accumulation of the synthetic materials. Thus, alginate and cellulose were chosen to encapsulate nitrogen and further release it. Briefly, the encapsulated systems were synthesized as follow: solutions containing ammonium nitrate, sodium alginate, cellulose nanofibrils and nano-silica were prepared. Each mixture was dropwise added into the calcium chloride (50 wt%) crosslinking agent solution. After the bead-forming reaction, the obtained material was filtered and dried at 60 deg C. The characterizations were performed by using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy coupled to scanning electron microscopy (SEMEDS), Fourier-transformed infrared spectroscopy (FT-IR) and release tests according to DIN EN 13266:2002. In general, the nano-silica was important for better handling the obtained beads; however, it changed the bead morphology and tended to increase the release rate of nitrogen. The best formulations were obtained with the presence of cellulose nanofibrils and few amounts of silica in the beads. At these compositions the systems follow the criteria of slow-release purposes, i.e., 15% released after 24h and less than 75% after 28 days. References: [1] Maxmen A, Nature vol. 501 (2013). (author)

A vortex-bowl disk atomizer system for the production of alginate beads in a 1500-liter fermentor.

Science.gov (United States)

Champagne, C P; Blahuta, N; Brion, F; Gagnon, C

2000-06-20

Using a model system, a concept for the immobilization of microbial cultures within alginate beads directly in a 1500-L fermentor with a height to diameter ratio of 1.85 is described. The system is comprised of a 60-cm diameter bowl fixed to the top of an agitation shaft, where calcium-ion-rich media is continuously recirculated from the bulk solution to the bowl. The rotation of the shaft and bowl creates a climbing film (vortex) of solution. An atomizing disk centrally recessed within the bowl sprays an alginate solution into the climbing film where the droplets harden into beads. The effect of heat treatment on the alginate solution on resulting bead properties was examined. The sterilization operation did not appear to have a major effect on the alginate bead mechanical properties of firmness and elasticity which was much more a function of alginate concentration. Beads of various sizes were produced by the unit. The system was characterized by the dimensionless numbers Reomega = (omega x rho x D(2))/mu and ReQ = (Q x rho)/(mu x D). At Reomega and ReQ values less than 500 and 0.15, respectively, the mechanism was direct drop. Parent droplets followed by satellite droplets were observed. When either the flow rate or speed was increased, filaments formed predominantly, which was unwanted in this system because filament breakdown into smaller droplets does not occur due to the proximity of the disk to the climbing film in the bowl. This system could be applied to the immobilization of microorganisms, as well as plant or animal cell cultures, and for other sizes or fermentors. The overflow from the bowl carries the gellified beads into the bulk solution where immobilized cells could act upon the fermentation media. Copyright 2000 John Wiley & Sons, Inc.

Improving the Stability of Astaxanthin by Microencapsulation in Calcium Alginate Beads.

Directory of Open Access Journals (Sweden)

Shen-Fu Lin

Full Text Available There has been considerable interest in the biological functions of astaxanthin and its potential applications in the nutraceutical, cosmetics, food, and feed industries in recent years. However, the unstable structure of astaxanthin considerably limits its application. Therefore, this study reports the encapsulation of astaxanthin in calcium alginate beads using the extrusion method to improve its stability. This study also evaluates the stability of the encapsulated astaxanthin under different storage conditions. The evaluation of astaxanthin stability under various environmental factors reveals that temperature is the most influential environmental factor in astaxanthin degradation. Stability analysis shows that, regardless of the formulation used, the content of astaxanthin encapsulated in alginate beads remains above 90% of the original amount after 21 days of storage at 25°C. These results suggest that the proposed technique is a promising way to enhance the stability of other sensitive compounds.

Alginate-based polysaccharide beads for cationic contaminant sorption from water

Science.gov (United States)

Mei Li; Thomas Elder; Gisela Buschle-Diller

2016-01-01

Massive amounts of agricultural and industrial water worldwide are polluted by different types of contaminants that harm the environment and impact human health. Removing the contaminants from effluents by adsorbent materials made from abundant, inexpensive polysaccharides is a feasible approach to deal with this problem. In this research, alginate beads combined with...

Immobilization of Lipase using Alginate Hydrogel Beads and Enzymatic Evaluation in Hydrolysis of p-Nitrophenol Butyrate

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shuang; Shang, Wenting; Yang, Xiaoxi; Zhang, Shujuan; Zhang, Xiaogang; Chen, Jiawei [Renmin Univ. of China, Beijing (China)

2013-09-15

The immobilization of enzyme is one of the key issues both in the field of enzymatic research and industrialization. In this work, we reported a facile method to immobilize Candida Antarctica lipase B (CALB) in alginate carrier. In the presence of calcium cation, the enzyme-alginate suspension could be cross-linked to form beads with porous structure at room temperature, and the enzyme CALB was dispersed in the beads. Activity of the enzyme-alginate composite was verified by enzymatic hydrolysis reaction of p-nitrophenol butyrate in aqueous phase. The effects of reaction parameters such as temperature, pH, embedding and lyophilized time on the reactive behavior were discussed. Reuse cycle experiments for the hydrolysis of p-nitrophenol butyrate demonstrated that activity of the enzyme-alginate composite was maintained without marked deactivation up to 6 repeated cycles.

Removal of organic dyes by magnetic alginate beads.

Science.gov (United States)

Rocher, Vincent; Siaugue, Jean-Michel; Cabuil, Valérie; Bee, Agnès

2008-02-01

This study deals with the development of a clean and safe process for water pollution remediation. We have synthesized a magnetic adsorbent in order to develop a solid-phase extraction process assisted by a magnetic field. To follow an 'ecoconception' approach, magnetic beads containing magnetic nanoparticles and activated carbon are prepared with a biopolymer extracted from algae, sodium alginate. The use of renewable bioresources of low cost and those disposable in large amount allows the development of a product with a low impact on the environment. The adsorption properties of activated carbon and magnetic properties of iron oxide nanoparticles are combined to produce an interesting magnetic composite. Synthesis and characterization of the magnetic beads have been reported. Their adsorption capacity was investigated by measuring the removal of two dyes (methylene blue and methyl orange) of different charges from aqueous solutions. The efficiency of the beads has been compared with that of non-encapsulated activated carbon. The effects of initial dye concentration, pH and calcium content of the beads have been studied. Adsorption kinetics experiments have been carried out and the data have been well fitted by a pseudo-second-order equation.

Dye decolorization and detoxification potential of Ca-alginate beads immobilized manganese peroxidase.

Science.gov (United States)

Bilal, Muhammad; Asgher, Muhammad

2015-12-10

In view of compliance with increasingly stringent environmental legislation, an eco-friendly treatment technology of industrial dyes and effluents is a major environmental challenge in the color industry. In present study, a promising and eco-friendly entrapment approach was adopted to immobilize purified manganese peroxidase (MnP) produced from an indigenous strain of Ganoderma lucidum IBL-05 on Ca-alginate beads. The immobilized MnP was subsequently used for enhanced decolorization and detoxification of textile reactive dyes). MnP isolated from solid-state culture of G. lucidum IBL-05, presented highest immobilization yield (83.9 %) using alginate beads prepared at optimized conditions of 4 % (w/v) sodium alginate, 2 % (w/v) Calcium chloride (CaCl2) and 0.5 mg/ml enzyme concentration. Immobilization of MnP enhanced optimum temperature but caused acidic shift in optimum pH of the enzyme. The immobilized MnP showed optimum activity at pH 4.0 and 60 °C as compared to pH 5.0 and 35 °C for free enzyme. The kinetic parameters K(m) and V(max) of MnP were significantly improved by immobilization. The enhanced catalytic potential of immobilized MnP led to 87.5 %, 82.1 %, 89.4 %, 95.7 % and 83 % decolorization of Sandal-fix Red C4BLN, Sandal-fix Turq Blue GWF, Sandal-fix Foron Blue E2BLN, Sandal-fix Black CKF and Sandal-fix Golden Yellow CRL dyes, respectively. The insolubilized MnP was reusable for 7 repeated cycles in dye color removal. Furthermore, immobilized MnP also caused a significant reduction in biochemical oxygen demand (BOD) (94.61-95.47 %), chemical oxygen demand (COD) (91.18-94.85 %), and total organic carbon (TOC) (89.58-95 %) of aqueous dye solutions. G. lucidum MnP was immobilized in Ca-alginate beads by entrapment method to improve its practical effectiveness. Ca-alginate bound MnP was catalytically more vigorous, thermo-stable, reusable and worked over wider ranges of pH and temperature as compared to its free counterpart. Results of cytotoxicity like

Preservation of viability and antibacterial activity of Lactobacillus spp. in calcium alginate beads.

Science.gov (United States)

Brachkova, Mariya I; Duarte, Maria A; Pinto, João F

2010-12-23

The objective of the study was to produce calcium alginate beads able to deliver Lactobacillus spp. (Lactobacillus plantarum, Lactobacillus rhamnosus GG, Lactobacillus bulgaricus and Lactobacillus lactis) with preserved viability and antibacterial activity. Four types of beads, containing entrapped (E), surface and entrapped (ES), surface (S) and concentrated surface and entrapped lactobacilli (C(ES)) were prepared and physically characterized. The antibacterial activity of lactobacilli cultures before and after immobilization, freeze-drying and throughout storage was studied in relationship to the viable number of lactobacilli. Multi-resistant clinical isolates (methicillin-resistant Staphylococcus aureus, vancomycine-resistant Enterococcus faecalis, VIM-2-metalo-β-lactamase producing Pseudomonas aeruginosa and CTX-M-15-β-lactamase producing strains: Escherichia coli and Klebsiella pneumoniae) were used as indicator strains. Alginate beads in which lactobacilli proliferated to the beads surface (ES and C(ES)) differed significantly from the other types of beads in their physicochemical properties, showing smoother surface morphology, more spherical shape, bigger weight, lower calcium content, density and crushing force. Lactobacilli cultures, at high cell concentrations (10(8)cfu/ml) were active against both Gram-positive and negative multi-resistant bacteria. Beads containing both entrapped and surface lactobacilli (ES) resulted in viability and antibacterial activity most similar to non-processed lactobacilli cultures. The viability and antibacterial activity of the immobilized lactobacilli remained stable after 6 months storage. Copyright © 2010 Elsevier B.V. All rights reserved.

Tapioca starch blended alginate mucoadhesive-floating beads for intragastric delivery of Metoprolol Tartrate.

Science.gov (United States)

Biswas, Nikhil; Sahoo, Ranjan Kumar

2016-02-01

The objective of the study was to develop tapioca starch blended alginate mucoadhesive-floating beads for the intragastric delivery of Metoprolol Tartrate (MT). The beads were prepared by ionotropic gelation method using calcium chloride as crosslinker and gas forming calcium carbonate (CaCO3) as floating inducer. The alginate gel beads having 51-58% entrapped MT showed 90% release within 45 min in gastric medium (pH 1.2). Tapioca starch blending markedly improved the entrapment efficiency (88%) and sustained the release for 3-4 h. A 12% w/w HPMC coating on these beads extended the release upto 9-11 h. In vitro wash off and buoyancy test in gastric media revealed that the beads containing CaCO3 has gastric residence of more than 12 h. In vitro optimized multi-unit formulation consisting of immediate and sustained release mucoadhesive-floating beads (40:60) showed good initial release of 42% MT within 1h followed by a sustained release of over 90% for 11 h. Pharmacokinetic study performed in rabbit model showed that the relative oral bioavailability of MT after administration of oral solution, sustain release and optimized formulation was 51%, 67% and 87%, respectively. Optimized formulation showed a higher percent inhibition of isoprenaline induced heart rate in rabbits for almost 12 h. Copyright © 2015 Elsevier B.V. All rights reserved.

Electrophoretic co-deposition of polyvinyl alcohol (PVA) reinforced alginate-Bioglass® composite coating on stainless steel: mechanical properties and in-vitro bioactivity assessment.

Science.gov (United States)

Chen, Qiang; Cabanas-Polo, Sandra; Goudouri, Ourania-Menti; Boccaccini, Aldo R

2014-07-01

PVA reinforced alginate-bioactive glass (BG) composite coatings were produced on stainless steel by a single step electrophoretic deposition (EPD) process. The present paper discusses the co-deposition mechanism of the three components and presents a summary of the relevant properties of the composite coatings deposited from suspensions with different PVA concentrations. Homogeneous composite coatings with compact microstructure and increased thickness, i.e. as high as 10 μm, were observed by scanning electron microscopy (SEM). The surface roughness of coatings with different PVA contents was slightly increased, while a significant increase of water contact angles due to PVA addition was detected and discussed. Improved adhesion strength of coatings containing different amounts of PVA was quantitatively and qualitatively confirmed by pull-off adhesion and cycled bending tests, respectively. In-vitro bioactivity tests were performed in simulated body fluid (SBF) for 0.5, 1, 2, 4, 7, and 14 days, respectively. The decomposition rate of the coatings was reduced with PVA content, and rapid hydroxyapatite forming ability of the composite coatings in SBF was confirmed by FTIR and XRD analyses. According to the results of this study, composite alginate-Bioglass® bioactive coatings combined with PVA are proposed as promising candidates for dental and orthopedic applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Alginate submicron beads prepared through w/o emulsification and gelation with CaCl2 nanoparticles

NARCIS (Netherlands)

Paques, J.P.; Linden, van der E.; Rijn, van C.J.M.; Sagis, L.M.C.

2013-01-01

A simple method for preparing gelled alginate beads with a diameter smaller than 5 µm is described. A 1% alginate solution and a medium chain triglyceride (MCT) oil are used to prepare a water-in-oil (w/o) emulsion, stabilized by polyglycerol polyricinoleate. CaCl2 nanoparticles with dimensions in

Comparison of four supports for adsorption of reactive dyes by immobilized Aspergillus fumigatus beads

Institute of Scientific and Technical Information of China (English)

WANG Bao-e; HU Yong-you

2007-01-01

Four materials, sodium carboxymethylcellulose (Na-CMC), sodium alginate (SA), polyvinyl alcohol (PVA), and chitosan (CTS), were prepared as supports for entrapping fungus Aspergillus fumigatus. The adsorption of synthetic dyes, reactive brilliant blue KN-R, and reactive brilliant red K-2BP, by these immobilized gel beads and plain gel beads was evaluated. The adsorption efficiencies of reactive brilliant red K-2BP and reactive brilliant blue KN-R by CTS immobilized beads were 89.1% and 93.5% in 12 h, respectively. The adsorption efficiency by Na-CMC immobilized beads was slightly lower than that of mycelial pellets. But the dye culture mediums were almost completely decolorized in 48 h using the above-mentioned two immobilized beads (exceeding 95%). The adsorption efficiency by SA immobilized beads exceeded 92% in 48 h. PVA-SA immobilized beads showed the lowest adsorption efficiency, which was 79.8% for reactive brilliant red K-2BP and 92.5% for reactive brilliant blue KN-R in 48 h. Comparing the adsorption efficiency by plain gel beads, Na-CMC plain gel beads ranked next to CTS ones. SA and PVA-SA plain gel beads hardly had the ability of adsorbing dyes. Subsequently, the growth of mycelia in Na-CMC and SA immobilized beads were evaluated. The biomass increased continuously in 72 h. The adsorption capacity of reactive brilliant red K-2BP and reactive brilliant blue KN-R by Na-CMC immobilized beads was 78.0 and 86.7 mg/g, respectively. The SEM micrographs show that the surface structure of Na-CMC immobilized bead is loose and finely porous, which facilitates diffusion of the dyes.

Alginate-Poly(ethylene glycol Hybrid Microspheres for Primary Cell Microencapsulation

Directory of Open Access Journals (Sweden)

Redouan Mahou

2014-01-01

Full Text Available The progress of medical therapies, which rely on the transplantation of microencapsulated living cells, depends on the quality of the encapsulating material. Such material has to be biocompatible, and the microencapsulation process must be simple and not harm the cells. Alginate-poly(ethylene glycol hybrid microspheres (alg-PEG-M were produced by combining ionotropic gelation of sodium alginate (Na-alg using calcium ions with covalent crosslinking of vinyl sulfone-terminated multi-arm poly(ethylene glycol (PEG-VS. In a one-step microsphere formation process, fast ionotropic gelation yields spherical calcium alginate gel beads, which serve as a matrix for simultaneously but slowly occurring covalent cross-linking of the PEG-VS molecules. The feasibility of cell microencapsulation was studied using primary human foreskin fibroblasts (EDX cells as a model. The use of cell culture media as polymer solvent, gelation bath, and storage medium did not negatively affect the alg-PEG-M properties. Microencapsulated EDX cells maintained their viability and proliferated. This study demonstrates the feasibility of primary cell microencapsulation within the novel microsphere type alg-PEG-M, serves as reference for future therapy development, and confirms the suitability of EDX cells as control model.

Efficient biodegradation of cyanide and ferrocyanide by Na-alginate beads immobilized with fungal cells of Trichoderma koningii.

Science.gov (United States)

Zhou, Xiaoying; Liu, Lixing; Chen, Yunpeng; Xu, Shufa; Chen, Jie

2007-09-01

Cyanide or metal cyanide contaminations have become serious environmental and food-health problems. A fungal mutant of Trichoderma koningii, TkA8, constructed by restriction enzyme-mediated integration, has been verified to have a high cyanide degradation ability in our previous study. In this study, the mutant cells were entrapped in sodium-alginate (Na-alginate) immobilization beads to degrade cyanide and ferrocyanide in a liquid mineral medium. The results showed that the fungus in immobilization beads consisting of 3% Na-alginate and 3% CaCl2 could degrade cyanide more efficiently than a nonimmobilized fungal culture. For maximum degradation efficiency, the optimal ratio of Na-alginate and wet fungal biomass was 20:1 (m/m) and the initial pH was 6.5. In comparison, cell immobilization took at least 3 and 8 days earlier, respectively, to completely degrade cyanide and ferrocyanide. In addition, we showed that the immobilized beads could be easily recovered from the medium and reused for up to 5 batches without significant losses of fungal remediation abilities. The results of this study provide a promising alternative method for the large-scale remediation of soil or water systems from cyanide contamination.

Speciation-dependent studies on removal of arsenic by iron-doped calcium alginate beads

International Nuclear Information System (INIS)

Banerjee, Anupam; Nayak, Dalia; Lahiri, Susanta

2007-01-01

This work aims to study the differential attitude of Fe-doped calcium alginate (Fe-CA) beads towards As(III) and As(V) compounds so that speciation-dependent environmentally sustainable methodologies can be developed for removal of arsenic from contaminated water. Throughout the experiment, 76 As has been used as precursor of stable arsenic. The affinity of As(V) towards the Fe-CA beads is greater than that of As(III). Removal efficiency of Fe-CA beads for As(V) increases with increasing number of beads and longer shaking times. At pH 3, 30 Fe-CA beads remove As(V) completely from a solution containing 20 mg kg -1 As(V). The technique has been successfully applied to the ground water collected from an arsenic-contaminated area

Iron Nanoparticles (Fe3O4 Used to Synthesize Magnetic Sodium Alginate Hydrogel Beads for the Removal of Basic Blue 159 from Aqueous Solutions

Directory of Open Access Journals (Sweden)

Atiyeh Ghajarieh

2017-11-01

Full Text Available Dyes are a main source of pollutants in textile plant effluents. Due to their molecular structure, they are usually toxic, carcinogenous, and persistent in the environment. The aim of the present work was to explore the removal of basic blue159 (BB159 using magnetic sodium alginate hydrogel beads. Magnetic sodium alginate hydrogel beads were initially synthesized  accoriodng to Rocher method using CaCl2 as a crosslink agent. Fourier transform infrared spectroscopy (FTIR was then employed to examine the functional groups on the surface of the magnetic sodium alginate hydrogel beads. In a third stage, the magnetic properties of the beads were measured using a vibrating sample magnetometer (VSM and the magnetic parameters were calculated. Subsequently, the effects of such parameters as adsorbent dosage, pH, initial concentration of dye, and contact time were evaluated on the BB159 removal efficiency of the adsorbent used. Finally, the Langmuir, Freundlich, Temkin, and B.E.T models were exploited to study the adsorption isotherm of BB159 onto the magnetic sodium alginate hydrogel beads. It was found that the magnetic sodium alginate beads possess both –COO and –OH groups that play important roles in the adsorption of the positively charged BB159 dye. A saturation magnetization equal to 21/8(emu/g was obtained for the sodium alginate beads/nano Fe3O4. Results also revealed that the highest dye removal from aqueous solutions was achieved at pH=11 in 120 minutes for 9 grams of the adsorbent. The study indicated that BB159 removal using the magnetic sodium alginate hydrogel beads as the adsorbent obeys the Langmuir model. Moreover, it was shown that the efficiency of the process for BB159 removal from aqueous solutions was satisfactory (85%.

Development of alginate gel beads with a potential use in the treatment against acute lead poisoning.

Science.gov (United States)

Tahtat, Djamel; Bouaicha, Malika Nawel; Benamer, Samah; Nacer-Khodja, Assia; Mahlous, Mohamed

2017-12-01

The objective was to develop alginate beads that could adsorb lead ions in gastric pH, in view to preconize their use in gastric lavage following lead poisoning. The swelling measurements of both, dry and hydrated beads, were carried out in simulated gastric fluid (SGF). The sorption kinetics was examined at lead concentrations ranging from 50 to 200mg/l. Calcium released during the sorption process was investigated. The swelling rate of the dry beads increased considerably with time increase and reached the equilibrium at 736% after 240min; concerning the hydrated beads, the equilibrium swelling reached 139% after 180min. The adsorption of Pb (II) in SGF by dry beads increased with the increase of time and initial lead concentration. The adsorption kinetics of Pb ions by hydrated alginate beads indicated a rapid binding of Pb ions to the sorbent during the first 15min for all the concentrations, followed by a slow increase until the equilibrium was reached after 90min. The adsorption capacity of Pb ions increased with the increase of the storage time in water at 4°C and with the weight. The amount of Ca 2+ released by the beads increased with the increase of Pb ions a rate. Copyright © 2017 Elsevier B.V. All rights reserved.

Production of tannase by the immobilized cells of Bacillus licheniformis KBR6 in Ca-alginate beads.

Science.gov (United States)

Mohapatra, P K D; Mondal, K C; Pati, B R

2007-06-01

The present study was aimed at finding the optimal conditions for immobilization of Bacillus licheniformis KBR6 cells in calcium-alginate (Ca-alginate) beads and determining the operational stability during the production of tannin-acyl-hydrolase (tannase) under semicontinous cultivation. The active cells of B. licheniformis KBR6 were immobilized in Ca-alginate and used for the production of tannase. The influence of alginate concentration (5, 10, 20 and 30 g l(-1)) and initial cell loading on enzyme production were studied. The production of tannase increased significantly with increasing alginate concentration and reached a maximum enzyme yield of 0.56 +/- 0.03 U ml(-1) at 20 g l(-1). This was about 1.70-fold higher than that obtained by free cells. The immobilized cells produced tannase consistently over 13 repeated cycles and reached a maximum level at the third cycle. Scanning electron microscope study indicated that the cells in Ca-alginate beads remain in normal shape. The Ca-alginate entrapment is a promising immobilization method of B. licheniformis KBR6 for repeated tannase production. Tannase production by immobilized cells is superior to that of free cells because it leads to higher volumetric activities within the same period of fermentation. This is the first report of tannase production from immobilized bacterial cells. The bacterium under study can produce higher amounts of tannase with respect to other fungal strains within a short cultivation period.

Bioethanol Production by Calcium Alginate-Immobilised St1 Yeast System: Effects of Size of Beads, Ratio and Concentration

Directory of Open Access Journals (Sweden)

Masniroszaime Md Zain

2011-12-01

Full Text Available Immobilized yeast-cell technology posses several advantages in bioethanol production due to its potential to increase the ethanol yield by eliminating unit process used. Thus, process expenses in cell recovery and reutilization can be minimised. The aim of this study is to investigate the influence of three parameters (substrate concentrations, size of alginate beads and ratio of volume of beads to volume of medium on local isolated yeast (ST1 which immobilized using calcium alginate fermentation system. The most affected ethanol production by calcium alginate-immobilised ST1 yeast system were ratio of volume of the beads to the volume of substrate and concentration of LBS. Highest theoretical yield, 78% was obtained in ST1-alginate beads with the size of beads 0.5cm, ratio volume of beads to the volume of LBS media 0.4 and 150g/l concentration of LBS.ABSTRAK: Teknologi sel yis pegun memiliki beberapa kelebihan dalam penghasilan bioetanol kerana ia berpotensi meningkatkan pengeluaran etanol dengan menyingkirkan unit proses yang digunakan. Maka, proses pembiayaan dalam perolehan sel dan penggunaan semula boleh dikurangkan. Tujuan kajian ini adalah untuk mengkaji pengaruh tiga parameter (kepekatan substrat, saiz manik alginat dan nisbah isipadu manik terhadap isipadu bahantara ke atas sel tempatan terasing (local isolated yeast (ST1 yang dipegun menggunakan sistem penapaian kalsium alginat. Penghasilan etanol yang paling berkesan dengan menggunakan sistem yis ST1 kalsium alginat-pegun adalah dengan kadar nisbah isipadu manik terhadap isipadu substrat dan kepekatan LBS. Kadar hasil teori tertinggi iaitu 78% didapati menerusi manik alginat-ST1 dengan saiz manik 0.5cm, nisbah isipadu 0.4 terhadap perantara LBS dan kepekatan LBS sebanyak 150g/l. Normal 0 false false false EN-US X-NONE X-NONE

Butyl acetate synthesis using immobilized lipase in calcium alginate beads

International Nuclear Information System (INIS)

Mohd Zulkhairi Abdul Rahim; Lee, Pat M.; Lee, Kong H.

2008-01-01

The esterification reaction of acetic acid and n-butanol using immobilized lipase encapsulated in calcium alginate beads (Lipase - CAB) and in chitosan coated calcium alginate beads (Lipase-CCAB) in n-hexane under mild reaction conditions were studied. Effects of temperature and substrate concentration (acetic acid and n-butanol) using Lipase - CAB, Lipase - CCAB and free lipase on the esterification reaction and their thermal stability towards esterification reaction were investigated. Results of temperature studies showed that the butyl acetate conversion increased with increase of temperature and reached the highest yield of about 70% around 50 degree Celsius for both immobilized systems but the yield of product catalyzed by free enzyme decreased as temperature was increased. Thermal stabilities studies showed that the Lipase-CCAB and Lipase-CAB were stable throughout the temperature range of 30-60 degree Celsius. However, free lipase became less stable at temperatures higher than 50 degree Celsius. The substrates, n-butanol and acetic acid exerted different effects on the esterification reaction and the reaction was favoured by higher acetic acid concentration than butanol. Kinetics parameters, Km and Vmax values for both substrates and the specific activities of the three enzyme system were also determined. The beads morphology was examined using SEM. Batch-wise operational stability studies for both immobilized systems demonstrated that the immobilized lipase performed better in the batch wise reactor system than the continuous bioreactor system and that the immobilized lipase remained active for at least 5 cycles of batch wise esterification reactions. (author)

Alginate-caseinate composites: Molecular interactions and characterization of cross-linked beads for the delivery of anticandidals.

Science.gov (United States)

Khlibsuwan, Rapee; Khunkitti, Watcharee; Pongjanyakul, Thaned

2018-04-19

Polysaccharide-protein composites offer potential utility for the delivery of drugs. The objectives of this work were to investigate the molecular interactions between sodium alginate (SA) and sodium caseinate (SC) in dispersions and films and to characterize calcium alginate (CA) beads mixed with SC for the delivery of fluconazole (FZ) and clotrimazole (CZ). The results demonstrated that SA could interact with SC, which caused a viscosity synergism in the dispersions. Hydrogen bonding between the carboxyl or hydroxyl groups of SA and the amide groups of SC led to the formation of soluble complexes that could reinforce the CA beads prepared by calcium cross-linking. The SC-CA beads provided higher drug entrapment efficiency, lower water uptake and erosion, and slower drug release than for the CA beads. The loaded FZ was an amorphous form, but CZ crystals were embedded in the bead matrix due to the low water solubility of this drug. However, SC micellization could enhance the water solubility and efficacy of CZ against Candida albicans. This finding indicates that SA can interact with SC via hydrogen bonding to form complexes and that the anticandidal-loaded SC-CA beads can be used as drug delivery systems and drug reservoirs in tablets for oral candidiasis. Copyright © 2018 Elsevier B.V. All rights reserved.

Hybrid membranes PVA/silicon for use in fuel cells; Membranas hibridas de PVA/silica para aplicacao em celula a combustivel

Energy Technology Data Exchange (ETDEWEB)

Aguiar, Liz C.V. de; Almeida, Raquel D. de; Gomes, Ailton de S. [Universidade Federal do Rio de Janeiro - UFRJ, Instituto de Macromoleculas Professora Eloisa Mano - IMA, RJ (Brazil)], e-mail: lizcontino@ima.ufrj.br; Ramos Filho, Florencio G. de [Centro Universitario Estadual da Zona Oeste - UEZO, Rio de Janeiro, RJ (Brazil)

2011-07-01

Hybrids organic-inorganic membranes PVA-silica have been prepared using sol-gel process in situ with the objective of study the influence of inorganic particles incorporation on the water uptake, pervaporation and proton conductivity of PVA membranes. The silica was constituted of mercaptopropyltrimethoxysilane (MPTMS) with or without the mixture with the tetra ethoxysilane (TEOS). The hybrids membranes were oxidated to convert the -SH groups in -SO{sub 3}H groups, becoming them proton conducting. The hybrids membranes not oxidated showed lesser water uptake and pervaporated material, probably, due to the formation of crosslink that restricted the swell of the PVA membrane. The protonic conductivity of the hybrid membranes after the oxidation was up to 26 times bigger than of the membrane not oxidated. (author)

Preparation of Bio-beads and Their Atrazine Degradation Characteristics

Institute of Scientific and Technical Information of China (English)

BI Hai-tao; ZHANG Lan-ying; LIU Na; ZHU Bo-lin

2011-01-01

Screened atrazine-mineralizing bacterium-Pseudomonas W4 was embedded inside an improved PVAH3BO3 embedment matrix to make bio-beads to degrade atrazine. The atrazine degradation characteristics were studied. The preparation procedure of bio-beads was as follows: (1) preparing a mixture of 100, 12.5, 10, 1.5 and 1 g/L PVA, bentonite(Ca), activated carbon powder, sodium alginate and centrifuged Pseudomonas W4 bacterium, respectively; (2) the mixture was dropped into a gently stirred cross linker solution(pH=6.7) and cured at 10 ℃ for 24 h.The optimal atrazine degradation conditions by bio-beads were as follows: pH=7, the auxiliary carbon source was glucose, and the concentration of glucose was greater than 325 mg/L. The bio-beads demonstrated stronger tolerance ability than the free microorganism to the increase of PCBs, hydrogen ion and hydroxide ion. SEM images show the uniform distribution of the microorganism inside bio-beads and the porous cross-linked structure of bio-beads which provides excellent mass transfer capacity.

Adsorption of arsenic by activated carbon, calcium alginate and their composite beads.

Science.gov (United States)

Hassan, A F; Abdel-Mohsen, A M; Elhadidy, H

2014-07-01

The present investigation deals with preparation of three different adsorbent materials namely; potassium hydroxide activated carbon based apricot stone (C), calcium alginate beads (G) and calcium alginate/activated carbon composite beads (GC) were used for the removal of arsenic. The prepared adsorbent materials were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), N2-adsorption at -196°C and point of zero charge. From the obtained results, it was found that the porosity, surface area and total pore volume of the adsorbent material C>GC>G respectively, however, the G adsorbent has more acidic function group than the other adsorbents. The influence of pH, time, temperature and initial concentration of arsenic(V) were studied and optimized. GC exhibits the maximum As(V) adsorption (66.7mg/g at 30°C). The adsorption of arsenic ions was observed to follow pseudo-second order mechanism as well as the thermodynamic parameters confirm also the endothermic spontaneous and a physisorption process. Copyright © 2014 Elsevier B.V. All rights reserved.

Lipase in biphasic alginate beads as a biocatalyst for esterification of butyric acid and butanol in aqueous media.

Science.gov (United States)

Ng, Choong Hey; Yang, Kun-Lin

2016-01-01

Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp. Copyright © 2015 Elsevier Inc. All rights reserved.

Sodium lauryl sulfate impedes drug release from zinc-crosslinked alginate beads: switching from enteric coating release into biphasic profiles.

Science.gov (United States)

Taha, Mutasem O; Nasser, Wissam; Ardakani, Adel; Alkhatib, Hatim S

2008-02-28

The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xanthan gum. Calcium cross-linking failed to reproduce the same behavior, probably due to the mainly ionic nature of calcium-carboxylate bonds compared to the coordinate character of their zinc-carboxylate counterparts. Apparently, moderate levels of SLS repel water penetration into the beads, and therefore minimize chlorpheniramine release. However, higher SLS levels seem to discourage polymeric cross-linking and therefore allow biphasic drug release.

Effect of algal density in bead, bead size and bead concentrations ...

African Journals Online (AJOL)

Laboratory experiments were performed to study nitrogen and phosphorus uptake by the unicellular green microalga Chlorella vulgaris immobilized in calcium alginate beads. Different cell stockings in beads, different bead sizes and different algal bead concentrations in wastewaters were tested. Significant higher nutrients ...

Selective removal for Pb2+ in aqueous environment by using novel macroreticular PVA beads

International Nuclear Information System (INIS)

Zhang Yun; Li Yanfeng; Li Xiaoli; Yang Liuqing; Bai Xue; Ye Zhengfang; Zhou Lincheng; Wang Liyuan

2010-01-01

Batch sorption experiments were conducted using macroreticular poly(vinyl alcohol) (MR-PVA) beads as a adsorbent to adsorb Pb(II) from both single component system and multi-metal solution in which experimental parameters were studied including solution pH, contact time, adsorbent dose, initial concentration of metal ions and ionic strength. The equilibrium isotherms were determined at pH 6 under constant ionic strength and at different temperatures. The results showed that the maximum adsorption capacity of Pb(II) (213.98 mg g -1 ) with 1 g L -1 of adsorbent was observed at 300 mg L -1 at an initial pH value of 6.0 under temperature of 288 K. Removals of about 60% occurred in 30 min, and equilibrium was attained at around 150 min. The equilibrium data for the adsorption of Pb(II) on MR-PVA beads was tested with various adsorption isotherm models among which three models were found to be suitable for the Pb(II) adsorption. In addition, the kinetic adsorption fitted well to the pseudo-second-order model and the corresponding rate constants were obtained. Thermodynamic aspects of the adsorption process were also investigated.

Degradation of trichloroethylene (TCE) by nanoscale zero-valent iron (nZVI) immobilized in alginate bead

Energy Technology Data Exchange (ETDEWEB)

Kim, Hojeong [Division of Water and Environment, Korea Environment Institute (KEI), Seoul (Korea, Republic of); Hong, Hye-Jin; Jung, Juri; Kim, Seong-Hye [Dept. of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejon (Korea, Republic of); Yang, Ji-Won, E-mail: jwyang@kaist.ac.kr [Dept. of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejon (Korea, Republic of)

2010-04-15

Abstracts: Nowadays, many researchers have studied the environmental application of the nanoscale zero-valent iron (nZVI) and several field applications for the groundwater remediation have been reported. Still, there are many concerns on the fate and transport of the nZVI and the corresponding risks. To avoid such concerns, it was investigated to immobilize nZVI in a support and then it was applied to degrade trichloroethylene (TCE). The nZVI and palladium-doped nZVI (Fe(0)- and Fe/Pd-alginate) were immobilized in the alginate bead where ferric and barium ions are used as the cross-linking cations of the bead. According to TEM (transmission electron microscopy), the size of the immobilized ZVI was as small as a few nanometers. From the surface analysis of the Fe/Pd-alginate, it is found that the immobilized nZVI has the core-shell structure. The core is composed of single crystal Fe{sup 0}, while most of irons on the surface are oxidized to Fe{sup 3+}. When 50 g/L of Fe/Pd-alginate (3.7 g Fe/L) was introduced to the aqueous solution, >99.8% of TCE was removed and the release of metal from the support was <3% of the loaded iron. The removal of TCE by Fe/Pd-alginate followed pseudo-first-order kinetics. The observed pseudo-first-order reaction constant (k{sub obs}) of Fe/Pd-alginate was 6.11 h{sup -1} and the mass normalized rate constant (k{sub m}) was 1.6 L h{sup -1} g{sup -1}. The k{sub m} is the same order of magnitude with that of iron nanoparticles. In conclusion, it is considered that Fe/Pd-alginate can be used efficiently in the treatment of chlorinated solvent.

The Drug Release Profile from Calcium-induced Alginate Gel Beads Coated with an Alginate Hydrolysate

Directory of Open Access Journals (Sweden)

Susumu Kawashima

2007-11-01

Full Text Available Calcium-induced alginate gel bead (Alg-Ca coated with an alginate hydrolysate(Alg, e.g. the guluronic acid block (GB was prepared and the model drug, hydrocortisonerelease profiles were investigated under simulated gastrointestinal conditions. Theirmolecular weights were one sixth or one tenth that of Alg and the diffraction patterns of thehydrolysates resembled that of Alg. The drug release rate from Alg-Ca coated with GBapparently lowered than that of Alg-Ca (coating-free in the gastric juice (pH1.2. And thecoating did not resist the disintegration of Alg-Ca in the intestinal juice (pH 6.8 and thegel erosion accelerated the drug release. On the other hand, for the coated Alg-Cacontaining chitosan, the drug release showed zero-order kinetics without rapid erosion ofAlg-Ca. The drug release rate from Alg-Ca was able to be controlled by the coating andmodifying the composition of the gel matrix.

Numerical Modelling of Insulin and Amyloglucosidase Release from Swelling Ca-Alginate Beads

DEFF Research Database (Denmark)

Rasmussen, Michael R.; Snabe, T.; Pedersen, Lars Haastrup

2003-01-01

The release of insulin hexamer (39 kD) and amyloglucosidase (AMG, 97 kD), entrapped in spherical Ca–alginate beads, was investigated. While the release of insulin could be described solely by diffusion this was not the case for the 1.6 (r m /r m) larger AMG protein, where rm is the Stokes....... Although it should be expected that the effective diffusion coefficient of AMG is only slightly lower than that of insulin, the results show that the effective diffusions coefficient of AMG was found to be much smaller. In the case of AMG, it was shown that including bead size changes and the resulting...

海藻酸镧颗粒除氟研究：吸附剂物性和吸附机理%Fluoride Removal by Lanthanum Alginate Bead:Adsorbent Characterization and Adsorption Mechanism

Institute of Scientific and Technical Information of China (English)

霍亚坤; 丁文明; 黄霞; 徐静年; 赵梦华

2011-01-01

Lanthanum alginate bead is a new, highly active adsorbent. In the present study, we investigated its adsorption performance and its adsorption mechanism. The adsorption isotherm for fluoride onto lanthanum alginate bead fits the Langmuir model well, and the maximum adsorption capacity is 197.2 mg·g-1. X-ray diffraction shows the amorphous nature of lanthanum alginate bead, which allows for better accessibility to fluoride and thus better activity. Infrared spectra of lanthanum alginate bead before and after adsorption confirm its stable skeletal structure.Scanning electron microscopy shows that the dense surface structure of the adsorbent appear cracks after adsorption.The adsorption mechanism of lanthanum alginate bead is considered as an ion exchange between F- and Cl- or OH-,as verified from the adsorbent and the solution by pH effect, energy dispersive X-ray, and ion chromatography.

Alginate-okra gum blend beads of diclofenac sodium from aqueous template using ZnSO4 as a cross-linker.

Science.gov (United States)

Sinha, Priyanka; Ubaidulla, U; Hasnain, M Saquib; Nayak, Amit Kumar; Rama, Bobba

2015-08-01

Zinc (Zn(2+))-ion induced diclofenac sodium (DS)-loaded alginate-okra (Hibiscus esculentus) gum (OG) blend beads was successfully formulated through Zn(2+)-ion induced ionic-gelation cross-linking method in a complete aqueous environment. Effects of polymer-blend ratio and cross-linker concentration on drug encapsulation efficiency (DEE) and cumulative drug release at 8 h (R8h) were optimized by 3(2)-factorial design. The optimized formulation of Zn(2+)-ion induced DS-loaded alginate-OG beads demonstrated 89.27±3.58% of DEE and 43.73±2.83% of R8h. The bead sizes were within 1.10±0.07 to 1.38±0.14 mm. The bead surface morphology was analyzed by SEM. The drug-polymer interaction in the optimized bead matrix was analyzed by FTIR and P-XRD. These beads exhibited sustained in vitro drug release over a prolonged period of 8h and followed controlled-release (zero-order) pattern with super case-II transport mechanism. The swelling and degradation of the optimized beads was influenced by the pH of test mediums, which might be suitable for intestinal drug delivery. Copyright © 2015 Elsevier B.V. All rights reserved.

Increased Growth of the Microalga Chlorella vulgaris when Coimmobilized and Cocultured in Alginate Beads with the Plant-Growth-Promoting Bacterium Azospirillum brasilense†

Science.gov (United States)

Gonzalez, Luz E.; Bashan, Yoav

2000-01-01

Coimmobilization of the freshwater microalga Chlorella vulgaris and the plant-growth-promoting bacterium Azospirillum brasilense in small alginate beads resulted in a significantly increased growth of the microalga. Dry and fresh weight, total number of cells, size of the microalgal clusters (colonies) within the bead, number of microalgal cells per cluster, and the levels of microalgal pigments significantly increased. Light microscopy revealed that both microorganisms colonized the same cavities inside the beads, though the microalgae tended to concentrate in the more aerated periphery while the bacteria colonized the entire bead. The effect of indole-3-acetic acid addition to microalgal culture prior to immobilization of microorganisms in alginate beads partially imitated the effect of A. brasilense. We propose that coimmobilization of microalgae and plant-growth-promoting bacteria is an effective means of increasing microalgal populations within confined environments. PMID:10742237

Analysis of removal of cadmium by action of immobilized Chlorella sp. micro-algae in alginate beads [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Christian Valdez

2018-01-01

Full Text Available Cadmium (Cd is a metal that can negatively interfere with the metabolic systems of living beings. The objective of this work was to evaluate the capacity for cadmium removal in aqueous solutions by immobilized Chlorella sp. in calcium alginate beads. Beads without Chlorella sp. were used as a control. All the treatments were established in triplicate for 80 min, at four concentrations of cadmium (0, 20, 100 and 200 ppm, taking samples of aqueous solution every 10 min, to be read using atomic absorption equipment. The study determined that the treatment of alginate beads with immobilized Chlorella sp. removed 59.67% of cadmium at an initial concentration of 20 ppm, this being the best removal result.

Adsorption of arsenic by activated carbon, calcium alginate and their composite beads

Czech Academy of Sciences Publication Activity Database

Hassan, A F.; Abdel-Mohsen, A. M.; Elhadidy, Hassan

2014-01-01

Roč. 68, JUL (2014), s. 125-130 ISSN 0141-8130 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068; GA MŠk(CZ) EE2.3.20.0214 Institutional support: RVO:68081723 Keywords : Apricot stone * Alginate beads * Composite * Arsenic * Adsorption Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.858, year: 2014

Factors influencing the mechanical stability of alginate beads applicable for immunoisolation of mammalian cells.

Science.gov (United States)

Bhujbal, Swapnil V; Paredes-Juarez, Genaro A; Niclou, Simone P; de Vos, Paul

2014-09-01

Transplantation of microencapsulated cells has been proposed as a cure for many types of endocrine disorders. Alginate-based microcapsules have been used in many of the feasibility studied addressing cure of the endocrine disorders, and different cancer types. Despite years of intensive research it is still not completely understood which factors have to be controlled and documented for achieving adequate mechanical stability. Here we studied the strength and elasticity of microcapsules of different composition with and without cell load. We compared strength (force) versus elasticity (time) required to compress individual microcapsule to 60% deformation. It is demonstrated that the alginate viscosity, the size of the beads, the alginate type, the gelling time, the storage solution and the cell load are dominant factors in determining the final strength of alginate-based microcapsules while the type of gelling ion, the polyamino acid incubation time, the type of polyamino acid and the culturing time determines the elasticity of the alginate-based microcapsules. Our data underpin the essence of documenting the above mentioned factors in studies on encapsulated cells as mechanical stability is an essential factor in the success and failure of encapsulated grafts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fabrication and characterization of PVA/Gum tragacanth/PCL hybrid nanofibrous scaffolds for skin substitutes.

Science.gov (United States)

Zarekhalili, Zahra; Bahrami, S Hajir; Ranjbar-Mohammadi, M; Milan, Peiman Brouki

2017-01-01

In this work three dimensional biodegradable nanofiberous scaffolds containing poly(ε-caprolactone) (PCL), poly(vinyl alcohol) (PVA) and gum tragacanth (GT) were successfully fabricated through two nozzles electrospinning process. For this purpose, PVA/GT blend (Blend: B) solution (60:40wt%) was injected from one syringe and poly(ε-caprolactone) solution from the other one. Presence of PVA and PCL in the formulation improved the electrospinning process of GT solution and mechanical properties of the fabricated nanofibers. Scanning electron microscopy (SEM) results showed uniform PVA/GT-PCL blend-hybrid (Blend-Hybrid: B-H) nanofibers with the diameter ranging about 132±27nm. Hybrid nanofibers were evaluated by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) tests. The antibacterial activities of the PVA/GT-PCL (B-H) nanofibers were conducted against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and results indicated that the hybrid nanofibers were 95.19% antibacterial against S. aureus bacterium. NIH 3T3 fibroblast cells growth and MTT assay were carried out on the scaffolds. Hydrophilicity nature, favorable mechanical properties of the fabricated hybrid nanofibers, along with their structure in biological media, biocompatibility, as well as antibacterial property indicate scaffolds prepared are suitable for tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of a silica-PVA hybrid for high density and stable silver dissolution

Energy Technology Data Exchange (ETDEWEB)

Dorin, Bryce, E-mail: bryce.dorin@postgrad.manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Zhu, Guangyu, E-mail: g.zhu@liverpool.ac.uk [Lairdside Laser Engineering Centre, The University of Liverpool, Campbeltown Road, Merseyside, CH41 9HP (United Kingdom); Parkinson, Patrick, E-mail: patrick.parkinson@manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Perrie, Walter, E-mail: wpfemto1@liverpool.ac.uk [Lairdside Laser Engineering Centre, The University of Liverpool, Campbeltown Road, Merseyside, CH41 9HP (United Kingdom); Benyezzar, Med, E-mail: med.benyezzar@manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Scully, Patricia, E-mail: patricia.scully@manchester.ac.uk [The Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom)

2016-07-01

A silica and polyvinyl alcohol (PVA) hybrid material mixed with a high density of silver ions is synthesised and characterized in this work. The hybrid material can be cast into thick films, which we determined to be homogeneous using Raman spectroscopy. We observed that the silver ions remain stable in the material over time and at temperatures of 100 °C, which represents a marked improvement over previous solid solutions of silver. Differential scanning calorimetry and thermogravimetric analysis indicate the rapid activation of silver at 173 °C, resulting in a dense formation of silver nanoparticles within the hybrid. The activation of silver was also demonstrated in 3-dimensional geometries using femtosecond duration laser pulses. These results illustrate the silica-PVA hybrid is an attractive material for developing silver-insulator composites. - Highlights: • A novel PVA-silica hybrid is developed for silver ion dissolution. • The hybrid exhibits a high silver saturation point and good silver stability. • Heating and laser irradiation are capable of converting the silver ions to metal. • The hybrid material enables the fabrication of 3D metal-insulator composites.

Multilayer sodium alginate beads with porous core containing chitosan based nanoparticles for oral delivery of anticancer drug.

Science.gov (United States)

Li, Jing; Jiang, Changqing; Lang, Xuqian; Kong, Ming; Cheng, Xiaojie; Liu, Ya; Feng, Chao; Chen, Xiguang

2016-04-01

To develop efficient and safe anticancer drug doxorubicin hydrochloride (DOX) delivery system for oral chemotherapy, chitosan based nanoparticles (CS/CMCS-NPs) composed of chitosan (CS) and o-carboxymeymethy chitosan (CMCS) were immobilized in multilayer sodium alginate beads (NPs-M-Beads). Two kinds of NPs-M-Beads, with or without porous core, were respectively prepared by internal or external ionic gelation method. In the small intestine, the intact CS/CMCS-NPs were able to escape from porous-beads and sustained release the loading DOX. In vivo results showed that the DOX could be efficiently absorbed by small intestine of SD rat and the higher concentration of the DOX in major organs of rats were found after oral administration of Porous-Beads, which were about 2-4 folds higher than that of non-porous-beads. These results suggested that the NPs-M-Beads with porous core to be exciting and promising for oral delivery of DOX. Copyright © 2015 Elsevier B.V. All rights reserved.

Post-crosslinking towards stimuli-responsive sodium alginate beads for the removal of dye and heavy metals.

Science.gov (United States)

Lu, Ting; Xiang, Tao; Huang, Xue-Lian; Li, Cheng; Zhao, Wei-Feng; Zhang, Qian; Zhao, Chang-Sheng

2015-11-20

Post-crosslinking as a new strategy to prepare sodium alginate (SA) beads with controllable swelling behavior, pH sensitivity and adsorption capacity was developed by using the solution of glutaraldehyde (GA), acetic acid and hydrochloric acid as the coagulating agent, for which could be used to fabricate polysaccharide beads in a large scale. Fourier transform infrared spectroscopy and thermogravimetric analysis convinced the successful cross-linking of SA by GA. The macro-porous structures of the beads were observed by scanning electron microscopy. Both acetic acid and hydrochloric acid had great effects on the swelling behavior and pH sensitivity of the SA beads. The SA beads could adsorb cationic dye (methylene blue) as high as 572mg/g and other metal ions (Cu(2+), Ag(+) and Fe(3+)). The adsorption processes fitted well with the pseudo-second-order kinetic model and the Freundlich isotherm. The large-scale production of SA beads with tunable properties opens a new route to industrially utilize polysaccharide beads in wastewater treatments, intelligent separation and so on. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microencapsulation of probiotics in hydrogel particles: enhancing Lactococcus lactis subsp. cremoris LM0230 viability using calcium alginate beads.

Science.gov (United States)

Yeung, Timothy W; Arroyo-Maya, Izlia J; McClements, David J; Sela, David A

2016-04-01

Probiotics are beneficial microbes often added to food products to enhance the health and wellness of consumers. A major limitation to producing efficacious functional foods containing probiotic cells is their tendency to lose viability during storage and gastrointestinal transit. In this study, the impact of encapsulating probiotics within food-grade hydrogel particles to mitigate sensitivity to environmental stresses was examined. Confocal fluorescence microscopy confirmed that Lactococcus lactis were trapped within calcium alginate beads formed by dripping a probiotic-alginate mixture into a calcium solution. Encapsulation improved the viability of the probiotics during aerobic storage: after seven days, less than a two-log reduction was observed in encapsulated cells stored at room temperature, demonstrating that a high concentration of cells survived relative to non-encapsulated bacteria. These hydrogel beads may have applications for improving the stability and efficacy of probiotics in functional foods.

Isolation of Inositol Hexaphosphate (IHP)-Degrading Bacteria from Arbuscular Mycorrhizal Fungal Hyphal Compartments Using a Modified Baiting Method Involving Alginate Beads Containing IHP

Science.gov (United States)

Hara, Shintaro; Saito, Masanori

2016-01-01

Phytate (inositol hexaphosphate; IHP)-degrading microbes have been suggested to contribute to arbuscular mycorrhizal fungi (AMF)-mediated P transfer from IHP to plants; however, no IHP degrader involved in AMF-mediated P transfer has been isolated to date. We herein report the isolation of IHP-degrading bacteria using a modified baiting method. We applied alginate beads as carriers of IHP powder, and used them as recoverable IHP in the AM fungal compartment of plant cultivation experiments. P transfer from IHP in alginate beads via AMF was confirmed, and extracted DNA from alginate beads was analyzed by denaturing gradient gel electrophoresis targeting the 16S rRNA gene and a clone library method for the beta-propeller phytase (BPP) gene. The diversities of the 16S rRNA and BPP genes of microbes growing on IHP beads were simple and those of Sphingomonas spp. and Caulobacter spp. dominated. A total of 187 IHP-utilizing bacteria were isolated and identified, and they were consistent with the results of DNA analysis. Furthermore, some isolated Sphingomonas spp. and Caulobacter sp. showed IHP-degrading activity. Therefore, we successfully isolated dominant IHP-degrading bacteria from IHP in an AMF hyphal compartment. These strains may contribute to P transfer from IHP via AMF. PMID:27383681

Caffeine: A novel green precursor for synthesis of magnetic CoFe2O4 nanoparticles and pH-sensitive magnetic alginate beads for drug delivery.

Science.gov (United States)

Amiri, Mahnaz; Salavati-Niasari, Masoud; Pardakhty, Abbas; Ahmadi, Meysam; Akbari, Ahmad

2017-07-01

Hydrogel beads are promising delivery systems for encapsulation and release of drugs due to the mild process of their fabrication from biopolymers. Magnetic CoFe 2 O 4 nanoparticles (MCFO, 9.72nm in diameter) were synthesized via a co-precipitation method using caffeine as a new environmentally friendly material in order to alkalinize the medium. Drug-targeting Magnetic beads based on CoFe 2 O 4 nanoparticles, sodium alginate and chlorpheniramine maleate (CPAM) were synthesized in the presence of Ca 2+ ions to obtain ionic cross-linked magnetic hydrogel beads. Nanoparticles as well as produced magnetic beads were thoroughly characterized by FTIR, XRD, SEM, nanosizer and VSM techniques. The swelling ratio of beads indicated pH-dependent property with maximum water absorbing at pH7.4. The in vitro release of beads exhibited significant behavior on the subject of nanoparticles concentration and alginate content. Biocompatibility of the CFO nanoparticles and MCFO/Alg beads are demonstrated through cytotoxicity test via MTT assay on U87 cell lines. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis, characterization and optical properties of hybridized CdS-PVA nanocomposites

International Nuclear Information System (INIS)

Wang Hongmei; Chen Zhe; Fang Pengfei; Wang Shaojie

2007-01-01

Hybrid nanocomposites of CdS nanoparticles embedded in poly(vinyl alcohol)(PVA) matrixes had been prepared and characterized. The -OH groups acted as the coordination sites for cadmium ion aggregations and nanosized CdS particles were successfully grown in situ at these sites with the release of S 2- ions from thioacetamide. The density and size of the nanoparticles were found to be a function of molar quantity of cadmium ion used. X-ray diffraction results showed that the obtained CdS nanoparticles were hexagonal phase. Ionic clustering within the PVA matrix occurred and had provided a confined medium for particles growth in uniform size. The optical properties of the prepared CdS-PVA hybrid nanocomposites were characterized by absorption and emission spectroscopies. The absorption spectra showed a blue shift as compared to bulk CdS band-gap. The photoluminescence studies indicated the emission peak observed in samples could be assigned to the optical transition of the first excitonic state of the CdS nanoparticles

Modeling studies: Adsorption of aniline blue by using Prosopis Juliflora carbon/Ca/alginate polymer composite beads.

Science.gov (United States)

Kumar, M; Tamilarasan, R

2013-02-15

The research article describes the experimental and modeling study for the adsorptive removal of aniline blue dye (AB dye) from aqueous matrices using a Prosopis Juliflora modified carbon/Ca/alginate polymer bead as a low cost and eco-friendly adsorbent. The rate of adsorption was investigated under various experimental parameters such as contact time, adsorbent dose, dye concentration, pH and temperature. The kinetics, equilibrium and thermodynamic studies were assessed to find out the efficiency of the adsorption process. The equilibrium uptake capacity of the adsorption process was found with Freundlich and Langmuir adsorption isotherm equations and it was evaluated by dimensionless separation factor (R(L)). The dynamics of adsorption was predicted by pseudo-first order, pseudo-second order Lagergren's equation and intra particle diffusion model. Adsorption feasibility was assessed with thermodynamic parameters such as isosteric heat of adsorption (ΔH°), standard entropy (ΔS°) and Gibbs free energy (ΔG°) using VantHoff plot. The alginate bead was characterized with FTIR spectroscopy and Scanning Electron Microscopy (SEM). Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Optimisation of decolourisation and degradation of Reactive Black 5 dye under electro-Fenton process using Fe alginate gel beads.

Science.gov (United States)

Iglesias, O; Fernández de Dios, M A; Rosales, E; Pazos, M; Sanromán, M A

2013-04-01

The aim of this work was to improve the ability of the electro-Fenton process using Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes and using a model diazo dye such as Reactive Black 5 (RB5). Batch experiments were conducted to study the effects of main parameters, such as voltage, pH and iron concentration. Dye decolourisation, reduction of chemical oxygen demand (COD) and energy consumption were studied. Central composite face-centred experimental design matrix and response surface methodology were applied to design the experiments and to evaluate the interactive effects of the three studied parameters. A total of 20 experimental runs were set, and the kinetic data were analysed using first-order and second-order models. In all cases, the experimental data were fitted to the empirical second-order model with a suitable degree for the maximum decolourisation of RB5, COD reduction and energy consumption by electro-Fenton-Fe alginate gel beads treatment. Working with the obtained empirical model, the optimisation of the process was carried out. The second-order polynomial regression model suggests that the optimum conditions for attaining maximum decolourisation, COD reduction and energy consumption are voltage, 5.69 V; pH 2.24 and iron concentration, 2.68 mM. Moreover, the fixation of iron on alginate beads suggests that the degradation process can be developed under this electro-Fenton process in repeated batches and in a continuous mode.

Engineering sodium alginate-based cross-linked beads with high removal ability of toxic metal ions and cationic dyes.

Science.gov (United States)

Shao, Zi-Jian; Huang, Xue-Lian; Yang, Fan; Zhao, Wei-Feng; Zhou, Xin-Zhi; Zhao, Chang-Sheng

2018-05-01

Sodium alginate (SA) beads with ultrahigh adsorption capacity were prepared via hydrogen bonds between SA and 2-acrylamido-2-methylpropa-1-propanesulfonic acid (AMPS), and the AMPS was then post-cross-linked to manufacture SA/PAMPS beads. The equilibrium adsorption capacities of methylene blue (MB) and Pb 2+ for the SA/PAMPS10 beads were 2977 and 2042 mg/g, respectively. Although the SA beads exhibited higher equilibrium adsorption capacities of MB and Pb 2+ than those of the SA/PAMPS10 beads, the SA/PAMPS10 beads had better mechanical property and higher stability. The pseudo-second-order kinetic model and the Langmuir isotherm described the adsorption processes of the SA/PAMPS10 beads for MB well. In addition, the SA/PAMPS10 beads could be reused with stable adsorption capacity for at least three cycles. The beads also had excellent performances on absorbing methylene violet and other heavy metal ions (Cu 2+ , Cd 2+ and Ni 2+ ). Therefore, the SA-based beads with high adsorption capacity might be good candidates for industrial pollutant treatments. Copyright © 2018 Elsevier Ltd. All rights reserved.

Equilibrium, kinetic and thermodynamic studies of uranium biosorption by calcium alginate beads

International Nuclear Information System (INIS)

Bai, Jing; Fan, Fangli; Wu, Xiaolei; Tian, Wei; Zhao, Liang; Yin, Xiaojie; Fan, Fuyou; Li, Zhan; Tian, Longlong; Wang, Yang; Qin, Zhi; Guo, Junsheng

2013-01-01

Calcium alginate beads are potential biosorbent for radionuclides removal as they contain carboxyl groups. However, until now limited information is available concerning the uptake behavior of uranium by this polymer gel, especially when sorption equilibrium, kinetics and thermodynamics are concerned. In present work, batch experiments were carried out to study the equilibrium, kinetics and thermodynamics of uranium sorption by calcium alginate beads. The effects of initial solution pH, sorbent amount, initial uranium concentration and temperature on uranium sorption were also investigated. The determined optimal conditions were: initial solution pH of 3.0, added sorbent amount of 40 mg, and uranium sorption capacity increased with increasing initial uranium concentration and temperature. Equilibrium data obtained under different temperatures were fitted better with Langmuir model than Freundlich model, uranium sorption was dominated by a monolayer way. The kinetic data can be well depicted by the pseudo-second-order kinetic model. The activation energy derived from Arrhenius equation was 30.0 kJ/mol and the sorption process had a chemical nature. Thermodynamic constants such as ΔH 0 , ΔS 0 and ΔG 0 were also evaluated, results of thermodynamic study showed that the sorption process was endothermic and spontaneous. -- Highlights: • Equilibrium, kinetics and thermodynamics of uranium sorption by CaAlg were studied. • Equilibrium studies show that Langmuir isotherm better fit with experimental data. • Pseudo-second-order kinetics model is found to be well depicting the kinetic data. • Thermodynamic study shows that the sorption process is endothermic and spontaneous

Development and evaluation of alginate-chitosan gastric floating beads loading with oxymatrine solid dispersion.

Science.gov (United States)

Liu, Yanhua; Chen, Lihong; Zhou, Chengming; Yang, Jianhong; Hou, Yanhui; Wang, Wenping

2016-01-01

Oxymatrine (OM) can be metabolized to matrine in gastrointestinal ileocecal valve after oral administration, which affects pharmacological activity and reduce bioavailability of OM. A type of multiple-unit alginate-chitosan (Alg-Cs) floating beads was prepared by the ionotropic gelation method for gastroretention delivery of OM. A solid dispersion technique was applied and incorporated into beads to enhance the OM encapsulation efficiency (EE) and sustain the drug release. The surface morphology and internal hollow structure of beads were evaluated using optical microscopy and scanning electron microscopy (SEM). The developed Alg-Cs beads were spherical in shape with hollow internal structure and had particle size of 3.49 ± 0.09 mm and 1.33 ± 0.09 mm for wet and dried beads. Over 84% of the optimized OM solid dispersion-loaded Alg-Cs beads were able to continuously float over the simulated gastric fluid for 12 h in vitro. The OM solid dispersion-loaded Alg-Cs beads showed drug EE of 67.07%, which was much higher than that of beads loading with pure OM. Compared with the immediate release of OM capsules and pure OM-loaded beads, the release of OM from solid dispersion-loaded Alg-Cs beads was in a sustained-release manner for 12 h. Prolonged gastric retention time of over 8.5 h was achieved for OM solid dispersion-loaded Alg-Cs floating beads in healthy rabbit in in vivo floating ability evaluated by X-ray imaging. The developed Alg-Cs beads loading with OM solid dispersion displayed excellent performance features characterized by excellent gastric floating ability, high drug EE and sustained-release pattern. The study illustrated the potential use of Alg-Cs floating beads combined with the solid dispersion technique for prolonging gastric retention and sustaining release of OM, which could provide a promising drug delivery system for gastric-specific delivery of OM for bioavailability enhancement.

Lipofection of rabbit chondrocytes and long lasting expression of a lacZ reporter system in alginate beads.

Science.gov (United States)

Stöve, J; Fiedler, J; Huch, K; Günther, K-P; Puhl, W; Brenner, R

2002-03-01

Our aim was to investigate the maintenance of the transfection status of non-viral transfected chondrocytes in an alginate culture system. Chondrocytes harvested from rabbit knees were isolated by sequential digestion and cultivated in monolayer culture. At 60-70% cell density, chondrocytes were transfected with different transfection systems (FuGENE6, CaCl2, Lipofectin). A lac Z expression vector (pcDNA 3.1/Myc-His+ lacZ) was used as a reporter system. In order to improve transfection rates, hyaluronidase (4 U/ml) was used prior and during the transfection procedure. Thereafter, transfected cells were either kept in monolayer culture or embedded in alginate beads and kept in culture for up to the next 30 weeks. Transfection efficiency was maximal using FuGENE6TM/DNA at a ratio of 3:2 and hyaluronidase (4 U/ml). Transfection efficiency reached up to 40.8% (+/- 3.2%) after 36 h. In alginate beads lac Z positive cells declined to 8.5% +/- 3.3% after 4 weeks and to 4.6% +/- 3.2% after 12 weeks of culturing. After 30 weeks 3% of chondrocytes still expressed lac Z. In contrast, during culturing in monolayer, no lac Z expression was detectable after 4 weeks. Differentiation status of the chondrocytes was confirmed by histology and immunohistochemistry methods. After successful gene transfer to rabbit chondrocytes the alginate system made it possible to culture lipofected chondrocytes phenotypically stable. Genetically engineered chondrocytes express the lac Z reporter gene over a period of at least 30 weeks. This transfection and culture system provides a promising tool to further investigate the over-expression of growth factors and enzyme inhibitors. Copyright 2002 OsteoArthritis Research Society International.

The impact of functionalized CNT in the network of sodium alginate-based nanocomposite beads on the removal of Co(II) ions from aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Karkeh-abadi, Fatemeh [Department of Chemistry, University of Kashan, Kashan (Iran, Islamic Republic of); Saber-Samandari, Samaneh, E-mail: samaneh.saber@gmail.com [Department of Chemistry, Eastern Mediterranean University, Gazimagusa, TRNC via Mersin 10 (Turkey); Saber-Samandari, Saeed, E-mail: saeedss@aut.ac.ir [New Technologies Research Center, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

2016-07-15

Highlights: • The sodium alginate-hydroxyapatite-CNT nanocomposite beads were prepared. • Amide functionalized CNT imprinted in the network of sodium alginate containing HAp. • The prepared beads were used as adsorbents of cobalt ions from an aqueous solution. • The adsorption was fit with the Freundlich isotherm and second-order kinetic models. • The endothermic adsorption process is spontaneous and thermodynamically favorable. - Abstract: Significant efforts have been made to develop highly efficient adsorbents to remove radioactive Co(II) ion pollutants from medical and industrial wastewaters. In this study, amide group functionalized multi-walled carbon nanotube (CNT-CONH{sub 2}) imprinted in the network of sodium alginate containing hydroxyapatite, and new nanocomposite beads were synthesized. Then, they were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The prepared nanocomposite beads were used as an adsorbent of Co(II) ions from an aqueous solution. The presence and distribution of Co(II) ions in the surface of the nanocomposite beads was confirmed using FESEM, EDS and metal mapping analysis. The effect of various experimental conditions such as time, pH, and initial concentration of the adsorbate solution and temperature on the adsorption capacity of the nanocomposite beads were explored. The maximum Co(II) ions adsorption capacity of the prepared nanocomposite beads with the largest surface area of 163.4 m{sup 2} g{sup −1} was 347.8 mg g{sup −1} in the optimized condition. The adsorption mechanism followed a pseudo-second-order kinetic model. Furthermore, the Freundlich appears to produce better fit than the Langmuir adsorption isotherm. Finally, thermodynamic studies suggest that endothermic adsorption process of Co(II) ions is spontaneous and

Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate.

Science.gov (United States)

Dong, Yuwei; Zhang, Yanqiu; Tu, Baojun

Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30°C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Application of Microbial BOD Sensors in Marine Monitoring

Institute of Scientific and Technical Information of China (English)

张悦; 王建龙; 李花子; 施汉昌; 竺建荣

2001-01-01

A strain of yeast, which can endure high osmotic pressure, is employed for the sensitive material of the microbial BOD sensor. Two immobilization methods are used, I.e. Calcium alginate gel be ads and PV A gel beads. The results show that the PVA gel beads is better. The influences of osmosis and heavy metal ions on the yeast entrapped in the PVA gel beads are also studied in the experiment.

Osteogenic differentiation of human mesenchymal stem cells in mineralized alginate matrices.

Science.gov (United States)

Westhrin, Marita; Xie, Minli; Olderøy, Magnus Ø; Sikorski, Pawel; Strand, Berit L; Standal, Therese

2015-01-01

Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC) in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP) for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and alginate beads mineralized with ALP to generate a polymer/hydroxyapatite scaffold mimicking the composition of bone. The initial scaffold mineralization induced further mineralization of the beads with nanosized particles, and scanning electron micrographs demonstrated presence of collagen in the mineralized and unmineralized alginate beads cultured in osteogenic medium. Cells in both types of beads sustained high viability and metabolic activity for the duration of the study (21 days) as evaluated by live/dead staining and alamar blue assay. MSC in beads induced to differentiate in osteogenic direction expressed higher mRNA levels of osteoblast-specific genes (RUNX2, COL1AI, SP7, BGLAP) than MSC in traditional cell cultures. Furthermore, cells differentiated in beads expressed both sclerostin (SOST) and dental matrix protein-1 (DMP1), markers for late osteoblasts/osteocytes. In conclusion, Both ALP-modified and unmodified alginate beads provide an environment that enhance osteogenic differentiation compared with traditional 2D culture. Also, the ALP-modified alginate beads showed profound mineralization and thus have the potential to serve as a bone substitute in tissue engineering.

Controlled ice nucleation using freeze-dried Pseudomonas syringae encapsulated in alginate beads.

Science.gov (United States)

Weng, Lindong; Tessier, Shannon N; Swei, Anisa; Stott, Shannon L; Toner, Mehmet

2017-04-01

The control of ice nucleation is of fundamental significance in many process technologies related to food and pharmaceutical science and cryobiology. Mechanical perturbation, electromagnetic fields and ice-nucleating agents (INAs) have been known to induce ice nucleation in a controlled manner. But these ice-nucleating methods may suffer from cumbersome manual operations, safety concerns of external fields, and biocompatibility and recovery issues of INA particles, especially when used in living systems. Given the automatic ice-seeding nature of INAs, a promising solution to overcome some of the above limitations is to engineer a biocomposite that accommodates the INA particles but minimizes their interactions with biologics, as well as enabling the recovery of used particles. In this study, freeze-dried Pseudomonas syringae, a model ice-nucleating agent, was encapsulated into microliter-sized alginate beads. We evaluated the performance of the bacterial hydrogel beads to initiate ice nucleation in water and aqueous glycerol solution by investigating factors including the size and number of the beads and the local concentration of INA particles. In the aqueous sample of a fixed volume, the total mass of the INA particles (m) was found to be the governing parameter that is solely responsible for determining the ice nucleation performance of the bacterial hydrogel beads. The freezing temperature has a strong positive linear correlation with log 10 m. The findings in this study provide an effective, predictable approach to control ice nucleation, which can improve the outcome and standardization of many ice-assisted process technologies. Copyright © 2017 Elsevier Inc. All rights reserved.

Osteogenic differentiation of human mesenchymal stem cells in mineralized alginate matrices.

Directory of Open Access Journals (Sweden)

Marita Westhrin

Full Text Available Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and alginate beads mineralized with ALP to generate a polymer/hydroxyapatite scaffold mimicking the composition of bone. The initial scaffold mineralization induced further mineralization of the beads with nanosized particles, and scanning electron micrographs demonstrated presence of collagen in the mineralized and unmineralized alginate beads cultured in osteogenic medium. Cells in both types of beads sustained high viability and metabolic activity for the duration of the study (21 days as evaluated by live/dead staining and alamar blue assay. MSC in beads induced to differentiate in osteogenic direction expressed higher mRNA levels of osteoblast-specific genes (RUNX2, COL1AI, SP7, BGLAP than MSC in traditional cell cultures. Furthermore, cells differentiated in beads expressed both sclerostin (SOST and dental matrix protein-1 (DMP1, markers for late osteoblasts/osteocytes. In conclusion, Both ALP-modified and unmodified alginate beads provide an environment that enhance osteogenic differentiation compared with traditional 2D culture. Also, the ALP-modified alginate beads showed profound mineralization and thus have the potential to serve as a bone substitute in tissue engineering.

In vitro propagation of Acacia hybrid through alginate-encapsulated ...

African Journals Online (AJOL)

Seed collected from Acacia hybrid trees yields highly variable and poorly performing offspring and are not commonly used in regeneration. The present study described the incapsulation of Acacia hybrid shoots and axillary buds in the calcium alginate gel. The aim of the study was to evaluate the germination of the buds in ...

Gel spinning of PVA composite fibers with high content of multi-walled carbon nanotubes and graphene oxide hybrids

International Nuclear Information System (INIS)

Wei, Yizhe; Lai, Dengpan; Zou, Liming; Ling, Xinlong; Lu, Hongwei; Xu, Yongjing

2015-01-01

In this report, poly (vinyl alcohol) (PVA) composite fibers with high content of multi-walled carbon nanotubes and graphene oxide (MWCNTs-GO) hybrids were prepared by gel spinning, and were characterized by TGA, DSC, SEM, XL-2 yarn strength tester and electrical conductivity measurement. The total content of MWCNTs-GO hybrids in the PVA composite fibers, which is up to 25 wt%, was confirmed by TGA analysis. The DSC measurement shows that the melting and crystallization peaks decreased after the addition of nano-fillers. This is due to the reason that the motion of PVA chains is completely confined by strong hydrogen bonding interaction between PVA and nano-fillers. After the addtion of GO, the dispersibility of MWCNTs in composite fibers improved slightly. And the tensile strength and Young's modulus increased by 38% and 67%, respectively. This is caused by the increased hydrogen bonding interaction and synergistic effect through hybridization of MWCNTs and GO. More significantly, the electrical conductivity of PVA/MWCNTs/GO composite fibers enhanced by three orders of magnitude with the addition of GO. (paper)

Chitosan cocrystals embedded alginate beads for enhancing the solubility and bioavailability of aceclofenac.

Science.gov (United States)

Ganesh, Mani; Jeon, Ung Jin; Ubaidulla, Udhumansha; Hemalatha, Pushparaj; Saravanakumar, Arthanari; Peng, Mei Mei; Jang, Hyun Tae

2015-03-01

Enhanced oral bioavailability of aceclofenac has been achieved using chitosan cocrystals of aceclofenac and its entrapment into alginate matrix a super saturated drug delivery system (SDDS). Prepared SDDS were evaluated by various physiochemical and pharmacological methods. The result revealed that the primary cocrystals enhanced the solubility of the drug and the thick gelled polymer matrix that formed from swelling of calcium alginate beads makes it to release the drug in continuous and sustained manner by supersaturated drug diffusion. The Cmax, Tmax and relative bioavailability for aceclofenac cocrystal and aceclofenac SDDS were 2.06±0.42 μg/ml, 1 h, 159.72±10.84 and 2.01 μg/ml, 1 h, 352.76±12.91, respectively. Anti-inflammatory activity of aceclofenac was significantly improved with the SDDS. With respect to the results, it revealed that the SDDS described herein might be a promising tool for the oral sustained release of aceclofenac and likely for that of various other poorly soluble drugs. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis of zinc-crosslinked thiolated alginic acid beads and their in vitro evaluation as potential enteric delivery system with folic acid as model drug.

Science.gov (United States)

Taha, M O; Aiedeh, K M; Al-Hiari, Y; Al-Khatib, H

2005-10-01

The aim of this study is to explore the potential of synthetic modifications of alginic acid as a method to enhance the stability of its complexes with divalent cations under physiological conditions. A fraction of algin's carboxylic acid moieties was substituted with thiol groups to different substitution degrees through conjugating alginate to cysteine to produce alginate-cysteine (AC) conjugates. Infrared spectrophotometry and iodometry were used to characterize the resulting polymeric conjugates in terms of structure and degree of substitution. Moreover, zinc ions were used to crosslink the resulting AC polymers. Folic acid loaded beads were prepared from Zinc-crosslinked AC polymers (AC-Zn) of different cysteine substitution degrees. The generated beads were then investigated in vitro for their capacity to modify folic acid release. AC-Zn polymeric beads resisted drug release under acidic conditions (pH 1.0). However, upon transfer to a phosphate buffer solution (pH 7.0) they released most of their contents almost immediately. This change in drug release behavior is most probably due to the sequestering of zinc cations by phosphate ions within the buffer solution to form insoluble chelates and, to a lesser extent, the ionization of the carboxylic acid and thiol moieties. Removal of zinc ions from the polymeric matrix seems to promote polymeric disintegration and subsequent drug release. A similar behavior is expected in vivo due to the presence of natural zinc sequestering agents in the intestinal fluids. AC-Zn polymers provided a novel approach for enteric drug delivery as drug release from these matrices complied with the USP specifications for enteric dosage forms.

Removal of uranium from aqueous solution by aliginate beads

Energy Technology Data Exchange (ETDEWEB)

Yu, Jing; Wang, Jian Long [Collaborative Innovation Center for Advanced Nuclear Energy Technology, INET, Tsinghua University, Beijing (China); Jiang, Yizhou [Northwest Institute of Nuclear Technology, Xian (China)

2017-04-15

The adsorption of uranium (VI) by calcium alginate beads was examined by batch experiments. The effects of environmental conditions on U (VI) adsorption were studied, including contact time, pH, initial concentration of U (VI), and temperature. The alginate beads were characterized by using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Fourier transform infrared spectra indicated that hydroxyl and alkoxy groups are present at the surface of the beads. The experimental results showed that the adsorption of U (VI) by alginate beads was strongly dependent on pH, the adsorption increased at pH 3∼7, then decreased at pH 7∼9. The adsorption reached equilibrium within 2 minutes. The adsorption kinetics of U (VI) onto alginate beads can be described by a pseudo first-order kinetic model. The adsorption isotherm can be described by the Redlich-Peterson model, and the maximum adsorption capacity was 237.15 mg/g. The sorption process is spontaneous and has an exothermic reaction.

Low temperature superparamagnetic nanocomposites obtained by Fe(acac3-SiO2-PVA hybrid xerogel thermolysis

Directory of Open Access Journals (Sweden)

Catalin Ianasi

2016-12-01

Full Text Available Fe(acac3/silica/PVA hybrid xerogel nanocomposite was obtained by one pot acid catalysed sol-gel synthesis using the homogeneous mixture of iron(III acetylacetonate (Fe(acac3, tetraethylorthosilicate (TEOS, and polyvinyl alcohol (PVA. Nominal composition ratio of iron oxide/silica was 15/85 (weight percent. Nitric acid was used as catalyst. Another sample of Fe(acac3/silica xerogel without PVA addition was prepared in the similar processing conditions. Based on thermal analysis studies, the thermal behaviour of both xerogel samples was unveiled and it allowed choosing the optimal calcination temperatures in order to obtain iron oxide silica magnetic nanocomposite samples. The two xerogel (with and without PVA samples were thermally treated, in air, at 220, 260 and 300 °C and characterized by different techniques. XRD investigations revealed phase composition evolution with calcination temperature, from cubic spinel phase (maghemite to hexagonal stable hematite containing nanocomposite of 10–20 nm average crystallite size. These findings were confirmed by Mössbauer spectroscopy. Up to 300 °C, the surface area and total pores volume increased with temperature for all samples. By calcination at the same temperature, the hybrid xerogel containing PVA resulted in significantly higher magnetization and free volume values in comparison with the sample without PVA.

Encapsulated human hepatocellular carcinoma cells by alginate gel beads as an in vitro metastasis model

International Nuclear Information System (INIS)

Xu, Xiao-xi; Liu, Chang; Liu, Yang; Li, Nan; Guo, Xin; Wang, Shu-jun; Sun, Guang-wei; Wang, Wei; Ma, Xiao-jun

2013-01-01

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and often forms metastases, which are the most important prognostic factors. For further elucidation of the mechanism underlying the progression and metastasis of HCC, a culture system mimicking the in vivo tumor microenvironment is needed. In this study, we investigated the metastatic ability of HCC cells cultured within alginate gel (ALG) beads. In the culture system, HCC cells formed spheroids by proliferation and maintained in nuclear abnormalities. The gene and protein expression of metastasis-related molecules was increased in ALG beads, compared with the traditional adhesion culture. Furthermore, several gene expression levels in ALG bead culture system were even closer to liver cancer tissues. More importantly, in vitro invasion assay showed that the invasion cells derived from ALG beads was 7.8-fold higher than adhesion cells. Our results indicated that the in vitro three-dimensional (3D) model based on ALG beads increased metastatic ability compared with adhesion culture, even partly mimicked the in vivo tumor tissues. Moreover, due to the controllable preparation conditions, steady characteristics and production at large-scale, the 3D ALG bead model would become an important tool used in the high-throughput screening of anti-metastasis drugs and the metastatic mechanism research. -- Highlights: •We established a 3D metastasis model mimicking the metastatic ability in vivo. •The invasion ability of cells derived from our model was increased significantly. •The model is easy to reproduce, convenient to handle, and amenable for large-scale

Process engineering of high voltage alginate encapsulation of mesenchymal stem cells

International Nuclear Information System (INIS)

Gryshkov, Oleksandr; Pogozhykh, Denys; Zernetsch, Holger; Hofmann, Nicola; Mueller, Thomas; Glasmacher, Birgit

2014-01-01

Encapsulation of stem cells in alginate beads is promising as a sophisticated drug delivery system in treatment of a wide range of acute and chronic diseases. However, common use of air flow encapsulation of cells in alginate beads fails to produce beads with narrow size distribution, intact spherical structure and controllable sizes that can be scaled up. Here we show that high voltage encapsulation (≥ 15 kV) can be used to reproducibly generate spherical alginate beads (200–400 μm) with narrow size distribution (± 5–7%) in a controlled manner under optimized process parameters. Flow rate of alginate solution ranged from 0.5 to 10 ml/h allowed producing alginate beads with a size of 320 and 350 μm respectively, suggesting that this approach can be scaled up. Moreover, we found that applied voltages (15–25 kV) did not alter the viability and proliferation of encapsulated mesenchymal stem cells post-encapsulation and cryopreservation as compared to air flow. We are the first who employed a comparative analysis of electro-spraying and air flow encapsulation to study the effect of high voltage on alginate encapsulated cells. This report provides background in application of high voltage to encapsulate living cells for further medical purposes. Long-term comparison and work on alginate–cell interaction within these structures will be forthcoming. - Highlights: • High voltage alginate encapsulation of mesenchymal stem cells (MSCs) was designed. • Reproducible and spherical alginate beads were generated via high voltage. • Air flow encapsulation was utilized as a comparative approach to high voltage. • High voltage did not alter the viability and proliferation of encapsulated MSCs. • High voltage encapsulation can be scaled up and applied in cell-based therapy

Effect of non-cross-linked calcium on characteristics, swelling behaviour, drug release and mucoadhesiveness of calcium alginate beads.

Science.gov (United States)

Dalaty, Adnan Al; Karam, Ayman; Najlah, Mohammad; Alany, Raid G; Khoder, Mouhamad

2016-04-20

In this study, ibuprofen-loaded calcium alginate beads (CABs) with varying amounts of non-cross-linked calcium (NCL-Ca) were prepared using different washing methods. The influence of NCL-Ca on beads properties was investigated. Increasing the number or duration of washes led to significant decreases in the amount of NCL-Ca whereas the impact of the volume of washes was not significant. Approximately 70% of the initial amount of Ca(2+) was NCL-Ca which was removable by washing while only 30% was cross-linked (CL-Ca). Ca(2+) release from the CABs was bimodal; NCL-Ca was burst-released followed by a slower release of CL-Ca. Washing methods and the amount of NCL-Ca had significant influences on the encapsulation efficiency, beads weight, beads swelling, drug release profile and the mucoadhesiveness of CABs. This study highlighted the importance of washing methods and the amount of NCL-Ca to establish CABs properties and understand their behaviour in the simulated intestinal fluids (SIFs). Copyright © 2015 Elsevier Ltd. All rights reserved.

Three-dimensional alginate spheroid culture system of murine osteosarcoma.

Science.gov (United States)

Akeda, Koji; Nishimura, Akinobu; Satonaka, Haruhiko; Shintani, Ken; Kusuzaki, Katsuyuki; Matsumine, Akihiko; Kasai, Yuichi; Masuda, Koichi; Uchida, Atsumasa

2009-11-01

Osteosarcoma (OS) is the most common primary malignant tumor of the bone and often forms pulmonary metastases, which are the most important prognostic factor. For further elucidation of the mechanism underlying the progression and metastasis of human OS, a culture system mimicking the microenvironment of the tumor in vivo is needed. We report a novel three-dimensional (3D) alginate spheroid culture system of murine osteosarcoma. Two different metastatic clones, the parental Dunn and its derivative line LM8, which has a higher metastatic potential to the lungs, were encapsulated in alginate beads to develop the 3D culture system. The beads containing murine OS cells were also transplanted into mice to determine their metastatic potential in vivo. In this culture system, murine OS cells encapsulated in alginate beads were able to grow in a 3D structure with cells detaching from the alginate environment. The number of detaching cells was higher in the LM8 cell line than the Dunn cell line. In the in vivo alginate bead transplantation model, the rate of pulmonary metastasis was higher with LM8 cells compared with that of Dunn cells. The cell characteristics and kinetics in this culture system closely reflect the original malignant potential of the cells in vivo.

Magnesium Oxide Nanoparticles Reinforced Electrospun Alginate-Based Nanofibrous Scaffolds with Improved Physical Properties

Directory of Open Access Journals (Sweden)

R. T. De Silva

2017-01-01

Full Text Available Mechanically robust alginate-based nanofibrous scaffolds were successfully fabricated by electrospinning method to mimic the natural extracellular matrix structure which benefits development and regeneration of tissues. Alginate-based nanofibres were electrospun from an alginate/poly(vinyl alcohol (PVA polyelectrolyte complex. SEM images revealed the spinnability of the complex composite nanofibrous scaffolds, showing randomly oriented, ultrafine, and virtually defects-free alginate-based/MgO nanofibrous scaffolds. Here, it is shown that an alginate/PVA complex scaffold, blended with near-spherical MgO nanoparticles (⌀ 45 nm at a predetermined concentration (10% (w/w, is electrospinnable to produce a complex composite nanofibrous scaffold with enhanced mechanical stability. For the comparison purpose, chemically cross-linked electrospun alginate-based scaffolds were also fabricated. Tensile test to rupture revealed the significant differences in the tensile strength and elastic modulus among the alginate scaffolds, alginate/MgO scaffolds, and cross-linked alginate scaffolds (P<0.05. In contrast to cross-linked alginate scaffolds, alginate/MgO scaffolds yielded the highest tensile strength and elastic modulus while preserving the interfibre porosity of the scaffolds. According to the thermogravimetric analysis, MgO reinforced alginate nanofibrous scaffolds exhibited improved thermal stability. These novel alginate-based/MgO scaffolds are economical and versatile and may be further optimised for use as extracellular matrix substitutes for repair and regeneration of tissues.

Immobilization of tomato (Lycopersicon esculentum) pectinmethylesterase in calcium alginate beads and its application in fruit juice clarification.

Science.gov (United States)

Bogra, Pushpa; Kumar, Ashwani; Kuhar, Kalika; Panwar, Surbhi; Singh, Randhir

2013-11-01

Clarity of fruit juices is desirable to maintain an aesthetically pleasing quality and international standards. The most commonly used enzymes in juice industries are pectinases. A partially-purified pectinmethylesterase from tomato was entrapped in calcium alginate beads and used for juice clarification. The activity yield was maximum at 1 % (w/v) CaCl2 and 2.5 % (w/v) alginate. The immobilized enzyme retained ~55 % of its initial activity (5.7 × 10(-2) units) after more than ten successive batch reactions. The Km, pH and temperature optima were increased after immobilization. The most effective clarification of fruit juice (%T620 ~60 %) by the immobilized enzyme was at 4 °C with a holding time of 20 min. The viscosity dropped by 56 % and the filterability increased by 260 %. The juice remains clear after 2 months of storage at 4 °C.

Systematic study of alginate-based microcapsules by micropipette aspiration and confocal fluorescence microscopy.

Science.gov (United States)

Kleinberger, Rachelle M; Burke, Nicholas A D; Dalnoki-Veress, Kari; Stöver, Harald D H

2013-10-01

Micropipette aspiration and confocal fluorescence microscopy were used to study the structure and mechanical properties of calcium alginate hydrogel beads (A beads), as well as A beads that were additionally coated with poly-L-lysine (P) and sodium alginate (A) to form, respectively, AP and APA hydrogels. A beads were found to continue curing for up to 500 h during storage in saline, due to residual calcium chloride carried over from the gelling bath. In subsequent saline washes, micropipette aspiration proved to be a sensitive indicator of gel weakening and calcium loss. Aspiration tests were used to compare capsule stiffness before and after citrate extraction of calcium. They showed that the initial gel strength is largely due to the calcium alginate gel cores, while the long term strength is solely due to the poly-L-lysine-alginate polyelectrolyte complex (PEC) shells. Confocal fluorescence microscopy showed that calcium chloride exposure after PLL deposition led to PLL redistribution into the hydrogel bead, resulting in thicker but more diffuse and weaker PEC shells. Adding a final alginate coating to form APA capsules did not significantly change the PEC membrane thickness and stiffness, but did speed the loss of calcium from the bead core. © 2013.

Chitosan coated alginate-xanthan gum bead enhanced pH and thermotolerance of Lactobacillus plantarum LAB12.

Science.gov (United States)

Fareez, Ismail M; Lim, Siong Meng; Mishra, Rakesh K; Ramasamy, Kalavathy

2015-01-01

The vulnerability of probiotics at low pH and high temperature has limited their optimal use as nutraceuticals. This study addressed these issues by adopting a physicochemical driven approach of incorporating Lactobacillus plantarum LAB12 into chitosan (Ch) coated alginate-xanthan gum (Alg-XG) beads. Characterisation of Alg-XG-Ch, which elicited little effect on bead size and polydispersity, demonstrated good miscibility with improved bead surface smoothness and L. plantarum LAB12 entrapment when compared to Alg, Alg-Ch and Alg-XG. Sequential incubation of Alg-XG-Ch in simulated gastric juice and intestinal fluid yielded high survival rate of L. plantarum LAB12 (95%) at pH 1.8 which in turn facilitated sufficient release of probiotics (>7 log CFU/g) at pH 6.8 in both time- and pH-dependent manner. Whilst minimising viability loss at 75 and 90 °C, Alg-XG-Ch improved storage durability of L. plantarum LAB12 at 4 °C. The present results implied the possible use of L. plantarum LAB12 incorporated in Alg-XG-Ch as new functional food ingredient with health claims. Copyright © 2014 Elsevier B.V. All rights reserved.

In vitro release of metformin hydrochloride from sodium alginate/polyvinyl alcohol hydrogels.

Science.gov (United States)

Martínez-Gómez, Fabián; Guerrero, Juan; Matsuhiro, Betty; Pavez, Jorge

2017-01-02

Hydrogels, based on polysaccharides have found a number of applications as drug delivery carriers. In this work, hydrogels of full characterized sodium alginate (Mn 87,400g/mol) and commercial poly(vinyl alcohol) (PVA) sensitive to pH and temperature stimuli were obtained using a simple, controlled, green, low cost method based on freeze-thaw cycles. Stable hydrogels of sodium alginate/PVA with 0.5:1.5 and 1.0:1.0w/v concentrations showed very good swelling ratio values in distilled water (14 and 20g/g, respectively). Encapsulation and release of metformin hydrochloride in hydrogels of 1.0:1.0w/v sodium alginate/PVA was followed by UV spectroscopy. The hydrogel released a very low amount of metformin hydrochloride at pH 1.2; the highest release value (55%) was obtained after 6h at pH 8.0. Also, the release of metformin hydrochloride was studied by 1 H NMR spectroscopy, the temporal evolution of methyl group signals of metformin showed 30% of drug release after 3h. Copyright © 2016 Elsevier Ltd. All rights reserved.

Diffusion of Acetic Acid Across Oil/Water Interface in Emulsification-Internal Gelation Process for Preparation of Alginate Gel Beads

Institute of Scientific and Technical Information of China (English)

LIU Xiu-dong; YU Wei-ting; LIN Jun-zhang; MA Xiao-jun; YUAN Quan

2007-01-01

Alginate has been widely used in cell microencapsulation and drug delivery systems in the form of gel beads or microcapsules. Although an alternative novel emulsification-internal gelation technology has been established and both the properties and the potential applications of the beads in drug delivery systems have been studied, the mechanism has not been well understood compared with the traditional droplet method( external gelation technology). On the basis of our previous knowledge that the novel technology is composed of complicatedly consecutive processes with multistep diffusion and re action, and the diffusion of acetic acid across oil/water interface being the prerequisite that determines the occurrence and rate for the reactions and the structures and properties of final produced gel beads, a special emphasis was placed on the diffusion process. With the aid of diffusion modeling and simple experimental design, the diffusion rate constant and diffusion coefficient of acetic acid across oil/water interface were determined to be in the orders of magnitude of 10-6 and 10-16, respectively. This knowledge will be of particular importance in understanding and interpreting the formation, structure of the gel beads and the relationship between the structure and properties and guiding the preparation and quality control of the gel beads.

Mussel-inspired alginate gel promoting the osteogenic differentiation of mesenchymal stem cells and anti-infection

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shiwen [Department of Mechanical Engineering, Faculty of Engineering and Department of Biochemistry & Genetics, Faculty of Medicine and Manitoba Institute of Child Health, The University of Manitoba, Winnipeg, Manitoba (Canada); Children Hospital Research Institute of Manitoba, Winnipeg (Canada); Sichuan University, Chengdu (China); Xu, Kaige; Darabi, Mohammad Ali [Children Hospital Research Institute of Manitoba, Winnipeg (Canada); Yuan, Quan [Sichuan University, Chengdu (China); Xing, Malcolm [Department of Mechanical Engineering, Faculty of Engineering and Department of Biochemistry & Genetics, Faculty of Medicine and Manitoba Institute of Child Health, The University of Manitoba, Winnipeg, Manitoba (Canada)

2016-12-01

Alginate hydrogels have been used in cell encapsulation for many years but a prevalent issue with pure alginates is that they are unable to provide enough bioactive properties to interact with mammalian cells. This paper discusses the modification of alginate with mussel-inspired dopamine for cell loading and anti-infection. Mouse bone marrow stem cells were immobilized into alginate and alginate-dopamine beads and fibers. Through live-dead and MTT assay, alginates modified by dopamine promoted cell viability and proliferation. In vitro cell differentiation results showed that such an alginate-dopamine gel can promote the osteogenic differentiation of mesenchymal stem cell after PCR and ALP assays. In addition to that, the adhesive prosperities of dopamine allowed for coating the surface of alginate-dopamine gel with silver nanoparticles, which provided the gel with significant antibacterial characteristics. Overall, these results demonstrate that a dopamine-modified alginate gel can be a great tool for cell encapsulation to promote cell proliferation and can be applied to bone regeneration, especially in contaminated bone defects. - Highlights: • Dopamine modified alginate bead and fiber promote cell viability and proliferation. • Alginate-dopamine gel promotes osteogenic differentiation of MSCs. • Dopamine reduced nanosilver for anti-infection. • Alginate-dopamine bead and fiber for delivery of mesenchymal stem cells (MSCs)

Mussel-inspired alginate gel promoting the osteogenic differentiation of mesenchymal stem cells and anti-infection

International Nuclear Information System (INIS)

Zhang, Shiwen; Xu, Kaige; Darabi, Mohammad Ali; Yuan, Quan; Xing, Malcolm

2016-01-01

Alginate hydrogels have been used in cell encapsulation for many years but a prevalent issue with pure alginates is that they are unable to provide enough bioactive properties to interact with mammalian cells. This paper discusses the modification of alginate with mussel-inspired dopamine for cell loading and anti-infection. Mouse bone marrow stem cells were immobilized into alginate and alginate-dopamine beads and fibers. Through live-dead and MTT assay, alginates modified by dopamine promoted cell viability and proliferation. In vitro cell differentiation results showed that such an alginate-dopamine gel can promote the osteogenic differentiation of mesenchymal stem cell after PCR and ALP assays. In addition to that, the adhesive prosperities of dopamine allowed for coating the surface of alginate-dopamine gel with silver nanoparticles, which provided the gel with significant antibacterial characteristics. Overall, these results demonstrate that a dopamine-modified alginate gel can be a great tool for cell encapsulation to promote cell proliferation and can be applied to bone regeneration, especially in contaminated bone defects. - Highlights: • Dopamine modified alginate bead and fiber promote cell viability and proliferation. • Alginate-dopamine gel promotes osteogenic differentiation of MSCs. • Dopamine reduced nanosilver for anti-infection. • Alginate-dopamine bead and fiber for delivery of mesenchymal stem cells (MSCs)

Drying and Rehydration of Calcium Alginate Gels

NARCIS (Netherlands)

Vreeker, R.; Li, L.; Fang, Y.; Appelqvist, I.; Mendes, E.

2008-01-01

In this paper, we study the rehydration properties of air-dried calcium alginate gel beads. Rehydration is shown to depend on alginate source (i.e. mannuronic to guluronic acid ratio) and the salt concentration in the rehydration medium. Rehydration curves are described adequately by the empirical

A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure

OpenAIRE

Sun, Xiaoxia; Uyama, Hiroshi

2013-01-01

A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructu...

Sensitive detection of nucleic acids by PNA hybridization directed co-localization of fluorescent beads

DEFF Research Database (Denmark)

Shiraishi, Takehiko; Deborggraeve, Stijn; Büscher, Philippe

2011-01-01

)avidin-coated fluorescent beads, differing in size and color [green beads (1 µm) and red beads (5.9 µm)], thereby allowing distinct detection of each PNA probe by conventional fluorescence microscopy. These two PNA beads showed easily detectable co-localization when simultaneously hybridizing to a target nucleic acid...

Preparation and swelling properties of pH-sensitive composite hydrogel beads based on chitosan-g-poly (acrylic acid)/vermiculite and sodium alginate for diclofenac controlled release.

Science.gov (United States)

Wang, Qin; Xie, Xiaoling; Zhang, Xiaowei; Zhang, Junping; Wang, Aiqin

2010-04-01

A series of pH-sensitive composite hydrogel beads, chitosan-g-poly (acrylic acid)/vermiculite/sodium alginate (CTS-g-PAA/VMT/SA), was prepared using CTS-g-PAA/VMT composite and SA by Ca(2+) as the crosslinking agent. The structure and morphologies of the developed composite hydrogel beads were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The swelling properties and pH-sensitivity of the beads were investigated. In addition, the drug loading and controlled release behaviors of the beads were also evaluated using diclofenac sodium (DS) as the model drug in stimulated gastric fluids (pH 2.1) and intestinal fluids (pH 6.8). The results indicate that the composite hydrogel beads showed good pH-sensitivity. The release rate of the drug from the composite hydrogel beads is remarkably slowed down, which indicated that incorporating VMT into the composite hydrogel beads can improve the burst release effect of the drug. Copyright 2010 Elsevier B.V. All rights reserved.

Alginate-Chitosan Particulate System for Sustained Release of ...

African Journals Online (AJOL)

Erah

1School of Pharmacy and Health Sciences, International Medical University, Kuala Lumpur, Malaysia, 2Division of ... Both calcium alginate beads and the beads treated with chitosan failed to release ..... also found to fit the classical power law.

Design, characterisation and application of alginate-based encapsulated pig liver esterase.

Science.gov (United States)

Pauly, Jan; Gröger, Harald; Patel, Anant V

2018-06-05

Encapsulation of hydrolases in biopolymer-based hydrogels often suffers from low activities and encapsulation efficiencies along with high leaching and unsatisfactory recycling properties. Exemplified for the encapsulation of pig liver esterase the coating of alginate and chitosan beads have been studied by creating various biopolymer hydrogel beads. Enzyme activity and encapsulation efficiency were notably enhanced by chitosan coating of alginate beads while leaching remained nearly unchanged. This was caused by the enzymatic reaction acidifying the matrix, which increased enzyme retention through enhanced electrostatic enzyme-alginate interaction but decreased activity through enzyme deactivation. A practical and ready-to-use method for visualising pH in beads during reaction by co-encapsulation of a conventional pH indicator was also found. Our method proves that pH control inside the beads can only be realised by buffering. The resulting beads provided a specific activity of 0.267 μmol ∙ min -1 ∙ mg -1 , effectiveness factor 0.88, encapsulation efficiency of 88%, 5% leaching and good recycling properties. This work will contribute towards better understanding and application of encapsulated hydrolases for enzymatic syntheses. Copyright © 2018 Elsevier B.V. All rights reserved.

A VERSATILE ALGINATE DROPLET GENERATOR APPLICABLE FOR MICROENCAPSULATION OF PANCREATIC-ISLETS

NARCIS (Netherlands)

WOLTERS, GHJ; FRITSCHY, WM; GERRITS, D; VANSCHILFAGAARDE, R

1992-01-01

Alginate beads for immunoisolation of pancreatic islets by microencapsulation should be small, smooth, and spherical in order to ensure that around the islets a strong alginate-polylysine-alginate capsule will be formed with optimal biocompatibility and diffusion of nutrients and hormones. However,

Determining the selectivity of divalent metal cations for the carboxyl group of alginate hydrogel beads during competitive sorption.

Science.gov (United States)

An, Byungryul; Lee, Healim; Lee, Soonjae; Lee, Sang-Hyup; Choi, Jae-Woo

2015-11-15

To investigate the competitive sorption of divalent metal ions such as Ca(2+), Cu(2+), Ni(2+), and Pb(2+) on alginate hydrogel beads, batch and column tests were conducted. The concentration of carboxyl group was found to be limited in the preparation of spherical hydrogel beads. From kinetic test results, 80% of sorption was observed within 4h, and equilibrium was attained in 48 h. According to the comparison of the total uptake and release, divalent metal ions were found to stoichiometrically interact with the carboxyl group in the alginate polymer chain. From the Langmuir equation, the maximum capacities of Pb(2+), Cu(2+), and Ni(2+) were calculated to be 1.1, 0.48, and 0.13 mmol/g, respectively. The separation factor (α) values for αPb/Cu, αPb/Ni, and αCu/Ni were 14.0, 98.9, and 7.1, respectively. The sorption capacity of Pb(2+) was not affected by the solution pH; however, the sorption capacities of Cu(2+) and Ni(2+) decreased with increasing solution pH, caused by competition with hydrogen. According to the result from the fixed column test, Pb(2+) exhibited the highest affinity, followed by Cu(2+) and Ni(2+), which is in exact agreement with those of kinetic and isotherm tests. The sorbent could be regenerated using 4% HCl, and the regenerated sorbent exhibited 90% capacity upto 9 cycles. Copyright © 2015 Elsevier B.V. All rights reserved.

Alginate as a cell culture substrate for growth and differentiation of human retinal pigment epithelial cells.

Science.gov (United States)

Heidari, Razeih; Soheili, Zahra-Soheila; Samiei, Shahram; Ahmadieh, Hamid; Davari, Maliheh; Nazemroaya, Fatemeh; Bagheri, Abouzar; Deezagi, Abdolkhalegh

2015-03-01

The purpose of this study was to evaluate retinal pigment epithelium (RPE) cells' behavior in alginate beads that establish 3D environment for cellular growth and mimic extracellular matrix versus the conventional 2D monolayer culture. RPE cells were encapsulated in alginate beads by dripping alginate cell suspension into CaCl2 solution. Beads were suspended in three different media including Dulbecco's modified Eagle's medium (DMEM)/F12 alone, DMEM/F12 supplemented with 10 % fetal bovine serum (FBS), and DMEM/F12 supplemented with 30 % human amniotic fluid (HAF). RPE cells were cultivated on polystyrene under the same conditions as controls. Cell phenotype, cell proliferation, cell death, and MTT assay, immunocytochemistry, and real-time RT-PCR were performed to evaluate the effect of alginate on RPE cells characteristics and integrity. RPE cells can survive and proliferate in alginate matrixes. Immunocytochemistry analysis exhibited Nestin, RPE65, and cytokeratin expressions in a reasonable number of cultured cells in alginate beads. Real-time PCR data demonstrated high levels of Nestin, CHX10, RPE65, and tyrosinase gene expressions in RPE cells immobilized in alginate when compared to 2D monolayer culture systems. The results suggest that alginate can be used as a reliable scaffold for maintenance of RPE cells' integrity and in vitro propagation of human retinal progenitor cells for cell replacement therapies in retinal diseases.

In-situ preparation of NaA zeolite/chitosan porous hybrid beads for removal of ammonium from aqueous solution.

Science.gov (United States)

Yang, Kai; Zhang, Xiang; Chao, Cong; Zhang, Bing; Liu, Jindun

2014-07-17

Inorganic/organic hybrid materials play important roles in removal of contaminants from wastewater. Herein, we used the natural materials of halloysite and chitosan to prepare a new adsorbent of NaA zeolite/chitosan porous hybrid beads by in-situ hydrothermal synthesis method. SEM indicated that the porous hybrid beads were composed of 6-8 μm sized cubic NaA zeolite particles congregated together with chitosan. The adsorption behavior of NH4(+) from aqueous solution onto hybrid beads was investigated at different conditions. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. A maximum adsorption capacity of 47.62 mg/g at 298 K was achieved according to Langmuir model. The regenerated or reused experiments indicated that the adsorption capacity of the hybrid beads could maintain in 90% above after 10 successive adsorption-desorption cycles. The high adsorption and reusable ability implied potential application of the hybrid beads for removing NH4(+) pollutants from wastewater. Copyright © 2014 Elsevier Ltd. All rights reserved.

Poly (vinyl alcohol-alginate physically crosslinked hydrogel membranes for wound dressing applications: Characterization and bio-evaluation

Directory of Open Access Journals (Sweden)

Elbadawy A. Kamoun

2015-01-01

Full Text Available PVA-sodium alginate (SA hydrogel membranes containing sodium ampicillin as a topical antibiotic were developed using the freeze–thawing method for wound dressing application. Aqueous solution of sodium alginate has been blended in a certain ratio with PVA, followed by the crosslinking method has been conducted by freeze–thawing method as physical crosslinking instead of the use of traditional chemical crosslinking to avoid riskiness of chemical reagents and crosslinkers. The physicochemical properties of PVA-SA membranes e.g. gel fraction and water uptake % have been performed. Increased SA content with PVA decreased gel fraction, elasticity, and elongation to break of PVA-SA membranes. However, it resulted in an increase in swelling degree, protein adsorption, and roughness of membrane surface. High SA content in PVA membranes had apparently an impact on surface morphology structure of hydrogel membranes. Pore size and pore area distribution have been observed with addition of high SA concentration. However, high SA content had an insignificant effect on the release of ampicillin. The hydrolytic degradation of PVA-SA membranes has prominently increased with increasing SA content. Furthermore, hemolysis (% and in vitro inhibition (% for both Gram positive and negative bacteria have been sharply affected by addition of SA into PVA, indicating the improved blood hemocompatibility. Thus, PVA-SA hydrogel membrane based wound dressing system containing ampicillin could be a good polymeric membrane candidate in wound care.

Ag2O/sodium alginate-reduced graphene oxide aerogel beads for efficient visible light driven photocatalysis

Science.gov (United States)

Ma, Yuhua; Wang, Jiajia; Xu, Shimei; Feng, Shun; Wang, Jide

2018-02-01

In this work, one facile and green method was developed to resolve the instinct defects of pure Ag2O and increase visible-light photocatalytic activity of Ag2O-based catalyst. In which, Ag2O was immobilized in sodium alginate-reduced graphene oxide (ALG-rGO) aerogel beads. The as-prepared aerogel beads showed a well-defined interconnected three-dimensional porous network and displayed the highest photocatalytic activity with a mass ratio of 40:1 (ALG:rGO). For the degradation of cationic Rhodamine B (RhB) and anionic dye Orange II (OII) dyes, rate constants were 1.95 × 10-2 min-1 and 4.13 × 10-2 min-1, which were 2.4 and 3.1 times higher than those of Ag2O/ALG aerogel beads, respectively. The further studies demonstrated that presence of rGO can effectively decrease the size of Ag2O, extend photoresponding range (UV to near-infrared light spectrum), speed-up separate photogenerated electrons and holes, retard charge recombination, and prolong electron lifetime and effective carrier diffusion length. The potential mechanism for RhB and OII degrading was expounded, and main active species in the degradation reactions of dyes were investigated by a series of trapping experiments. It offered a promising photocatalyst to purify the wastewater, and provided a sophisticated understanding of the pivotal role rGO acting in photocatalysis.

Synergistic effect of cellulose nanocrystals/graphene oxide nanosheets as functional hybrid nanofiller for enhancing properties of PVA nanocomposites.

Science.gov (United States)

El Miri, Nassima; El Achaby, Mounir; Fihri, Aziz; Larzek, Mohamed; Zahouily, Mohamed; Abdelouahdi, Karima; Barakat, Abdellatif; Solhy, Abderrahim

2016-02-10

Novel functional hybrid nanofillers composed of cellulose nanocrystals (CNC) and graphene oxide nanosheets (GON), at different weight ratios (2:1, 1:1 and 1:2), were successfully prepared and characterized, and their synergistic effect in enhancing the properties of poly(vinyl alcohol) (PVA) nanocomposites was investigated. Due to the synergistic reinforcement, it was found that the Young's modulus, tensile strength and toughness of the PVA nanocomposite containing 5 wt% hybrid nanofiller (1:2) were significantly improved by 320%, 124% and 159%, respectively; and the elongation at break basically remained compared to the neat PVA matrix. In addition, the glass and melting temperatures as well as the moisture sorption of nanocomposites were also enhanced. This synergistic effect improved the dispersion homogeneity by avoiding the agglomeration phenomenon of nanofillers within the polymer matrix, resulting in nanocomposites with largely enhanced properties compared to those prepared from single nanofiller (CNC or GON). The preparation of these hybrid nanofillers and their incorporation into a polymer provided a novel method for the development of novel multifunctional nanocomposites based on the combination of existing nanomaterials. Copyright © 2015 Elsevier Ltd. All rights reserved.

Isolation and characterization of Linum usitatisimum polysaccharide to prepare mucoadhesive beads of diclofenac sodium.

Science.gov (United States)

Saquib Hasnain, M; Rishishwar, Poonam; Rishishwar, Sanjay; Ali, Sadath; Nayak, Amit Kumar

2018-05-01

The present research deals with the usefulness of isolated linseed polysaccharide (LP) as polymeric-blends with an anionic polymer, sodium alginate to prepare ionotropically cross-linking gelled mucoadhesive beads for controlled drug release. From the mature and ripe linseeds (Linum usitatisimum; family Liliaceae), LP was isolated and its colour, odour, taste, solubility in water, pH and viscosity were studied. Isolated LP was also characterized by FTIR spectroscopy and 1 H NMR analyses. LP‑calcium alginate beads loaded with diclofenac sodium were formulated via ionotropically crosslinking gelation method using calcium chloride as ionotropic crosslinker. These ionotropically crosslinked beads showed diclofenac sodium encapsulation efficiencies in these newly prepared beads were 60.78 ± 2.47 to 93.16 ± 4.08% and average bead-sizes of 1.17 ± 0.10 to 1.33 ± 0.12 mm. All LP‑calcium alginate beads loaded with diclofenac sodium demonstrated a sustained drug releasing profile over 8 h with a zero-order model of drug releasing (controlled drug releasing pattern). The LP‑calcium alginate beads loaded with diclofenac sodium displayed a pH responsive swelling and excellent biomucoadhesivity prospective with the intestinal mucosal tissue in both the acidic and alkaline pH (pH 1.2 and 7.4, respectively). These beads were also characterized by SEM and FTIR spectroscopy. Copyright © 2017. Published by Elsevier B.V.

Preparation of highly stable zeolite-alginate foam composite for strontium(90Sr) removal from seawater and evaluation of Sr adsorption performance.

Science.gov (United States)

Hong, Hye-Jin; Kim, Byoung-Gyu; Ryu, Jungho; Park, In-Su; Chung, Kang-Sup; Lee, Sang Moon; Lee, Jin-Bae; Jeong, Hyeon Su; Kim, Hyunchul; Ryu, Taegong

2018-01-01

Alginate bead is a promising strontium (Sr) adsorbent in seawater, but highly concentrated Na ions caused over-swelling and damaged the hydrogel bead. To improve the mechanical stability of alginate bead, flexible foam-type zeolite-alginate composite was synthesized and Sr adsorption performance was evaluated in seawater; 1-10% zeolite immobilized alginate foams were prepared by freeze-dry technique. Immobilization of zeolite into alginate foam converted macro-pores to meso-pores which lead to more compact structure. It resulted in less swollen composite in seawater medium and exhibited highly improved mechanical stability compared with alginate bead. Besides, Sr adsorption efficiency and selectivity were enhanced by immobilization of zeolite in alginate foam due to the increase of Sr binding sites (zeolite). In particular, Sr selectivity against Na was highly improved. The 10% zeolite-alginate foam exhibited a higher log K d of 3.3, while the pure alginate foam exhibited 2.7 in the presence of 0.1 M Na. Finally, in the real seawater, the 10% zeolite-alginate foam exhibited 1.5 times higher Sr adsorption efficiency than the pure alginate foam. This result reveals that zeolite-alginate foam composite is appropriate material for Sr removal in seawater due to its swelling resistance as well as improved Sr adsorption performance in complex media. Copyright © 2017 Elsevier Ltd. All rights reserved.

Separation of yttrium using carbon nanotube doped polymeric beads impregnated with D2EHPA

International Nuclear Information System (INIS)

Dasgupta, Kinshuk; Yadav, Kartikey K.; Singh, D.K.; Anitha, M.; Singh, H.

2013-01-01

Di-2-ethylhexyl phosphoric acid impregnated polyethersulfone based composite beads in combination with additives such as polyvinyl alcohol (PVA) and multiwalled carbon nanotube (MWCNT) has been prepared by non-solvent phase inversion method. The synthesized beads were characterized by scanning electron microscopy, thermogravimetry and infra-red spectroscopy. Effect of additives on bead morphology, solvent impregnation capacity, extractability and stability has been examined to compare their suitability for yttrium recovery from acidic medium. Microstructural investigation as well as experimental findings confirmed the role of additives in modifying the pore structures in beads, responsible for varied degree of yttrium extraction. Further the role of metal ion concentration in aqueous phase on its recovery by polymeric beads was also evaluated. Among the tested beads PES/D2EHPA/MWCNT/PVA beads were found to be superior for Y(Ill) extraction. (author)

Thermodynamic, Kinetic, and Equilibrium Parameters for the Removal of Lead and Cadmium from Aqueous Solutions with Calcium Alginate Beads

Directory of Open Access Journals (Sweden)

Ruth Alfaro-Cuevas-Villanueva

2014-01-01

Full Text Available The sorption of cadmium (Cd and lead (Pb by calcium alginate beads (CAB from aqueous solutions in batch systems was investigated. The kinetic and thermodynamic parameters, as well as the sorption capacities of CAB in each system at different temperatures, were evaluated. The rate of sorption for both metals was rapid in the first 10 minutes and reached a maximum in 50 minutes. Sorption kinetic data were fitted to Lagergren, pseudo-second-order and Elovich models and it was found that the second-order kinetic model describes these data for the two metals; comparing kinetic parameters for Cd and Pb sorption a higher kinetic rate (K2 for Pb was observed, indicating that the interaction between lead cations and alginate beads was faster than for cadmium. Similarly, isotherm data were fitted to different models reported in literature and it was found that the Langmuir-Freundlich (L-F and Dubinin-Radushkevich (D-R models describe the isotherms in all cases. CAB sorption capacity for cadmium was 27.4 mg/g and 150.4 mg/g for lead, at 25°C. Sorption capacities of Cd and Pb increase as temperature rises. According to the thermodynamic parameters, the cadmium and lead adsorption process was spontaneous and endothermic. It was also found that pH has an important effect on the adsorption of these metals by CAB, as more were removed at pH values between 6 and 7.

Removal of Lead from Water Using Calcium Alginate Beads Doped with Hydrazine Sulphate-Activated Red Mud as Adsorbent

Directory of Open Access Journals (Sweden)

A. Naga Babu

2017-01-01

Full Text Available Calcium alginate beads doped with hydrazine sulphate-treated red mud are investigated as adsorbent for extracting lead ions from water using batch methods of extraction. Different extraction conditions are optimised for maximum lead extraction. Substantial amount of lead is removed, and the adsorption ability is found to be 138.6 mg/g. Surface characterization using FTIR, EDX, and FESEM confirms that lead is “onto” the surface of the adsorbent. Thermodynamic parameters, adsorption isotherms, and kinetics of adsorption are analysed. Adsorption is “physisorption” in nature and spontaneous. The adsorbent developed can be regenerated using 0.1 M HCl. Thus regenerated adsorbent can be used as the adsorbent for further removal of lead at least 10 times, and this enables the complete removal of lead from water by repetitive use of the regenerated adsorbent. The beads facilitate the easy filtration. The methodology developed is successfully applied for removing lead from industrial waste waters.

Arsenate removal by layered double hydroxides embedded into spherical polymer beads: Batch and column studies.

Science.gov (United States)

Nhat Ha, Ho Nguyen; Kim Phuong, Nguyen Thi; Boi An, Tran; Mai Tho, Nguyen Thi; Ngoc Thang, Tran; Quang Minh, Bui; Van Du, Cao

2016-01-01

In this study, the performance of poly(layered double hydroxides) [poly(LDHs)] beads as an adsorbent for arsenate removal from aqueous solution was investigated. The poly(LDHs) beads were prepared by immobilizing LDHs into spherical alginate/polyvinyl alcohol (PVA)-glutaraldehyde beads (spherical polymer beads). Batch adsorption studies were conducted to assess the effect of contact time, solution pH, initial arsenate concentrations and co-existing anions on arsenate removal performance. The potential reuse of these poly(LDHs) beads was also investigated. Approximately 79.1 to 91.2% of arsenic was removed from an arsenate solution (50 mg As L(-1)) by poly(LDHs). The adsorption data were well described by the pseudo-second-order kinetics model and the Langmuir isotherm model, and the adsorption capacities of these poly(LDHs) beads at pH 8 were from 1.64 to 1.73 mg As g(-1), as calculated from the Langmuir adsorption isotherm. The adsorption ability of the poly(LDHs) beads decreased by approximately 5-6% after 5 adsorption-desorption cycles. Phosphates markedly decreased arsenate removal. The effect of co-existing anions on the adsorption capacity declined in the following order: HPO4 (2-) > HCO3 (-) > SO4 (2-) > Cl(-). A fixed-bed column study was conducted with real-life arsenic-containing water. The breakthrough time was found to be from 7 to 10 h. Under optimized conditions, the poly(LDHs) removed more than 82% of total arsenic. The results obtained in this study will be useful for further extending the adsorbents to the field scale or for designing pilot plants in future studies. From the viewpoint of environmental friendliness, the poly(LDHs) beads are a potential cost-effective adsorbent for arsenate removal in water treatment.

Molecular and biopharmaceutical investigation of alginate-inulin synbiotic coencapsulation of probiotic to target the colon.

Science.gov (United States)

Atia, Abdelbasset; Gomma, Ahmed I; Fliss, Ismail; Beyssac, Eric; Garrait, Ghislain; Subirade, Muriel

2017-03-01

Colon targeting, as a site-specific delivery for oral formulation, remains a major challenge, especially for sensitive bioactive components such as therapeutic forms of phages, live attenuated virus and prebiotics-probiotics association. Synbiotics could be used to protect encapsulated probiotics during the gastrointestinal tract and control their release in the colon. To achieve these goals, effective prebiotics, such as inulin, could be combined with alginate - the most exploited polymer used for probiotic encapsulation - in the form of beads. This work aimed to study the biopharmaceutical behaviour of alginate beads (A) and inulin-alginate beads of different inulin concentrations (5 or 20%) in 2% alginate (AI5, AI20). Beads were loaded with three probiotic strains (Pediococcus acidilactici Ul5, Lactobacillus reuteri and Lactobacillus salivarius). Dissolution of beads was studied by USP4 under conditions simulating the gastrointestinal condition. The survival rates of the bacterial strains were measured by a specific qPCR bacterial count. Mucoadhesiveness of beads was studied by an ex vivo method using intestinal mucosa. To understand the behaviour of each formulation, the ultrastructure of the polymeric network was studied using scanning electron microscopy (SEM). Molecular interactions between alginate and inulin were studied by Fourier transform infra-red spectroscopy (FTIR). Dissolution results suggested that the presence of inulin in beads provided more protection for the tested bacterial strains against the acidic pH. AI5 was the most effective formulation to deliver probiotics to the colon simulation conditions. FTIR and SEM investigations explained the differences in behaviour of each formula. The developed symbiotic form provided a promising matrix for the development of colonic controlled release systems.

Preparation and characterization of polysaccharides/PVA blend nanofibrous membranes by electrospinning method.

Science.gov (United States)

Santos, Carla; Silva, Carla J; Büttel, Zsófia; Guimarães, Rodrigo; Pereira, Sara B; Tamagnini, Paula; Zille, Andrea

2014-01-01

A series of polyvinyl alcohol (PVA), PVA/chitosan (CS) and PVA/cyanobacterial extracellular polymeric substances (EPS) blended nanofibrous membranes were produced by electrospinning using a microfiltration poly(vinylidene fluoride) (PVDF) basal membrane, for potential applications in water filtration. Nanofibres were obtained from solutions of 20% (w/w) PVA with 1% (w/w) CS or EPS, using a weight ratio of 60/40. Blended nanofibres have shown a smooth morphology, no beads formation and diameters between 50 and 130 nm. Thermo-mechanical analysis demonstrated that there were inter and/or intramolecular hydrogen bonds between the molecules of PVA/CS and PVA/EPS in the blends. The electrospun blended PVA/EPS membrane showed better tensile mechanical properties when compared with PVA and PVA/CS, and resisted more against disintegration in the temperature range between 10 and 50 °C. Finally, the blended membranes have shown an increase in chromium binding capacity of 5%. This is the first successful report of a blended membrane of electrospinned cyanobacterial polysaccharide with PVA. Copyright © 2013 Elsevier Ltd. All rights reserved.

Polyvinyl alcohol (PVA)-cellulose nanofibril (CNF)-multiwalled carbon nanotube (MWCNT) hybrid organic aerogels with superior mechanical properties

Science.gov (United States)

Qifeng Zheng; Alireza Javadi; Ronald Sabo; Zhiyong Cai; Shaoqin Gong

2013-01-01

Polyvinyl alcohol (PVA)–cellulose nanofibril (CNF)–multiwalled carbon nanotube (MWCNT) hybrid organic aerogels were prepared using an environmentally friendly freeze-drying process with renewable materials. The material properties of these “green” hybrid aerogels were characterized extensively using various techniques. It was found that adding a small amount of CNFs...

Immobilization of alginate-encapsulated Bacillus thuringiensis var. israelensis containing different multivalent counterions for mosquito control.

Science.gov (United States)

Prabakaran, G; Hoti, S L

2008-08-01

Immobilized techniques have been used widely for the controlled release formulation of mosquitoes. Among the microbial formulations, polymeric matrices play an important role in the controlled release of microbial pesticide at rates sufficiently effective to kill mosquitoes in the field. The advantage of these matrices is that they enhance the stability of both spores and toxin against pH, temperature variations, and UV irradiation. The disadvantage of using calcium alginate beads is that they are unstable upon contact with phosphate of potassium or sodium ions rich in the mosquito habitats. To overcome these problems, attempts were made to encapsulate Bacillus thuringiensis var. israelensis within alginate by using different multivalent counterions, namely, calcium chloride, zinc sulfate, copper sulfate, cobalt chloride, and ferric chloride, and the beads formed were tested for its mosquito larvicidal activity. Among all the beads tested, zinc alginate beads resulted in maximum larvicidal activity of 98% (+/-1.40 SE) against Culex quinquefasciatus IIIrd instar larvae and maximum spore count of 3.36 x 10(5) (+/-5291.50 SE) CFU/ml. Zinc alginate beads maintained their structure for up to 48 h when shaken vigorously on a rotary shaker at 180 rpm in the presence of 10 mM potassium phosphate buffer (pH 6.8 +/- 0.1). In conclusion, our results suggest that the use of zinc sulfate as counterions to encapsulate B. thuringiensis var. israelensis within alginate may be a potent mosquito control program in the habitats where more phosphate ions are present.

Hybrid shell engineering of animal cells for immune protections and regulation of drug delivery: towards the design of "artificial organs".

Science.gov (United States)

Dandoy, Philippe; Meunier, Christophe F; Michiels, Carine; Su, Bao-Lian

2011-01-01

With the progress in medicine, the average human life expectancy is continuously increasing. At the same time, the number of patients who require full organ transplantations is augmenting. Consequently, new strategies for cell transplantation are the subject of great interest. This work reports the design, the synthesis and the characterisation of robust and biocompatible mineralised beads composed of two layers: an alginate-silica composite core and a Ca-alginate layer. The adequate choice of materials was achieved through cytotoxicity LDH release measurement and in vitro inflammatory assay (IL-8) to meet the biocompatibility requirements for medical purpose. The results obtained following this strategy provide a direct proof of the total innocuity of silica and alginate networks for human cells as underscored by the non-activation of immune defenders (THP-1 monocytes). The accessible pore size diameter of the mineralised beads synthesized was estimated between 22 and 30 nm, as required for efficient immuno-isolation without preventing the diffusion of nutrients and metabolites. The model human cells, HepG2, entrapped within these hybrid beads display a high survival rate over more than six weeks according to the measurements of intracellular enzymatic activity, respiration rate, as well as the "de novo" biosynthesis and secretion of albumin out of the beads. The current study shows that active mammalian cells can be protected by a silica-alginate hybrid shell-like system. The functionality of the cell strain can be maintained. Consequently, cells coated with an artificial and a biocompatible mineral shell could respond physiologically within the human body in order to deliver therapeutic agents in a controlled fashion (i.e. insulin), substituting the declining organ functions of the patient.

Calcium alginate microspheres containing metformin hydrochloride niosomes and chitosomes aimed for oral therapy of type 2 diabetes mellitus.

Science.gov (United States)

Maestrelli, Francesca; Mura, Paola; González-Rodríguez, María Luisa; Cózar-Bernal, María José; Rabasco, Antonio María; Di Cesare Mannelli, Lorenzo; Ghelardini, Carla

2017-09-15

Metformin is an oral hypoglycemic agent used in the type 2 diabetes, whose poor bioavailability and short half-life make the development of effective extended-release formulations highly desirable. Different metformin-loaded chitosomal and niosomal formulations were developed and suitably characterized, but were unable to provide the desired sustained release. The entrapment of both kinds of colloidal dispersions in calcium alginate beads enabled to strongly reduce the amount of drug released at gastric level (from 18 up to a maximum of 30%), and to obtain a sustained release in simulated intestinal fluid, which was properly tuned by varying the percentage of calcium alginate in the beads. In vivo studies on rats revealed a significant improvement of metformin hypoglycemic effect when orally administered as chitosomal and even more as niosomal dispersion entrapped in alginate beads, not only with respect to the drug as such, but also to the alginate beads loaded with the plain drug. The more intense and sustained therapeutic effect with time provided by the drug-in niosomes-in alginate bead formulation could be very profitable for maintaining tight blood glucose levels over prolonged period of time after oral administration, allowing a reduction of its dose and related collateral effects, and improving patient compliance. Copyright © 2017 Elsevier B.V. All rights reserved.

Alginate oligosaccharides

DEFF Research Database (Denmark)

Falkeborg, Mia; Cheong, Ling-Zhi; Gianfico, Carlo

2014-01-01

the presence of the conjugated alkene acid structure formed during enzymatic depolymerization. According to the resonance hybrid theory, the parent radicals of AOs are delocalized through allylic rearrangement, and as a consequence, the reactive intermediates are stabilized. AOs were weak ferrous ion chelators......Alginate oligosaccharides (AOs) prepared from alginate, by alginate lyase-mediated depolymerization, were structurally characterized by mass spectrometry, infrared spectrometry and thin layer chromatography. Studies of their antioxidant activities revealed that AOs were able to completely (100....... This work demonstrated that AOs obtained from a facile enzymatic treatment of abundant alginate is an excellent natural antioxidant, which may find applications in the food industry....

Improvement of Biodesulfurization Rate of Alginate Immobilized Rhodococcus erythropolis R1.

Science.gov (United States)

Derikvand, Peyman; Etemadifar, Zahra

2014-03-01

Sulfur oxides released from the burning of oil causes severe environmental pollution. The sulfur can be removed via the 4S pathway in biodesulfurization (BDS). Immobilization approaches have been developed to prevent cell contamination of oil during the BDS process. The encapsulation of Rhodococcus erythropolis R1 in calcium alginate beads was studied in order to enhance conversion of dibenzothiophene (DBT) to 2-hydroxy biphenyl (2-HBP) as the final product. Also the effect of different factors on the BDS process was investigated. Calcium alginate capsules were prepared using peristaltic pumps with different needle sizes to control the beads sizes. Scanning electron microscopy and flow cytometry methods were used to study the distribution and viability of encapsulated cells, respectively. Two non-ionic surfactants and also nano Ƴ-Al2O3were used with the ratio of 0.5% (v/v) and 1:5 (v/v) respectively to investigate their BDS efficiency. In addition, the effect of different bead sizes and different concentrations of sodium alginate in BDS activity was studied. The 2% (w/v) sodium alginate beads with 1.5mm size were found to be the optimum for beads stability and efficient 2-HBP production. The viability of encapsulated cells decreased by 12% after 20 h of desulfurization, compared to free cells. Adding the non-ionic surfactants markedly enhanced the rate of BDS, because of increasing mass transfer of DBT to the gel matrix. In addition, Span 80 was more effective than Tween 80. The nanoƳ-Al2O3 particles could increase BDS rate by up to two-folds greater than that of the control beads. The nano Ƴ-Al2O3 can improve the immobilized biocatalyst for excellent efficiency of DBT desulfurization. Also the BDS activity can be enhanced by setting the other explained factors at optimum levels.

Polyvinyl-alcohol-based magnetic beads for rapid and efficient separation of specific or unspecific nucleic acid sequences

International Nuclear Information System (INIS)

Oster, J.; Parker, Jeffrey; Brassard, Lothar

2001-01-01

The versatile application of polyvinyl-alcohol-based magnetic M-PVA beads is demonstrated in the separation of genomic DNA, sequence specific nucleic acid purification, and binding of bacteria for subsequent DNA extraction and detection. It is shown that nucleic acids can be obtained in high yield and purity using M-PVA beads, making sample preparation efficient, fast and highly adaptable for automation processes

Preparation and characterization of alginate and gelatin microcapsules containing Lactobacillus rhamnosus.

Science.gov (United States)

Lopes, Susiany; Bueno, Luciano; Aguiar, Francisco DE; Finkler, Christine

2017-01-01

This paper describes the preparation and characterization of alginate beads coated with gelatin and containing Lactobacillus rhamnosus. Capsules were obtained by extrusion method using CaCl2 as cross linker. An experimental design was performed using alginate and gelatin concentrations as the variables investigated, while the response variable was the concentration of viable cells. Beads were characterized in terms of size, morphology, scanning electron microscopy (SEM), moisture content, Fourier Transform Infrared Spectrometry (FTIR), thermal behavior and cell viability during storage. The results showed that the highest concentration of viable cells (4.2 x 109 CFU/g) was obtained for 1 % w/v of alginate and 0.1 % w/v of gelatin. Capsules were predominantly spherical with a rough surface, a narrow size distribution ranging from 1.53 to 1.90 mm and a moisture content of 97.70 ± 0.03 %. Furthermore, FTIR and thermogravimetric analysis indicated an interaction between alginate-gelatin. Cell concentration of alginate/gelatin microcapsules was 105 CFU/g after 4 months of storage at 8 oC.

Preparation and characterization of alginate and gelatin microcapsules containing Lactobacillus rhamnosus

Directory of Open Access Journals (Sweden)

SUSIANY LOPES

2017-08-01

Full Text Available ABSTRACT This paper describes the preparation and characterization of alginate beads coated with gelatin and containing Lactobacillus rhamnosus. Capsules were obtained by extrusion method using CaCl2 as cross linker. An experimental design was performed using alginate and gelatin concentrations as the variables investigated, while the response variable was the concentration of viable cells. Beads were characterized in terms of size, morphology, scanning electron microscopy (SEM, moisture content, Fourier Transform Infrared Spectrometry (FTIR, thermal behavior and cell viability during storage. The results showed that the highest concentration of viable cells (4.2 x 109 CFU/g was obtained for 1 % w/v of alginate and 0.1 % w/v of gelatin. Capsules were predominantly spherical with a rough surface, a narrow size distribution ranging from 1.53 to 1.90 mm and a moisture content of 97.70 ± 0.03 %. Furthermore, FTIR and thermogravimetric analysis indicated an interaction between alginate-gelatin. Cell concentration of alginate/gelatin microcapsules was 105 CFU/g after 4 months of storage at 8 oC.

Silk sericin-alginate-chitosan microcapsules: hepatocytes encapsulation for enhanced cellular functions.

Science.gov (United States)

Nayak, Sunita; Dey, Sanchareeka; Kundu, Subhas C

2014-04-01

The encapsulation based technology permits long-term delivery of desired therapeutic products in local regions of body without the need of immunosuppressant drugs. In this study microcapsules composed of sericin and alginate micro bead as inner core and with an outer chitosan shell are prepared. This work is proposed for live cell encapsulation for potential therapeutic applications. The sericin protein is obtained from cocoons of non-mulberry silkworm Antheraea mylitta. The sericin-alginate micro beads are prepared via ionotropic gelation under high applied voltage. The beads further coated with chitosan and crosslinked with genipin. The microcapsules developed are nearly spherical in shape with smooth surface morphology. Alamar blue assay and confocal microscopy indicate high cell viability and uniform encapsulated cell distribution within the sericin-alginate-chitosan microcapsules indicating that the microcapsules maintain favourable microenvironment for the cells. The functional analysis of encapsulated cells demonstrates that the glucose consumption, urea secretion rate and intracellular albumin content increased in the microcapsules. The study suggests that the developed sericin-alginate-chitosan microcapsule contributes towards the development of cell encapsulation model. It also offers to generate enriched population of metabolically and functionally active cells for the future therapeutics especially for hepatocytes transplantation in acute liver failure. Copyright © 2014 Elsevier B.V. All rights reserved.

Floating-bioadhesive gastroretentive Caesalpinia pulcherrima-based beads of amoxicillin trihydrate for Helicobacter pylori eradication.

Science.gov (United States)

Thombre, Nilima A; Gide, Paraag S

2016-01-01

An oral dosage form containing floating bioadhesive gastroretentive microspheres forms a stomach-specific drug delivery system for the treatment of Helicobacter pylori. To prepare and evaluate controlled release floating bioadhesive gastroretentive chitosan-coated amoxicillin trihydrate-loaded Caesalpinia pulcherrima galactomannan (CPG)-alginate beads (CCA-CPG-A), for H. pylori eradication. CCA-CPG-A beads were prepared by ionotropic gelation, using 2(3) factorial design with quantity of drug, combination of CPG with sodium alginate and concentration of calcium chloride as variables. Beads facilitated mucoadhesion to gastric mucosa with floating nature caused by chitosan coating for wide distribution throughout GIT. Developed beads were evaluated for characteristics like beads size-morphology, entrapment efficiency, DSC, XRD, FTIR, swelling ratio, in vitro mucoadhesion, in vitro drug release, in vitro floating and in vitro H. pylori growth inhibition studies. CCA-CPG-A beads were studied in Wistar rats for in vivo gastric mucoadhesion, in vivo H. pylori growth inhibition studies using PCR amplification of isolated DNA, rapid urease test. Developed beads possess drug release of 79-92%, entrapment efficiency of 65-89%, mucoadhesion of 61-89%. In vivo mucoadhesion study showed more than 85% mucoadhesion of beads even after 7th hour. In vitro-in vivo growth inhibition study showed complete eradication of H. pylori. CPG-alginate and chitosan in beads interacts with gastric mucosubstrate surface for prolonged gastric residence with floating bioadhesion mechanism for H. pylori eradication in rats. Floating bioadhesive CCA-CPG-A beads offer a promising drug delivery system for H. pylori eradication at lower dose, reduced adverse effect and enhance bioavailability.

Hybrid shell engineering of animal cells for immune protections and regulation of drug delivery: towards the design of "artificial organs".

Directory of Open Access Journals (Sweden)

Philippe Dandoy

Full Text Available BACKGROUND: With the progress in medicine, the average human life expectancy is continuously increasing. At the same time, the number of patients who require full organ transplantations is augmenting. Consequently, new strategies for cell transplantation are the subject of great interest. METHODOLOGY/PRINCIPAL FINDINGS: This work reports the design, the synthesis and the characterisation of robust and biocompatible mineralised beads composed of two layers: an alginate-silica composite core and a Ca-alginate layer. The adequate choice of materials was achieved through cytotoxicity LDH release measurement and in vitro inflammatory assay (IL-8 to meet the biocompatibility requirements for medical purpose. The results obtained following this strategy provide a direct proof of the total innocuity of silica and alginate networks for human cells as underscored by the non-activation of immune defenders (THP-1 monocytes. The accessible pore size diameter of the mineralised beads synthesized was estimated between 22 and 30 nm, as required for efficient immuno-isolation without preventing the diffusion of nutrients and metabolites. The model human cells, HepG2, entrapped within these hybrid beads display a high survival rate over more than six weeks according to the measurements of intracellular enzymatic activity, respiration rate, as well as the "de novo" biosynthesis and secretion of albumin out of the beads. CONCLUSIONS/SIGNIFICANCE: The current study shows that active mammalian cells can be protected by a silica-alginate hybrid shell-like system. The functionality of the cell strain can be maintained. Consequently, cells coated with an artificial and a biocompatible mineral shell could respond physiologically within the human body in order to deliver therapeutic agents in a controlled fashion (i.e. insulin, substituting the declining organ functions of the patient.

Encapsulation of protease from Aspergillus oryzae and lipase from Thermomyces lanuginoseus using alginate and different copolymer types

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Truong Thi Mong Thu

2016-05-01

Full Text Available Although the application of enzymes in food as a food processing aid and enzyme supplement is of interest and widely used, the enzymes can be easily deactivated or lose their activity due to many causes such as pH and moisture as well as through the introduction of incompatible ingredients during food processing and storage. These problems can be solved by the encapsulation technique, especially in a gel matrix. The influences were studied of the alginate concentration, types of copolymer and their concentrations on the bead size, encapsulation yield (EY, encapsulation efficiency (EE, leakage and the retention of enzyme activity during storage period of encapsulated protease from Aspergillus oryzae and lipase from Thermomyces lanuginosus beads. A solution of purified protease or lipase was encapsulated in calcium alginate-chitosan beads (CACB, calcium alginate-xanthan gum beads (CAXB and calcium alginate-maltodextrin beads (CAMB using the extrusion method. Increasing the alginate and copolymer concentrations in the solution increased the bead size, EY, EE and the retention of enzyme activity during the storage period and reduced leakage of both the encapsulated protease and lipase. In addition, different types of copolymer significantly (p ≤ 0.05 affected these properties of both encapsulated enzymes. Furthermore, protease encapsulated using 2.0% alginate and 0.2% chitosan provided the highest EY (81.7% and EE (77.2% with a bead size of 1.85 mm and 8.1% leakage. The retention of encapsulated protease activity and the shelf-life of encapsulated enzyme which was expressed as half-life, the time required for the enzyme activity to decrease by half (thalf life were 75.8% and 27.2 wk, respectively after storage at 4 °C for 10 wk. For lipase, encapsulation using 2.0% alginate and 0.4% xanthan gum provided the highest EY (42.5% and EE (43.9% and the bead size and leakage were 1.81 mm and 6.2%, respectively. The retention of encapsulated

3D Cell Culture in Alginate Hydrogels

Directory of Open Access Journals (Sweden)

Therese Andersen

2015-03-01

Full Text Available This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent, and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue.

Improvement of Biodesulfurization Rate of Alginate Immobilized Rhodococcus erythropolis R1

Science.gov (United States)

Derikvand, Peyman; Etemadifar, Zahra

2014-01-01

Background: Sulfur oxides released from the burning of oil causes severe environmental pollution. The sulfur can be removed via the 4S pathway in biodesulfurization (BDS). Immobilization approaches have been developed to prevent cell contamination of oil during the BDS process. Objectives: The encapsulation of Rhodococcus erythropolis R1 in calcium alginate beads was studied in order to enhance conversion of dibenzothiophene (DBT) to 2-hydroxy biphenyl (2-HBP) as the final product. Also the effect of different factors on the BDS process was investigated. Materials and Methods: Calcium alginate capsules were prepared using peristaltic pumps with different needle sizes to control the beads sizes. Scanning electron microscopy and flow cytometry methods were used to study the distribution and viability of encapsulated cells, respectively. Two non-ionic surfactants and also nano Ƴ-Al2O3were used with the ratio of 0.5% (v/v) and 1:5 (v/v) respectively to investigate their BDS efficiency. In addition, the effect of different bead sizes and different concentrations of sodium alginate in BDS activity was studied. Results: The 2% (w/v) sodium alginate beads with 1.5mm size were found to be the optimum for beads stability and efficient 2-HBP production. The viability of encapsulated cells decreased by 12% after 20 h of desulfurization, compared to free cells. Adding the non-ionic surfactants markedly enhanced the rate of BDS, because of increasing mass transfer of DBT to the gel matrix. In addition, Span 80 was more effective than Tween 80. The nanoƳ-Al2O3 particles could increase BDS rate by up to two-folds greater than that of the control beads. Conclusions: The nano Ƴ-Al2O3 can improve the immobilized biocatalyst for excellent efficiency of DBT desulfurization. Also the BDS activity can be enhanced by setting the other explained factors at optimum levels. PMID:25147685

Fabrication of PEDOT coated PVA-GO nanofiber for supercapacitor

International Nuclear Information System (INIS)

Mohd Abdah, Muhammad Amirul Aizat; Zubair, Nur Afifah; Azman, Nur Hawa Nabilah; Sulaiman, Yusran

2017-01-01

Conducting nanofibers comprised of poly(vinyl alcohol) (PVA)-graphene oxide (GO) nanofiber coated with poly(3,4-ethylenedioxythiophene) (PEDOT) for supercapacitor application was prepared through integrated techniques i.e. electrospinning and electrodeposition. The formation of smooth cross-linking nanofibers without beads proved that GO has uniformly distributed into PVA with an average diameter of 117 ± 32 nm. Field emission scanning electron microscopy (FESEM) images revealed that cauliflower-like structure of PEDOT grew well on the surface of PVA-GO nanofibers with high porosity. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy proved the existence of PVA, GO, and PEDOT. PVA-GO/PEDOT nanocomposite showed the highest specific capacitance (224.27 F/g) compared to PEDOT (167.92 F/g) and PVA/PEDOT (182.73 F/g). PVA-GO/PEDOT nanocomposite exhibited 1.8 V wide operating potential windows which significantly can enhance its capacitive behaviour. PVA-GO/PEDOT nanocomposite has also demonstrated superior performance with the energy density and power density of 9.58 Wh/kg and 304.37 W/kg, respectively at 1.0 A/g current density. PVA-GO/PEDOT nanocomposite revealed the smallest resistance of charge transfer (R_c_t) and equivalent series resistance (ESR) indicating excellent charge propagation behaviour at the interfacial region. The composite exhibits a good capacity retention of 82.41% after 2000 CV cycles and further drops 11.27% after 5000 cycles caused by the swelling and shrinkage of the electrode material during the charging and discharging processes. - Highlights: • PVA-GO/PEDOT was prepared via electrospinning and electrodeposition. • PVA-GO/PEDOT displays high capacitance value with wide potential window of 1.8 V. • PVA-GO/PEDOT exhibits high energy and power density, low R_c_t and ESR.

Fabrication of PEDOT coated PVA-GO nanofiber for supercapacitor

Energy Technology Data Exchange (ETDEWEB)

Mohd Abdah, Muhammad Amirul Aizat; Zubair, Nur Afifah; Azman, Nur Hawa Nabilah [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Sulaiman, Yusran, E-mail: yusran@upm.edu.my [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Functional Device Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia)

2017-05-01

Conducting nanofibers comprised of poly(vinyl alcohol) (PVA)-graphene oxide (GO) nanofiber coated with poly(3,4-ethylenedioxythiophene) (PEDOT) for supercapacitor application was prepared through integrated techniques i.e. electrospinning and electrodeposition. The formation of smooth cross-linking nanofibers without beads proved that GO has uniformly distributed into PVA with an average diameter of 117 ± 32 nm. Field emission scanning electron microscopy (FESEM) images revealed that cauliflower-like structure of PEDOT grew well on the surface of PVA-GO nanofibers with high porosity. Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy proved the existence of PVA, GO, and PEDOT. PVA-GO/PEDOT nanocomposite showed the highest specific capacitance (224.27 F/g) compared to PEDOT (167.92 F/g) and PVA/PEDOT (182.73 F/g). PVA-GO/PEDOT nanocomposite exhibited 1.8 V wide operating potential windows which significantly can enhance its capacitive behaviour. PVA-GO/PEDOT nanocomposite has also demonstrated superior performance with the energy density and power density of 9.58 Wh/kg and 304.37 W/kg, respectively at 1.0 A/g current density. PVA-GO/PEDOT nanocomposite revealed the smallest resistance of charge transfer (R{sub ct}) and equivalent series resistance (ESR) indicating excellent charge propagation behaviour at the interfacial region. The composite exhibits a good capacity retention of 82.41% after 2000 CV cycles and further drops 11.27% after 5000 cycles caused by the swelling and shrinkage of the electrode material during the charging and discharging processes. - Highlights: • PVA-GO/PEDOT was prepared via electrospinning and electrodeposition. • PVA-GO/PEDOT displays high capacitance value with wide potential window of 1.8 V. • PVA-GO/PEDOT exhibits high energy and power density, low R{sub ct} and ESR.

Hybrid 3D printing and electrodeposition approach for controllable 3D alginate hydrogel formation.

Science.gov (United States)

Shang, Wanfeng; Liu, Yanting; Wan, Wenfeng; Hu, Chengzhi; Liu, Zeyang; Wong, Chin To; Fukuda, Toshio; Shen, Yajing

2017-06-07

Calcium alginate hydrogels are widely used as biocompatible materials in a substantial number of biomedical applications. This paper reports on a hybrid 3D printing and electrodeposition approach for forming 3D calcium alginate hydrogels in a controllable manner. Firstly, a specific 3D hydrogel printing system is developed by integrating a customized ejection syringe with a conventional 3D printer. Then, a mixed solution of sodium alginate and CaCO 3 nanoparticles is filled into the syringe and can be continuously ejected out of the syringe nozzle onto a conductive substrate. When applying a DC voltage (∼5 V) between the substrate (anode) and the nozzle (cathode), the Ca 2+ released from the CaCO 3 particles can crosslink the alginate to form calcium alginate hydrogel on the substrate. To elucidate the gel formation mechanism and better control the gel growth, we can further establish and verify a gel growth model by considering several key parameters, i.e., applied voltage and deposition time. The experimental results indicate that the alginate hydrogel of various 3D structures can be formed by controlling the movement of the 3D printer. A cell viability test is conducted and shows that the encapsulated cells in the gel can maintain a high survival rate (∼99% right after gel formation). This research establishes a reliable method for the controllable formation of 3D calcium alginate hydrogel, exhibiting great potential for use in basic biology and applied biomedical engineering.

Bioactive apatite incorporated alginate microspheres with sustained drug-delivery for bone regeneration application

Energy Technology Data Exchange (ETDEWEB)

Li, Haibin; Jiang, Fei; Ye, Song; Wu, Yingying; Zhu, Kaiping; Wang, Deping, E-mail: wdpshk@tongji.edu.cn

2016-05-01

The strontium-substituted hydroxyapatite microspheres (SrHA) incorporated alginate composite microspheres (SrHA/Alginate) were prepared via adding SrHA/alginate suspension dropwise into calcium chloride solution, in which the gel beads were formed by means of crosslinking reaction. The structure, morphology and in vitro bioactivity of the composite microspheres were studied by using XRD, SEM and EDS methods. The biological behaviors were characterized and analyzed through inductively coupled plasma optical emission spectroscopy (ICP-OES), CCK-8, confocal laser microscope and ALP activity evaluations. The experimental results indicated that the synthetic SrHA/Alginate showed similar morphology to the well-known alginate microspheres (Alginate) and both of them possessed a great in vitro bioactivity. Compared with the control Alginate, the SrHA/Alginate enhanced MC3T3-E1 cell proliferation and ALP activity by releasing osteoinductive and osteogenic Sr ions. Furthermore, vancomycin was used as a model drug to investigate the drug release behaviors of the SrHA/Alginate, Alginate and SrHA. The results suggested that the SrHA/Alginate had a highest drug-loading efficiency and best controlled drug release properties. Additionally, the SrHA/Alginate was demonstrated to be pH-sensitive as well. The increase of the pH value in phosphate buffer solution (PBS) accelerated the vancomycin release. Accordingly, the multifunctional SrHA/Alginate can be applied in the field of bioactive drug carriers and bone filling materials. - Highlights: • The pH-sensitive composite alginate beads incorporating Sr-doped HA microspheres (SrHA) have been prepared. • The incorporation of the SrHA enhanced the drug loading and release properties of the alginate microspheres. • The composite microspheres showed excellent osteogenic effect by releasing osteogenic Sr ions.

Study and Understanding Behavior of Alginate-Inulin Synbiotics Beads for Protection and Delivery of Antimicrobial-Producing Probiotics in Colonic Simulated Conditions.

Science.gov (United States)

Atia, Abdelbasset; Gomaa, Ahmed; Fernandez, Benoit; Subirade, Muriel; Fliss, Ismail

2018-06-01

According to the World Health Organization (WHO), using antibiotics as growth promoters for livestock-particularly swine-is the principal cause of antibiotic resistance. It is therefore clear that finding an alternative to antibiotics becomes an emergency. Hundreds of recent studies have appointed probiotics as potential candidates to replace or to be used in combination with antibiotics. However, bringing probiotics alive to the colon-their site of action-remains a big challenge because of different physiological barriers encountered in proximal gastrointestinal tract (GIT) such as acidic pH and bile salts that may affect the viability of probiotic cultures. To overcome this problem, in previous studies, we developed and characterize a synbiotic formula consisting of beads of a mixture of alginate and inulin. Three potential probiotics strains namely Pediococcus acidilactici UL5 (UL5), Lactobacillus reuteri (LR), and Lactobacillus salivarius (LS) were encapsulated to study their release and the behavior of this synbiotic formula throughout the GIT using in vitro models. The survival and the release of bacteria from beads were studied by specific PMA-qPCR counting. The microscopic aspects of the beads were studied using scanning electron microscopy (SEM). Moreover, the microbial dynamics inside beads were studied by fluorescence microscopy using the live/dead test. Our results have shown that the beads containing 5% inulin were the most stable in the stomach and throughout the small intestine. However, beads were completely degraded in approximately 3 h of incubation in the fermented medium that mimic the colon. These results were confirmed by SEM and fluorescence microscopy images. Therefore, it can be stated that the AI5 formulation well protected the bacteria in the upper part of the digestive tract and allowed their controlled release in the colon.

Efficacy of polymer coating of probiotic beads suspended in pressurized and pasteurized longan juices on the exposure to simulated gastrointestinal environment.

Science.gov (United States)

Chaikham, Pittaya; Apichartsrangkoon, Arunee; George, Trevor; Jirarattanarangsri, Wachira

2013-11-01

Alginate-coated Lactobacillus acidophilus LA5 or Lactobacillus casei 01 was recoated with either 0.1-0.5% (w/v) alginate or 0.05-0.15% (w/v) poly-L-lysine (PLL) plus 0.2% (w/v) alginate or 5-15% (w/v) gelatin, after which they were determined for survivability in gastric or bile longan juices. The morphology of encapsulated probiotic cells illustrated that recoated beads with 0.5% alginate showed a more compact surface and a greater protective effect than other recoating materials. The recoated beads with 0.5% alginate and 0.05-0.15% PLL plus 0.2% alginate of both strains showed the highest viability in gastric longan juice. In bile longan juice, only 0.5% alginate showed the best protection for both recoated beads. When considering the storage stability, encapsulated L. acidophilus LA5 exhibited a higher viable count than those of the free cells, whereas L. casei 01 showed equivalent viability of both free and double-coated cells. Based on the impact of pressurization or pasteurization, both processed juices gave rise to equivalent survivability of the probiotic cells during storage.

Method To immobilize the aphid-pathogenic fungus erynia neoaphidis in an alginate matrix for biocontrol

Science.gov (United States)

Shah; Aebi; Tuor

1998-11-01

Erynia neoaphidis is an important fungal pathogen of aphid pests worldwide. There have been few reported attempts to formulate this natural agent for use in biocontrol. In the current study, factors involved in the immobilization of E. neoaphidis hyphae in an alginate matrix were investigated. Hyphae of two isolates cultured in liquid medium were 220 to 620 &mgr;m in length and 7 to 19 &mgr;m in diameter with a 74 to 83% cytoplasmic content. The optimal concentration of low-viscosity sodium alginate for production of conidia from entrapped hyphae was 1.5% (wt/vol), and 0.1 and 0.25 M calcium chloride were equally suitable for use as the gelling solution. Alginate beads were rinsed with 10% sucrose after gelling. However, beads should not be left for longer than 40 min in 0.1 M calcium chloride or 10% sucrose to prevent a 10% loss in conidial production. A 40% (vol/vol) concentration of fungal biomass produced significantly more conidia than either 20% or the standard concentration of 10%. This effect persisted even after beads were dried overnight in a laminar flow hood and stored at 4 degreesC for 4 days. Conidia from freshly produced alginate beads caused 27 to 32% infection in Pea aphids as determined by standardized laboratory bioassays. This finding was not significantly different from infections in aphids inoculated with fresh mycelial mats or plugs from Petri dish cultures. In conclusion, algination appears to be a promising technique for utilizing E. neoaphidis in the biocontrol of aphid pests.

TiO₂ beads and TiO₂-chitosan beads for urease immobilization.

Science.gov (United States)

Ispirli Doğaç, Yasemin; Deveci, Ilyas; Teke, Mustafa; Mercimek, Bedrettin

2014-09-01

The aim of the present study is to synthesize TiO2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO2 beads. In the first method (A), urease enzyme was immobilized onto TiO2 beads by adsorption and then crosslinking. In the second method (B), TiO2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5mg/ml for A and 1.0mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60°C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70°C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30°C (A), 40°C (B) and 35°C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65°C. However, at this temperature free urease protected only 15% activity. Copyright © 2014 Elsevier B.V. All rights reserved.

One pot synthesis of new poly(vinyl alcohol) blended natural polymer based magnetic hydrogel beads: Controlled natural anticancer alkaloid delivery system.

Science.gov (United States)

Kesavan, Mookkandi Palsamy; Ayyanaar, Srinivasan; Lenin, Nayagam; Sankarganesh, Murugesan; Dhaveethu Raja, Jeyaraj; Rajesh, Jegathalaprathaban

2018-02-01

Facile one-pot synthesis has been demonstrated for new biocompatible and dual responsive magnetic iron oxide nanoparticles cross-linked poly(vinyl alcohol) (PVA) blended natural polymer chitosan (CS) based hydrogel beads (mCS-PVA) as a controlled natural anticancer alkaloid Luotonin A (LuA) delivery system. The prepared magnetic hydrogel beads were characterized using powder X-ray diffraction measurement, Fourier transform-infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and vibrating sample magnetometer. The magnetic hydrogel beads are exhibited significant water retention and follow the second order kinetic model in swelling study. The swelling ratio of the magnetic gel beads increased by the addition of PVA and showed a maximum swelling ratio of 40.83 ± 1.01 g/g and follows non-Fickian water transport mechanism. Stimuli responsive mCS and mCS-PVA hydrogel beads functionalized with LuA is demonstrated for controlled release at physiological pH and under magnetic field. The magnetic hydrogel beads show highest LuA releasing efficacy at acidic medium (pH = 5.0) with maximum efficiency of 73.33 ± 1.44%. This efficacy may also be tuned by altering the external magnetic field as well as the weight percentage (wt %) of polyethylene glycol. It is clearly that the newly produced magnetic hydrogel beads can be served as an effective intestinal LuA delivery system. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 543-551, 2018. © 2017 Wiley Periodicals, Inc.

Fabrication of magnetic alginate beads with uniform dispersion of CoFe2O4 by the polydopamine surface functionalization for organic pollutants removal

Science.gov (United States)

Li, Xiaoli; Lu, Haijun; Zhang, Yun; He, Fu; Jing, Lingyun; He, Xinghua

2016-12-01

A simple and efficient method for production of magnetic composites by decorating CoFe2O4 with polydopamine (PDA) through oxidative polymerization of dopamine was conducted. Further, magnetic alginate beads with porous structure containing well-dispersed CoFe2O4-PDA were fabricated by ionic crosslinking technology. The resulting SA@CoFe2O4-PDA beads were characterized using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometer, vibrating sample magnetometer and X-ray photoelectron spectroscopy. Adsorption potential of SA@CoFe2O4-PDA beads for organic dyes including Methylene Blue (MB), Crystal Violet (CV) and Malachite Green (MG) was evaluated. SA@CoFe2O4-PDA beads exhibited excellent adsorption performances due to the composite effect, large surface area and porous structure. Organic dyes could be removed from water solution with high efficiency in a wide pH range of 4.0-9.0. Moreover, it exhibited much higher adsorptivity towards MB and CV with the maximum adsorption capacities of 466.60 and 456.52 mg/g, respectively, which were much higher than that of MG (248.78 mg/g). Ca-electrolyte had obvious adverse effects on MB and CV adsorption than MG. FTIR and XPS demonstrated that carboxylate, catechol, hydroxyl and amine groups might be involved in adsorption of organic dyes. The characteristics of wide pH range, high adsorption capacity and convenient magnetic separation would make SA@CoFe2O4-PDA beads as effective adsorbent for removal of organic dyes from wastewater.

Biological Effects of Drug-Free Alginate Beads Cross-Linked by Copper Ions Prepared Using External Ionotropic Gelation.

Science.gov (United States)

Pavelková, M; Kubová, K; Vysloužil, J; Kejdušová, M; Vetchý, D; Celer, V; Molinková, D; Lobová, D; Pechová, A; Vysloužil, J; Kulich, P

2017-05-01

External ionotropic gelation offers a unique possibility to entrap multivalent ions in a polymer structure. The aim of this experimental study was to prepare new drug-free sodium alginate (ALG) particles cross-linked by Cu 2+ ions and to investigate their technological parameters (particle size, sphericity, surface topology, swelling capacity, copper content, release of Cu 2+ ions, mucoadhesivity) and biological activity (cytotoxicity and efficiency against the most common vaginal pathogens-Herpes simplex, Escherichia coli, Candida albicans) with respect to potential vaginal administration. Beads prepared from NaALG dispersions (3 or 4%) were cross-linked by Cu 2+ ions (0.5 or 1.0 M CuCl 2 ) using external ionotropic gelation. Prepared mucoadhesive beads with particle size over 1000 μm exhibited sufficient sphericity (all ˃0.89) and copper content (214.8-249.07 g/kg), which increased with concentration of polymer and hardening solution. Dissolution behaviour was characterized by extended burst effect, followed by 2 h of copper release. The efficiency of all samples against the most common vaginal pathogens was observed at cytotoxic Cu 2+ concentrations. Anti-HSV activity was demonstrated at a Cu 2+ concentration of 546 mg/L. Antibacterial activity of beads (expressed as minimum inhibition concentration, MIC) was influenced mainly by the rate of Cu 2+ release which was controlled by the extent of swelling capacity. Lower MIC values were found for E. coli in comparison with C. albicans. Sample ALG-3_1.0 exhibited the fastest copper release and was proved to be the most effective against both bacteria. This could be a result of its lower polymer concentration in combination with smaller particle size and thus larger surface area.

TiO2 beads and TiO2-chitosan beads for urease immobilization

International Nuclear Information System (INIS)

Ispirli Doğaç, Yasemin; Deveci, İlyas; Teke, Mustafa; Mercimek, Bedrettin

2014-01-01

The aim of the present study is to synthesize TiO 2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO 2 beads. In the first method (A), urease enzyme was immobilized onto TiO 2 beads by adsorption and then crosslinking. In the second method (B), TiO 2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2 mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5 mg/ml for A and 1.0 mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0 mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4–70 °C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30 °C (A), 40 °C (B) and 35 °C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65 °C. However, at this temperature free urease protected only 15% activity. - Highlights: • TiO 2 and TiO 2 -chitosan beads for urease immobilization have been prepared and characterized. • The beads used in this work are good matrices for the immobilization of urease. • The immobilized urease was shown to have good properties and stabilities (pH and thermal stability, operational stability). • The 50

Characteristics of Immobilized Urease on Grafted Alginate Bead Systems

Directory of Open Access Journals (Sweden)

Enas N. Danial

2015-04-01

Full Text Available This study evaluated the biological importance of immobilized urease enzyme over the free urease. The support material used for urease immobilization was alginate. Generally, the immobilization of urease in alginate gel showed a marked increase in Km and Vmax. However, the immobilized urease showed higher thermal stability than that of free enzyme. The rate of thermal inactivation of the immobilized enzyme decreased due to entrapment in gel matrix. Also, the activity of the immobilized urease was more stable in retention than that of the free enzyme during the storage in solution, although the activity of the immobilized enzyme was lower in comparison with the free enzyme. A stable immobilized system and long storage life are convenient for applications that would not be feasible with a soluble enzyme system. These results highlighted the technical and biochemical benefits of immobilized urease over the free enzyme.

Detection of a magnetic bead by hybrid nanodevices using scanning gate microscopy

Science.gov (United States)

Corte-León, H.; Krzysteczko, P.; Marchi, F.; Motte, J.-F.; Manzin, A.; Schumacher, H. W.; Antonov, V.; Kazakova, O.

2016-05-01

Hybrid ferromagnetic(Py)/non-magnetic metal(Au) junctions with a width of 400 nm are studied by magnetotransport measurements, magnetic scanning gate microscopy (SGM) with a magnetic bead (MB) attached to the probe, and micromagnetic simulations. In the transverse geometry, the devices demonstrate a characteristic magnetoresistive behavior that depends on the direction of the in plane magnetic field, with minimum/maximum variation when the field is applied parallel/perpendicular to the Py wire. The SGM is performed with a NdFeB bead of 1.6 μm diameter attached to the scanning probe. Our results demonstrate that the hybrid junction can be used to detect this type of MB. A rough approximation of the sensing volume of the junction has the shape of elliptical cylinder with the volume of ˜1.51 μm3. Micromagnetic simulations coupled to a magnetotransport model including anisotropic magnetoresistance and planar Hall effects are in good agreement with the experimental findings, enabling the interpretation of the SGM images.

Production and Investigation of Controlled Drug Release Properties of Tamoxifen Loaded Alginate-Gum Arabic Microbeads

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Rukiye Yavaşer

2016-08-01

Full Text Available The entrapment of tamoxifen onto alginate-gum arabic beads and the production of controlled drug release was investigated in this study. The polymeric system that would provide the controlled release of tamoxifen was formed using alginate and gum arabic. In the first phase of the study, the optimization of the alginate-gum arabic beads production was conducted; then the study continued with drug entrapment experiments. Tamoxifen entrapment yield was found to be approximately 90% of initial tamoxifen concentration. In vitro drug release experiments were performed in simulated gastric juice and intestinal fluid where the tamoxifen release was 20% and 53% of the initial drug present, respectively. As a result of this study, it is expected that a valuable contribution to the field of controlled drug release system production is realized.

Alginate as immobilization matrix and stabilizing agent in a two-phase liquid system: application in lipase-catalysed reactions.

Science.gov (United States)

Hertzberg, S; Kvittingen, L; Anthonsen, T; Skjåk-Braek, G

1992-01-01

Alginate was evaluated as an immobilization matrix for enzyme-catalyzed reactions in organic solvents. In contrast to most hydrogels, calcium alginate was found to be stable in a range of organic solvents and to retain the enzyme inside the gel matrix. In hydrophobic solvents, the alginate gel (greater than 95% water) thus provided a stable, two-phase liquid system. The lipase from Candida cylindracea, after immobilization in alginate beads, catalysed esterification and transesterification in n-hexane under both batch and continuous-flow conditions. The operational stability of the lipase was markedly enhanced by alginate entrapment. In the esterification of butanoic acid with n-butanol, better results were obtained in the typical hydrophilic calcium alginate beads than in less hydrophilic matrices. The effects of substrate concentration, matrix area, and polarity of the substrate alcohols and of the organic solvent on the esterification activity were examined. The transesterification of octyl 2-bromopropanoate with ethanol was less efficient than that of ethyl 2-bromopropanoate with octanol. By using the hydrophilic alginate gel as an immobilization matrix in combination with a mobile hydrophobic phase, a two-phase liquid system was achieved with definite advantages for a continuous, enzyme-catalysed process.

Improved stability and catalytic activity of graphene oxide/chitosan hybrid beads loaded with porcine liver esterase.

Science.gov (United States)

Sunderrajan, Shruthi; Miranda, Lima Rose; Pennathur, Gautam

2018-04-21

Graphene oxide/chitosan and reduced graphene oxide/chitosan (GO/CS and RGO/CS) beads were prepared by precipitation with NaOH. Porcine liver esterase was immobilized on these beads to give GO/CS/E and RGO/CS/E beads. The optimum conditions for the maximum activity of RGO/CS/E beads were pH 8 and 50°C. The stability of the enzyme immobilized on GO/CS/E and RGO/CS/E was high in the pH range of 5-8. The GO/CS/E beads showed superior stability compared to that of the free enzyme and CS/E beads between 20 and 50°C. Kinetic analysis showed that GO/CS/E was a better catalyst than the RGO/CS/E beads with a lower K m value of 0.9 mM. The hybrid beads also retained more than 95% activity after 10 consecutive cycles. The GO/CS/E and RGO/CS/E beads retained 84% and 87% activity after 40 days at 4°C. The GO/CS/E beads were used for the successful hydrolysis of methyl 4-hydroxy benzoate.

Controlled swelling and degradation studies of alginate microbeads in dilute natrium-citrate solutions

Directory of Open Access Journals (Sweden)

Mitrović Dragana D.

2010-01-01

Full Text Available Alginate hydrogels are widely used in biomedicine due to alginate availability, hydrophilic nature, biocompatibility and biodegradability. Alginate microbeads are particularly attractive for applications in pharmacy and regenerative medicine due to high surface to volume ratio, low mass transfer limitations and simple implantation by injection. Aim of this work was to investigate possibilities for controlled degradation of alginate microbeads in cell culture medium (Dulbecco’s modified Eagle’s medium with Na-citrate added in small concentrations (0.05 - 0.5 mM. Alginate microbeads (1.5% w/w, 800 m in diameter were produced by electrostatic droplet extrusion and evaluated over a period of 10 days regarding appearance, kinetics and degree of swelling as well as biomechanical properties determined in a novel bioreactor with mechanical stimulation under in vivo-like conditions in articular cartilage (10% strain, 337.5 m/s compression rate. In the citrate concentration range investigated, microbeads initially swelled reaching an equilibrium value (~150-170% with respect to the initial mass, upon which they appeared stable for a certain period of time (1 to over 7 days followed by bead bursting and degradation. This degradation process indicated that Na+ ions from the solution initially replaced Ca2+ ions bound mainly to COO- groups in polymannuronate sequences inducing electrostatic repulsion of polymer chains and, consequently, swelling of the beads. Citrate ions assisted in this process by forming insoluble calcium citrate. Thus, the specific rate of the bead swelling increased with the increase in citrate concentration approaching a maximal value of ~0.34 d-1. In the last phase, the beads burst into pieces, which slowly continued to degrade by replacement of Ca2+ ions bonded to polyguluronate blocks in the egg-box structure. Compression moduli for packed beds of control, freshly produced microbeads, and microbeads swelled at the equilibrium

Towards Hypoxia-responsive Drug-eluting Embolization Beads.

Science.gov (United States)

Ashrafi, Koorosh; Heaysman, Clare L; Phillips, Gary J; Lloyd, Andrew W; Lewis, Andrew L

2017-05-30

Drug release from chemoembolization microspheres stimulated by the presence of a chemically reducing environment may provide benefits for targeting drug resistant and metastatic hypoxic tumours. A water-soluble disulfide-based bifunctional cross-linker bis(acryloyl)-(l)-cystine (BALC) was synthesised, characterised and incorporated into a modified poly(vinyl) alcohol (PVA) hydrogel beads at varying concentrations using reverse suspension polymerisation. The beads were characterised to confirm the amount of cross-linker within each formulation and its effects on the bead properties. Elemental and UV/visible spectroscopic analysis confirmed the incorporation of BALC within the beads and sizing studies showed that in the presence of a reducing agent, all bead formulations increased in mean diameter. The BALC beads could be loaded with doxorubicin hydrochloride and amounts in excess of 300mg of drug per mL of hydrated beads could be achieved but required conversion of the carboxylic acid groups of the BALC to their sodium carboxylate salt forms. Elution of doxorubicin from the beads demonstrated a controlled release via ionic exchange. Some formulations exhibited an increase in size and release of drug in the presence of a reducing agent, and therefore demonstrated the ability to respond to an in vitro reducing environment. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Swirl Flow Bioreactor coupled with Cu-alginate beads: A system for the eradication of Coliform and Escherichia coli from biological effluents.

Science.gov (United States)

Atkinson, Sov; Thomas, Simon F; Goddard, Paul; Bransgrove, Rachel M; Mason, Paul T; Oak, Ajeet; Bansode, Anand; Patankar, Rohit; Gleason, Zachary D; Sim, Marissa K; Whitesell, Andrew; Allen, Michael J

2015-05-21

It is estimated that approximately 1.1 billion people globally drink unsafe water. We previously reported both a novel copper-alginate bead, which quickly reduces pathogen loading in waste streams and the incorporation of these beads into a novel swirl flow bioreactor (SFB), of low capital and running costs and of simple construction from commercially available plumbing pipes and fittings. The purpose of the present study was to trial this system for pathogen reduction in waste streams from an operating Dewats system in Hinjewadi, Pune, India and in both simulated and real waste streams in Seattle, Washington, USA. The trials in India, showed a complete inactivation of coliforms in the discharged effluent (Mean Log removal Value (MLRV) = 3.51), accompanied by a total inactivation of E. coli with a MLRV of 1.95. The secondary clarifier effluent also showed a 4.38 MLRV in viable coliforms during treatment. However, the system was slightly less effective in reducing E. coli viability, with a MLRV of 1.80. The trials in Seattle also demonstrated the efficacy of the system in the reduction of viable bacteria, with a LRV of 5.67 observed of viable Raoultella terrigena cells (100%).

Calcium-Alginate-Inulin Microbeads as Carriers for Aqueous Carqueja Extract.

Science.gov (United States)

Balanč, Bojana; Kalušević, Ana; Drvenica, Ivana; Coelho, Maria Teresa; Djordjević, Verica; Alves, Vitor D; Sousa, Isabel; Moldão-Martins, Margarida; Rakić, Vesna; Nedović, Viktor; Bugarski, Branko

2016-01-01

Carqueja (Pterospartum tridentatum) is an endemic species and various bioactive compounds have been identified in its aqueous extract. The aim of this study was to protect the natural antioxidants from the aqueous extract of carqueja by encapsulation in Ca-alginate microbeads and Ca-alginate microbeads containing 10% and 20% (w/v) of inulin. The microbeads produced by electrostatic extrusion technique had an average diameter from 625 μm to 830 μm depending on the portion of inulin. The sphericity factor of the hydrogel microbeads had values between 0.014 and 0.026, while freeze dried microbeads had irregular shape, especially those with no excipient. The reduction in microbeads size after freeze drying process (expressed as shrinkage factor) ranged from 0.338 (alginate microbeads with 20% (w/v) of inulin) to 0.523 (plain alginate microbeads). The expressed radical scavenging activity against ABTS and DPPH radicals was found to be between 30% and 40% for encapsulated extract, while the fresh extract showed around 47% and 57% of radical scavenging activity for ABTS and DPPH radicals, respectively. The correlation between antioxidant activity and the total phenolic content were found to be positive (in both assay methods, DPPH and ABTS), which indicate that the addition of inulin didn't have influence on antioxidant activity. The presence of inulin reduced stiffness of the hydrogel, and protected bead structure from collapse upon freeze-drying. Alginate-inulin beads are envisaged to be used for delivery of aqueous P. tridentatum extract in functional food products. © 2015 Institute of Food Technologists®

A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure.

Science.gov (United States)

Sun, Xiaoxia; Uyama, Hiroshi

2013-10-04

A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructural control of the blend monolith is readily achieved by optimizing the fabrication conditions. Brunauer Emmett Teller measurement shows that the obtained blend monolith has a large surface area. Pore size distribution plot for the blend monolith obtained by the non-local density functional theory method reveals the existence of the nanoscale porous structure. Fourier transform infrared analysis reveals the strong interactions between PVA and SA. The pH-responsive property of the blend monolith is investigated on the basis of swelling ratio in different pH solutions. The present blend monolith of biocompatible and biodegradable PVA and SA with nanoscale porous structure has large potential for applications in biomedical and environmental fields.

Ionic conductivity studies in crystalline PVA/NaAlg polymer blend electrolyte doped with alkali salt KCl

Science.gov (United States)

Sheela, T.; Bhajantri, R. F.; Ravindrachary, V.; Pujari, P. K.; Rathod, Sunil G.; Naik, Jagadish

2014-04-01

Potassium Chloride (KCl) doped poly(vinyl alcohol) (PVA)/sodium alginate (NaAlg) in 60:40 wt% polymer blend electrolytes were prepared by solution casting method. The complexation of KCl with host PVA/NaAlg blend is confirmed by FTIR and UV-Vis spectra. The XRD studies show that the crystallinity of the prepared blends increases with increase in doping. The dc conductivity increases with increase in dopant concentration. Temperature dependent dc conductivity shows an Arrhenius behavior. The dielectric properties show that both the dielectric constant and dielectric loss increases with increase in KCl doping concentration and decreases with frequency. The cole-cole plots show a decrease in bulk resistance, indicates the increase in ac conductivity, due to increase in charge carrier mobility. The doping of KCl enhances the mechanical properties of PVA/NaAlg, such as Young's modulus, tensile strength, stiffness.

Detection of a magnetic bead by hybrid nanodevices using scanning gate microscopy

Directory of Open Access Journals (Sweden)

H. Corte-León

2016-05-01

Full Text Available Hybrid ferromagnetic(Py/non-magnetic metal(Au junctions with a width of 400 nm are studied by magnetotransport measurements, magnetic scanning gate microscopy (SGM with a magnetic bead (MB attached to the probe, and micromagnetic simulations. In the transverse geometry, the devices demonstrate a characteristic magnetoresistive behavior that depends on the direction of the in plane magnetic field, with minimum/maximum variation when the field is applied parallel/perpendicular to the Py wire. The SGM is performed with a NdFeB bead of 1.6 μm diameter attached to the scanning probe. Our results demonstrate that the hybrid junction can be used to detect this type of MB. A rough approximation of the sensing volume of the junction has the shape of elliptical cylinder with the volume of ∼1.51 μm3. Micromagnetic simulations coupled to a magnetotransport model including anisotropic magnetoresistance and planar Hall effects are in good agreement with the experimental findings, enabling the interpretation of the SGM images.

The Surface Imprinted Polystyrene Beads Prepared via Emulsion Templates

Institute of Scientific and Technical Information of China (English)

Guo Xiang CHENG; Guang Ling PEI; Ling Gang ZENG; Li Yong ZHANG; Chao LIU

2004-01-01

In this paper, the surface imprinted cross-linked polystyrene beads were prepared via suspension polymerization with styrene (St), divinylbezene (DVB), polyvinyl alcohol (PVA1788), the mixture of Span 85 and xylene or the mixture of Span 85 and paraffin as monomer, cross-linking agent, dispersion stabilizer and templates, respectively. The results indicate that there are dense cavities on the surface of beads, and the diameter and density of cavity are related with the composition and amount of emulsion template. The forming mechanism of cavity from thermodynamics and dynamics was proposed.

Single-step laser-based fabrication and patterning of cell-encapsulated alginate microbeads

International Nuclear Information System (INIS)

Kingsley, D M; Dias, A D; Corr, D T; Chrisey, D B

2013-01-01

Alginate can be used to encapsulate mammalian cells and for the slow release of small molecules. Packaging alginate as microbead structures allows customizable delivery for tissue engineering, drug release, or contrast agents for imaging. However, state-of-the-art microbead fabrication has a limited range in achievable bead sizes, and poor control over bead placement, which may be desired to localize cellular signaling or delivery. Herein, we present a novel, laser-based method for single-step fabrication and precise planar placement of alginate microbeads. Our results show that bead size is controllable within 8%, and fabricated microbeads can remain immobilized within 2% of their target placement. Demonstration of this technique using human breast cancer cells shows that cells encapsulated within these microbeads survive at a rate of 89.6%, decreasing to 84.3% after five days in culture. Infusing rhodamine dye into microbeads prior to fluorescent microscopy shows their 3D spheroidal geometry and the ability to sequester small molecules. Microbead fabrication and patterning is compatible with conventional cellular transfer and patterning by laser direct-write, allowing location-based cellular studies. While this method can also be used to fabricate microbeads en masse for collection, the greatest value to tissue engineering and drug delivery studies and applications lies in the pattern registry of printed microbeads. (paper)

Alginate-encapsulation of shoot tips of jojoba [Simmondsia chinensis (Link) Schneider] for germplasm exchange and distribution.

Science.gov (United States)

Kumar, Sunil; Rai, Manoj K; Singh, Narender; Mangal, Manisha

2010-12-01

Shoot tips excised from in vitro proliferated shoots derived from nodal explants of jojoba [Simmondsia chinensis (Link) Schneider] were encapsulated in calcium alginate beads for germplasm exchange and distribution. A gelling matrix of 3 % sodium alginate and 100 mM calcium chloride was found most suitable for formation of ideal calcium alginate beads. Best response for shoot sprouting from encapsulated shoot tips was recorded on 0.8 % agar-solidified full-strength MS medium. Rooting was induced upon transfer of sprouted shoots to 0.8 % agar-solidified MS medium containing 1 mg l(-1) IBA. About 70 % of encapsulated shoot tips were rooted and converted into plantlets. Plants regenerated from encapsulated shoot tips were acclimatized successfully. The present encapsulation approach could also be applied as an alternative method of propagation of desirable elite genotype of jojoba.

A BOD monitoring disposable reactor with alginate-entrapped bacteria.

Science.gov (United States)

Villalobos, Patricio; Acevedo, Cristian A; Albornoz, Fernando; Sánchez, Elizabeth; Valdés, Erika; Galindo, Raúl; Young, Manuel E

2010-10-01

Biochemical oxygen demand (BOD) is a measure of the amount of dissolved oxygen that is required for the biochemical oxidation of the organic compounds in 5 days. New biosensor-based methods have been conducted for a faster determination of BOD. In this study, a mathematical model to evaluate the feasibility of using a BOD sensor, based on disposable alginate-entrapped bacteria, for monitoring BOD in situ was applied. The model considers the influences of alginate bead size and bacterial concentration. The disposable biosensor can be adapted according to specific requirements depending on the organic load contained in the wastewater. Using Klein and Washausen parameter in a Lineweaver-Burk plot, the glucose diffusivity was calculated in 6.4 × 10(-10) (m2/s) for beads of 1 mm in diameter and slight diffusion restrictions were observed (n = 0.85). Experimental results showed a correlation (p < 0.05) between the respirometric peak and the standard BOD test. The biosensor response was representative of BOD.

Diffusion Retardation by Binding of Tobramycin in an Alginate Biofilm Model

DEFF Research Database (Denmark)

Cao, Bao; Christophersen, Lars; Kolpen, Mette

2016-01-01

Microbial cells embedded in a self-produced extracellular biofilm matrix cause chronic infections, e. g. by Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The antibiotic killing of bacteria in biofilms is generally known to be reduced by 100–1000 times relative to planktonic...... bacteria. This makes such infections difficult to treat. We have therefore proposed that biofilms can be regarded as an independent compartment with distinct pharmacokinetics. To elucidate this pharmacokinetics we have measured the penetration of the tobramycin into seaweed alginate beads which serve...... to be uniformly distributed throughout the volume of the alginate bead. The power-law appears to be a consequence of binding to a multitude of different binding sites. In a diffusion model these results are shown to produce pronounced retardation of the penetration of tobramycin into the biofilm. This filtering...

Design of novel hybrid organic-inorganic nanostructured biomaterials for immunoassay applications

Energy Technology Data Exchange (ETDEWEB)

Andrade, G [Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, PO Box 486, 31270.901, Belo Horizonte, MG (Brazil); Barbosa-Stancioli, E F [Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, PO Box 486, 31270.901, Belo Horizonte, MG (Brazil); Piscitelli Mansur, A A [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil); Vasconcelos, W L [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil); Mansur, H S [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil)

2006-12-01

The purpose of this study was to develop novel hybrid organic-inorganic materials based on poly(vinyl alcohol) (PVA) polymer chemically crosslinked network to be tested as solid support on bovine herpesvirus immunoassay. Hybrids were synthesized by reacting PVA with three different alkoxysilanes modifying chemical groups: tetraethoxysilane (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). PVA-derived hybrids were also modified by chemically crosslinking with glutaraldehyde (GA) during the synthesis reaction. In order to investigate the structure in the nanometer-scale, PVA-derived hybrids were characterized by using small-angle x-ray scattering synchrotron radiation (SAXS) and x-ray diffraction (XRD). PVA hybrids' chemical functionalities and their interaction with herpesviruses were also characterized by Fourier transform infrared spectroscopy (FTIR). The bioactivity assays were tested through enzyme linked immunosorbent assay (ELISA). SAXS results have indicated nano-ordered disperse domains for PVA hybrids with different x-ray scattering patterns for PVA polymer and PVA-derived hybrids. FTIR spectra have shown major vibration bands associated with organic-inorganic chemical groups present in the PVA, PVA-derived by silane modifier and PVA chemically crosslinked by GA. The immunoassay results have shown that PVA hybrids with chemically functionalized structures regulated to some extent the specific bioimmobilization of herpesvirus onto solid phase. We think that it is due to the overall balance of forces associated with van der Waals interaction, hydrophilic and hydrophobic forces and steric hindrance acting at the surface. PVA and PVA-derived hybrid materials were successfully produced with GA crosslinking in a nanometer-scale network. Also, such a PVA-based material could be advantageously used in immunoassays with enhanced specificity for diagnosis.

Design of novel hybrid organic-inorganic nanostructured biomaterials for immunoassay applications

Energy Technology Data Exchange (ETDEWEB)

Andrade, G [Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, PO Box 486, 31270.901, Belo Horizonte, MG (Brazil); Barbosa-Stancioli, E F [Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, PO Box 486, 31270.901, Belo Horizonte, MG (Brazil); Piscitelli Mansur, A A [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil); Vasconcelos, W L [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil); Mansur, H S [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil)

2006-12-01

The purpose of this study was to develop novel hybrid organic-inorganic materials based on poly(vinyl alcohol) (PVA) polymer chemically crosslinked network to be tested as solid support on bovine herpesvirus immunoassay. Hybrids were synthesized by reacting PVA with three different alkoxysilanes modifying chemical groups: tetraethoxysilane (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). PVA-derived hybrids were also modified by chemically crosslinking with glutaraldehyde (GA) during the synthesis reaction. In order to investigate the structure in the nanometer-scale, PVA-derived hybrids were characterized by using small-angle x-ray scattering synchrotron radiation (SAXS) and x-ray diffraction (XRD). PVA hybrids' chemical functionalities and their interaction with herpesviruses were also characterized by Fourier transform infrared spectroscopy (FTIR). The bioactivity assays were tested through enzyme linked immunosorbent assay (ELISA). SAXS results have indicated nano-ordered disperse domains for PVA hybrids with different x-ray scattering patterns for PVA polymer and PVA-derived hybrids. FTIR spectra have shown major vibration bands associated with organic-inorganic chemical groups present in the PVA, PVA-derived by silane modifier and PVA chemically crosslinked by GA. The immunoassay results have shown that PVA hybrids with chemically functionalized structures regulated to some extent the specific bioimmobilization of herpesvirus onto solid phase. We think that it is due to the overall balance of forces associated with van der Waals interaction, hydrophilic and hydrophobic forces and steric hindrance acting at the surface. PVA and PVA-derived hybrid materials were successfully produced with GA crosslinking in a nanometer-scale network. Also, such a PVA-based material could be advantageously used in immunoassays with enhanced specificity for diagnosis.

Ca alginate as scaffold for iron oxide nanoparticles synthesis

Directory of Open Access Journals (Sweden)

P. V. Finotelli

2008-12-01

Full Text Available Recently, nanotechnology has developed to a stage that makes it possible to process magnetic nanoparticles for the site-specific delivery of drugs. To this end, it has been proposed as biomaterial for drug delivery system in which the drug release rates would be activated by a magnetic external stimuli. Alginate has been used extensively in the food, pharmaceutical and biomedical industries for their gel forming properties in the presence of multivalent cations. In this study, we produced iron oxide nanoparticles by coprecipitation of Fe(III and Fe(II. The nanoparticles were entrapped in Ca alginate beads before and after alginate gelation. XRD analysis showed that particles should be associated to magnetite or maghemite with crystal size of 9.5 and 4.3 nm, respectively. Studies using Mössbauer spectroscopy corroborate the superparamagnetic behavior. The combination of magnetic properties and the biocompatibility of alginate suggest that this biomaterial may be used as biomimetic system.

Synthesis and characterizations of alginate-α-tricalcium phosphate microparticle hybrid film with flexibility and high mechanical property as a biomaterial.

Science.gov (United States)

Das, Dipankar; Zhang, Shengmin; Noh, Insup

2018-01-24

A biocompatible hybrid film has been fabricated using alginate (Alg), α-tricalcium phosphate (α-TCP) microparticle and calcium chloride through ionic crosslinking as a biomaterial. The 'screeding method' (like a concrete finishing process) has been employed to develop the Alg-α-TCP film. For this method, the Alg/α-TCP blend has been prepared using an ultra-sonicator and then put on a glass slide. After that, the excess volume of blend has been cut off by skidding another slide along with the surface of the blend to achieve proper grade and flatness. The mechanical strength and flexibility of the film (Alg-α-TCP) has been controlled by changing its compositions. The crosslinking phenomenon has been confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), 13 C nuclear magnetic resonance (NMR), x-ray diffraction and thermogravimetric analyses. The ATR-FTIR and 13 C NMR analysis results suggest that carboxylate groups of the alginate are ionically cross-linked with Ca 2+ ions, while the α-TCP particles reside in the network by physical interaction. The micro-fatigue test results imply high tensile strength (up to 257 MPa) and flexibility (up to 13% elongation) of the Alg-α-TCP hybrid films. The SEM analysis suggests the α-TCP particles are homogeneously distributed on the surface of Alg-α-TCP films, whereas cross-sectional images confirmed the presence of α-TCP in the cross-linked network. TGA results demonstrated that thermal stability of the hybrid film was enhanced due to ionic crosslinking and interfacial interaction between alginate and α-TCP. The incorporation of α-TCP particles diminished the swelling ratio of the hybrid film. The in vitro bone cell (MC3T3) culture and cytotoxicity tests showed that the hybrid film is biocompatible. The hybrid film releases bovine serum albumin and dimethyloxaloylglycine in a controlled way at pH 7 and 7.4, and 37 °C. Overall, the biocompatible Alg-α-TCP hybrid film with

A novel approach of utilization of the fungal conidia biomass to remove heavy metals from the aqueous solution through immobilization

Science.gov (United States)

Cai, Chun-Xiang; Xu, Jian; Deng, Nian-Fang; Dong, Xue-Wei; Tang, Hao; Liang, Yu; Fan, Xian-Wei; Li, You-Zhi

2016-11-01

The biomass of filamentous fungi is an important cost-effective biomass for heavy metal biosorption. However, use of free fungal cells can cause difficulties in the separation of biomass from the effluent. In this study, we immobilized the living conidia of the heavy metal-resistant Penicillium janthinillum strain GXCR by polyvinyl alcohol (PVA)-sodium alginate (SA) beads to remove heavy metals from an aqueous solution containing a low concentration (70 mg/L) of Cu, Pb, and Cd. The PVA-SA-conidia beads showed perfect characters of appropriate mechanical strength suitable for metal removal from the dynamic wastewater environment, an ideal settleability, easy separation from the solution, and a high metal biosorption and removal rate even after four cycles of successive sorption-desorption of the beads, overcoming disadvantages when fungal biomasses alone are used for heavy metal removal from wastewater. We also discuss the major biosorption-affecting factors, biosorption models, and biosorption mechanisms.

Encapsulating betalains from Opuntia ficus-indica fruits by ionic gelation: Pigment chemical stability during storage of beads.

Science.gov (United States)

Otálora, María Carolina; Carriazo, José Gregorio; Iturriaga, Laura; Osorio, Coralia; Nazareno, Mónica Azucena

2016-07-01

Betalain encapsulation was performed by ionic gelation as a stabilization strategy for these natural pigments. Betalains were extracted from purple cactus fruits and encapsulated in calcium-alginate and in combination of calcium alginate and bovine serum albumin. Beads were characterised by scanning electron microscopy and thermal analysis using differential scanning calorimetry and thermogravimetry. Moisture sorption isotherms were determined. Bead morphology was affected by matrix composition. Pigments storage stability was evaluated at different equilibrium relative humidity and temperatures. Pigment composition of beads was determined by HPLC-MS-MS and degradation products were also analysed after storage; betalamic acid being the major one. Both types of matrices protected the encapsulated pigments, being their storage stability better at low relative humidity than that of the non-encapsulated control material. Antiradical activities of beads were proportional to remaining betalain contents. At high relative humidity, there was no protection and low storage stability was observed in the samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Calcium Pectinate Beads Formation: Shape and Size Analysis

Directory of Open Access Journals (Sweden)

Boon-Beng Lee

2014-04-01

Full Text Available The aim of this study was to investigate the inter-relationship between process variables and the size and shape of pectin solution droplets upon detachment from a dripping tip as well as Ca-pectinate beads formed after gelation via image analysis. The sphericity factor (SF of the droplets was generally smaller than 0.05. There was no specific trend between the SF of the droplets and the pectin concentration or the dripping tip radius. The SF the beads formed from high-concentration pectin solutions and a small dripping tip was smaller than 0.05. The results show that the Reynolds number and Ohnesorge number of the droplets fall within the operating region for forming spherical beads in the shape diagram, with the exception to the lower boundary. The lower boundary of the operating region has to be revised to Oh = 2.3. This is because the critical viscosity for Ca-pectinate bead formation is higher than that of Ca-alginate beads. On the other hand, the radius of the droplets and beads increased as the dripping tip radius increased. The bead radius can easily be predicted by Tate’s law equation.

Sodium Alginate with PEG/PEO Blends as a Floating Drug Delivery Carrier – In vitro Evaluation

Directory of Open Access Journals (Sweden)

Christe Sonia Mary

2016-09-01

Full Text Available Purpose: Floating drug delivery system reduces the quantity of drug intake and the risk of overloading the organs with excess drug. Methods: In the present study, we prepared the blends of sodium alginate with polyethylene glycol (PEG and polyethylene oxide (PEO as a matrix, sodium hydrogen carbonate as a pore forming agent, methyl cellulose as a binder and barium chloride containing 10% acetic acid as a hardening agent. Different ratios of pore forming agent to the polymer blend was used to prepare the floating beads with different porosity and morphology. Ciprofloxacin hydrochloride was used as a model drug for the release kinetics studies. Results: The beads were characterized by optical and FESEM microscopy to study the morphology and pore dimensions. The results obtained shows decrease in beads size with increase in the concentration of the pore forming agent. The swelling properties of the beads were found to be in the range of 80% to 125%. The release kinetics of the ciprofloxacin from the beads was measured by UV-Visible spectroscopy at λmax of 278nm and the results shows for highly porous beads. Conclusion: By varying the amount of alginate and pore forming agent the release kinetics is found to get altered. As a result, ciprofloxacin hydrochloride release is found to be sustained from the blended beads.

Synthetic seed technology for encapsulation and regrowth of in vitro ...

African Journals Online (AJOL)

In this study, various concentrations of sodium alginate solutions and calcium chloride solutions were tested in order to optimize the size, shape and texture of alginate synthetic seeds or beads for Acacia hybrid bud-sprouting. The shoot buds and axillary buds from in vitro Acacia hybrids, as explants were encapsulated with ...

Effects of production methods and protective ingredients on the viability of probiotic Lactobacillus rhamnosus R0011 in air-dried alginate beads.

Science.gov (United States)

Champagne, Claude P; Raymond, Yves; Arcand, Yves

2017-01-01

The goal of this study was to use a microencapsulation technology to prepare air-dried concentrated cultures of Lactobacillus rhamnosus R0011. The cultures were microencapsulated in alginate beads, which were added to a growth medium to allow cell multiplication inside the matrix; the beads were recovered, dipped in protective solutions, and air-dried. The effects of fermentation technology and of the composition of the protective solutions on subsequent survival during air-drying were examined. The cells prepared under a constant pH of 6.2 had only 2.5% survival to air-drying at 25 °C when the protective solution was composed of sucrose and phosphate. Allowing the pH to drop to 4.2 during the biomass production step and using a protective medium composed of glycerol, maltodextrin, yeast extract, and ascorbate increased survival to 20%. If the ingredients of the protective medium at the beginning of drying were concentrated at a water activity of 0.96 rather than 0.98, survival during air-drying increased further to 56%. This rate was similar to that of a traditional freeze-drying process. These data suggest that applying a combination of acid and osmotic stresses to L. rhamnosus R0011 cells improves their subsequent stability during the air-drying process. Dried microencapsulated cultures having 2.6 × 10 11 CFU·g -1 were obtained.

Formulation and statistical optimization of gastric floating alginate/oil/chitosan capsules loading procyanidins: in vitro and in vivo evaluations.

Science.gov (United States)

Chen, Rencai; Guo, Xiaomin; Liu, Xuecong; Cui, Haiming; Wang, Rui; Han, Jing

2018-03-01

The aim of the present work was to develop gastric floating capsules containing oil-entrapped beads loading procyanidins. The floating beads were prepared by ionotropic gelation method using sodium alginate, CaCl 2 and chitosan. The effect of three independent parameters (concentration of sodium alginate, CaCl 2 and chitosan) on entrapment efficiency were analyzed by Box-Behnken design. The floating beads were evaluated for surface morphology, particle size, density, entrapment efficiency, buoyancy, release behavior in vitro and floating ability in vivo. The prepared beads were grossly spherical in shape and the mean size was approximately 1.54±0.17mm. The density was 0.97g/cm 3 . And the optimal conditions were as follows: concentration of sodium alginate, CaCl 2 and chitosan were 33.75mg/mL, 9.84mg/mL and 9.05mg/mL, respectively. The optimized formulation showed entrapment efficiency of 88.84±1.04% within small error-value (0.65). The release mechanism of floating capsules followed Korsmeyer-Peppas model (r 2 =0.9902) with non-Fickian release. The gastric floating capsules exhibited 100% floating percentage in vitro and they could float on the top of gastric juice for 5h in vivo. Therefore, the floating capsules are able to prolong the gastroretentive delivery of procyanidins. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of UV irradiation on optical, mechanical and microstructural properties of PVA/NaAlg blends

Science.gov (United States)

Sheela, T.; Bhajantri, R. F.; Ravindrachary, V.; Rathod, Sunil G.; Pujari, P. K.; Poojary, Boja; Somashekar, R.

2014-10-01

Poly(vinyl alcohol) (PVA)/Sodium alginate (NaAlg) blend films with 60:40 wt% were prepared by solution casting method and subjected to UV irradiation for different intervals of time. The optical, mechanical and morphological properties of the blend films were modified after UV irradiation. The FTIR and FT-Raman results show the chemical interaction between PVA and NaAlg. The UV-vis absorption peak at 278 nm shifts slightly towards longer wavelength and the absorption increases with irradiation time, indicate the increase in crosslinking network. The XRD results show an increase in amorphous nature with increase in UV irradiation time. The DSC/TGA results show a single glass transition temperature (Tg), which confirm that the blends are completely miscible and thermally stable up to 250 °C. The Young's modulus, tensile strength and stiffness of the blend films increase with increase in UV irradiation time. The SEM images confirm that the surface of 48 h UV irradiated PVA:NaAlg blend is more photo-resistant than unirradiated blend.

Detoxification of Hg(II) from aqueous and enzyme media: Pristine vs. tailored calcium alginate hydrogels.

Science.gov (United States)

Sarkar, Kangkana; Ansari, Zarina; Sen, Kamalika

2016-10-01

Calcium alginate (CA) hydrogels were tailored using phenolic compounds (PC) like, thymol, morin, catechin, hesperidin, during their preparation. The PC incorporated gels show modified surface features as indicated by scanning electron microscopic images (SEM). The rheological studies show that excepting the hesperidin incorporated gels all the other kinds including calcium alginate pristine have similar mechanical strength. The hesperidine incorporated CA gels had the maximum capacity to adsorb Hg. The Freundlich adsorption isotherms show higher values of adsorption capacity for all PC incorporated CA beads than the pristine CA (PCA). The hesperidin incorporated CA gels were found to show the best adsorption condition at neutral pH and an optimum contact time of 2.5h at 25°C. Considering the possibility of ingested Hg detoxification from human alimentary tract, the hesperidin and morin incorporated CA beads were further modified through incorporation of cod liver oil as the digestion time of fat in stomach is higher. In vitro uptake capacities of Hg in pepsin and pancreatin containing enzyme media were studied with hesperidin and morin incorporated beads and their corresponding fat incorporated beads also. In the pepsin medium, there was no uptake by hesperidin and fat-hesperidin incorporated beads, which is possibly due to the higher acidity of the medium. But in pancreatin medium Hg was taken up by both kinds of beads. Morin and morin-fat incorporated beads were efficient to uptake Hg from both the pepsin and pancreatin medium. The tailored CA beads may therefore serve as efficient scaffolds to rescue Hg ingested individuals. Copyright © 2016 Elsevier B.V. All rights reserved.

Novel porous graphene oxide and hydroxyapatite nanosheets-reinforced sodium alginate hybrid nanocomposites for medical applications

International Nuclear Information System (INIS)

Xiong, Guangyao; Luo, Honglin; Zuo, Guifu; Ren, Kaijing; Wan, Yizao

2015-01-01

Graphene oxide (GO) and hydroxyapatite (HAp) are frequently used as reinforcements in polymers to improve mechanical and biological properties. In this work, novel porous hybrid nanocomposites consisting of GO, HAp, and sodium alginate (SA) have been prepared by facile solution mixing and freeze drying in an attempt to obtain a scaffold with desirable mechanical and biological properties. The as-prepared porous GO/HAp/SA hybrid nanocomposites were characterized by SEM, XRD, FTIR, TGA, and mechanical testing. In addition, preliminary cell behavior was assessed by CCK8 assay. It is found that the GO/HAp/SA nanocomposites show improved compressive strength and modulus over neat SA and HAp/SA nanocomposites. CCK8 results reveal that the GO/HAp/SA nanocomposites show enhanced cell proliferation over neat SA and GO/SA nanocomposite. It has been demonstrated that GO/HAp20/SA holds promise in bone tissue engineering. - Graphical abstract: Display Omitted - Highlights: • Graphene oxide (GO), hydroxyapatite (HAp), and alginate (SA) nanocomposites were fabricated. • The novel porous composites were prepared by solution mixture and freeze drying. • The GO/HAp/SA had porous structure with porosity > 85% and pore size > 150 μm. • The GO/HAp/SA exhibited improved mechanical properties over HAp/SA counterparts. • The GO/HAp/SA showed enhanced cell proliferation over GO/SA counterparts

Novel porous graphene oxide and hydroxyapatite nanosheets-reinforced sodium alginate hybrid nanocomposites for medical applications

Energy Technology Data Exchange (ETDEWEB)

Xiong, Guangyao [School of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang 330013 (China); Luo, Honglin [Research Institute of Biomaterials and Transportation, East China Jiaotong University, Nanchang 330013 (China); School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China); Zuo, Guifu [Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials, College of Materials Science and Engineering, Hebei United University, Tangshan 063009 (China); Ren, Kaijing [Department of Joint Surgery, Tianjin Hospital, Tianjin 300211 (China); Wan, Yizao, E-mail: yzwantju@126.com [Research Institute of Biomaterials and Transportation, East China Jiaotong University, Nanchang 330013 (China); School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China)

2015-09-15

Graphene oxide (GO) and hydroxyapatite (HAp) are frequently used as reinforcements in polymers to improve mechanical and biological properties. In this work, novel porous hybrid nanocomposites consisting of GO, HAp, and sodium alginate (SA) have been prepared by facile solution mixing and freeze drying in an attempt to obtain a scaffold with desirable mechanical and biological properties. The as-prepared porous GO/HAp/SA hybrid nanocomposites were characterized by SEM, XRD, FTIR, TGA, and mechanical testing. In addition, preliminary cell behavior was assessed by CCK8 assay. It is found that the GO/HAp/SA nanocomposites show improved compressive strength and modulus over neat SA and HAp/SA nanocomposites. CCK8 results reveal that the GO/HAp/SA nanocomposites show enhanced cell proliferation over neat SA and GO/SA nanocomposite. It has been demonstrated that GO/HAp20/SA holds promise in bone tissue engineering. - Graphical abstract: Display Omitted - Highlights: • Graphene oxide (GO), hydroxyapatite (HAp), and alginate (SA) nanocomposites were fabricated. • The novel porous composites were prepared by solution mixture and freeze drying. • The GO/HAp/SA had porous structure with porosity > 85% and pore size > 150 μm. • The GO/HAp/SA exhibited improved mechanical properties over HAp/SA counterparts. • The GO/HAp/SA showed enhanced cell proliferation over GO/SA counterparts.

Electrospining method to synthesize compositebased on alginate-polyvinyl alcohol with addition of snail (Achatina fulica)

International Nuclear Information System (INIS)

Meilanny DKP; Pranjono; Dyah Hikmawati

2015-01-01

Many materials that can be used as wound coverings, one is alginate. Alginate has a high absorption capacity and has a role as a gelling agent which has hemostatic properties. Rigid and brittle nature is weakness of alginate and to improve the properties of the alginate can be mixed with the vinyl polymers are compatible and flexible. PVA is a water-soluble polymer, has a good ability to form fibers, biocompatible, has a chemical resistance, and biodegradable. For further improve the quality of wound closure, this research used the method electrospining . This experiment was carried out at a distance of 8 cm with a voltage of 17 kV, 20 kV, 23 kV, 25 kV and 27 kV. Testing is done using FTIR test to determine functional groups which is formed and analysis of the microstructure using SEM. FTIR test results showed that with the addition of lendr snail does not produce new functional groups. At a voltage of 23 kV can produce a fibers with micro size with nano fiber produced is also very continuous. (author)

Alginate based nanocomposite for microencapsulation of probiotic: Effect of cellulose nanocrystal (CNC) and lecithin.

Science.gov (United States)

Huq, Tanzina; Fraschini, Carole; Khan, Avik; Riedl, Bernard; Bouchard, Jean; Lacroix, Monique

2017-07-15

Probiotic (Lactobacillus rhamnosus ATCC 9595) was encapsulated in alginate-CNC-lecithin microbeads to produce nutraceutical microcapsules. Addition of CNC and lecithin in alginate microbeads (ACL-1) improved the viability of L. rhamnosus during gastric passage and storage. The compression strength of the freeze-dried ACL-1 microbeads improved 40% compared to alginate microbeads alone. Swelling studies revealed that addition of CNC and lecithin in alginate microbeads decreased (around 47%) the gastric fluid absorption but increased the dissolution time by 20min compared to alginate microbeads (A-0). During transition through the gastric passage, the viability of L. rhamnosus in dried ACL-1 microbeads was increased 37% as compared to A-0 based beads. At 25 and 4°C storage conditions, the viability of L. rhamnosus encapsulated in ACL-1 microbeads decreased by 1.23 and 1.08 log respectively, whereas the encapsulation with A-0 microbeads exhibited a 3.17 and 1.93 log reduction respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Honey/PVA hybrid wound dressings with controlled release of antibiotics: Structural, physico-mechanical and in-vitro biomedical studies.

Science.gov (United States)

Tavakoli, Javad; Tang, Youhong

2017-08-01

Hydrogel/honey hybrids manifest an attractive design with an exclusive therapeutic property that promotes wound healing process. The greater the concentration of honey within the formulation, the better the biomedical properties that will be achieved. However, an increase in the percentage of honey can negatively affect the physico-chemical and mechanical properties of hybrid hydrogels. The need exists, therefore, to prepare wound dressings that contain high honey density with optimal biomedical, mechanical and physicochemical properties. In this study, a simple method for the preparation of a highly concentrated honey/PVA hybrid hydrogel with borax as the crosslinking agent is reported. Comprehensive evaluations of the morphology, swelling kinetics, permeability, bio-adhesion, mechanical characteristics, cytotoxicity, antibacterial property, cell proliferation ability and their controlling release properties were conducted as a function of crosslinking density. All the borax-induced hydrogels showed acceptable biocompatibility, and the incorporation of 1% borax in the hydrogel formulation produced optimal behaviours for wound addressing applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of hemocompatibility and endothelialization of hybrid poly(vinyl alcohol) (PVA)/gelatin polymer films.

Science.gov (United States)

Ino, Julia M; Sju, Ervi; Ollivier, Véronique; Yim, Evelyn K F; Letourneur, Didier; Le Visage, Catherine

2013-11-01

Engineered grafts are still needed for small diameter blood vessels reconstruction. Ideal materials would prevent thrombosis and intimal hyperplasia by displaying hemocompatibility and mechanical properties close to those of native vessels. In this study, poly(vinyl alcohol) (PVA)/gelatin blends were investigated as a potential vascular support scaffold. We modified a chemically crosslinked PVA hydrogel by incorporation of gelatin to improve endothelial cell attachment with a single-step method. A series of crosslinked PVA/gelatin films with specific ratios set at 100:0, 99:1, 95:5, and 90:10 (w/w) were prepared and their mechanical properties were examined by uniaxial tensile testing. Tubes, obtained from sutured films, were found highly compliant (3.1-4.6%) and exhibited sufficient mechanical strength to sustain hemodynamic strains. PVA-based hydrogels maintained low level of platelet adhesion and low thrombogenic potential. Endothelial cell adhesion and proliferation were drastically improved on PVA/gelatin films with a feed gelatin content as low as 1% (w/w), leading to the formation of a confluent endothelium. Hydrogels with higher gelatin content did not sustain complete endothelialization because of modifications of the film surface, including phase segregation and formation of microdomains. Thus, PVA/gelatin (99:1, w/w) hydrogels appear as promising materials for the design of endothelialized vascular materials with long-term patency. Copyright © 2013 Wiley Periodicals, Inc.

Fabrication of magnetic alginate beads with uniform dispersion of CoFe{sub 2}O{sub 4} by the polydopamine surface functionalization for organic pollutants removal

Energy Technology Data Exchange (ETDEWEB)

Li, Xiaoli, E-mail: lixiaoli@lzu.edu.cn [Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000 (China); Lu, Haijun, E-mail: 784616040@qq.com [Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000 (China); Zhang, Yun, E-mail: zhangyun@lzu.edu.cn [Institute of Biochemical Engineering & Environmental Technology, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); He, Fu, E-mail: hef15@lzu.edu.cn [Institute of Biochemical Engineering & Environmental Technology, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Jing, Lingyun, E-mail: jingly12@lzu.edu.cn [Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000 (China); He, Xinghua, E-mail: 466410250@qq.com [Institute of Biochemical Engineering & Environmental Technology, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

2016-12-15

Highlights: • SA@CoFe{sub 2}O{sub 4}-PDA with magnetic particles and biopolymers were used for dye removal. • SA@CoFe{sub 2}O{sub 4}-PDA exhibited the synergistic effect. • High adsorption capacities and fast kinetics were obtained. • Cationic dyes could be removed with high efficiency in a wide pH range. • Possible mechanism of adsorption was investigated. - Abstract: A simple and efficient method for production of magnetic composites by decorating CoFe{sub 2}O{sub 4} with polydopamine (PDA) through oxidative polymerization of dopamine was conducted. Further, magnetic alginate beads with porous structure containing well-dispersed CoFe{sub 2}O{sub 4}-PDA were fabricated by ionic crosslinking technology. The resulting SA@CoFe{sub 2}O{sub 4}-PDA beads were characterized using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometer, vibrating sample magnetometer and X-ray photoelectron spectroscopy. Adsorption potential of SA@CoFe{sub 2}O{sub 4}-PDA beads for organic dyes including Methylene Blue (MB), Crystal Violet (CV) and Malachite Green (MG) was evaluated. SA@CoFe{sub 2}O{sub 4}-PDA beads exhibited excellent adsorption performances due to the composite effect, large surface area and porous structure. Organic dyes could be removed from water solution with high efficiency in a wide pH range of 4.0–9.0. Moreover, it exhibited much higher adsorptivity towards MB and CV with the maximum adsorption capacities of 466.60 and 456.52 mg/g, respectively, which were much higher than that of MG (248.78 mg/g). Ca-electrolyte had obvious adverse effects on MB and CV adsorption than MG. FTIR and XPS demonstrated that carboxylate, catechol, hydroxyl and amine groups might be involved in adsorption of organic dyes. The characteristics of wide pH range, high adsorption capacity and convenient magnetic separation would make SA@CoFe{sub 2}O{sub 4}-PDA beads as effective adsorbent for removal of organic dyes from wastewater.

Uniquely different PVA-xanthan gum irradiated membranes as transdermal diltiazem delivery device.

Science.gov (United States)

Bhunia, Tridib; Giri, Arindam; Nasim, Tanbir; Chattopadhyay, Dipankar; Bandyopadhyay, Abhijit

2013-06-05

This paper reports interesting differences between physical and mechanical properties of various membranes prepared from high and low molecular weight poly (vinyl alcohol) (PVA) and xanthan gum (XG) blends irradiated under low dose electron beam. The membranes were designed for sustained delivery of diltiazem hydrochloride through skin. Electron beam irradiation produced crosslinks and turned PVA into crystalline phase from its amorphous organization in the unirradiated state. PVA crystals were fibrillar at low XG content (1 wt.%) when the molecular weight was high while similar orientation at higher XG content (5 wt.%) when the molecular weight was low. Low molecular weight PVA-XG membranes showed equivalent physical properties under dry condition but wet-mechanical properties were superior for high molecular weight PVA-XG hybrids. Both of them showed slow and sustained diltiazem release but the later induced slightly slower release despite low drug encapsulation efficiency due to its better wet mechanical strength. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synthesis of collagen by bovine chondrocytes cultured in alginate; posttranslational modifications and cell-matrix interaction

NARCIS (Netherlands)

Beekman, B.; Verzijl, N.; Bank, R.A.; Von Der Mark, K.; TeKoppele, J.M.

1997-01-01

The extracellular matrix synthesized by articular chondrocytes cultured in alginate beads was investigated. Collagen levels increased sigmoidally with time and remained constant after 2 weeks of culture. The presence of cartilage-specific type II collagen was confirmed immunohistochemically.

Preparation and thermomechanical properties of Ag-PVA nanocomposite films

International Nuclear Information System (INIS)

Gautam, Anurag; Ram, S.

2010-01-01

Metal-polymer hybrid nanocomposites have been prepared from an aqueous solution of polyvinyl alcohol (PVA) and silver nitrate (AgNO 3 ). The silver nanoparticles were generated in PVA matrix by the reduction of silver ions with PVA molecule at 60-70 deg. C over magnetic stirrer. UV-vis analysis, X-ray diffraction studies, transmission electron microscopy, scanning electron microscopy and current-voltage analysis were used to characterize the nanocomposite films prepared. The X-ray diffraction analysis reveals that silver metal is present in face centered cubic (fcc) crystal structure. Average crystallite size of silver nanocrystal is 19 nm, which increases to 22 nm on annealing the film at 150 deg. C in air. This result is in good agreement with the result obtained from TEM. The UV-vis spectrum shows a single peak at 433 nm, arising from the surface plasmon absorption of silver nanocolloids. This result clearly indicates that silver nanoparticles are embedded in PVA. An improvement of mechanical properties (storage modulus) was also noticed due to a modification of PVA up to 0.5 wt% of silver content. The current-voltage (I-V) characteristic of nanocomposite films shows increase in current drawn with increasing Ag-content in the films.

Separation of magnetic beads in a hybrid continuous flow microfluidic device

Energy Technology Data Exchange (ETDEWEB)

Samanta, Abhishek [Haldia Institute of Technology, Production Engineering Department, Haldia (India); Ganguly, Ranjan; Datta, Amitava [Jadavpur University, Power Engineering Department (India); Modak, Nipu, E-mail: nmechju@gmail.com [Jadavpur University, Mechanical Engineering Department (India)

2017-04-01

Magnetic separation of biological entities in microfluidic environment is a key task for a large number of bio-analytical protocols. In magnetophoretic separation, biochemically functionalized magnetic beads are allowed to bind selectively to target analytes, which are then separated from the background stream using a suitably imposed magnetic field. Here we present a numerical study, characterizing the performance of a magnetophoretic hybrid microfluidic device having two inlets and three outlets for immunomagnetic isolation of three different species from a continuous flow. The hybrid device works on the principle of split-flow thin (SPLITT) fractionation and field flow fractionation (FFF) mechanisms. Transport of the magnetic particles in the microchannel has been predicted following an Eulerian-Lagrangian model and using an in-house numerical code. Influence of the salient geometrical parameters on the performance of the separator is studied by characterizing the particle trajectories and their capture and separation indices. Finally, optimum channel geometry is identified that yields the maximum capture efficiency and separation index. - Highlights: • Immunomagnetic separation in a hybrid microchannel design is investigated numerically. • Influence of salient geometric parameters on the device performance is analysed. • Optimum device dimension for best separation parameters are identified. • Optimized design of hybrid separator performs better than FFF or SPLITT devices.

Alginate Production from Alternative Carbon Sources and Use of Polymer Based Adsorbent in Heavy Metal Removal

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Çiğdem Kıvılcımdan Moral

2016-01-01

Full Text Available Alginate is a biopolymer composed of mannuronic and guluronic acids. It is harvested from marine brown algae; however, alginate can also be synthesized by some bacterial species, namely, Azotobacter and Pseudomonas. Use of pure carbohydrate sources for bacterial alginate production increases its cost and limits the chance of the polymer in the industrial market. In order to reduce the cost of bacterial alginate production, molasses, maltose, and starch were utilized as alternative low cost carbon sources in this study. Results were promising in the case of molasses with the maximum 4.67 g/L of alginate production. Alginates were rich in mannuronic acid during early fermentation independent of the carbon sources while the highest guluronic acid content was obtained as 68% in the case of maltose. The polymer was then combined with clinoptilolite, which is a natural zeolite, to remove copper from a synthetic wastewater. Alginate-clinoptilolite beads were efficiently adsorbed copper up to 131.6 mg Cu2+/g adsorbent at pH 4.5 according to the Langmuir isotherm model.

First transplantation of isolated murine follicles in alginate.

Science.gov (United States)

Vanacker, Julie; Dolmans, Marie-Madeleine; Luyckx, Valérie; Donnez, Jacques; Amorim, Christiani A

2014-01-01

Our aim is to develop an artificial ovary allowing survival and growth of isolated follicles and ovarian cells, to restore fertility in women diagnosed with pathologies at high risk of ovarian involvement. For this, alginate beads containing isolated preantral follicles and ovarian cells were autografted to immunocompetent mice. One week after grafting, the beads were invaded by proliferating murine cells (12.1%) and capillaries. The recovery rate of follicles per graft ranged from 0% to 35.5%. Of the analyzed follicles, 77% were Ki67-positive and 81%, TUNEL-negative. Three antral follicles were also identified, evidencing their ability to grow in the matrix. Our results suggest that an artificial ovary is now conceivable, opening new perspectives to restore fertility in women.

The effects of magnetic nanoparticles embedded with SA/PVA and pH on chemical-mechanical polishing wastewater and magnetic particle regeneration and recycle

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Chung-Fu Huang

2017-12-01

Full Text Available Experiments were conducted using sodium alginate (SA and polyvinyl alcohol (PVA as embedded materials for Fe3O4 magnetic nanoparticles (MNPs. The materials provided excellent protection to the embedded MNPs in low-pH conditions. This study observed and compared the adsorption capacity of the unaltered and embedded MNPs. At pH 3 and without additional magnetic fields, the wastewater turbidity removal rate of the embedded MNPs reached a maximum of 95%, similar to that of the unaltered MNPs. Moreover, this study examined the recyclability and reusability of the unaltered and embedded MNPs and discovered that the embedded MNPs could be reused up to seven times. Overall, the use of SA/PVA prevented MNPs from disintegrating and contaminating the wastewater through the dissolution of Fe ions. SA and PVA also increased the reusability of the unaltered MNPs.

Gamma-irradiation assisted seeded growth of Ag nanoparticles within PVA matrix

International Nuclear Information System (INIS)

Eisa, Wael H.; Abdel-Moneam, Yasser K.; Shaaban, Yasser; Abdel-Fattah, Atef A.; Abou Zeid, Amira M.

2011-01-01

Highlights: → Nucleation and growth must be two completely separated steps. → The amount of zerovalent nuclei can be controlled by varying the irradiation dose. → PVA act as physical barrier to inhibit aggregation or the growth of Ag nanoparticles. - Abstract: Polyvinyl alcohol (PVA)/Ag hybrid nanocomposites have been prepared from polymeric film of PVA and silver nitrate (AgNO 3 ). The silver nanoparticles were generated in PVA matrix by the reduction of silver ions with gamma-irradiation. UV-visible spectra showed a single peak at 422 nm, arising from the surface plasmon absorption of silver nanoparticles. The shifting of surface plasmon resonance peak after irradiation reveals that the gamma irradiation can be used as a size controlling agent for the preparation of silver nanoparticles embedded in PVA film. This result was in good agreement with the result obtained from TEM images. The TEM images showed the narrow size distribution of the obtained Ag nanoparticles with average particle size of 30 nm, which decreased to 17 nm with increasing irradiation dose. The X-ray diffraction analysis revealed that silver metal was present in face centered cubic (fcc) crystal structure. These results clearly indicate that monodispersed silver nanoparticles are embedded homogenously in PVA matrix.

Bead-size directed distribution of Pseudomonas aeruginosa results in distinct inflammatory response in a mouse model of chronic lung infection

DEFF Research Database (Denmark)

Christophersen, L J; Trøstrup, H; Damlund, Dina Silke Malling

2012-01-01

or in the peripheral respiratory zone. To study this we produced two distinct sizes of small alginate beads (SB) and large beads (LB) containing P. aeruginosa. In total, 175 BALB/c mice were infected with either SB or LB. At day 1 the quantitative bacteriology was higher in the SB group compared to the LB group (P

Oily wastewater treatment using a novel hybrid PBR-UASB system.

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Jeganathan, Jeganaesan; Nakhla, George; Bassi, Amarjeet

2007-04-01

In this study, anaerobic treatability of oily wastewater was investigated in a hybrid reactor system consisting of a packed bed reactor (PBR) followed by an upflow anaerobic sludge blanket (UASB) reactor at 35 degrees C. The system was operated using real pet food wastewater at different hydraulic retention times and loading rates for 165 d. The PBR was packed with sol-gel/alginate beads containing immobilized enzyme which hydrolyzed the oil and grease (O&G) into free long chain fatty acids, that were biodegraded by the UASB. The hybrid system was operated up to an oil loading rate of 4.9 kg O&Gm(-3)d(-1) (to the PBR) without any operational problems for a period of 100 d, with COD and O&G removal efficiencies above 90% and no sludge flotation was observed in the UASB. Beads supplement to the PBR was less than 2 g d(-1) and the relative activity was about 70%. Further increment in O&G loading to 18.7 kg O&Gm(-3)d(-1) caused destabilization of the system with 0.35% (v float/v feed) sludge float removed from the UASB.

Production optimization of flying fish roe analogs using calcium alginate hydrogel beads

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Bom-Bi Ha

2016-09-01

Full Text Available Abstract Due to decreased supplies of marine resources and byproducts, new processing technologies for the development of analogs for natural fishery products are becoming increasingly important in the fishing industry. In the present study, we investigated the optimal processing conditions for flying fish roe analogs based on alginate hydrogels. Optimized processing of these analogs was performed by response surface methodology. The optimal processing conditions for the flying fish roe analogs (based on sphericity were at a sodium alginate concentration of 2.41 %, calcium chloride solution curing time of 40.65 min, calcium chloride concentration of 1.51 %, and a reactor stir speed of 254×g. When the experiment was performed under these optimized conditions, the size (mm, sphericity (%, and rupture strength (kPa of the analogs were 2.2 ± 0.12, 98.2 ± 0.2, and 762 ± 24.68, respectively, indicating physical properties similar to their natural counterparts.

Encapsulation of Lactobacillus kefiri in alginate microbeads using a double novel aerosol technique.

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Demitri, Christian; Lamanna, Leonardo; De Benedetto, Egidio; Damiano, Fabrizio; Cappello, Maria Stella; Siculella, Luisa; Sannino, Alessandro

2017-08-01

Alginate micro beads containing Lactobacillus kefiri (the principal bacteria present in the kefir probiotic drink) were produced by a novel technique based on dual aerosols spaying of alginate based solution and CaCl 2 as cross linking agent. Carboxymethylcellulose (CMC) has been also added to the alginate in order to change the physic-chemical properties (viscosity and permeability) of the microbeads. Calcium alginate and CMC are biopolymers that can be used for developing oral drug-delivery systems. These biopolymers have been reported to show a pH-dependent swelling behaviour. Calcium alginate and CMC have also been known to possess an excellent mucoadhesive property. The loaded microbeads have been characterized in terms of morphology, chemical composition and stability in different conditions mimicking the gastric environment. In this study, we demonstrate the feasibility of a continuous fabrication of alginate microbeads in a range of 50-70μm size, encapsulating L. kefiri as active ingredient. The technique involves the use of a double aerosols of alginate based solution and CaCl 2 as crosslinking agent. Moreover, the encapsulation process was proved to be effective and not detrimental to bacteria viability. At the same time, it was verified the protective efficacy of the microcapsules against the gastric environment using both SGF pH1.2 (fasted state) and pH2.2 (feed state). Copyright © 2017 Elsevier B.V. All rights reserved.

Investigations of Al:CdS/PVA nanocomposites: A joint theoretical and experimental approach

Energy Technology Data Exchange (ETDEWEB)

Bala, Vaneeta, E-mail: b.vnita@gmail.com; Sharma, Mamta, E-mail: mamta.phy85@gmail.com; Tripathi, S.K., E-mail: surya@pu.ac.in; Kumar, Ranjan, E-mail: ranjan@pu.ac.in

2014-08-01

In the present work we investigate the aluminium doped cadmium sulphide (Al:CdS) nanoparticles embedded in polyvinyl alcohol (PVA) matrix by chemical route and density functional theory (DFT) based simulations. Supertetrahedron (T{sub n}) cluster models are considered for the simulation of CdS nanoparticles. Using DFT simulations on T{sub n} clusters, we observe that band gap of ligated clusters is slightly more as compare to bare clusters. This indicates the ability of organic ligands (PVA) to open the band gap of inorganic CdS nanoclusters. Negative value of binding energy indicates the stability of the inorganic–organic hybrid system. Frontier molecular orbitals (FMOs) indicate the charge transfer between organic and inorganic moieties which provides stability and longevity to nanoparticles, a prime function of ligands in nanocomposites. Absorption spectra of pure and doped clusters are calculated using time dependent density functional theory (TDDFT). CdS/PVA and Al:CdS/PVA samples are synthesized at room temperature by chemical method. Their structure, size and band gap is characterized by XRD, TEM, FTIR and UV spectroscopy. Optical band gap values as observed experimentally are in agreement with simulated TDDFT results. - Highlights: • Highly c-axis oriented Al doped CdS/PVA nanocomposites were deposited on glass slide using aqueous solutions. • Optical band gap reduced on Al doping. • DFT is used to simulate atomistic models of inorganic–organic hybrid nanocomposites. • FMOs used to study charge transfer behaviour between inorganic and organic moieties.

A comparison between ultraviolet disinfection and copper alginate beads within a vortex bioreactor for the deactivation of bacteria in simulated waste streams with high levels of colour, humic acid and suspended solids.

Science.gov (United States)

Thomas, Simon F; Rooks, Paul; Rudin, Fabian; Atkinson, Sov; Goddard, Paul; Bransgrove, Rachel M; Mason, Paul T; Allen, Michael J

2014-01-01

We show in this study that the combination of a swirl flow reactor and an antimicrobial agent (in this case copper alginate beads) is a promising technique for the remediation of contaminated water in waste streams recalcitrant to UV-C treatment. This is demonstrated by comparing the viability of both common and UV-C resistant organisms in operating conditions where UV-C proves ineffective - notably high levels of solids and compounds which deflect UV-C. The swirl flow reactor is easy to construct from commonly available plumbing parts and may prove a versatile and powerful tool in waste water treatment in developing countries.

Novel ionically crosslinked acrylamide-grafted poly(vinyl alcohol)/sodium alginate/sodium carboxymethyl cellulose pH-sensitive microspheres for delivery of Alzheimer's drug donepezil hydrochloride: Preparation and optimization of release conditions.

Science.gov (United States)

Bulut, Emine; Şanlı, Oya

2016-01-01

In this work, the graft copolymer, poly(vinyl alcohol)-grafted polyacrylamide (PVA-g-PAAm), was synthesized and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and elemental analysis. Microspheres of PVA-g-PAAm/sodium alginate (NaAlg)/sodium carboxymethyl cellulose (NaCMC) were prepared by the emulsion-crosslinking method and used for the delivery of an Alzheimer's drug, donepezil hydrochloride (DP). The release of DP increased with the increase in drug/polymer ratio (d/p) and PVA-g-PAAm/NaAlg/NaCMC ratio, while it decreased with the increase in the extent of crosslinking. The optimum DP release was obtained as 92.9% for a PVA-g-PAAm/NaAlg/NaCMC ratio of 1/2/1, d/p ratio of 1/8, and FeCl3 concentration of 7% (w/v).

Development and blood compatibility assessment of electrospun polyvinyl alcohol blended with metallocene polyethylene and plectranthus amboinicus (PVA/mPE/PA) for bone tissue engineering.

Science.gov (United States)

Qi, Jie; Zhang, Huang; Wang, Yingzhou; Mani, Mohan Prasath; Jaganathan, Saravana Kumar

2018-01-01

Currently, the design of extracellular matrix (ECM) with nanoscale properties in bone tissue engineering is challenging. For bone tissue engineering, the ECM must have certain properties such as being nontoxic, highly porous, and should not cause foreign body reactions. In this study, the hybrid scaffold based on polyvinyl alcohol (PVA) blended with metallocene polyethylene (mPE) and plectranthus amboinicus (PA) was fabricated for bone tissue engineering via electrospinning. The fabricated hybrid nanocomposites were characterized by scanning electron microscopy (SEM), Fourier transform and infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), contact angle measurement, and atomic force microscopy (AFM). Furthermore, activated partial thromboplastin time (APTT), prothrombin time (PT), and hemolytic assays were used to investigate the blood compatibility of the prepared hybrid nanocomposites. The prepared hybrid nanocomposites showed reduced fiber diameter (238±45 nm) and also increased porosity (87%) with decreased pore diameter (340±86 nm) compared with pure PVA. The interactions between PVA, mPE, and PA were identified by the formation of the additional peaks as revealed in FTIR. Furthermore, the prepared hybrid nanocomposites showed a decreased contact angle of 51°±1.32° indicating a hydrophilic nature and exhibited lower thermal stability compared to pristine PVA. Moreover, the mechanical results revealed that the electrospun scaffold showed an improved tensile strength of 3.55±0.29 MPa compared with the pristine PVA (1.8±0.52 MPa). The prepared hybrid nanocomposites showed delayed blood clotting as noted in APTT and PT assays indicating better blood compatibility. Moreover, the hemolysis assay revealed that the hybrid nanocomposites exhibited a low hemolytic index of 0.6% compared with pure PVA, which was 1.6% suggesting the safety of the developed nanocomposite to red blood cells (RBCs). The prepared nanocomposites exhibited better physico

Effects of cell entrapment in Ca-alginate on the metabolism of yeast Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Galazzo, J.L.

1989-01-01

Saccharomyces cerevisiae cells grown in suspension have been immobilized in calcium-alginate beads. Fermentation rates and intracellular composition have been determined under nongrowing conditions in these Ca-alginate entrapped cells and for identical cells in suspension. Glucose uptake and ethanol and glycerol production are approximately two times faster in immobilized cells than in suspended cells. Intermediate metabolite levels such as fructose-1,6-diphosphate, glucose-6-phosphate and 3-phosphoglycerate have been determined by phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy under glucose fermenting conditions. Carbon-13 NMR shows an increase in polysaccharide production in immobilized cells. S. cerevisiae cells grown within a Ca-alginate matrix have a specific growth rate 40% lower than the growth rate of similar cells cultivated in suspension. Alginate-grown cells have been used to compare glucose fermentation under nongrowing conditions in suspended and Ca-entrapped cells. Fermentation rate is higher in immobilized cells than in suspended cells. The observed differences in intracellular components between suspended and immobilized cells are qualitatively similar to the differences observed for cells grown in suspension. Ethanol production rate is 2.7 times faster in immobilized alginate-grown cells than in suspended suspension-grown cells

Magnetic bionanoparticles of Penicillium sp. yz11-22N2 doped with Fe3O4 and encapsulated within PVA-SA gel beads for atrazine removal.

Science.gov (United States)

Yu, Jiaping; He, Huijun; Yang, William L; Yang, Chunping; Zeng, Guangming; Wu, Xin

2018-07-01

A novel magnetic bionanomaterial, Penicillium sp. yz11-22N2 doped with nano Fe 3 O 4 entrapped in polyvinyl alcohol-sodium alginate gel beads (PFEPS), was successfully synthesized. The factors including nutrient substance, temperature, pH, initial concentrations of atrazine and rotational speeds were presented and discussed in detail. Results showed that the highest removal efficiency of atrazine by PFEPS was 91.2% at 8.00 mg/L atrazine. The maximum removal capacity for atrazine was 7.94 mg/g. Meanwhile, it has been found that most of atrazine were removed by metabolism and degradation of Penicillium sp. yz11-22N2, which could use atrazine as the sole source of either carbon or nitrogen. Degradation kinetics of atrazine conformed to first-order kinetics model. The intermediates indicated that the possible pathway for atrazine degradation by PFEPS mainly included hydrolysis dechlorination, dealkylation, side-chain oxidation and ring-opening. Copyright © 2018 Elsevier Ltd. All rights reserved.

Binding and leakage of barium in alginate microbeads.

Science.gov (United States)

Mørch, Yrr A; Qi, Meirigeng; Gundersen, Per Ole M; Formo, Kjetil; Lacik, Igor; Skjåk-Braek, Gudmund; Oberholzer, Jose; Strand, Berit L

2012-11-01

Microbeads of alginate crosslinked with Ca(2+) and/or Ba(2+) are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared with high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. To reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation. Copyright © 2012 Wiley Periodicals, Inc.

Injectable alginate-O-carboxymethyl chitosan/nano fibrin composite hydrogels for adipose tissue engineering.

Science.gov (United States)

Jaikumar, Dhanya; Sajesh, K M; Soumya, S; Nimal, T R; Chennazhi, K P; Nair, Shantikumar V; Jayakumar, R

2015-03-01

Injectable, biodegradable scaffolds are required for soft tissue reconstruction owing to its minimally invasive approach. Such a scaffold can mimic the native extracellular matrix (ECM), provide uniform distribution of cells and overcome limitations like donor site morbidity, volume loss, etc. So, here we report two classes of biocompatible and biodegradable hydrogel blend systems namely, Alginate/O-carboxymethyl chitosan (O-CMC) and Alginate/poly (vinyl alcohol) (PVA) with the inclusion of fibrin nanoparticles in each. The hydrogels were prepared by ionic cross-linking method. The developed hydrogels were compared in terms of its swelling ratio, degradation profile, compressive strength and elastic moduli. From these preliminary findings, it was concluded that Alginate/O-CMC formed a better blend for tissue engineering applications. The potential of the formed hydrogel as an injectable scaffold was revealed by the survival of adipose derived stem cells (ADSCs) on the scaffold by its adhesion, proliferation and differentiation into adipocytes. Cell differentiation studies of fibrin incorporated hydrogel scaffolds showed better differentiation was confirmed by Oil Red O staining technique. These injectable gels have potential in soft tissue regeneration. Copyright © 2014 Elsevier B.V. All rights reserved.

Three-dimensional electrospun polycaprolactone (PCL)/alginate hybrid composite scaffolds.

Science.gov (United States)

Kim, Min Seong; Kim, GeunHyung

2014-12-19

Micro/nanofibrous scaffolds have been used widely in biomedical applications because the micro/nano-scale fibres resemble natural extracellular matrix and the high surface-to-volume ratio encourages cellular activities (attachment and proliferation). However, poor mechanical properties, low controllability of various shapes and difficulties in obtaining controllable pore structure have been obstacles to their use in hard-tissue regeneration. To overcome these shortcomings, we suggest a new composite system, which uses a combination method of wet electrospinning, rapid prototyping and a physical punching process. Using the process, we obtained polycaprolactone (PCL)/alginate composite scaffolds, consisting of electrospun PCL/alginate fibres and micro-sized PCL struts, with mean pore sizes of 821 ± 55 μm. To show the feasibility of the scaffolds for hard-tissue regeneration, the scaffolds were assessed not only for physical properties, including hydrophilicity, water absorption, and tensile and compressive strength, but also in vitro cellular responses (cell viability and proliferation) and osteogenic differentiation (alkaline phosphatase (ALP) activity, and mineralisation) by culturing with pre-osteoblasts (MC3T3-E1 cells). With the reinforcing micro-sized PCL struts, the elastic modulus of the PCL/alginate scaffold was significantly improved versus a pure PCL scaffold. Additionally, due to the alginate component in the fibrous scaffold, they showed significantly enhanced hydrophilic behaviour, water absorption (∼8-fold) and significant biological activities (∼1.6-fold for cell viability at 7 days, ∼2.3-fold for ALP activity at 14 days and ∼6.4-fold for calcium mineralisation at 14 days) compared with those of a pure PCL fibrous scaffold. Copyright © 2014 Elsevier Ltd. All rights reserved.

Alginate Bead-Encapsulated PEDF Induces Ectopic Bone Formation In Vivo in the Absence of Co-Administered Mesenchymal Stem Cells.

Science.gov (United States)

Elahy, Mina; Doschak, Michael R; Hughes, Jeffery D; Baindur-Hudson, Swati; Dass, Crispin R

2018-01-01

Bone defects can be severely debilitating and reduce quality of life. Osteoregeneration can alleviate some of the complications in bony defects. For therapeutic use in future, a single factor that can cause potent bone regeneration is highly preferred as it will be more costeffective, any off-target effects will be more easily monitored and potentially managed, and for ease of administration which would lead to better patient compliance and satisfaction. We demonstrate that pigment epithelium-derived factor (PEDF), one such factor that is known to be potent against angiogenesis, promotes osteoblastogenesis in mesenchymal stem cells in vitro, but does not need co-encapsulation of cells in alginate bead scaffolds for osteogeneration in vivo. Osteogenic differentiation by PEDF in vitro was confirmed with immunoblotting and immunocytochemical staining for bone markers (alkaline phosphatase, osteocalcin, osteopontin, collagen I), calcified mineral deposition, and assay for alkaline phosphatase activity. PEDF-mediated bone formation in a muscle pocket in vivo model was confirmed by microcomputed tomography (microCT), histology (haematoxylin and eosin, Alcian blue staining), immunostaining for bone markers and for collagen I-processing proteins (heat shock protein 47 and membrane type I matrix metalloproteinase). PEDF therefore presents itself as a promising biological for osteogeneration. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Comparison of cell behavior on pva/pva-gelatin electrospun nanofibers with random and aligned configuration

Science.gov (United States)

Huang, Chen-Yu; Hu, Keng-Hsiang; Wei, Zung-Hang

2016-12-01

Electrospinning technique is able to create nanofibers with specific orientation. Poly(vinyl alcohol) (PVA) have good mechanical stability but poor cell adhesion property due to the low affinity of protein. In this paper, extracellular matrix, gelatin is incorporated into PVA solution to form electrospun PVA-gelatin nanofibers membrane. Both randomly oriented and aligned nanofibers are used to investigate the topography-induced behavior of fibroblasts. Surface morphology of the fibers is studied by optical microscopy and scanning electron microscopy (SEM) coupled with image analysis. Functional group composition in PVA or PVA-gelatin is investigated by Fourier Transform Infrared (FTIR). The morphological changes, surface coverage, viability and proliferation of fibroblasts influenced by PVA and PVA-gelatin nanofibers with randomly orientated or aligned configuration are systematically compared. Fibroblasts growing on PVA-gelatin fibers show significantly larger projected areas as compared with those cultivated on PVA fibers which p-value is smaller than 0.005. Cells on PVA-gelatin aligned fibers stretch out extensively and their intracellular stress fiber pull nucleus to deform. Results suggest that instead of the anisotropic topology within the scaffold trigger the preferential orientation of cells, the adhesion of cell membrane to gelatin have substantial influence on cellular behavior.

The characterization of ceramic alumina prepared by using additive glass beads

Science.gov (United States)

Suprapedi; Muljadi; Sardjono, Priyo

2018-01-01

The ceramic alumina has been made by using additive glass bead (5 and 10 % wt.). There are two kinds of materials, such as : gamma Alumina and glass bead. Synthesis of alumina was done by ball milling for 24 hours, then the mixed powder was dried in drying oven at 100 °C for 6 hours. Furthermore, the dried powder was mixed by using 2 % of PVA and continued with compacted to form a pellet with pressure of 50 MPA. The next step is sintering process with variation temperature of 1150, 1200, 1250, 1300 and 1400 °C and holding time for 2 hours. The characterization conducted are consist of test density, hardness, shrinkage, and microstructure. The results show that ceramic alumina with addition of 10 % wt. glass bead has the higher value of density, hardness and shrinkage than addition of 5% wt. glass bead. The highest characterization of ceramic alumina with addition 10 % glass bead was achieved at sintering temperature of 1400 °C with density 3.68 g/cm3, hardness vickers 780.40 Hv and shrinkage 15.23 %. The XRD results show that it was founds a corrundum (alpha Alumina) as dominant phase and mullite as minor phase.

A comparison between ultraviolet disinfection and copper alginate beads within a vortex bioreactor for the deactivation of bacteria in simulated waste streams with high levels of colour, humic acid and suspended solids.

Directory of Open Access Journals (Sweden)

Simon F Thomas

Full Text Available We show in this study that the combination of a swirl flow reactor and an antimicrobial agent (in this case copper alginate beads is a promising technique for the remediation of contaminated water in waste streams recalcitrant to UV-C treatment. This is demonstrated by comparing the viability of both common and UV-C resistant organisms in operating conditions where UV-C proves ineffective - notably high levels of solids and compounds which deflect UV-C. The swirl flow reactor is easy to construct from commonly available plumbing parts and may prove a versatile and powerful tool in waste water treatment in developing countries.

Towards a fully synthetic substitute of alginate: optimization of a thermal gelation/chemical cross-linking scheme ("tandem" gelation) for the production of beads and liquid-core capsules.

Science.gov (United States)

Cellesi, F; Weber, W; Fussenegger, M; Hubbell, J A; Tirelli, N

2004-12-20

Fully synthetic polymers were used for the preparation of hydrogel beads and capsules, in a processing scheme that, originally designed for calcium alginate, was adapted to a "tandem" process, that is the combination a physical gelation with a chemical cross-linking. The polymers feature a Tetronic backbone (tetra armed Pluronics), which exhibits a reverse thermal gelation in water solutions within a physiological range of temperatures and pHs. The polymers bear terminal reactive groups that allow for a mild, but effective chemical cross-linking. Given an appropriate temperature jump, the thermal gelation provides a hardening kinetics similar to that of alginate. With slower kinetics, the chemical cross-linking then develops an irreversible and elastic gel structure, and determines its transport properties. In the present article this process has been optimized for the production of monodisperse, high elastic, hydrogel microbeads, and liquid-core microcapsules. We also show the feasibility of the use of liquid-core microcapsules in cell encapsulation. In preliminary experiments, CHO cells have been successfully encapsulated preserving their viability during the process and after incubation. The advantages of this process are mainly in the use of synthetic polymers, which provide great flexibility in the molecular design. This, in principle, allows for a precise tailoring of mechanical and transport properties and of bioactivity of the hydrogels, and also for a precise control in material purification.

Bioactive Films Containing Alginate-Pectin Composite Microbeads with Lactococcus lactis subsp. lactis: Physicochemical Characterization and Antilisterial Activity

Directory of Open Access Journals (Sweden)

Mariam Bekhit

2018-02-01

Full Text Available Novel bioactive films were developed from the incorporation of Lactococcus lactis into polysaccharide films. Two different biopolymers were tested: cellulose derivative (hydroxylpropylmethylcellulose (HPMC and corn starch. Lactic acid bacteria (LAB free or previously encapsulated in alginate-pectin composite hydrogel microbeads were added directly to the film forming solution and films were obtained by casting. In order to study the impact of the incorporation of the protective culture into the biopolymer matrix, the water vapour permeability, oxygen permeability, optical and mechanical properties of the dry films were evaluated. Furthermore, the antimicrobial effect of bioactive films against Listeria monocytogenes was studied in synthetic medium. Results showed that the addition of LAB or alginate-pectin microbeads modified slightly films optical properties. In comparison with HPMC films, starch matrix proves to be more sensitive to the addition of bacterial cells or beads. Indeed, mechanical resistance of corn starch films was lower but barrier properties were improved, certainly related to the possible establishment of interactions between alginate-pectin beads and starch. HPMC and starch films containing encapsulated bioactive culture showed a complete inhibition of listerial growth during the first five days of storage at 5 °C and a reduction of 5 logs after 12 days.

Preparation of hybrid biomaterials for bone tissue engineering

Directory of Open Access Journals (Sweden)

Vilma Conceição Costa

2007-03-01

Full Text Available Tissue engineering has evolved from the use of biomaterials for bone substitution that fulfill the clinical demands of biocompatibility, biodegradability, non-immunogeneity, structural strength and porosity. Porous scaffolds have been developed in many forms and materials, but few reached the need of adequate physical, biological and mechanical properties. In the present paper we report the preparation of hybrid porous polyvinyl alcohol (PVA/bioactive glass through the sol-gel route, using partially and fully hydrolyzed polyvinyl alcohol, and perform structural characterization. Hybrids containing PVA and bioactive glass with composition 58SiO2-33CaO-9P2O5 were synthesized by foaming a mixture of polymer solution and bioactive glass sol-gel precursor solution. Sol-gel solution was prepared from mixing tetraethoxysilane (TEOS, triethylphosphate (TEP, and calcium chloride as chemical precursors. The hybrid composites obtained after aging and drying at low temperature were chemically and morphologically characterized through infrared spectroscopy and scanning electron microscopy. The degree of hydrolysis of PVA, concentration of PVA solution and different PVA-bioglass composition ratios affect the synthesis procedure. Synthesis parameters must be very well combined in order to allow foaming and gelation. The hybrid scaffolds obtained exhibited macroporous structure with pore size varying from 50 to 600 µm.

Biotransformation of L-tyrosine to Dopamine by a Calcium Alginate Immobilized Mutant Strain of Aspergillus oryzae.

Science.gov (United States)

Ali, Sikander; Nawaz, Wajeeha

2016-08-01

The present research work is concerned with the biotransformation of L-tyrosine to dopamine (DA) by calcium alginate entrapped conidiospores of a mutant strain of Aspergillus oryzae. Different strains of A. oryzae were isolated from soil. Out of 13 isolated strains, isolate-2 (I-2) was found to be a better DA producer. The wild-type I-2 was chemically improved by treating it with different concentrations of ethyl methyl sulfonate (EMS). Among seven mutant variants, EMS-6 exhibiting maximal DA activity of 43 μg/ml was selected. The strain was further exposed with L-cysteine HCl to make it resistant against diversion and environmental stress. The conidiospores of selected mutant variant A. oryzae EMS-6 strain were entrapped in calcium alginate beads. Different parameters for immobilization were investigated. The activity was further improved from 44 to 62 μg/ml under optimized conditions (1.5 % sodium alginate, 2 ml inoculum, and 2 mm bead size). The best resistant mutant variable exhibited over threefold increase in DA activity (62 μg/ml) than did wild-type I-2 (21 μg/ml) in the reaction mixture. From the results presented in the study, it was observed that high titers of DA activity in vitro could effectively be achieved by the EMS-induced mutagenesis of filamentous fungus culture used.

Lysozyme-immobilized electrospun PAMA/PVA and PSSA-MA/PVA ion-exchange nanofiber for wound healing.

Science.gov (United States)

Tonglairoum, Prasopchai; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Opanasopit, Praneet

2014-08-27

Abstract This research was aimed to develop the lysozyme immobilized ion-exchange nanofiber mats for wound healing. To promote the healing process, the PSSA-MA/PVA and PAMA ion-exchange nanofiber mats were fabricated to mimic the extracellular matrix structure using electrospinning process followed by thermally crosslinked. Lysozyme was immobilized on the ion-exchane nanofibers by an adsorption method. The ion-exchange nanofibers were investigated using SEM, FTIR and XRPD. Moreover, the lysozyme-immobilized ion-exchange nanofibers were further investigated for lysozyme content and activity, lysozyme release and wound healing activity. The fiber diameters of the mats were in the nanometer range. Lysozyme was gradually absorbed into the PSSA-MA/PVA nanofiber with higher extend than that is absorbed on the PAMA/PVA nanofiber and exhibited higher activity than lysozyme-immobilized PAMA/PVA nanofiber. The total contents of lysozyme on the PSSA-MA/PVA and PAMA/PVA nanofiber were 648 and 166 µg/g, respectively. FTIR and lysozyme activity results confirmed the presence of lysozyme on the nanofiber mats. The lysozyme was released from the PSSA-MA/PVA and PAMA/PVA nanofiber in the same manner. The lysozyme-immobilized PSSA-MA/PVA nanofiber mats and lysozyme-immobilized PAMA/PVA nanofiber mats exhibited significantly faster healing rate than gauze and similar to the commercial antibacterial gauze dressing. These results suggest that these nanofiber mats could provide the promising candidate for wound healing application.

Factors influencing the mechanical stability of alginate beads applicable for immunoisolation of mammalian cells

NARCIS (Netherlands)

Bhujbal, Swapnil V.; Paredes, Genaro A.; Niclou, Simone P.; de Vos, Paul

Transplantation of microencapsulated cells has been proposed as a cure for many types of endocrine disorders. Alginate-based microcapsules have been used in many of the feasibility studied addressing cure of the endocrine disorders, and different cancer types. Despite years of intensive research it

Adsorption and recovery of lead(II) from aqueous solutions by immobilized Pseudomonas Aeruginosa PU21 beads

International Nuclear Information System (INIS)

Lin, C.-C.; Lai, Y.-T.

2006-01-01

In this study, immobilized Pseudomonas aeruginosa PU21 beads were used as an adsorbent for lead(II). Different weight percentages of chitosan were added to polyethylene glycol (PEG, 0.5 wt.% in aqueous solution) and alginate (18 wt.% in aqueous solution), and then blended or cross-linked using different concentrations of epichlorohydrin (ECH) to prepare beads of different sizes and increased mechanical strength. Before blending or cross-linking, different weight percentages of P. aeruginosa PU21 were added to increase lead(II) adsorption. Subsequently the optimized bead composition (concentration of ECH, percentages of chitosan and P. aeruginosa PU21) and the optimum adsorption conditions (agitation rate and pH in the aqueous solution) were ascertained. Finally, the optimized beads adsorbing lead(II) were regenerated by 0.1 M aqueous HCl solutions and the most effective desorption agitation rate was ascertained. The results indicate that the reuse of immobilized P. aeruginosa PU21 beads was feasible. In addition, the equilibrium adsorption, kinetics, changes in the thermodynamic properties of adsorption of lead(II) on optimized beads were also investigated

Alginate beads as a tool to handle, cryopreserve and culture isolated human primordial/primary follicles.

Science.gov (United States)

Camboni, A; Van Langendonckt, A; Donnez, J; Vanacker, J; Dolmans, M M; Amorim, C A

2013-08-01

One major concern of grafting cryopreserved ovarian tissue to restore fertility in cancer patients is the possibility of reintroducing tumor cells. Cryopreservation of isolated primordial/primary follicles (PFs) may circumvent this problem. The aim of our work was to compare dimethyl sulfoxide (ME2SO) and ethylene glycol (EG) as cryoprotectants (CPAs) for slow-freezing of isolated human PFs in alginate. Ovarian biopsies from four women were processed for follicle isolation. PFs were embedded in alginate (5-15 per group). Follicles were frozen-thawed using 1.4M ME2SO or 1.5M EG as CPAs. Fresh and cryopreserved isolated follicles were in vitro cultured (IVC) for 7 days. At different time periods (after isolation, cryopreservation and IVC), follicles were evaluated with live/dead assay (using fluorescent probes) and diameter measurement. Follicle viability was calculated according to the percentage of dead follicular cells and the presence of a live/dead oocyte. A total of 841 PFs were isolated, embedded in alginate and cryopreserved with ME2SO (n=424) or EG (n=259), or used as controls (n=158). After 7 days of IVC, a significant increase in follicle size was observed in the fresh and ME2SO groups, but not in the EG group. The percentage of totally viable PFs was not significantly different before or after seven days of culture in fresh (100% and 82%) or ME2SO (93.2% and 85.1%) tissue. The EG group showed significantly lower viability before (63.9%) and after IVC (66.2%) than the fresh and ME2SO groups. Our results show that 1.4M ME2SO yields better preservation of isolated PF viability after thawing and 7 days of IVC than 1.5M EG. Alginate constitutes an easy, safe hydrogel matrix to handle and cryopreserve isolated human follicles using ME2SO as a CPA. Copyright © 2013 Elsevier Inc. All rights reserved.

Equilibrium isotherms, kinetics, and thermodynamics studies for congo red adsorption using calcium alginate beads impregnated with nano-goethite.

Science.gov (United States)

Munagapati, Venkata Subbaiah; Kim, Dong-Su

2017-07-01

The present study is concerned with the batch adsorption of congo red (CR) from an aqueous solution using calcium alginate beads impregnated with nano-goethite (CABI nano-goethite) as an adsorbent. The optimum conditions for CR removal were determined by studying operational variables viz. pH, adsorbent dose, contact time, initial dye ion concentration and temperature. The CABI nano-goethite was characterized by Fourier transform infrared spectroscopy (FTIR), X- ray diffraction (XRD) and Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis. The CR sorption data onto CABI nano-goethite were described using Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. The results show that the best fit was achieved with the Langmuir isotherm model. The maximum adsorption capacity (181.1mg/g) of CR was occurred at pH 3.0. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Desorption experiments were carried out to explore the feasibility of regenerating the adsorbent and the adsorbed CR from CABI nano-goethite. The best desorbing agent was 0.1M NaOH with an efficiency of 94% recovery. The thermodynamic parameters ΔG°, ΔH°, and ΔS° for the CR adsorption were determined by using adsorption capacities at five different temperatures (293, 303, 313, 323 and 303K). Results show that the adsorption process was endothermic and favoured at high temperature. Copyright © 2017 Elsevier Inc. All rights reserved.

Controlled fabrication of multi-core alginate microcapsules.

Science.gov (United States)

Eqbal, Md Danish; Gundabala, Venkat

2017-12-01

In this work, we present a robust microfluidic platform for controlled and complete on-chip generation of alginate microcapsules with single and double liquid cores. A combined Coflow and T-junction configuration implemented in a hybrid glass-PDMS (Polydimethylsiloxane) device is used for the generation of microcapsules with oil as liquid core. Frequency matching of oil-alginate double emulsion generation with that of aqueous Calcium chloride droplet generation allows for controlled merging of the two, resulting in reliable production of microcapsules. Confocal imaging of microcapsule cross-section reveals presence of intact liquid core. In the case of double core microcapsules, the two cores are well separated by alginate layer ensuring their long term stability. The current approach is expected to have advantages over existing techniques for liquid core microcapsule generation in terms of continuity of the process, control over core stability, and non-damage to cells when used for cell encapsulation applications. Copyright © 2017 Elsevier Inc. All rights reserved.

Prednisolone Delivery Platforms: Capsules and Beads Combination for a Right Timing Therapy.

Directory of Open Access Journals (Sweden)

Andrea Cerciello

Full Text Available In this work, a platform of alginate beads loaded with Prednisolone in hypromellose/gellan gum capsules (F6/Cps able to delay steroidal anti-inflammatory drug (SAID release as needed for chronotherapy of rheumatoid arthritis is proposed. Rheumatoid arthritis, showing a worsening in symptoms in the morning upon waking, is a pathology that can benefit from chronotherapy. With the aim to maximize prednisolone therapeutic action allowing the right timing of glucocorticoid therapy, different engineered microparticles (gel-beads were manufactured using prilling (laminar jet break-up as micro-encapsulation technique and Zn-alginate as gastroresistant carrier. Starting from various feed solutions and process parameters, the effect of the variables on particles size, morphology, solid state properties and drug release was studied. The optimization of operative and prilling/ionotropic gelation variables led to microspheres with almost spherical shape and a narrow dimensional range. The feed solution with the highest alginate (2.5% w/v amount and drug/polymer ratio (1:5 w/w gave rise to the highest encapsulation efficiency (78.5% as in F6 formulation. As to drug release, F6 exhibited an interesting dissolution profile, releasing about 24% of the drug in simulated gastric fluid followed by a more sustained profile in simulated intestinal fluid. #F6, acting as a gastro-resistant and delayed release formulation, was selected for in vivo studies on male Wistar rats by means of a carrageenan-induced oedema model. Finally, this efficacious formulation was used as core material for the development of a final dosage form: F6/Cps allowed to significantly reduce prednisolone release in simulated gastric fluid (12.6% and delayed drug release up to about 390 minutes.

PVA/atapulgite hydrogels; Hidrogeis de PVA/atapulgita

Energy Technology Data Exchange (ETDEWEB)

Oliveira, R.N.; Soares, G.A., E-mail: nunes@metalmat.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Paranhos, C.M. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil); Barreto, L.S. [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil)

2010-07-01

PVA hydrogels can be used as wound-healing as a consequence of their biocompatibility, flexibility, etc. In order to improve mechanical resistance of wound-healing, polymeric hydrogels reinforced with clay have been studied. Among national clays, attapulgite stands out. Once it is a natural material, acid treatment can be required in order to remove impurities. In the present work, PVA hydrogels reinforced with attapulgite were produced and they were characterized by swelling behavior, XRD, DSC and traction test. Among all properties studied, hydrogels reinforced with activated attapulgite showed better mechanical resistance and Young module than the other samples. (author)

Optimization of pectinase immobilization on grafted alginate-agar gel beads by 24 full factorial CCD and thermodynamic profiling for evaluating of operational covalent immobilization.

Science.gov (United States)

Abdel Wahab, Walaa A; Karam, Eman A; Hassan, Mohamed E; Kansoh, Amany L; Esawy, Mona A; Awad, Ghada E A

2018-07-01

Pectinase produced by a honey derived from the fungus Aspergillus awamori KX943614 was covalently immobilized onto gel beads made of alginate and agar. Polyethyleneimine, glutaraldehyde, loading time and enzyme's units were optimized by 2 4 full factorial central composite design (CCD). The immobilization process increased the optimal working pH for the free pectinase from 5 to a broader range of pH4.5-5.5 and the optimum operational temperature from 55°C to a higher temperature, of 60°C, which is favored to reduce the enzyme's microbial contamination. The thermodynamics studies showed a thermal stability enhancement against high temperature for the immobilized formula. Moreover, an increase in half-lives and D-values was achieved. The thermodynamic studies proved that immobilization of pectinase made a remarkable increase in enthalpy and free energy because of enzyme stability enhancement. The reusability test revealed that 60% of pectinase's original activity was retained after 8 successive cycles. This gel formula may be convenient for immobilization of other industrial enzymes. Copyright © 2018 Elsevier B.V. All rights reserved.

Magnetic iron oxide nanoparticles (MIONs) cross-linked natural polymer-based hybrid gel beads: Controlled nano anti-TB drug delivery application.

Science.gov (United States)

Kesavan, Mookkandi Palsamy; Ayyanaar, Srinivasan; Vijayakumar, Vijayaparthasarathi; Dhaveethu Raja, Jeyaraj; Annaraj, Jamespandi; Sakthipandi, Kathiresan; Rajesh, Jegathalaprathaban

2018-04-01

The nanosized rifampicin (RIF) has been prepared to increase the solubility in aqueous solution, which leads to remarkable enhancement of its bioavailability and their convenient delivery system studied by newly produced nontoxic, biodegradable magnetic iron oxide nanoparticles (MIONs) cross-linked polyethylene glycol hybrid chitosan (mCS-PEG) gel beads. The functionalization of both nano RIF and mCS-PEG gel beads were studied using various spectroscopic and microscopic techniques. The size of prepared nano RIF was found to be 70.20 ± 3.50 nm. The mechanical stability and swelling ratio of the magnetic gel beads increased by the addition of PEG with a maximum swelling ratio of 38.67 ± 0.29 g/g. Interestingly, this magnetic gel bead has dual responsive assets in the nano drug delivery application (pH and the magnetic field). As we expected, magnetic gel beads show higher nano drug releasing efficacy at acidic medium (pH = 5.0) with maximum efficiency of 71.00 ± 0.87%. This efficacy may also be tuned by altering the external magnetic field and the weight percentage (wt%) of PEG. These results suggest that such a dual responsive magnetic gel beads can be used as a potential system in the nano drug delivery applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1039-1050, 2018. © 2017 Wiley Periodicals, Inc.

Functionalized graphene oxide quantum dot-PVA hydrogel: a colorimetric sensor for Fe2+, Co2+ and Cu2+ ions

Science.gov (United States)

Baruah, Upama; Chowdhury, Devasish

2016-04-01

Functionalized graphene oxide quantum dots (GOQDs)-poly(vinyl alcohol) (PVA) hybrid hydrogels were prepared using a simple, facile and cost-effective strategy. GOQDs bearing different surface functional groups were introduced as the cross-linking agent into the PVA matrix thereby resulting in gelation. The four different types of hybrid hydrogels were prepared using graphene oxide, reduced graphene oxide, ester functionalized graphene oxide and amine functionalized GOQDs as cross-linking agents. It was observed that the hybrid hydrogel prepared with amine functionalized GOQDs was the most stable. The potential applicability of using this solid sensing platform has been subsequently explored in an easy, simple, effective and sensitive method for optical detection of M2+ (Fe2+, Co2+ and Cu2+) in aqueous media involving colorimetric detection. Amine functionalized GOQDs-PVA hybrid hydrogel when put into the corresponding solution of Fe2+, Co2+ and Cu2+ renders brown, orange and blue coloration respectively of the solution detecting the presence of Fe2+, Co2+ and Cu2+ ions in the solution. The minimum detection limit observed was 1 × 10-7 M using UV-visible spectroscopy. Further, the applicability of the sensing material was also tested for a mixture of co-existing ions in solution to demonstrate the practical applicability of the system. Insight into the probable mechanistic pathway involved in the detection process is also being discussed.

Chemical and toxicological assessment of arsenic sorption onto Fe-sericite composite powder and beads.

Science.gov (United States)

Kim, Jiwon; Lee, Cheongho; Lee, Seung Mok; Lalhmunsiama; Jung, Jinho

2018-01-01

Batch sorption and leaching of arsenic (1-30mgL -1 ) on Fe-sericite composite powder and beads were investigated in this study. Fe-sericite composite powder was made from natural sericite modified with iron, and alginate was used to transform the powder into beads. The maximum sorption capacities of the Fe-sericite composite powder (15.04 and 13.21mgg -1 for As(III) and As(V), respectively) were higher than those of the corresponding beads (9.02 and 7.11mgg -1 for As(III) and As(V), respectively) owing to the higher specific surface area of the powder. In addition, the leaching amounts of As(III) from Fe-sericite composite beads (≤ 15.03%) were higher than those of the corresponding powder (≤ 5.71%). However, acute toxicity of As(III)-sorbed Fe-sericite composite beads toward Daphnia magna was not significantly different from that of the corresponding powder (p > 0.05). Considering higher uptake of the powder particles by the daphnids, Fe-sericite composite beads seem to be a more appropriate and safer sorbent for arsenic removal in practical application. Based on Fe content, Fe-sericite composite beads had similar or higher maximum sorption capacities (71.19 and 56.11mgg -1 Fe for As(III) and As(V), respectively) than those of previously reported sorbents. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of Cross-Linking on the Mechanical and Thermal Properties of Poly(amidoamine) Dendrimer/Poly(vinyl alcohol) Hybrid Membranes for CO2 Separation.

Science.gov (United States)

Duan, Shuhong; Kai, Teruhiko; Saito, Takashi; Yamazaki, Kota; Ikeda, Kenichi

2014-04-08

Poly(amidoamine) (PAMAM) dendrimers were incorporated into cross-linked poly(vinyl alcohol) (PVA) matrix to improve carbon dioxide (CO2) separation performance at elevated pressures. In our previous studies, PAMAM/PVA hybrid membranes showed high CO2 separation properties from CO2/H2 mixed gases. In this study, three types of organic Ti metal compounds were selected as PVA cross-linkers that were used to prepare PAMAM/cross-linked PVA hybrid membranes. Characterization of the PAMAM/cross-linked PVA hybrid membranes was conducted using nanoindentation and thermogravimetric analyses. The effects of the cross-linker and CO2 partial pressure in the feed gas on CO2 separation performance were discussed. H2O and CO2 sorption of the PAMAM/PVA hybrid membranes were investigated to explain the obtained CO2 separation efficiencies.

Adsorption of As(III), As(V) and Cu(II) on zirconium oxide immobilized alginate beads in aqueous phase.

Science.gov (United States)

Kwon, Oh-Hun; Kim, Jong-Oh; Cho, Dong-Wan; Kumar, Rahul; Baek, Seung Han; Kurade, Mayur B; Jeon, Byong-Hun

2016-10-01

A composite adsorbent to remove arsenite [As(III)], arsenate [As(V)], and copper [Cu(II)] from aqueous phase was synthesized by immobilizing zirconium oxide on alginate beads (ZOAB). The composition (wt%) of ZOAB (Zr-34.0; O-32.7; C-21.3; Ca-1.0) was confirmed by energy dispersive X-ray (EDX) analysis. Sorption studies were conducted on single and binary sorbate systems, and the effects of contact time, initial adsorbate concentration, and pH on the adsorption performance of ZOAB (pHPZC = 4.3) were monitored. The sorption process for As(III)/As(V) and Cu(II) reached an equilibrium state within 240 h and 24 h, respectively, with maximum sorption capacities of 32.3, 28.5, and 69.9 mg g(-1), respectively. The addition of Cu(II) was favorable for As(V) sorption in contrast to As(III). In the presence of 48.6 mg L(-1) Cu(II), the sorption capacity of As(V) increased from 1.5 to 3.8 mg g(-1) after 240 h. The sorption data for As(III)/As(V) and Cu(II) conformed the Freundlich and Langmuir isotherm models, respectively. The adsorption of As(III), As(V), and Cu(II) followed pseudo second order kinetics. The effect of arsenic species on Cu(II) sorption was insignificant. The results of present study demonstrated that the synthesized sorbent could be useful for the simultaneous removal of both anionic and cationic contaminants from wastewaters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Towards a programmable magnetic bead microarray in a microfluidic channel

DEFF Research Database (Denmark)

Smistrup, Kristian; Bruus, Henrik; Hansen, Mikkel Fougt

2007-01-01

to use larger currents and obtain forces of longer range than from thin current lines at a given power limit. Guiding of magnetic beads in the hybrid magnetic separator and the construction of a programmable microarray of magnetic beads in the microfluidic channel by hydrodynamic focusing is presented....

Fabrication of granular activated carbons derived from spent coffee grounds by entrapment in calcium alginate beads for adsorption of acid orange 7 and methylene blue.

Science.gov (United States)

Jung, Kyung-Won; Choi, Brian Hyun; Hwang, Min-Jin; Jeong, Tae-Un; Ahn, Kyu-Hong

2016-11-01

Biomass-based granular activated carbon was successfully prepared by entrapping activated carbon powder derived from spent coffee grounds into calcium-alginate beads (SCG-GAC) for the removal of acid orange 7 (AO7) and methylene blue (MB) from aqueous media. The dye adsorption process is highly pH-dependent and essentially independent of ionic effects. The adsorption kinetics was satisfactorily described by the pore diffusion model, which revealed that pore diffusion was the rate-limiting step during the adsorption process. The equilibrium isotherm and isosteric heat of adsorption indicate that SCG-GAC possesses an energetically heterogeneous surface and operates via endothermic process in nature. The maximum adsorption capacities of SCG-GAC for AO7 (pH 3.0) and MB (pH 11.0) adsorption were found to be 665.9 and 986.8mg/g at 30°C, respectively. Lastly, regeneration tests further confirmed that SCG-GAC has promising potential in its reusability, showing removal efficiency of more than 80% even after seven consecutive cycles. Copyright © 2016 Elsevier Ltd. All rights reserved.

PVA/Polysaccharides Blended Films: Mechanical Properties

Directory of Open Access Journals (Sweden)

Fábio E. F. Silva

2013-01-01

Full Text Available Blends of polyvinyl alcohol (PVA and angico gum (AG and/or cashew gum (CG were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO. The films presented thickness varying from 70 to 140 μm (PVA/AG and 140 to 200 μm (PVA/CG. Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher values of tensile strength (TS and elastic modulus (EM were observed in the film. On the other hand, PVA/CG and PVA/CG-AG presented the highest value of percentage of elongation (E%. Pearson’s Correlation Analysis revealed a positive correlation between TS and EM and a negative correlation between E% and EM. The PVA/CG film presented mechanical properties very similar to MBO, with the advantage of a higher E% (11.96 than MBO (2.94. The properties of the PVA blended films depended on the polysaccharide added in the blend, as well as the acid used as a catalyst. However, all produced films presented interesting mechanical characteristics which enables several biotechnological applications.

The Effect of Cell Immobilization by Calcium Alginate on Bacterially Induced Calcium Carbonate Precipitation

Directory of Open Access Journals (Sweden)

Mostafa Seifan

2017-10-01

Full Text Available Microbially induced mineral precipitation is recognized as a widespread phenomenon in nature. A diverse range of minerals including carbonate, sulphides, silicates, and phosphates can be produced through biomineralization. Calcium carbonate (CaCO3 is one of the most common substances used in various industries and is mostly extracted by mining. In recent years, production of CaCO3 by bacteria has drawn much attention because it is an environmentally- and health-friendly pathway. Although CaCO3 can be produced by some genera of bacteria through autotrophic and heterotrophic pathways, the possibility of producing CaCO3 in different environmental conditions has remained a challenge to determine. In this study, calcium alginate was proposed as a protective carrier to increase the bacterial tolerance to extreme environmental conditions. The model showed that the highest concentration of CaCO3 is achieved when the bacterial cells are immobilized in the calcium alginate beads fabricated using 1.38% w/v Na-alginate and 0.13 M CaCl2.

Effect of Cross-Linking on the Mechanical and Thermal Properties of Poly(amidoamine Dendrimer/Poly(vinyl alcohol Hybrid Membranes for CO2 Separation

Directory of Open Access Journals (Sweden)

Shuhong Duan

2014-04-01

Full Text Available Poly(amidoamine (PAMAM dendrimers were incorporated into cross-linked poly(vinyl alcohol (PVA matrix to improve carbon dioxide (CO2 separation performance at elevated pressures. In our previous studies, PAMAM/PVA hybrid membranes showed high CO2 separation properties from CO2/H2 mixed gases. In this study, three types of organic Ti metal compounds were selected as PVA cross-linkers that were used to prepare PAMAM/cross-linked PVA hybrid membranes. Characterization of the PAMAM/cross-linked PVA hybrid membranes was conducted using nanoindentation and thermogravimetric analyses. The effects of the cross-linker and CO2 partial pressure in the feed gas on CO2 separation performance were discussed. H2O and CO2 sorption of the PAMAM/PVA hybrid membranes were investigated to explain the obtained CO2 separation efficiencies.

Bioremediation of contaminated surface water by immobilized Micrococcus roseus.

Science.gov (United States)

Li, H; Li, P; Hua, T; Zhang, Y; Xiong, X; Gong, Z

2005-08-01

The problems caused by contaminated surface water have gradually become more serious in recent years. Although various remediation technologies were investigated, unfortunately, no efficient method was developed. In this paper, a new bioremediation technology was studied using Micrococcus roseus, which was immobilized in porous spherical beads by an improved polyvinyl alcohol (PVA) - sodium alginate (SA) embedding method. The experimental results indicated that COD removal rate could reach 64.7 % within 72 hours when immobilized M. roseus beads were used, which was ten times as high as that of free cells. The optimum inoculation rate of immobilized M. roseus beads was 10 % (mass percent of the beads in water sample, g g(-1)). Suitable aeration was proved necessary to enhance the bioremediation process. The immobilized cells had an excellent tolerance to pH and temperature changes, and were also more resistant to heavy metal stress compared with free cells. The immobilized M. roseus beads had an excellent regeneration capacity and could be reused after 180-day continuous usage. The Scanning Electronic Microscope (SEM) analysis showed that the bead microstructure was suitable for M. roseus growth, however, some defect structures should still be improved.

Effect of algal density in bead, bead size and bead concentrations ...

African Journals Online (AJOL)

Effect of algal density in bead, bead size and bead concentrations on wastewater nutrient removal. ... African Journal of Biotechnology ... The bioreactor containing algal beads (4 mm diameter) with 1.5 x 106 cells bead-1 (cell stocking) at concentration of 10.66 beads ml-1 wastewater (1:3 bead: wastewater, v/v) achieved ...

Fabrication of a microfluidic device for studying the in situ drug-loading/release behavior of graphene oxide-encapsulated hydrogel beads.

Science.gov (United States)

Veerla, Sarath Chandra; Kim, Da Reum; Yang, Sung Yun

2018-01-01

Controlled drug delivery system is highly important for not only prolonged the efficacy of drug but also cellular development for tissue engineering. A number of biopolymer composites and nanostructured carriers behave been used for the controlled drug delivery of therapeutics. Recently, in vitro microfluidic devices that mimic the human body have been developed for drug-delivery applications. A microfluidic channel was fabricated via a two-step process: (i) polydimethyl siloxane (PDMS) and curing agent were poured with a 10:2 mass ratio onto an acrylic mold with two steel pipes, and (ii) calcium alginate beads were synthesized using sodium alginate and calcium chloride solutions. Different amounts (10, 25, 50 μg) of graphene oxide (GO) were then added by Hummers method, and studies on the encapsulation and release of the model drug, risedronate (Ris), were performed using control hydrogel beads (pH 6.3), GO-containing beads (10GO, 25GO and 50GO), and different pH conditions. MC3T3 osteoblastic cells were cultured in a microchannel with Ris-loaded GO-hydrogel beads, and their proliferation, viability, attachment and spreading were assessed for a week. The spongy and textured morphology of pristine hydrogel beads was converted to flowery and rod-shaped structures in drug-loaded hydrogel beads at reduced pH (6.3) and at a lower concentration (10 μg) of GO. These latter 10GO drug-loaded beads rapidly released their cargo owing to the calcium phosphate deposited on the surface. Notably, beads containing a higher amount of GO (50GO) exhibited an extended drug-release profile. We further found that MC3T3 cells proliferated continuously in vitro in the microfluidic channel containing the GO-hydrogel system. MTT and live/dead assays showed similar proliferative potential of MC3T3 cells. Therefore, a microfluidic device with microchannels containing hydrogel beads formulated with different amounts of GO and tested under various pH conditions could be a promising system

Hydrogels based on chemically modified poly(vinyl alcohol (PVA-GMA and PVA-GMA/chondroitin sulfate: Preparation and characterization

Directory of Open Access Journals (Sweden)

E. C. Muniz

2012-05-01

Full Text Available This work reports the preparation of hydrogels based on PVA-GMA, PVA-GMA is poly(vinyl alcohol (PVA functionalized with vinyl groups from glycidyl methacrylate (GMA, and on PVA-GMA with different content of chondroitin sulfate (CS. The degrees of swelling of PVA-GMA and PVA-GMA/CS hydrogels were evaluated in distilled water and the swelling kinetics was performed in simulated gastric and intestinal fluids (SGF and SIF. PVA-GMA and PVAGMA/CS hydrogels demonstrated to be resistant on SGF and SIF fluids. The elastic modulus, E, of swollen-hydrogels were determined through compressive tests and, according to the obtained results, the hydrogels presented good mechanical properties. At last, the presence of CS enhances the hydrogel cell compatibility as gathered by cytotoxicity assays. It was concluded that the hydrogels prepared through this work presented characteristics that allow them to be used as biomaterial, as a carrier in drug delivery system or to act as scaffolds in tissue engineering as well.

Formulation of an alginate-vineyard pruning waste composite as a new eco-friendly adsorbent to remove micronutrients from agroindustrial effluents.

Science.gov (United States)

Vecino, X; Devesa-Rey, R; Moldes, A B; Cruz, J M

2014-09-01

The cellulosic fraction of vineyard pruning waste (free of hemicellulosic sugars) was entrapped in calcium alginate beads and evaluated as an eco-friendly adsorbent for the removal of different nutrients and micronutrients (Mg, P, Zn, K, N-NH4, SO4, TN, TC and PO4) from an agroindustrial effluent (winery wastewater). Batch adsorption studies were performed by varying the amounts of cellulosic adsorbent (0.5-2%), sodium alginate (1-5%) and calcium chloride (0.05-0.9M) included in the biocomposite. The optimal formulation of the adsorbent composite varied depending on the target contaminant. Thus, for the adsorption of cationic contaminants (Mg, Zn, K, N-NH4 and TN), the best mixture comprised 5% sodium alginate, 0.05M calcium chloride and 0.5% cellulosic vineyard pruning waste, whereas for removal of anionic compounds (P, SO4 and PO4), the optimal mixture comprised 1% sodium alginate, 0.9M calcium chloride and 0.5% cellulosic vineyard pruning waste. To remove TC from the winery wastewater, the optimal mixture comprised 3% of sodium alginate, 0.475M calcium chloride and 0.5% cellulosic vineyard pruning waste. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sorption of chrysoidine by row cork and cork entrapped in calcium alginate beads

Directory of Open Access Journals (Sweden)

Valeria M. Nurchi

2014-01-01

The influence on the sorption of pH, initial dye concentration, and particle size, as well as the efficiency of the entrapment, have been investigated. The maximum sorption was found for cork samples of fine particle size (FC, in both row and entrapped forms, at pH 7; conversely, at pH 4 the difference is significant (0.12 mmol/g for row cork and 0.20 mmol/g for entrapped cork, evoking a cooperation of alginate in binding the positively charged chrysoidine molecule.

A novel electrospun membrane based on moxifloxacin hydrochloride/poly(vinyl alcohol)/sodium alginate for antibacterial wound dressings in practical application.

Science.gov (United States)

Fu, Ruoqiu; Li, Chenwen; Yu, Caiping; Xie, Hong; Shi, Sanjun; Li, Zhuoheng; Wang, Qing; Lu, Laichun

2016-01-01

This study reports on the performance of sodium alginate (SA)/poly(vinyl alcohol) (PVA)/moxifloxacin hydrochloride (MH) nanofibrous membranes (NFM) capable of providing antibacterial agent delivery for wound-dressing applications. The aim of this work was to prepare antibacterial NFM with good permeability properties by employing PVA and SA as carriers. A group of 12% PVA/2% SA solutions blended in various ratios (8:2, 7:3, 6:4, 5:5 and 4:6, v/v) and containing 0.5, 1, 2 or 4 wt% MH were studied for electrospinning into nanoscale fibermats. The optimum ratio found to form smooth fibers with uniform fibrous features was 6:4. The drug release behavior of the electrospun, the antibacterial effects on Pseudomonas aeruginosa and Staphylococcus aureus and the animal wound dressing capabilities were also investigated. As much as 80% of the MH was released from the electrospun after 10 h of incubation at 37 °C. In addition, the NFM with 0.5 MH exhibited less activity, whereas those with higher concentrations of MH exhibited greater antibacterial effect. Furthermore, the MH-loaded electrospun accelerated the rate of wound dressing compared to other groups. The results of the in vitro and in vivo experiments suggest that MH/PVA/SA nanofibers might be an interesting bioactive wound dressing for clinical applications.

Effect of Diffusion on Discoloration of Congo Red by Alginate Entrapped Turnip (Brassica rapa Peroxidase

Directory of Open Access Journals (Sweden)

Afaf Ahmedi

2015-01-01

Full Text Available Enzymatic discoloration of the diazo dye, Congo red (CR, by immobilized plant peroxidase from turnip “Brassica rapa” is investigated. Partially purified turnip peroxidase (TP was immobilized by entrapment in spherical particles of calcium alginate and was assayed for the discoloration of aqueous CR solution. Experimental data revealed that pH, reaction time, temperature, colorant, and H2O2 concentration play a significant role in dye degradation. Maximum CR removal was found at pH 2.0, constant temperature of 40°C in the presence of 10 mM H2O2, and 180 mg/L of CR. More than 94% of CR was removed by alginate immobilized TP after 1 h of incubation in a batch process under optimal conditions. About 74% removal efficiency was retained after four recycles. Diffusional limitations in alginate beads such as effectiveness factor η, Thiele modulus Φ, and effective diffusion coefficients (De of Congo red were predicted assuming a first-order biodegradation kinetic. Results showed that intraparticle diffusion resistance has a significant effect on the CR biodegradation rate.

PVA/Polysaccharides Blended Films: Mechanical Properties

OpenAIRE

Silva, Fábio E. F.; Di-Medeiros, Maria Carolina B.; Batista, Karla A.; Fernandes, Kátia F.

2013-01-01

Blends of polyvinyl alcohol (PVA) and angico gum (AG) and/or cashew gum (CG) were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO). The films presented thickness varying from 70 to 140 μm (PVA/AG) and 140 to 200 μm (PVA/CG). Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher valu...

Property-based design: optimization and characterization of polyvinyl alcohol (PVA) hydrogel and PVA-matrix composite for artificial cornea.

Science.gov (United States)

Jiang, Hong; Zuo, Yi; Zhang, Li; Li, Jidong; Zhang, Aiming; Li, Yubao; Yang, Xiaochao

2014-03-01

Each approach for artificial cornea design is toward the same goal: to develop a material that best mimics the important properties of natural cornea. Accordingly, the selection and optimization of corneal substitute should be based on their physicochemical properties. In this study, three types of polyvinyl alcohol (PVA) hydrogels with different polymerization degree (PVA1799, PVA2499 and PVA2699) were prepared by freeze-thawing techniques. After characterization in terms of transparency, water content, water contact angle, mechanical property, root-mean-square roughness and protein adsorption behavior, the optimized PVA2499 hydrogel with similar properties of natural cornea was selected as a matrix material for artificial cornea. Based on this, a biomimetic artificial cornea was fabricated with core-and-skirt structure: a transparent PVA hydrogel core, surrounding by a ringed PVA-matrix composite skirt that composed of graphite, Fe-doped nano hydroxyapatite (n-Fe-HA) and PVA hydrogel. Different ratio of graphite/n-Fe-HA can tune the skirt color from dark brown to light brown, which well simulates the iris color of Oriental eyes. Moreover, morphologic and mechanical examination showed that an integrated core-and-skirt artificial cornea was formed from an interpenetrating polymer network, no phase separation appeared on the interface between the core and the skirt.

Synthesis of PVA Hydrogel for Prosthetic Discus Nucleus Pulposus: Formation of Interpenetrating Polymer Network (IPN) PVA Hydrogel by Gamma Rays

International Nuclear Information System (INIS)

Darwis, Darmawan; Erizal; Lely Hardiningsih; Razzak, Mirzan T.

2004-01-01

Research on synthesis of IPN PVA hydrogel for using as prosthetic discus nucleus has been carried out. Base hydrogel network (network I) was made by reacting the solution of polyvinyl alcohol (PVA) 10 - 15 % w/w with formaldehyde at 80 o C for several hours. Hydrogel network II (as IPN network) was then made by immersion of base hydrogel into polymer solution (PVP or PVA) until hydrogel swell to equilibrium volume. The hydrogel then irradiated using gamma rays at various doses. The results show that IPN PVA-PVP and IPN PVA-PVP hydrogels have higher compression strength compared to base hydrogel. IPN PVA-PVA hydrogel made by irradiating base hydrogel (immersed into polymer solution) with 25, 50 and 100 kGy have compression strength at 5 mm displacement 2.72; 2.83; and 3.25 kg/cm 2 respectively, While base hydrogel has compression strength of 1.75 kg/cm 2 . IPN PVA-PVP and PVA-PVA hydrogels made by irradiating base hydrogel with 100 kGy still retain high water content i.e. 72 and 74 % respectively. Beside that they show good re-absorption property after compression treatment that is hydrogel can return to the original shape after compressed to 12 mm displacement (80% of initial height on hydrogel) at relatively short time, less than 15 minutes. (author)

Tough Al-alginate/poly(N-isopropylacrylamide) hydrogel with tunable LCST for soft robotics.

Science.gov (United States)

Zheng, Wen Jiang; An, Ning; Yang, Jian Hai; Zhou, Jinxiong; Chen, Yong Mei

2015-01-28

Tough Al-alginate/poly(N-isopropylacrylamide) (PNIPAM) hydrogel has been synthesized by introducing an interpenetrating network with hybrid physically cross-linked alginate and chemically cross-linked PNIPAM. Varying the concentration of AlCl3 regulates the mechanical properties of the tough hydrogel and tunes its lower critical solution temperature (LCST) as well. The tough Al-alginate/PNIPAM exhibits 6.3 ± 0.3 MPa of compressive stress and 9.95 of uniaxial stretch. Tunability of LCST is also achieved in a wide range within 22.5-32 °C. A bending beam actuator and a four-arm gripper made of bilayer (Na-alginate/PNIPAM)/(Al-alginate/PNIPAM) hydrogel as prototype of all-hydrogel soft robotics are demonstrated. A finite element (FE) simulation model is developed to simulate the deformation of the soft robotics. The FE simulation not only reproduces the deformation process of performed experiments but also predicts more complicated devices that can be explored in the future. This work broadens the application of temperature-responsive PNIPAM-based hydrogels.

Biosorption of uranium from wastewater by ZVI-SRB immobilized in calcium alginate

International Nuclear Information System (INIS)

Wang Aihe; Zhang Wei; Hu Kaiguang

2009-01-01

A ZVI-SRB was immobilized in calcium alginate gel beads,and the immobilized ZVI-SRB was used for removing uranium from wasterwater. The kinetics of uranium biosorption by the immobilized ZVI-SRB and the immobilized SRB was investigated. The results show that the immobilized ZVI-SRB and SRB were effective in removing uranium from wasterwater, and their maximal absorption capacities were up to 312.50 and 256.41 mg/g respectively. The kinetics of uranium biosorption onto the immobilized ZVI-SRB and SRB followed pseudo-second order model. (authors)

Enhanced biological stabilization of heavy metals in sediment using immobilized sulfate reducing bacteria beads with inner cohesive nutrient

Energy Technology Data Exchange (ETDEWEB)

Li, Xin, E-mail: hgxlixin@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Dai, Lihua; Zhang, Chang; Zeng, Guangming; Liu, Yunguo [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Zhou, Chen [Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University (United States); Xu, Weihua; Wu, Youe; Tang, Xinquan; Liu, Wei; Lan, Shiming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China)

2017-02-15

Highlights: • Nutrient beads of immobilized SRB were more effective in transforming heavy metals into the more stable bound phases. • Inner cohesive nutrient effectively promoted the stabilization process of heavy metals. • The excellent removal efficiencies of Cu, Zn, Pb and Cd were 76.3%, 95.6%, 100% and 91.2%, respectively. • Easy to recycle and avoid secondary pollution. - Abstract: A series of experiments were conducted for treating heavy metals contaminated sediments sampled from Xiangjiang River, which combined polyvinyl alcohol (PVA) and immobilized sulfate reducing bacteria (SRB) into beads. The sodium lactate was served as the inner cohesive nutrient. Coupling the activity of the SRB with PVA, along with the porous structure and huge specific surface area, provided a convenient channel for the transmission of matter and protected the cells against the toxicity of metals. This paper systematically investigated the stability of Cu, Zn, Pb and Cd and its mechanisms. The results revealed the performance of leaching toxicity was lower and the removal efficiencies of Cu, Zn, Pb and Cd were 76.3%, 95.6%, 100% and 91.2%, respectively. Recycling experiments showed the beads could be reused 5 times with superbly efficiency. These results were also confirmed by continuous extraction at the optimal conditions. Furthermore, X-ray diffraction (XRD) and energy-dispersive spectra (EDS) analysis indicated the heavy metals could be transformed into stable crystal texture. The stabilization of heavy metals was attributed to the carbonyl and acyl amino groups. Results presented that immobilized bacteria with inner nutrient were potentially and practically applied to multi-heavy-metal-contamination sediment.

Preparation of Ca-alginate coated nZVI core shell beads for uranium (VI) removal from aqueous solution

International Nuclear Information System (INIS)

Shuhong Hu; Xiaoyan Lin; Yahui Zhang; Meiling Shi

2017-01-01

In this study, the core-shell nanoscale zero-valent iron (nZVI)@Alg-Ca beads were synthesized by coaxial electronic injection method for removal of U (VI) from aqueous solution, and characterized by SEM, EDX and XPS. The results showed that the pseudo-second-order models and the Langmuir isotherm model fitted well with the data obtained. The removal mechanism may include both physical adsorption of U (VI) on the surface or inside of core-shell nZVI@Alg-Ca beads and subsequent reduction of U (VI) to U (IV). Therefore, the core-shell nZVI@Alg-Ca beads would have an application prospect in effective removal of U (VI) contamination from aqueous solution. (author)

Development and blood compatibility assessment of electrospun polyvinyl alcohol blended with metallocene polyethylene and plectranthus amboinicus (PVA/mPE/PA for bone tissue engineering

Directory of Open Access Journals (Sweden)

Qi J

2018-05-01

Full Text Available Jie Qi,1,* Huang Zhang,2,* Yingzhou Wang,3 Mohan Prasath Mani,4 Saravana Kumar Jaganathan5–7 1Department of Orthopedics, Shaanxi Provincial People’s Hospital, 2Department of Orthopedics, Han Zhong People’s Hospital, Han Zhong, Shaanxi Province, 3Beijing Meinuoyikang Health Food Co., Ltd, Beijing, People’s Republic of China; 4Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia; 5Department for Management of Science and Technology Development, 6Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam; 7IJN-UTM Cardiovascular Engineering Centre, Department of Clinical Sciences, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia *These authors contributed equally to this work Introduction: Currently, the design of extracellular matrix (ECM with nanoscale properties in bone tissue engineering is challenging. For bone tissue engineering, the ECM must have certain properties such as being nontoxic, highly porous, and should not cause foreign body reactions. Materials and methods: In this study, the hybrid scaffold based on polyvinyl alcohol (PVA blended with metallocene polyethylene (mPE and plectranthus amboinicus (PA was fabricated for bone tissue engineering via electrospinning. The fabricated hybrid nanocomposites were characterized by scanning electron microscopy (SEM, Fourier transform and infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, contact angle measurement, and atomic force microscopy (AFM. Furthermore, activated partial thromboplastin time (APTT, prothrombin time (PT, and hemolytic assays were used to investigate the blood compatibility of the prepared hybrid nanocomposites. Results: The prepared hybrid nanocomposites showed reduced fiber diameter (238±45 nm and also increased porosity (87% with decreased pore diameter (340±86 nm compared with pure PVA. The interactions between PVA, m

Capture of DNA in microfluidic channel using magnetic beads: increasing capture efficiency with integrated microfluidic mixer

DEFF Research Database (Denmark)

Lund-Olesen, Torsten; Dufva, Hans Martin; Hansen, Mikkel Fougt

2007-01-01

We have studied the hybridization of target DNA in solution with probe DNA on magnetic beads immobilized on the channel sidewalls in a magnetic bead separator. The hybridization is carried out under a liquid flow and is diffusion limited. Two systems are compared: one with a straight microfluidic...... place on the surface in a microfluidic system....

FT-IR study of gamma-radiation induced degradation of polyvinyl alcohol (PVA) and PVA/humic acids blends

International Nuclear Information System (INIS)

Ilcin, M.; Hola, O.; Bakajova, B.; Kucerik, J.

2010-01-01

Samples of pure polyvinyl alcohol (PVA) and PVA doped with humic acids were exposed to gamma radiation. Gamma rays induced the degradation of the pure polymer. Degradation changes were observed using ATR FT-IR equipment. Dehydration, double bond creation, and their subsequent oxidation (surrounding atmosphere was air) were found out. Also, other degradation reactions (e.g. chain scission, cyclization) occur simultaneously. Formation of C=C and C=O bonds is apparent from FT-IR spectra. In contrast the presence of humic acids in the PVA sample showed stabilizing effect on PVA structure within the concentration range 0.5-10%. (author)

Biomimetically Reinforced Polyvinyl Alcohol-Based Hybrid Scaffolds for Cartilage Tissue Engineering

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Hwan D. Kim

2017-11-01

Full Text Available Articular cartilage has a very limited regeneration capacity. Therefore, injury or degeneration of articular cartilage results in an inferior mechanical stability, load-bearing capacity, and lubrication capability. Here, we developed a biomimetic scaffold consisting of macroporous polyvinyl alcohol (PVA sponges as a platform material for the incorporation of cell-embedded photocrosslinkable poly(ethylene glycol diacrylate (PEGDA, PEGDA-methacrylated chondroitin sulfate (PEGDA-MeCS; PCS, or PEGDA-methacrylated hyaluronic acid (PEGDA-MeHA; PHA within its pores to improve in vitro chondrocyte functions and subsequent in vivo ectopic cartilage tissue formation. Our findings demonstrated that chondrocytes encapsulated in PCS or PHA and loaded into macroporous PVA hybrid scaffolds maintained their physiological phenotypes during in vitro culture, as shown by the upregulation of various chondrogenic genes. Further, the cell-secreted extracellular matrix (ECM improved the mechanical properties of the PVA-PCS and PVA-PHA hybrid scaffolds by 83.30% and 73.76%, respectively, compared to their acellular counterparts. After subcutaneous transplantation in vivo, chondrocytes on both PVA-PCS and PVA-PHA hybrid scaffolds significantly promoted ectopic cartilage tissue formation, which was confirmed by detecting cells positively stained with Safranin-O and for type II collagen. Consequently, the mechanical properties of the hybrid scaffolds were biomimetically reinforced by 80.53% and 210.74%, respectively, compared to their acellular counterparts. By enabling the recapitulation of biomimetically relevant structural and functional properties of articular cartilage and the regulation of in vivo mechanical reinforcement mediated by cell–matrix interactions, this biomimetic material offers an opportunity to control the desired mechanical properties of cell-laden scaffolds for cartilage tissue regeneration.

Interpenetrating network hydrogel membranes of sodium alginate and poly(vinyl alcohol) for controlled release of prazosin hydrochloride through skin.

Science.gov (United States)

Kulkarni, Raghavendra V; Sreedhar, V; Mutalik, Srinivas; Setty, C Mallikarjun; Sa, Biswanath

2010-11-01

Interpenetrating network (IPN) hydrogel membranes of sodium alginate (SA) and poly(vinyl alcohol) (PVA) were prepared by solvent casting method for transdermal delivery of an anti-hypertensive drug, prazosin hydrochloride. The prepared membranes were thin, flexible and smooth. The X-ray diffraction studies indicated the amorphous dispersion of drug in the membranes. Differential scanning calorimetric analysis confirmed the IPN formation and suggests that the membrane stiffness increases with increased concentration of glutaraldehyde (GA) in the membranes. All the membranes were permeable to water vapors depending upon the extent of cross-linking. The in vitro drug release study was performed through excised rat abdominal skin; drug release depends on the concentrations of GA in membranes. The IPN membranes extended drug release up to 24 h, while SA and PVA membranes discharged the drug quickly. The primary skin irritation and skin histopathology study indicated that the prepared IPN membranes were less irritant and safe for skin application. Copyright © 2010 Elsevier B.V. All rights reserved.

Properties of nanoclay PVA composites materials

Directory of Open Access Journals (Sweden)

Mohamed H. M. Ali

2012-03-01

Full Text Available Polyvinyl alcohol (PVA/ Na-rich Montmorillonite (MMT nanocomposites were prepared using solution method to create polymer-clay nanocomposite (PCN material. The PCN material was studied using X-ray diffraction (XRD, demonstrating polymer-clay intercalation that has a high d-spacing (lower diffraction angles in the PCN XRD pattern, compared to the pure MMT clay XRD pattern, which has a low d-spacing (high diffraction angles. The nano-scanning electron microscope (NSEM was used to study the morphological image of the PVA, MMT and PCN materials. The results showed that intercalation that took place between the PVA and MMT produced the PCN material. The mechanical properties of the pure PVA and the intercalated polymer material were studied. It was found that the small amount of MMT clay made the tensile modulus and percentage of the total elongation of the nano-composite significantly higher than the pure PVA polymer value, due to polymer-clay intercalation. The thermal stability of the intercalated polymer has been studied using thermal analytical techniques such as thermogravimetric analysis (TGA and differential scanning calorimetry (DSC. The results showed that the PCN material is more thermally stable than the pure PVA polymer.

Effect of crosslinking functionality on microstructure, mechanical properties, and in vitro cytocompatibility of cellulose nanocrystals reinforced poly (vinyl alcohol)/sodium alginate hybrid scaffolds.

Science.gov (United States)

Kumar, Anuj; Lee, Yujin; Kim, Doyeon; Rao, Kummara Madhusudana; Kim, Jisoo; Park, Soyoung; Haider, Adnan; Lee, Do Hyun; Han, Sung Soo

2017-02-01

Cellulose nanocrystals reinforced poly (vinyl alcohol)/sodium alginate hybrid scaffolds were fabricated by using freeze casting and freeze drying method. In this study, the effect of crosslinking agents such as calcium chloride, orthophosphoric acid, and borax on morphological, structural, thermal, mechanical, and cytocompatibility (cell adhesion and proliferation) properties was investigated. The results showed that the change in type of crosslinking agent significantly changed the properties of the hybrid scaffolds. Based on this study, borax-crosslinked hybrid scaffold showed good fibrous porous structure with high porosity (95.2%), highest water uptake capacity, good thermal stability, mechanical stability (storage modulus), and in vitro cell adhesion and proliferation with fibroblast (NIH3T3) cells. This primarily research study explores the way for further use of this crosslinking agent to design and fabricate scaffolds for tissue engineering applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Recovery of uranium from phosphoric acid medium by polymeric composite beads encapsulating organophosphorus extractants

Energy Technology Data Exchange (ETDEWEB)

Singh, D.K.; Yadav, K.K.; Varshney, L.; Singh, H. [Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2013-07-01

The present study deals with the preparation and evaluation of the poly-ethersulfone (PES) based composite beads encapsulating synergistic mixture of D2EHPA and Cyanex 923 (at 4:1 mole ratio) for the separation of uranium from phosphoric acid medium. SEM was used for the characterization of the composite materials. Addition of 1% PVA (polyvinyl alcohol) improved the internal morphology and porosity of the beads. Additionally, microscopic examination of the composite bead confirmed central coconut type cavity surrounded by porous polymer layer of the beads through which exchange of metal ions take place. Effect of various experimental variables including aqueous acidity, metal ion concentration in aqueous feed, concentration of organic extractant inside the beads, extractant to polymer ratio, liquid to solid (L/S) ratio and temperature on the extraction of uranium was studied. Increase in acidity (1-6 M), L/S ratio (1- 10), metal ion concentration (0.2-3 g/L U{sub 3}O{sub 8}) and polymer to extractant ratio (1:4 -1:10) led to decrease in extraction of uranium. At 5.5 M (comparable to wet process phosphoric acid concentration) the extraction of uranium was about 85% at L/S ratio 5. Increase in extractant concentration inside the bead resulted in enhanced extraction of metal ion. Increase in temperature in the range of 30 to 50 Celsius degrees increased the extraction, whereas further increase to 70 C degrees led to the decrease in extraction of uranium. Amongst various reagents tested, stripping of uranium was quantitative by 12% Na{sub 2}CO{sub 3} solution. Polymeric beads were found to be stable and reusable up-to 10 cycles of extraction/stripping. (authors)

Efficient simultaneous removal of U(VI) and Cu(II) from aqueous solution using core-shell nZVI@SA/CMC-Ca beads

International Nuclear Information System (INIS)

Shuhong Hu; Xiaoyan Lin; Wenhui Zhao; Ministry of Education, Sichuan; Xuegang Luo

2018-01-01

Core-shell nanoscale zero-valent iron@alginate/carboxymethyl cellulose sodium composite loaded with calcium (nZVI@SA/CMC-Ca) beads were synthesized in this study using coaxial electronic injection method. The adsorbent structure was characterized via FT-IR, SEM, EDX and XPS. The adsorption behavior of U(VI) and Cu(II) on core-shell nZVI@SA/CMC-Ca beads was studied under various experimental parameters like pH, contact time and temperature. The isotherm and the kinetic data, pertaining to the adsorption of U(VI) and Cu(II) by core-shell nZVI@SA/CMC-Ca beads obeyed both the Langmuir and Freundlich isotherms model and the pseudo-second-order kinetics model, respectively. The thermodynamic parameters revealed the spontaneous and endothermic nature of the adsorption. The experiment of regeneration and reusability suggested core-shell nZVI@SA/CMC-Ca bead was a regenerated material. (author)

Development of a PCR/LDR/flow-through hybridization assay using a capillary tube, probe DNA-immobilized magnetic beads and chemiluminescence detection.

Science.gov (United States)

Hommatsu, Manami; Okahashi, Hisamitsu; Ohta, Keisuke; Tamai, Yusuke; Tsukagoshi, Kazuhiko; Hashimoto, Masahiko

2013-01-01

A polymerase chain reaction (PCR)/ligase detection reaction (LDR)/flow-through hybridization assay using chemiluminescence (CL) detection was developed for analyzing point mutations in gene fragments with high diagnostic value for colorectal cancers. A flow-through hybridization format using a capillary tube, in which probe DNA-immobilized magnetic beads were packed, provided accelerated hybridization kinetics of target DNA (i.e. LDR product) to the probe DNA. Simple fluid manipulations enabled both allele-specific hybridization and the removal of non-specifically bound DNA in the wash step. Furthermore, the use of CL detection greatly simplified the detection scheme, since CL does not require a light source for excitation of the fluorescent dye tags on the LDR products. Preliminary results demonstrated that this analytical system could detect both homozygous and heterozygous mutations, without the expensive instrumentation and cumbersome procedures required by conventional DNA microarray-based methods.

Alginate-polyvinyl alcohol based interpenetrating polymer network for prolonged drug therapy, Optimization and in-vitro characterization.

Science.gov (United States)

Anwar, Hina; Ahmad, Mahmood; Minhas, Muhammad Usman; Rehmani, Sahrish

2017-06-15

A new natural and synthetic polymeric blend to form interpenetrating polymer network (IPN) hydrogels was synthesized utilizing sodium alginate and PVA as polymers by free radical polymerization employing 2-Acylamido-2-methylpropane-sulfonic acid as monomer (AMPS) and tramadol HCl as model drug through 3 2 level full factorial design to evaluate the impact of selected independent factors i.e. polymer (sodium alginate) and monomer (AMPS) contents on swelling index at 18th hour, percent drug release at 18th hour, time required for 80% drug release and drug entrapment efficiency as dependent variables. FTIR, SEM, sol-gel analysis, equilibrium swelling studies and in-vitro release kinetics were performedfor in-vitro characterization of formulated IPN hydrogels. In-vitro studies carried out at pH 1.2 and pH 7.4 revealed pH independent swelling and drug release from polymeric IPN, providing controlled drug release for an extended period of time with improved entrapment efficiency, thereby concluding that this polymeric blend may be a promising system for the prolonged drug delivery. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sodium alginate-polyvinyl alcohol-bovin serum albumin coated Fe3O4 nanoparticles as anticancer drug delivery vehicle: Doxorubicin loading and in vitro release study and cytotoxicity to HepG2 and L02 cells.

Science.gov (United States)

Prabha, G; Raj, V

2017-10-01

The challenging part of this work was to research the potential aspects of sodium alginate (SA)-polyvinyl alcohol (PVA)-bovin serum albumin (BSA) coated Fe 3 O 4 nanoparticles (Fe 3 O 4 -SA-PVA-BSA) as a drug delivery system for doxorubicin (DOX). The anticancer drug doxorubicin was selected as a model drug which is powerful for numerous cancer treatments. Superparamagnetic Fe 3 O 4 nanoparticles were prepared by co-precipitation method. The mixture solution of Fe 3 O 4 -sodium alginate (SA) - doxorubicin (DOX) was crosslinked with Ca 2+ to form (Fe 3 O 4 -SA-DOX) nanoparticles and addition of PVA and BSA with (Fe 3 O 4 -SA-DOX) nanoparticles was prepared by coating procedure. Doxorubicin drug loaded NPs were prepared by a simple crosslinking method by calcium chloride solution. The prepared polymer coated magnetic nanoparticles (Fe 3 O 4 -SA-PVA-BSA) were characterized by using SEM, AFM, FT-IR, XRD and VSM. The mean sizes of the obtained drug loaded nanoparticles (Fe 3 O 4 -SA-DOX, Fe 3 O 4 -SA-DOX-PVA and Fe 3 O 4 -SA-DOX-PVA-BSA) were between 240±8.3 and 460±8.7nm and zeta potential of the particles also was evaluated using Malvern Zetasizer which ranged between -48.1±2.3 and -22.4±4.1mV. The encapsulation efficiency, was between 36.2±0.01 and 96.45±2.12. Moreover drug loading and drug release properties of the polymer coated magnetic nanoparticles loaded with doxorubicin (Fe 3 O 4 -SA-DOX-PVA-BSA) were also studied. In addition, the cytotoxicity of the created nanoparticles was performed by using MTT assay analysis which showed that DOX loaded nanoparticles (Fe 3 O 4 -SA-DOX-PVA-BSA) were toxic to HepG2 cell lines and non-toxic to L02 cell lines. The in-vitro drug release was studied by using UV-Visible spectrophotometer at acidic environment (pH5.0) and basic environment (pH7.4) as well as at different temperatures (37°C and 42°C). It was found that DOX drug is released much faster in acidic environment (pH5.0) than in the basic environment (pH7

Core drilling of drillholes ONK-PVA9 and ONK-PVA10 in ONKALO at Olkiluoto 2011

Energy Technology Data Exchange (ETDEWEB)

Toropainen, V. [Suomen Malmi Oy, Espoo (Finland)

2011-10-15

Suomen Malmi Oy (Smoy) core drilled two drillholes for groundwater monitoring stations in ONKALO at Eurajoki, Olkiluoto in 2011. The groundwater monitoring stations are used for monitoring changes in groundwater conditions. The drillhole ONK-PVA9 was drilled in March 2011 and the drillhole ONK-PVA10 in June 2011. The lengths of the drillholes are 15.95 and 20.10 m respectively. The drillholes are 75.7 mm by diameter. The drillhole ONK-PVA9 was drilled in a niche of the access tunnel at chainage 4366 and the ONK-PVA10 in the access tunnel wall at chainage 3851. The hydraulic DE 130 drilling rig was used. The drilling water was taken from the ONKALO drilling water pipeline and premixed sodium fluorescein was used as a label agent in the drilling water. The drillholes were measured with EMS deviation survey tool. In addition to drilling the drillcores were logged and reported by geologist. Geological logging included the following parameters: lithology, foliation, fracture parameters, fractured zones, core loss, weathering, fracture frequency, RQD and rock quality. The main rock types in the drillholes are veined gneiss and pegmatitic granite. The average fracture frequencies in drill cores are 2.9 pcs/m (ONK-PVA9) and 2.3 pcs/m (ONK-PVA10) and the average RQD values 81.6 % and 96.2 % respectively. (orig.)

Entrapment of active ion-permeable cyanobacteria (Anacystis nidulans) in calcium alginate

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Papageorgiou, G.C.; Kalosaka, K.; Sotiropoulou, G.; Barbotin, J.N.; Thomasset, B.; Thomas, T.

1988-12-01

Cells of the unicellular cyanobacterium Anacystis nidulans were made permeable to ions by treating them with lysozyme and EDTA in a way that leaves the photosynthetic water-splitting function, the photoreduction of exogenous oxidants and the peptidoglycan exoskeleton of the cell virtually intact. The permeabilized cells (permeaplasts) were subsequently immobilized by entrapment in calcium alginate beads. The immobilized preparation exhibits remarkable stability both on storage and in action. On prolonged storage at room temperature in darkness, its photosynthetic activity deteriorates one-third as fast as the activity of immobilized intact cells. Illumination accelerates deactivation. Tested in prolonged runs, however, performed in an illuminated open reactor, alginate-immobilized Anacystis permeaplasts were capable of photoreducing ionic oxidants (ferricyanide) and of exporting ionic reductants (ferrocyanide) to the suspension medium continuously for more than 5 h before being totally inactivated. It is also shown that the major impediment to the photoreduction performance of immobilized permeaplasts arises from diffusion limitations, while the photonic limitation due to light reflection and scattering is approx. 7%.

Enhancement of osteoblastic differentiation in alginate gel beads with bioactive octacalcium phosphate particles

International Nuclear Information System (INIS)

Endo, Kosei; Anada, Takahisa; Suzuki, Osamu; Yamada, Masumi; Seki, Minoru; Sasaki, Keiichi

2015-01-01

The present study investigated whether alginate (Alg) hydrogel microbeads have a role in maintaining mouse bone marrow stromal ST-2 cells and release the cells after being stimulated by synthetic octacalcium phosphate (OCP), which is a mineral crystal capable of stimulating osteoblastic differentiation during a conversion process to hydroxyapatite (HA). The ST-2 cell suspension in the alginate solution, which contained various concentrations of OCP granules with diameters less than 53 μm, was extruded drop-wise into a stirred gelation solution containing BaCl 2 using an encapsulator with nitrogen gas stream. The Alg-microbeads (Alg/OCP · ST-2 microbeads) that were generated, which had a diameter of approximately 400 μm, were incubated for up to 14 d and then assessed for osteoblastic differentiation. Alg-microbeads with cells were also incubated to identify the possible conversion from OCP to HA. Osteoblast differentiation markers in ST-2 cells, alkaline phosphatase (ALP) and collagen type I, were up-regulated in the presence of higher amounts of OCP. X-ray diffraction analysis and Fourier transform infrared spectroscopy confirmed that the OCP tended to convert to HA over time, suggesting that the OCP in Alg-microbeads interacts three-dimensionally with ST-2 cells and stimulates its osteoblastic differentiation. The release of ST-2 cells from the microbeads was also estimated. ST-2 cells were identified outside of the microbeads, although the cell number tended to decrease with increasing OCP. These results suggest that Alg/OCP microbeads could be used as a vehicle to activate osteoblastic cells and deliver them to sites where bone regeneration is needed. (paper)

Mechanical Behavior of Nanostructured Hybrids Based on Poly(Vinyl Alcohol/Bioactive Glass Reinforced with Functionalized Carbon Nanotubes

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H. S. Mansur

2012-01-01

Full Text Available This study reports the synthesis and characterization of novel tridimensional porous hybrids based on PVA combined with bioactive glass and reinforced by chemically functionalized carbon nanotubes (CNT for potential use in bone tissue engineering. The functionalization of CNT was performed by introducing carboxylic groups in multiwall nanotubes. This process aimed at enhancing the affinity of CNTs with the water-soluble PVA polymer derived by the hydrogen bonds formed among alcohol (PVA and carboxylic groups (CNT–COOH. In the sequence, the CNT–COOH (0.25 wt% were used as the nanostructure modifier for the hybrid system based on PVA associated with the bioactive glass (BaG. The mechanical properties of the nanostructured hybrids reinforced with CNT–COOH were evaluated by axial compression tests, and they were compared to reference hybrid. The averaged yield stresses of macroporous hybrids were (2.3 ± 0.9 and (4.4 ± 1.0 MPa for the reference and the CNT reinforced materials, respectively. Moreover, yield strain and Young's modulus were significantly enhanced by about 30% for the CNT–COOH hybrids. Hence, as far as the mechanical properties are concerned, the results have clearly showed the feasibility of utilizing these new hybrids reinforced with functionalized CNT in repairing cancellous bone tissues.

Removal of Uranium and Associated Contaminants from Aqueous Solutions Using Functional Carbon Nanotubes-Sodium Alginate Conjugates

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Hussein Allaboun

2016-02-01

Full Text Available Synthesis of hydrophilic/hydrophobic beads from functional carbon nanotubes (CNTs conjugated with sodium alginate was investigated. Glutaraldehyde was used as a coupling agent and Ca2+ as a crosslinking agent. The formed conjugate comprises two-dimensional sheets of sodium alginate bounded to long tufts of functional CNT tails of micro-size geometry. Detailed characterization of the conjugates was performed using thermogravimetric analysis (TGA and its first derivative (DTG, Fourier transform infrared (FTIR, and scanning electron microscope (SEM techniques. Different ratios of the conjugate were successfully prepared and used as biodegradable environmentally friendly sorbents. Removal of U6+, V3+, Cr3+, Mo3+, Pb2+, Mn2+, Cu2+, Ti4+ and Ni2+ from aqueous solutions using the synthesized biosorbent was experimentally demonstrated. Maximum metal uptake of 53 mg/g was achieved using the % Functional CNTs = 33 sample.

Cellulose Derivatives Enhanced Stability of Alginate-Based Beads Loaded with Lactobacillus plantarum LAB12 against Low pH, High Temperature and Prolonged Storage.

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Fareez, Ismail M; Lim, Siong Meng; Zulkefli, Nurul Aida Ashyqin; Mishra, Rakesh K; Ramasamy, Kalavathy

2017-05-10

The susceptibility of probiotics to low pH and high temperature has limited their use as nutraceuticals. In this study, enhanced protection of probiotics via microencapsulation was achieved. Lactobacillus plantarum LAB12 were immobilised within polymeric matrix comprised of alginate (Alg) with supplementation of cellulose derivatives (methylcellulose (MC), sodium carboxymethyl cellulose (NaCMC) or hydroxypropyl methylcellulose (HPMC)). L. plantarum LAB12 encapsulated in Alg-HPMC(1.0) and Alg-MC(1.0) elicited improved survivability (91%) in simulated gastric conditions and facilitated maximal release (∼100%) in simulated intestinal condition. Alg-HPMC(1.0) and Alg-MC(1.0) significantly reduced (P 7 log CFU g -1 . Alg-MC and Alg-HPMC improved the survival of LAB12 against simulated gastric condition (9.24 and 9.55 log CFU g -1 , respectively), temperature up to 90 °C (9.54 and 9.86 log CFU g -1 , respectively) and 4-week of storage at 4 °C (8.61 and 9.23 log CFU g -1 , respectively) with sustained release of probiotic in intestinal condition (>9 log CFU g -1 ). These findings strongly suggest the potential of cellulose derivatives supplemented Alg bead as protective micro-transport for probiotic strains. They can be safely incorporated into new functional food or nutraceutical products.

Preparation, characterization and in vitro evaluation of a polyvinyl alcohol/sodium alginate based orodispersible film containing sildenafil citrate.

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Shi, Li-Li; Xu, Wei-Juan; Cao, Qing-Ri; Yang, Mingshi; Cui, Jing-Hao

2014-05-01

In this work, we developed a sildenafil citrate (SC)-loaded polyvinyl alcohol (PVA)/sodium alginate (ALG-Na) based orodispersible film (ODF) using a solvent casting method. Formulation factors such as the type and amount of plasticizers and disintegrants were optimized on the basis of characteristics of blank ODF, including the disintegration time, elastic modulus (EM) and percentage of elongation (E%). SC-loaded ODF with a loading capacity up to 25 mg in an area of 6 cm2 was prepared and evaluated in terms of mechanical properties, disintegration time and dissolution rate. The surface morphology of ODF was visualized under a scanning electron microscope (SEM). The physicochemical properties of ODF were investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The blank ODF composed of PVA, polyethylene glycol 400 (PEG 400) and ALG-Na (20:5:2, w/w) had a remarkably short disintegration time of about 20 s. However, the loading of drug extended the disintegration time (100 s) of ODF, while it still maintained satisfactory mechanical properties. SC was homogenously dispersed throughout the films and the crystalline form of drug changed, with strong hydrogen bonding between the drug and carriers. The PVA/ALG-Na based ODF containing SC prepared by the simple solvent casting method might be an alternative to conventional SC tablets for the treatment of male erectile dysfunction.

Transparent and Printable Regenerated Kenaf Cellulose/PVA Film

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Hatika Kaco

2014-02-01

Full Text Available Cellulose was extracted from kenaf core powder by a series of bleaching processes and subsequently dissolved using an alkaline LiOH/urea solvent at low temperatures. The produced cellulose solution was mixed with polyvinyl alcohol (PVA with different ratios of cellulose/PVA and coagulated to produce regenerated transparent films. The films were then air dried to produce transparent film. The effects of PVA content on tensile index, transparency, pore size, and printability of the films were studied. A slight reduction of 7% on the tensile index of the film was observed when the content of PVA increased to 10%. Nevertheless, the addition of 10% of PVA increased the porosity of the regenerated cellulose/PVA film, while the transparency of the film increased by 10%. The films were color-printed using a laser printer and can be recycled, in which the printed ink can be removed easily from the films with higher amount of PVA content. In addition, the films can be reprinted repeatedly several times.

Biodegradation of blend films PVA/PVC, PVA/PCL in soil and soil with landfill leachate

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Adriana de Campos

2011-12-01

Full Text Available This study investigated the biodegradation of blends films of poly(vinyl alcohol/poly(vinyl chloride (PVA/PVC and poly(vinyl alcohol/poly(caprolactone (PVA/PCL blends films prepared with dimethylformamide under a variety of conditions by respirometry, spectrophotometry (FTIR, scanning electron microscopy (SEM, and contact angle. The films were buried in the garden soil and in the soil mixed with the landfill leachate for 120 days at 28ºC. Significant levels of biodegradation were achieved in fairly short incubation times in the soil. The results indicated that PVA was the most biodegradable film in the soil and in the soil with the leachate.

Radiation preparation of graphene/carbon nanotubes hybrid fillers for mechanical reinforcement of poly(vinyl alcohol) films

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Ma, Hui-Ling; Zhang, Long; Zhang, Youwei; Wang, Shuojue; Sun, Chao; Yu, Hongyan; Zeng, Xinmiao; Zhai, Maolin

2016-01-01

Graphene/carbon nanotubes (G/CNTs) hybrid fillers were synthesized by γ-ray radiation reduction of graphene oxide (GO) in presence of CNTs. The obtained hybrid fillers with three-dimensional (3D) interconnected network structure were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Poly(vinyl alcohol) (PVA) composite films with enhanced mechanical properties and thermal stability were subsequently prepared by solution blending of G/CNTs with PVA matrix. The tensile strength and Young's modulus of PVA composite films containing 1 wt% G/CNTs were measured to be 81.9 MPa and 3.9 GPa respectively, which were 56% and 33.6% higher than those of pure PVA. These substantial improvements could be attributed to the interconnected 3D structure of G/CNTs, homogeneous dispersion as well as the strong hydrogen-bonding interaction between G/CNTs and PVA macromolecular chains.

An additive manufacturing-based PCL-alginate-chondrocyte bioprinted scaffold for cartilage tissue engineering.

Science.gov (United States)

Kundu, Joydip; Shim, Jin-Hyung; Jang, Jinah; Kim, Sung-Won; Cho, Dong-Woo

2015-11-01

Regenerative medicine is targeted to improve, restore or replace damaged tissues or organs using a combination of cells, materials and growth factors. Both tissue engineering and developmental biology currently deal with the process of tissue self-assembly and extracellular matrix (ECM) deposition. In this investigation, additive manufacturing (AM) with a multihead deposition system (MHDS) was used to fabricate three-dimensional (3D) cell-printed scaffolds using layer-by-layer (LBL) deposition of polycaprolactone (PCL) and chondrocyte cell-encapsulated alginate hydrogel. Appropriate cell dispensing conditions and optimum alginate concentrations for maintaining cell viability were determined. In vitro cell-based biochemical assays were performed to determine glycosaminoglycans (GAGs), DNA and total collagen contents from different PCL-alginate gel constructs. PCL-alginate gels containing transforming growth factor-β (TGFβ) showed higher ECM formation. The 3D cell-printed scaffolds of PCL-alginate gel were implanted in the dorsal subcutaneous spaces of female nude mice. Histochemical [Alcian blue and haematoxylin and eosin (H&E) staining] and immunohistochemical (type II collagen) analyses of the retrieved implants after 4 weeks revealed enhanced cartilage tissue and type II collagen fibril formation in the PCL-alginate gel (+TGFβ) hybrid scaffold. In conclusion, we present an innovative cell-printed scaffold for cartilage regeneration fabricated by an advanced bioprinting technology. Copyright © 2013 John Wiley & Sons, Ltd.

Preparation and Characterization of Azadirachtin Alginate-Biosorbent Based Formulations: Water Release Kinetics and Photodegradation Study.

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Flores-Céspedes, Francisco; Martínez-Domínguez, Gerardo P; Villafranca-Sánchez, Matilde; Fernández-Pérez, Manuel

2015-09-30

The botanical insecticide azadirachtin was incorporated in alginate-based granules to obtain controlled release formulations (CRFs). The basic formulation [sodium alginate (1.47%) - azadirachtin (0.28%) - water] was modified by the addition of biosorbents, obtaining homogeneous hybrid hydrogels with high azadirachtin entrapment efficiency. The effect on azadirachtin release rate caused by the incorporation of biosorbents such as lignin, humic acid, and olive pomace in alginate formulation was studied by immersion of the granules in water under static conditions. The addition of the biosorbents to the basic alginate formulation reduces the rate of release because the lignin-based formulation produces a slower release. Photodegradation experiments showed the potential of the prepared formulations in protecting azadirachtin against simulated sunlight, thus improving its stability. The results showed that formulation prepared with lignin provided extended protection. Therefore, this study provides a new procedure to encapsulate the botanical insecticide azadirachtin, improving its delivery and photostability.

Enhanced production of alkaline thermostable keratinolytic protease from calcium alginate immobilized cells of thermoalkalophilic Bacillus halodurans JB 99 exhibiting dehairing activity.

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Shrinivas, Dengeti; Kumar, Raghwendra; Naik, G R

2012-01-01

The thermoalkalophilic Bacillus halodurans JB 99 cells known for production of novel thermostable alkaline keratinolytic protease were immobilized in calcium alginate matrix. Batch and repeated batch cultivation using calcium alginate immobilized cells were studied for alkaline protease production in submerged fermentation. Immobilized cells with 2.5% alginate and 350 beads/flask of initial cell loading showed enhanced production of alkaline protease by 23.2% (5,275 ± 39.4 U/ml) as compared to free cells (4,280 ± 35.4 U/ml) after 24 h. In the semicontinuous mode of cultivation, immobilized cells under optimized conditions produced an appreciable level of alkaline protease in up to nine cycles and reached a maximal value of 5,975 U/ml after the seventh cycle. The enzyme produced from immobilized cells efficiently degraded chicken feathers in the presence of a reducing agent which can help the poultry industry in the management of keratin-rich waste and obtaining value-added products.

Role of Lactobacillus acidophilus loaded floating beads in chronic fatigue syndrome: behavioral and biochemical evidences.

Science.gov (United States)

Singh, P K; Chopra, K; Kuhad, A; Kaur, I P

2012-04-01

  In recent years the interface between neuropsychiatry and gastroenterology has converged in to a new discipline referred to as enteric neuroscience. Implications of brain-gut communication in the pathogenesis of psychiatric disorders indicate a possible role of suitably packaged/delivered probiotics as newer therapeutic options. In the present study probable role of per-oral administration of free Lactobacillus acidophilus (LAB) and LAB loaded alginate beads in attenuation of the symptoms associated with chronic fatigue syndrome (CFS) were evaluated.   Chronic fatigue syndrome following physical fatigue was induced in rats by forcing them to swim (forced swim test; FST) in water till exhaustion, after weighing them down with 10% their body weight, daily for 28 days. Immobility (I) and postswim fatigue time (PSF) were taken as suitable markers. Free LAB and LAB loaded floating beads (FBs) were administered, from 21 to 28 days.   Immobility and PSF were found to increase considerably in FST rats (665 ± 22 s and 196 ± 6 s) as compared with the naïve (32 ± 7 s and 22 ± 2 s) at 20 days, establishing severe fatigue like behavior. FST control group exhibited significant (P < 0.05) hypertrophy of spleen, hypotrophy of thymus, and increased oxido-nitrosative stress in brain and tumor necrosis factor-α (TNF-α) levels in serum. Treatment with LAB and LAB FBs significantly decreased I and PSF and attenuated (P < 0.05) oxido-nitrosative stress and TNF-α levels. Spleen and thymus were also restored to their original size in this group.   The findings suggest a valuable therapeutic role of LAB especially when incorporated into alginate beads for the treatment of CFS. © 2012 Blackwell Publishing Ltd.

Processing and characterization of chitosan/PVA and methylcellulose porous scaffolds for tissue engineering

International Nuclear Information System (INIS)

Kanimozhi, K.; Khaleel Basha, S.; Sugantha Kumari, V.

2016-01-01

Biomimetic porous scaffold chitosan/poly(vinyl alcohol) CS/PVA containing various amounts of methylcellulose (MC) (25%, 50% and 75%) incorporated in CS/PVA blend was successfully produced by a freeze drying method in the present study. The composite porous scaffold membranes were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), swelling degree, porosity, degradation of films in Hank's solution and the mechanical properties. Besides these characterizations, the antibacterial activity of the prepared scaffolds was tested, toward the bacterial species Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). FTIR, XRD and DSC demonstrated that there was strong intermolecular hydrogen bonding between the molecules of CS/PVA and MC. The crystalline microstructure of the scaffold membranes was not well developed. SEM images showed that the morphology and diameter of the scaffolds were mainly affected by the weight ratio of MC. By increasing the MC content in the hybrid scaffolds, their swelling capacity and porosity increased. The mechanical properties of these scaffolds in dry and swollen state were greatly improved with high swelling ratio. The elasticity of films was also significantly improved by the incorporation of MC, and the scaffolds could also bear a relative high tensile strength. These findings suggested that the developed scaffold possess the prerequisites and can be used as a scaffold for tissue engineering. - Highlights: • The porous scaffolds of CS/PVA containing different MC contents were fabricated. • Addition of MC improved the compatibility between CS and PVA. • The mechanical properties of these scaffolds were greatly improved with high swelling ratio. • Biocompatibility test showed that the different MC content scaffolds had no cytotoxicity.

Processing and characterization of chitosan/PVA and methylcellulose porous scaffolds for tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Kanimozhi, K. [Department of Chemistry, Auxilium College, Vellore 632 006 (India); Khaleel Basha, S. [Department of Biochemistry, C. Abdul Hakeem College, Melvisharam 632 509 (India); Sugantha Kumari, V., E-mail: sheenasahana04@gmail.com [Department of Chemistry, Auxilium College, Vellore 632 006 (India)

2016-04-01

Biomimetic porous scaffold chitosan/poly(vinyl alcohol) CS/PVA containing various amounts of methylcellulose (MC) (25%, 50% and 75%) incorporated in CS/PVA blend was successfully produced by a freeze drying method in the present study. The composite porous scaffold membranes were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), swelling degree, porosity, degradation of films in Hank's solution and the mechanical properties. Besides these characterizations, the antibacterial activity of the prepared scaffolds was tested, toward the bacterial species Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). FTIR, XRD and DSC demonstrated that there was strong intermolecular hydrogen bonding between the molecules of CS/PVA and MC. The crystalline microstructure of the scaffold membranes was not well developed. SEM images showed that the morphology and diameter of the scaffolds were mainly affected by the weight ratio of MC. By increasing the MC content in the hybrid scaffolds, their swelling capacity and porosity increased. The mechanical properties of these scaffolds in dry and swollen state were greatly improved with high swelling ratio. The elasticity of films was also significantly improved by the incorporation of MC, and the scaffolds could also bear a relative high tensile strength. These findings suggested that the developed scaffold possess the prerequisites and can be used as a scaffold for tissue engineering. - Highlights: • The porous scaffolds of CS/PVA containing different MC contents were fabricated. • Addition of MC improved the compatibility between CS and PVA. • The mechanical properties of these scaffolds were greatly improved with high swelling ratio. • Biocompatibility test showed that the different MC content scaffolds had no cytotoxicity.

Physicochemical characterization and biocompatibility of alginate-polycation microcapsules designed for islet transplantation

Science.gov (United States)

Tam, Susan Kimberly

diabetic mice. To achieve these aims, extensive physicochemical analyses of the alginates and microcapsules were carried out. Among the properties of the alginates that were investigated include their purity (LAL assay, microBCA), chemical composition (nuclear magnetic resonance, NMR), elemental composition (x-ray photoelectron spectroscopy, XPS), and hydrophilicity (contact angle technique). As for the microcapsules, we also examined their surface chemical composition (XPS), hydrophilicity, as well as alginate-polycation interactions (Fourier transform infrared spectroscopy, FTIR), and membrane strength (osmotic swelling). The results of this research led to a number of important conclusions about the biocompatibility of alginates and alginate-based microcapsules. First of all, purifying an alginate does not guarantee its biocompatibility. Indeed, we provided evidence that both the alginate chemical composition (i.e. relative content of mannuronate and guluronate) and its intrinsic viscosity influence the extent of host cell adhesion to alginate gel beads. Using a biocompatible alginate, we then provided evidence that microcapsule biocompatibility is greatly compromised by its polycationic membrane. We showed that this membrane is responsible for the adsorption of opsonizing proteins in vitro and the adhesion of immune cells in vivo. That said, the severity of inflammatory response to the membrane can vary, and this depended on the microcapsule design, including the choice of alginate and polycation type. Results of our physicochemical analyses suggested that the most important factor determining biocompatibility is the ability of the polycation to diffuse into, and subsequently bind to, the alginate gel core. Moreover, adding a final coating of alginate had no significant effect on reversing the effects of the membrane on various microcapsule properties (surface composition, hydrophobicity, stability), nor did this coating reduce its immunogenicity. Although we

Optimization and spectroscopic studies on carbon nanotubes/PVA nanocomposites

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Naziha Suliman Alghunaim

Full Text Available Nanocomposite films of polyvinyl alcohol (PVA containing constant ratio of both single and multi-wall carbon nanotubes had been obtained by dispersion techniques and were investigated by different techniques. The infrared spectrum confirmed that SWNTs and MWNTs have been covalently related OH and CC bonds within PVA. The X-ray diffraction indicated lower crystallinity after the addition of carbon nanotubes (CNTs due to interaction between CNTs and PVA. Transmission electron microscope (TEM illustrated that SWNTs and MWNTs have been dispersed into PVA polymeric matrix and it wrapped with PVA. The properties of PVA were enhanced by the presence of CNTs. TEM images show uniform distribution of CNTs within PVA and a few broken revealing that CNTs broke aside as opposed to being pulled out from fracture surface which suggests an interfacial bonding between CNTs and PVA. Maximum value of AC conductivity was recorded at higher frequencies. The behavior of both dielectric constant (ɛ′ and dielectric loss (ɛ″ were decreased when frequency increased related to dipole direction within PVA films to orient toward the applied field. At higher frequencies, the decreasing trend seems nearly stable as compared with lower frequencies related to difficulty of dipole rotation. Keywords: CNTs, XRD, TEM, AC conductivity

Enhancement of survival of alginate-encapsulated Lactobacillus casei NCDC 298.

Science.gov (United States)

Mandal, Surajit; Hati, Subrota; Puniya, Anil Kumar; Khamrui, Kaushik; Singh, Kishan

2014-08-01

Micro-encapsulation of hydrocolloids improves the survival of sensitive probiotic bacteria in the harsh conditions that prevail in foods and during gastrointestinal passage by segregating them from environments. Incorporation of additives in encapsulating hydrocolloids and coatings of microcapsules further improves the survival of the probiotics. In this study, the effect of incorporation of resistant-maize starch in alginate for micro-encapsulation and coating of microcapsules with poly-l-lysine, stearic acid and bees wax on the survival of encapsulated Lactobacillus casei NCDC 298 at pH 1.5, 2% high bile salt, 65 °C for 20 min and release of viable lactobacilli cells from the capsule matrix in simulated aqueous solutions of colonic pH were assessed. Addition of resistant maize starch (2%) improved the survival of encapsulated L. casei NCDC 298. Coating of microcapsules with poly-L-lysine did not further improve the protection of encapsulated cells from the harsh conditions; however, bees wax and stearic acid (2%) improved the survival under similar conditions. Incorporation of maize starch (2%) in alginate followed by coating of beads with stearic acid (2%) led to better protection and complete release of entrapped lactobacilli in simulated colonic pH solution was observed. Additional treatments improve the survival of alginate-encapsulated lactobacilli cells without hindering the release of active cells from the capsule matrix and hence, the resulting encapsulated probiotics can be exploited in the development of probiotic functional foods with better survival of sensitive probiotic organisms. © 2013 Society of Chemical Industry.

Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water

Energy Technology Data Exchange (ETDEWEB)

Jin Jing [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Yang Lihua [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Chan, Sidney M.N. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Luan Tiangang, E-mail: cesltg@mail.sysu.edu.cn [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong); Li Yan [MOE Key Laboratory of Aquatic Product Safety, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Tam, Nora F.Y., E-mail: bhntam@cityu.edu.hk [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon (Hong Kong)

2011-01-30

The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency.

Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water.

Science.gov (United States)

Jin, Jing; Yang, Lihua; Chan, Sidney M N; Luan, Tiangang; Li, Yan; Tam, Nora F Y

2011-01-30

The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency. Copyright © 2010 Elsevier B.V. All rights reserved.

Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water

International Nuclear Information System (INIS)

Jin Jing; Yang Lihua; Chan, Sidney M.N.; Luan Tiangang; Li Yan; Tam, Nora F.Y.

2011-01-01

The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency.

Polyionic hydrocolloids for the intestinal delivery of protein drugs: alginate and chitosan--a review.

Science.gov (United States)

George, Meera; Abraham, T Emilia

2006-08-10

The protein pharmaceutical market is rapidly growing, since it is gaining support from the recombinant DNA technology. To deliver these drugs via the oral route, the most preferred route, is the toughest challenge. In the design of oral delivery of peptide or protein drugs, pH sensitive hydrogels like alginate and chitosan have attracted increasing attention, since most of the synthetic polymers are immunogenic and the incorporation of proteins in to these polymers require harsh environment which may denature and inactivate the desired protein. Alginate is a water-soluble linear polysaccharide composed of alternating blocks of 1-4 linked alpha-L-guluronic and beta-D-mannuronic acid residues where as chitosan is a co polymer of D-glucosamine and N-acetyl glucosamine. The incorporation of protein into these two matrices can be done under relatively mild environment and hence the chances of protein denaturation are minimal. The limitations of these polymers, like drug leaching during preparation can be overcome by different techniques which increase their encapsulation efficiency. Alginate, being an anionic polymer with carboxyl end groups, is a good mucoadhesive agent. The pore size of alginate gel microbeads has been shown to be between 5 and 200 nm and coated beads and microspheres are found to be better oral delivery vehicles. Cross-linked alginate has more capacity to retain the entrapped drugs and mixing of alginate with other polymers such as neutral gums, pectin, chitosan, and eudragit have been found to solve the problem of drug leaching. Chitosan has only limited ability for controlling the release of encapsulated compound due to its hydrophilic nature and easy solubility in acidic medium. By simple covalent modifications of the polymer, its physicochemical properties can be changed and can be made suitable for the peroral drug delivery purpose. Ionic interactions between positively charged amino groups in chitosan and the negatively charged mucus gel layer

On-chip magnetic bead-based DNA melting curve analysis using a magnetoresistive sensor

International Nuclear Information System (INIS)

Rizzi, Giovanni; Østerberg, Frederik W.; Henriksen, Anders D.; Dufva, Martin; Hansen, Mikkel F.

2015-01-01

We present real-time measurements of DNA melting curves in a chip-based system that detects the amount of surface-bound magnetic beads using magnetoresistive magnetic field sensors. The sensors detect the difference between the amount of beads bound to the top and bottom sensor branches of the differential sensor geometry. The sensor surfaces are functionalized with wild type (WT) and mutant type (MT) capture probes, differing by a single base insertion (a single nucleotide polymorphism, SNP). Complementary biotinylated targets in suspension couple streptavidin magnetic beads to the sensor surface. The beads are magnetized by the field arising from the bias current passed through the sensors. We demonstrate the first on-chip measurements of the melting of DNA hybrids upon a ramping of the temperature. This overcomes the limitation of using a single washing condition at constant temperature. Moreover, we demonstrate that a single sensor bridge can be used to genotype a SNP. - Highlights: • We apply magnetoresistive sensors to study solid-surface hybridization kinetics of DNA. • We measure DNA melting profiles for perfectly matching DNA duplexes and for a single base mismatch. • We present a procedure to correct for temperature dependencies of the sensor output. • We reliably extract melting temperatures for the DNA hybrids. • We demonstrate direct measurement of differential binding signal for two probes on a single sensor

Transplantation of an alginate-matrigel matrix containing isolated ovarian cells: first step in developing a biodegradable scaffold to transplant isolated preantral follicles and ovarian cells.

Science.gov (United States)

Vanacker, Julie; Luyckx, Valérie; Dolmans, Marie-Madeleine; Des Rieux, Anne; Jaeger, Jonathan; Van Langendonckt, Anne; Donnez, Jacques; Amorim, Christiani A

2012-09-01

For women diagnosed with leukemia, transplantation of cryopreserved ovarian tissue after disease remission is not advisable. Therefore, to restore fertility in these patients, we aim to develop a biodegradable artificial ovary that offers an environment where isolated follicles and ovarian cells (OCs) can survive and grow. Four NMRI mice were ovariectomized and their ovaries used to isolate OCs. Groups of 50,000 OCs were embedded in an alginate-matrigel matrix for further fixation (fresh controls), one week of in vitro culture (IVC) or heterotopic autografting. OC proliferation (Ki67), apoptosis (TUNEL), scaffold degradation, vessel formation (CD34) and inflammation (CD45) were analyzed. Ki67-positive OCs were found in 2.3%, 9.0% and 15.5% cells of cases in fresh, IVC and grafted beads respectively, while cells were TUNEL-positive in 0%, 1.5% and 6.9% of cases. After IVC or grafting, the beads degraded, losing their original round aspect, and infiltrating blood capillaries could be observed in the grafted beads. CD34-positive cells and 22% CD45-positive cells were found around and inside the matrix. In conclusion, our results demonstrate that an alginate-based matrix is a promising proposition to graft isolated OCs. After transplantation, this matrix was able to degrade, allowed vascularization and elicited a low inflammatory response. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Influence of Uranium Content and PVA/U Ratio on Physical Propertiesof PVA-U Gel and Its Oxide

International Nuclear Information System (INIS)

Damunir; W, Bangun; Indra-Suryawan; Endang-Nawangsih

2000-01-01

The influence of uranium content and PVA/U ratio on physical propertiesof PVA-U gel and its oxide has been investigated. Fifty milliliters of uranylnitrate solution containing 100 g U/l was neutralized using 1M NH 4 0H. Thesolution was converted into PVA-U sol by adding 9.18 % PVA while mixed andheated at 80 o C for 20 minutes. In order to find spherical gel, the solsolution was dropped into a 5 M NH 4 0H solution at room temperature. Theshape formed of the gels small spherical, shape of the formed gels werefiltered, washed and heated at 120 o C. After that the gels were calcined at800 o C for 4 hours. The formed U 3 O 8 particles. Under a similar method, theinfluence of uranium content from 150-400 g/l and the influence of PVA/Uratio of 6.5-12.5 % in 100 g U/l were studied. Characterization of the resultwas obtained from physical properties of the gel and its oxide in the form ofdensity using pycnometer, surface area using surface areameter with N 2 asabsorbent and particle size/ shape using a loop and optical microscope. Theexperimental results showed that both uranium content and PVA/U ratioaffected the physical properties of the kernel properties. The best resultoccurred at uranium content of 100 g/l and PVA/U 9.18 %. The resulted gelwith solid content of 89.17 %, density of 3.36 g/l and size of 124 μm. Theresulted oxide U 3 0 8 had density of 7.98 g U/l, surface area of specific of0.449 m 2 /g and grain size of 810 μm. (author)

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.

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

Kefiran-alginate gel microspheres for oral delivery of ciprofloxacin.

Science.gov (United States)

Blandón, Lina M; Islan, German A; Castro, Guillermo R; Noseda, Miguel D; Thomaz-Soccol, Vanete; Soccol, Carlos R

2016-09-01

Ciprofloxacin is a broad-spectrum antibiotic associated with gastric and intestinal side effects after extended oral administration. Alginate is a biopolymer commonly employed in gel synthesis by ionotropic gelation, but unstable in the presence of biological metal-chelating compounds and/or under dried conditions. Kefiran is a microbial biopolymer able to form gels with the advantage of displaying antimicrobial activity. In the present study, kefiran-alginate gel microspheres were developed to encapsulate ciprofloxacin for antimicrobial controlled release and enhanced bactericidal effect against common pathogens. Scanning electron microscopy (SEM) analysis of the hybrid gel microspheres showed a spherical structure with a smoother surface compared to alginate gel matrices. In vitro release of ciprofloxacin from kefiran-alginate microspheres was less than 3.0% and 5.0% at pH 1.2 (stomach), and 5.0% and 25.0% at pH 7.4 (intestine) in 3 and 21h, respectively. Fourier transform infrared spectroscopy (FTIR) of ciprofloxacin-kefiran showed the displacement of typical bands of ciprofloxacin and kefiran, suggesting a cooperative interaction by hydrogen bridges between both molecules. Additionally, the thermal analysis of ciprofloxacin-kefiran showed a protective effect of the biopolymer against ciprofloxacin degradation at high temperatures. Finally, antimicrobial assays of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhymurium, and Staphylococcus aureus demonstrated the synergic effect between ciprofloxacin and kefiran against the tested microorganisms. Copyright © 2016 Elsevier B.V. All rights reserved.

The adsorption of Cs+ from wastewater using lithium-modified montmorillonite caged in calcium alginate beads.

Science.gov (United States)

Xia, Meng; Zheng, Xianming; Du, Mingyang; Wang, Yingying; Ding, Aizhong; Dou, Junfeng

2018-07-01

The increasing nuclear energy consumption has posed serious environmental concerns (e.g. nuclear leakage), and the removal of radionuclides such as cesium becomes an urgent issue to be solved currently. In this research, a novel non-toxic adsorbent lithium-modified montmorillonite clay encapsulated in calcium alginate microbeads (MCA/Li) was fabricated by using ion-exchange method and then used successfully in the remediation of cesium-contaminated wastewater. Analyses of scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the physicochemical properties of adsorbent MCA/Li, such as internal crystal structure, constituent elements, and functional groups. The effects of concentration ratios (sodium alginate/montmorillonite), solution pH, contacting time and initial Cs + concentration on the adsorption behavior were carefully investigated via batch adsorption experiments. The adsorbent MCA/Li exhibited higher selectivity and removal efficiency towards Cs + with the maximum adsorption capacity of 100.25 mg/g. In the kinetics study, the pseudo-first-order fitted the cesium adsorption data of MCA/Li better than the pseudo-second-order. The adsorption mechanism studies revealed the process followed the Langmuir isotherm model, which suggested that Cs + adsorption onto MCA/Li is a monolayer homogeneous adsorption process. The research findings indicated this novel adsorbent MCA/Li demonstrated great potential in radioactive wastewater treatment due to its convenience in synthesis, high adsorption capacity, and low cost. Copyright © 2018 Elsevier Ltd. All rights reserved.

Self-assembled gold coating enhances X-ray imaging of alginate microcapsules

Science.gov (United States)

Qie, Fengxiang; Astolfo, Alberto; Wickramaratna, Malsha; Behe, Martin; Evans, Margaret D. M.; Hughes, Timothy C.; Hao, Xiaojuan; Tan, Tianwei

2015-01-01

Therapeutic biomolecules produced from cells encapsulated within alginate microcapsules (MCs) offer a potential treatment for a number of diseases. However the fate of such MCs once implanted into the body is difficult to establish. Labelling the MCs with medical imaging contrast agents may aid their detection and give researchers the ability to track them over time thus aiding the development of such cellular therapies. Here we report the preparation of MCs with a self-assembled gold nanoparticle (AuNPs) coating which results in distinctive contrast and enables them to be readily identified using a conventional small animal X-ray micro-CT scanner. Cationic Reversible Addition-Fragmentation chain Transfer (RAFT) homopolymer modified AuNPs (PAuNPs) were coated onto the surface of negatively charged alginate MCs resulting in hybrids which possessed low cytotoxicity and high mechanical stability in vitro. As a result of their high localized Au concentration, the hybrid MCs exhibited a distinctive bright circular ring even with a low X-ray dose and rapid scanning in post-mortem imaging experiments facilitating their positive identification and potentially enabling them to be used for in vivo tracking experiments over multiple time-points.Therapeutic biomolecules produced from cells encapsulated within alginate microcapsules (MCs) offer a potential treatment for a number of diseases. However the fate of such MCs once implanted into the body is difficult to establish. Labelling the MCs with medical imaging contrast agents may aid their detection and give researchers the ability to track them over time thus aiding the development of such cellular therapies. Here we report the preparation of MCs with a self-assembled gold nanoparticle (AuNPs) coating which results in distinctive contrast and enables them to be readily identified using a conventional small animal X-ray micro-CT scanner. Cationic Reversible Addition-Fragmentation chain Transfer (RAFT) homopolymer modified Au

PVA hydrogel properties for biomedical application.

Science.gov (United States)

Jiang, Shan; Liu, Sha; Feng, Wenhao

2011-10-01

PVA has been proposed as a promising biomaterial suitable for tissue mimicking, vascular cell culturing and vascular implanting. In this research, a kind of transparent PVA hydrogel has been investigated in order to mimic the creatural soft tissue deformation during mini-invasive surgery with needle intervention, such as brachytherapy. Three kinds of samples with the same composition of 3 g PVA, 17 g de-ionized water, 80 g dimethyl-sulfoxide but different freeze/thaw cycles have been prepared. In order to investigate the structure and properties of polyvinyl alcohol hydrogel, micro-structure, mechanical property and deformation measurement have been conducted. As the SEM image comparison results show, with the increase of freeze/thaw cycles, PVA hydrogel revealed the similar micro-structure to porcine liver tissue. With uniaxial tensile strength test, the above composition with a five freeze/thaw cycle sample resulted in Young's modulus similar to that of porcine liver's property. Through the comparison of needle insertion deformation experiment and the clinical experiment during brachytherapy, results show that the PVA hydrogel had the same deformation property as prostate tissue. These transparent hydrogel phantom materials can be suitable soft tissue substitutes in needle intervention precision or pre-operation planning studies, particularly in the cases of mimicking creatural tissue deformation and analysing video camera images. Copyright © 2011 Elsevier Ltd. All rights reserved.

On-chip magnetic bead-based DNA melting curve analysis using a magnetoresistive sensor

DEFF Research Database (Denmark)

Rizzi, Giovanni; Østerberg, Frederik Westergaard; Henriksen, Anders Dahl

2014-01-01

We present real-time measurements of DNA melting curves in a chip-based system that detects the amount of surface-bound magnetic beads using magnetoresistive magnetic field sensors. The sensors detect the difference between the amount of beads bound to the top and bottom sensor branches....... The beads are magnetized by the field arising from the bias current passed through the sensors. We demonstrate the first on-chip measurements of the melting of DNA hybrids upon a ramping of the temperature. This overcomes the limitation of using a single washing condition at constant temperature. Moreover...

Preparation and properties of GO-PVA composite hydrogel with oriented structure

Science.gov (United States)

Liu, Huanqing; Zhang, Gongzheng; Li, Huanjun

2017-03-01

We fabricated GO-PVA composite hydrogels with oriented structure by directional freezing and repeated freeze-thawing, which owned superior mechanical property and thermostability than PVA hydrogel. Due to physical interactions such as hydrogen bonding between surface of GO and PVA chains, GO-PVA composite hydrogel possessed higher crosslinking density and smaller pore size and can resist higher temperature and stronger force from outside than PVA hydrogel. These unique properties will endow GO-PVA hydrogel with greater potential application in biomedical materials.

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)

Deformation of ovalbumin-alginate capsules in a T-Junction

Science.gov (United States)

Häner, Edgar; Juel, Anne

2015-11-01

We study experimentally the flow-induced deformation of liquid-filled ovalbumin-alginate capsules in a T-junction. In applications, capsules/cells often negotiate branched networks with junctions thus experiencing large deformations. We investigate the constant volume-flux viscous flow of buoyancy-neutral thin-walled capsules close to the centreline of rectangular channels, by comparison to near-rigid gelled beads. The motion of the capsules in straight channels scales with the capillary number - the ration of viscous to elastic forces. However, the effect of elastic deformation on the motion is sufficiently weak that a rigid sphere model predicts the velocity of capsules with diameters of up to 70% of that of the channel to within 5%. In the T-junction, systematic selection of daughter channel (right-left) occurs outside a finite region around the channel centreline, by contrast with near-rigid gelled beads, where the actual centreline is the separator. We quantify the behaviour of capsules in terms of their longitudinal stretching (up to a factor of three without rupture). We show the large range of deformations encountered can be applied to the measurement of the elastic properties of capsules as well as to the geometric-induced sorting and manipulation of capsules.

Production of BCG alginate-PLL microcapsules by emulsification/internal gelation.

Science.gov (United States)

Esquisabel, A; Hernández, R M; Igartua, M; Gascón, A R; Calvo, B; Pedraz, J L

1997-01-01

A biocompatible emulsification method for microencapsulation of live cells and enzymes within a calcium alginate matrix applied to Bacillus Calmette-Guérin (BCG) has been developed. Small-diameter alginate beads (microcapsules) were formed via internal gelation of an alginate solution emulsified within vegetable oil. Five different oils (sesame, sweet almond, perhydrosqualene, camomile and jojoba) were used. The rheological analysis of the oils showed a Newtonian behaviour, with viscosities = 30.0, 37.7, 51.2, 59.3 and 67.1 mPa.s for perhydrosqualene, jojoba, camomile, sesame and sweet almond oil respectively. The particle size of the microcapsules obtained ranged from 30.3 microns for the microcapsules prepared with sweet almond oil to 57.0 microns for those made with perhydrosqualene. The mean particle diameter obtained was found to be dependent on the viscosity of the oil employed, according to the equation: phi (micron) = 76.6-0.628 eta (mPa.s) (r2 = 0.943). The encapsulated BCG was identified by the Difco TB stain set K, followed by observation under optical microscopy. Freeze-drying of the microcapsules was carried out to ensure their stability during storage. Two batches of microcapsules (those prepared with sesame and jojoba oil) and four types of cryoprotectors (glucose, trehalose, mannitol and sorbitol), at three concentration levels (5, 10 and 20% w/v) were studied. The parameters evaluated were particle size, physical appearance, reconstitution of lyophilizates and microscopical evaluation. For both batches of microcapsules the best results were obtained with trehalose 5%, showing particle sizes of 42.1 microns in the case of the microcapsules prepared with sesame oil, and of 45.3 microns for those prepared with jojoba.

Swelling kinetics and antimicrobial activity of radiolytically synthesized nano-Ag/PVA hydrogels

International Nuclear Information System (INIS)

Krstic, J.; Spasojevic, J.; Krkljes, A.; Kacarevic-Popovic, Z.

2011-01-01

Complete text of publication follows. Synthesis of nanocomposite materials for biomedical applications, is being systematically developed. The materials having metal nanoparticles incorporated into polymer network have been widely investigated due to their unique properties induced by the synergy of two different materials. Silver nanoparticles (nano-Ag) have been proved to be effective antimicrobial agent and their enhanced antibacterial properties have been demonstrated both in vitro and in vivo. Recent research efforts are directed towards exploiting the in situ synthesis of nano-Ag within polymeric network architectures and products of these approaches are new hybrid nanocomposite systems. Due to characteristic properties such as swellability in water, hydrophilicity, biocompatibility and lack of toxicity, hydrogels have been utilized in a wide range of biological, medical, pharmaceutical and environmental applications. Among different synthetic methods, γ-irradiation induced synthesis has been recognized as highly suitable tool for production of hydrogel nanocomposites due to formation and sterilization of material in one technological step. In this work, the swelling kinetics of PVA and nano-Ag/PVA hydrogels in distilled water and Kokubo's Simulated Body Fluid (SBF), at 25 and 37 deg C, was investigated. The obtained hydrogel nanocomposites had greater swelling capacity and diffusion coefficient compared to PVA hydrogel. Both hydrogel systems show non-Fickian diffusion and Schott second order kinetics, at early and extensive stage of swelling, respectively. Investigated nano-Ag/PVA hydrogel nanocomposites show continuous release of silver over a long period of time and, as consequence, the test of antimicrobial activity was performed. Antimicrobial efficiency was determined by agar-diffusion test and the obtained results clearly show the formation of inhibition zone towards Escherichia coli and Staphylococcus aureus in the case of higher nano

Hemicelluloses/montmorillonite hybrid films with improved mechanical and barrier properties

Science.gov (United States)

Chen, Ge-Gu; Qi, Xian-Ming; Li, Ming-Peng; Guan, Ying; Bian, Jing; Peng, Feng; Yao, Chun-Li; Sun, Run-Cang

2015-11-01

A facile and environmentally friendly method was introduced to incorporate montmorillonite (MMT) as an inorganic phase into quaternized hemicelluloses (QH) for forming hemicellulose-based films. Two fillers, polyvinyl alcohol (PVA) and chitin nanowhiskers (NCH), were added into the hemicelluloses/MMT hybrid matrices to prepare hybrid films, respectively. The hybrid films were nanocomposites with nacre-like structure and multifunctional characteristics including higher strength and good oxygen barrier properties via the electrostatic and hydrogen bonding interactions. The addition of PVA and NCH could induce changes in surface topography, and effectively enhance mechanical strength, thermal stability, transparency, and oxygen barrier properties. The tensile strengths of the composite films FPVA(0.3), FPVA(0.5), and FNCH(0.8) were 53.7, 46.3, and 50.1 MPa, respectively, which were 171%, 134%, and 153% larger than the FQH-MMT film (19.8 MPa). The tensile strength, and oxygen transmission rate of QH-MMT-PVA film were better than those of quaternized hemicelluloses/MMT films. Thus, the proper filler is very important for the strength of the hybrid film. These results provide insights into the understanding of the structural relationships of hemicellulose-based composite films in coating and packaging application for the future.

Synthesis and characterization of CdS/PVA nanocomposite films

Science.gov (United States)

Wang, Hongmei; Fang, Pengfei; Chen, Zhe; Wang, Shaojie

2007-08-01

A series CdS/PVA nanocomposite films with different amount of Cd salt have been prepared by means of the in situ synthesis method via the reaction of Cd 2+-dispersed poly vinyl-alcohol (PVA) with H 2S. The as-prepared films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption, photoluminescence (PL) spectra, Fourier transform infrared spectroscope (FTIR) and thermogravimetric analysis (TGA). The XRD results indicated the formation of CdS nanoparticles with hexagonal phase in the PVA matrix. The primary FTIR spectra of CdS/PVA nanocomposite in different processing stages have been discussed. The vibrational absorption peak of Cd sbnd S bond at 405 cm -1 was observed, which further testified the generation of CdS nanoparticles. The TGA results showed incorporation of CdS nanoparticles significantly altered the thermal properties of PVA matrix. The photoluminescence and UV-vis spectroscopy revealed that the CdS/PVA films showed quantum confinement effect.

Synthesis and characterization of CdS/PVA nanocomposite films

International Nuclear Information System (INIS)

Wang Hongmei; Fang Pengfei; Chen Zhe; Wang Shaojie

2007-01-01

A series CdS/PVA nanocomposite films with different amount of Cd salt have been prepared by means of the in situ synthesis method via the reaction of Cd 2+ -dispersed poly vinyl-alcohol (PVA) with H 2 S. The as-prepared films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption, photoluminescence (PL) spectra, Fourier transform infrared spectroscope (FTIR) and thermogravimetric analysis (TGA). The XRD results indicated the formation of CdS nanoparticles with hexagonal phase in the PVA matrix. The primary FTIR spectra of CdS/PVA nanocomposite in different processing stages have been discussed. The vibrational absorption peak of Cd-S bond at 405 cm -1 was observed, which further testified the generation of CdS nanoparticles. The TGA results showed incorporation of CdS nanoparticles significantly altered the thermal properties of PVA matrix. The photoluminescence and UV-vis spectroscopy revealed that the CdS/PVA films showed quantum confinement effect

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)

Immobilization of Bacillus megaterium MTCC 2444 by Ca-alginate entrapment method for enhanced alkaline protease production

Directory of Open Access Journals (Sweden)

Soma Mrudula

2012-02-01

Full Text Available Optimization of culture conditions and immobilization parameters for alkaline protease production was carried out by employing Bacillus megaterium MTCC2444. The partially purified enzyme was tested for its stability in the presence of oxidants, surfactants and commercial detergents. The optimum temperature, pH, incubation time and inoculum size were 55 ºC, 11, 48 h, 1 %, respectively. Calcium alginate was used as the immobilization matrix and the effects of gel concentration, bead size, age of immobilized cells, solidification period and initial biomass concentration on alkaline protease production and cell leakage were investigated. The results indicated that the immobilization was most effective with 4 % gel concentration, bead size of 3 mm, 24 h aged immobilized cells for a solidification period of 12 h at 1.5 % initial biomass concentration. The enzyme showed good stability in the presence of oxidants, surfactants and commercial detergents.

Effects of PVA(Polyvinyl Alcohol) on Supercooling Phenomena of Water

Science.gov (United States)

Kumano, Hiroyuki; Saito, Akio; Okawa, Seiji; Takizawa, Hiroshi

In this paper, effects of polymer additive on supercooling of water were investigated experimentally. Poly-vinyl alcohol (PVA) were used as the polymer, and the samples were prepared by dissolving PVA in ultra pure water. Concentration, degree of polymerization and saponification of PVA were varied as the experimental parameters. The sample was cooled, and the temperature at the instant when ice appears was measured. Since freezing of supercooled water is statistical phenomenon, many experiments were carried out and average degrees of supercooling were obtained for each experimental condition. As the result, it was found that PVA affects nucleation of supercooling and the degree of supercooling increases by adding the PVA. Especially, it is found that the average degree of supercooling increases and the standard deviation of average degree of supercooling decreases with increase of degree of saponification of PVA. However, the average degree of supercooling are independent of the degree of polymerization of PVA in the range of this study.

Preparation, characterization, and application of poly(vinyl alcohol)-graft-poly(ethylene glycol) resins: novel polymer matrices for solid-phase synthesis.

Science.gov (United States)

Luo, Juntao; Pardin, Christophe; Zhu, X X; Lubell, William D

2007-01-01

Spherical crosslinked poly(vinyl alcohol) (PVA) beads with good mechanical stability were prepared by reverse-suspension polymerization, using dimethyl sulfoxide (DMSO) as a cosolvent in an aqueous phase. Poly(ethylene glycol)s with varying chain lengths were grafted onto the PVA beads by anionic polymerization of ethylene oxide. The thermal behavior, morphology, and swelling were evaluated for each of the new polymer matrices. High loading and good swelling in water and organic solvents were characteristic of the PEG-grafted PVA beads. The polymer beads also exhibited good mechanical and chemical stability and were unaffected by treatment with 6 N HCl and with 6 N NaOH. The hydroxyl groups of the PVA-PEG beads were converted into aldehyde, carboxylic acid, and isocyanate functions to provide scavenger resins and were extended by way of a benzyl alcohol in a Wang linker. The transglutaminase substrates dipeptides (Z-Gln-Gly) and heptapeptides (Pro-Asn-Pro-Gln-Leu-Pro-Phe) were synthesized on PVA-PEG_5, PVA-PEG_20, and the Wang linker-derivatized PVA-PEG resins. The cleavage of the peptides from the resins using MeOH/NH3 mixture at different temperatures (0 degrees C and room temp) and 50% TFA/DCM provided, respectively, peptide methyl esters, amides, and acids in good yields and purity as assessed by LC-MS analysis.

Preparation, optimization and property of PVA-HA/PAA composite hydrogel.

Science.gov (United States)

Chen, Kai; Liu, Jinlong; Yang, Xuehui; Zhang, Dekun

2017-09-01

PVA-HA/PAA composite hydrogel is prepared by freezing-thawing, PEG dehydration and annealing method. Orthogonal design method is used to choose the optimization combination. Results showed that HA and PVA have the maximum effect on water content. PVA and freezing-thawing cycles have the maximum effect on creep resistance and stress relaxation rate of hydrogel. Annealing temperature and freezing-thawing cycles have the maximum effect on compressive elastic modulus of hydrogel. Comparing with the water content and mechanical properties of 16 kinds of combination, PVA-HA/PAA composite hydrogel with freezing-thawing cycles of 3, annealing temperature of 120°C, PVA of 16%, HA of 2%, PAA of 4% has the optimization comprehensive properties. PVA-HA/PAA composite hydrogel has a porous network structure. There are some interactions between PVA, HA and PAA in hydrogel and the properties of hydrogel are strengthened. The annealing treatment improves the crystalline and crosslinking of hydrogel. Therefore, the annealing PVA-HA/PAA composite hydrogel has good thermostability, strength and mechanical properties. It also has good lubrication property and its friction coefficient is relative low. Copyright © 2017 Elsevier B.V. All rights reserved.

Beads.

Science.gov (United States)

Weewish Tree, 1979

1979-01-01

Beads served both as ornaments and as a medium of exchange, and the Indians manufactured them from such natural sources as bones, stones, beans, nuts, animal teeth, and polished antlers. Even after the introduction of European glass beads, the Indians continued to make their favorite beads from the natural sources. (DS)

Preparation methods of alginate nanoparticles

NARCIS (Netherlands)

Paques, J.P.; Linden, van der E.; Rijn, van C.J.M.; Sagis, L.M.C.

2014-01-01

This article reviews available methods for the formation of alginate nano-aggregates, nanocapsules and nanospheres. Primarily, alginate nanoparticles are being prepared by two methods. In the “complexation method”, complex formation on the interface of an oil droplet is used to form alginate

Natural and Modified Zeolite—Alginate Composites. Application for Removal of Heavy Metal Cations from Contaminated Water Solutions

Directory of Open Access Journals (Sweden)

Milan Kragović

2018-01-01

Full Text Available In present paper, the influence of the initial pH and concentration of Pb2+ on its adsorption by the natural (NZA and Fe(III-modified zeolite-alginate beads (FeA was studied. Results showed that modification of the starting materials have a positive effect on their adsorption capacities (102 and 136 mg/g for the NZA and FeA, respectively. After encapsulation, the mechanism of lead adsorption by both adsorbents was changed and ion exchange dominates. The best adsorption was achieved for initial pH > 3.8. Cation exchange capacity, structural properties, and hydrophobicity of samples were also determined, and the presence of the alginate has no significant influence on investigated properties of samples. Experiments on wastewater from tailings of lead and zinc mine Grot, Serbia, showed that after treatment with both adsorbents, the content of the most abundant heavy metals (Pb, Zn, Hg, and Mn significantly decreased.

Silica in situ enhanced PVA/chitosan biodegradable films for food packages.

Science.gov (United States)

Yu, Zhen; Li, Baoqiang; Chu, Jiayu; Zhang, Peifeng

2018-03-15

Non-degradable plastic food packages threaten the security of environment. The cost-effective and biodegradable polymer films with good mechanical properties and low permeability are very important for food packages. Among of biodegradable polymers, PVA/chitosan (CS) biodegradable films have attracted considerable attention because of feasible film forming ability. However, PVA/CS biodegradable films suffered from poor mechanical properties. To improve mechanical properties of PVA/CS biodegradable films, we developed SiO 2 in situ to enhance PVA/CS biodegradable films via hydrolysis of sodium metasilicate in presence of PVA and chitosan solution. The tensile strength of PVA/CS biodegradable films was improved 45% when 0.6 wt.% SiO 2 was incorporated into the films. Weight loss of PVA/CS biodegradable films was 60% after 30 days in the soil. The permeability of oxygen and moisture of PVA/CS biodegradable films was reduced by 25.6% and 10.2%, respectively. SiO 2 in situ enhanced PVA/CS biodegradable films possessed not only excellent mechanical properties, but also barrier of oxygen and water for food packages to extend the perseveration time. Copyright © 2017 Elsevier Ltd. All rights reserved.

Calcium alginate particles for the combined delivery of platelet lysate and vancomycin hydrochloride in chronic skin ulcers.

Science.gov (United States)

Mori, Michela; Rossi, Silvia; Bonferoni, Maria Cristina; Ferrari, Franca; Sandri, Giuseppina; Riva, Federica; Del Fante, Claudia; Perotti, Cesare; Caramella, Carla

2014-01-30

The aim of the present work was the development of a powder formulation for the combined delivery of platelet lysate and of a model antibiotic drug, vancomycin hydrochloride (VCM), in chronic skin ulcers. Calcium alginate particles were prepared by freeze-drying beads obtained by ionic gelation method. The experimental conditions adopted permitted the complete loading of VCM and of PDGF AB, the growth factor chosen as representative of those contained in PL. Such particles where able to absorb PBS (mimicking wound exudate), to form a gel and to modulate the release of VCM and of PDGF AB. They are characterized by enhancement properties of human fibroblast proliferation due to PL presence. In particular, PL, when loaded in alginate particles, was able not only to increase the number of viable cells, but also the number of cells in proliferative phase. Such properties were comparable to those of fresh PL indicating the capability of calcium alginate particles to load PL bioactive substances without altering their activity. The formulation developed is characterized by an easier and a less painful administration with respect to traditional gauzes and semisolid preparations and permits the loading in the same dosage form of active substances of different nature avoiding eventual incompatibility problems. Copyright © 2013 Elsevier B.V. All rights reserved.

Electrospinning, mechanical properties, and cell behavior study of chitosan/PVA nanofibers.

Science.gov (United States)

Koosha, Mojtaba; Mirzadeh, Hamid

2015-09-01

Electrospinning process has been widely used to produce nanofibers from polymer blends. Poly(vinyl alcohol) (PVA) and chitosan (CS) have numerous biomedical applications such as wound healing and tissue engineering. Nanofibers of CS/PVA have been prepared by many works, however, a complete physicochemical and mechanical characterization as well as cell behavior has not been reported. In this study, PVA and CS/PVA blend solutions in acetic acid 70% with different volume ratios (30/70, 50/50, and 70/30) were electrospun in constant electrospinning process parameters. The structure and morphology of nanofibrous mats were characterized by SEM, FTIR, and XRD methods. The best nanofibrous mat was achieved from the CS/PVA 30/70 blend solution regarding the electrospinning throughput. The dynamic mechanical thermal analysis (DMTA) of PVA and CS/PVA 30/70 nanofibrous mats were measured which were not considered in the previous studies. DMTA results in accordance to the DSC analysis approved the partial compatibility between the two polymers, while a single glass transition temperature was not observed for the blend. The tensile strength of PVA and CS/PVA nanofibers were also reported. Results of cell behavior study indicated that the heat stabilized nanofibrous mat CS/PVA 30/70 was able to support the attachment and proliferation of the fibroblast cells. © 2015 Wiley Periodicals, Inc.

Water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels

Energy Technology Data Exchange (ETDEWEB)

Wang, Qingguo, E-mail: qwang@qust.edu.cn [Key Laboratory of Rubber-Plastics of Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao 266042 (China); Zhou, Xue; Zeng, Jinxia; Wang, Jizeng [Key Laboratory of Rubber-Plastics of Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China)

2016-02-01

In this paper, the electron beam irradiation technology being more suitable for the industry application is explored to fabricate the acrylic acid (AAc) monomer-grafted polyvinyl alcohol (PVA-g-AAc) hydrogels. ATR-IR spectra of the PVA-g-AAc hydrogels shows an obvious absorption peak of the −C=O group at 1701 cm{sup −1}, indicating that the AAc monomers were grafted onto the PVA macromolecules. This paper also studied some effects of the mass ratio of PVA/AAc, pH of buffer solution and irradiation dosage on the water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels. The water swelling ratio of PVA-g-AAc hydrogels decreases with increased irradiation dosage and mass ratio of PVA/AAc, whereas swelling ratio increases with increased pH of buffer solution and soaking time. The water-swelling behavior of PVA-g-AAc hydrogels occurred easily in an alkaline environment, particularly in a buffer solution with pH 9.2. Both PVA-g-AAc hydrogels (PVA/AAc = 1/5, w/w) irradiated with 5 kilogray (kGy) and PVA-g-AAc hydrogels (PVA/AAc = 1/1, w/w) irradiated with 15 kGy could easily absorb water and lead to high water swelling ratios (up to about 600%), which are potential candidates to meet the requirements for some biomedical applications.

Baryonic hybrids: Gluons as beads on strings between quarks

International Nuclear Information System (INIS)

Cornwall, John M.

2005-01-01

V. Although we do not consider it in full detail, we show that in the qqG hybrid the gluon is a bead that can slide without friction on a string joining the q and q. We comment briefly on the significance of our findings to fluctuations of the minimal surface, a subject difficult to understand from the point of view of center vortices

Papain wound dressings obtained from poly(vinyl alcohol)/calcium alginate blends as new pharmaceutical dosage form: Preparation and preliminary evaluation.

Science.gov (United States)

Dutra, J A P; Carvalho, S G; Zampirolli, A C D; Daltoé, R D; Teixeira, R M; Careta, F P; Cotrim, M A P; Oréfice, R L; Villanova, J C O

2017-04-01

Transparent, soft, flexible, mechanically resistant films, which are ideal for use as wound dressings were prepared in the presence of 2% papain, a proteolytic enzyme that can play a role in the chemical debridement of the skin and can accelerate the healing process. The films, based on poly(vinyl alcohol):calcium alginate blends with increasing concentrations of polysaccharide (10, 20, and 30% v/v), were obtained by casting method. FTIR and DSC analyses were performed to assess the composition and miscibility of blends. Mechanical properties such as tensile strength, elasticity modulus, and elongation at breakpoint were evaluated. The influence of different concentrations of calcium alginate on physical attributes of films like wettability, swelling capacity and mechanical properties was determined. The stability of papain in the films was assessed indirectly by hemolytic activity assay employing direct contact method and confirmed by technique based on blood agar diffusion. Preliminary cytotoxicity was evaluated with the XTT method. The results showed that at the polymer concentrations tested, the blends were miscible. The increase in the content of the calcium alginate increased the wettability and swelling capacity of the films, which is desirable in wound dressings. On the other hand, mechanical resistance decreased without causing breakage of the films during the swelling tests. The hemolytic activity of the films was maintained during the studied period, suggesting the stability of papain in the proposed formulations. Cellular viability indicated that the films were non-toxic. The analysis of the results showed that it is possible to prepare interactive and bioactive wound dressing containing papain from blends of PVA and calcium alginate polymers. Copyright © 2016 Elsevier B.V. All rights reserved.

Alginate-modifying enzymes: Biological roles and biotechnological uses

Directory of Open Access Journals (Sweden)

Helga eErtesvåg

2015-05-01

Full Text Available Alginate denotes a group of industrially important 1-4-linked biopolymers composed of the C-5-epimers β-D-mannuronic acid (M and α-L-guluronic acid (G. The polysaccharide is manufactured from brown algae where it constitutes the main structural cell wall polymer. The physical properties of a given alginate molecule, e.g. gel-strength, water-binding capacity, viscosity and biocompatibility, are determined by polymer length, the relative amount and distribution of G residues and the acetyl content, all of which are controlled by alginate modifying enzymes. Alginate has also been isolated from some bacteria belonging to the genera Pseudomonas and Azotobacter, and bacterially synthesized alginate may be O-acetylated at O-2 and/or O-3. Initially, alginate is synthesized as polymannuronic acid, and some M residues are subsequently epimerized to G residues. In bacteria a mannuronan C-5-epimerase (AlgG and an alginate acetylase (AlgX are integral parts of the protein complex necessary for alginate polymerisation and export. All alginate-producing bacteria use periplasmic alginate lyases to remove alginate molecules aberrantly released to the periplasm. Alginate lyases are also produced by organisms that utilize alginate as carbon source. Most alginate-producing organisms encode more than one mannuronan C-5 epimerase, each introducing its specific pattern of G residues. Acetylation protects against further epimerization and from most alginate lyases. One enzyme with alginate deacetylase activity from Pseudomonas syringae has been reported. Functional and structural studies reveal that alginate lyases and epimerases have related enzyme mechanisms and catalytic sites. Alginate lyases are now utilized as tools for alginate characterization. Secreted epimerases have been shown to function well in vitro, and have been engineered further in order to obtain enzymes that can provide alginates with new and desired properties for use in medical and

PVA matches human liver in needle-tissue interaction.

Science.gov (United States)

de Jong, Tonke L; Pluymen, Loes H; van Gerwen, Dennis J; Kleinrensink, Gert-Jan; Dankelman, Jenny; van den Dobbelsteen, John J

2017-05-01

Medical phantoms can be used to study needle-tissue interaction and to train medical residents. The purpose of this research is to study the suitability of polyvinyl alcohol (PVA) as a liver tissue mimicking material in terms of needle-tissue interaction. Insertions into ex-vivo human livers were used for reference. Six PVA samples were created by varying the mass percentage of PVA to water (4m% and 7m%) and the number of freeze-thaw cycles (1, 2 and 3 cycles, 16hours of freezing at -19°C, 8hours of thawing). The inner needle of an 18 Gauge trocar needle with triangular tip was inserted 13 times into each of the samples, using an insertion velocity of 5 mm/s. In addition, 39 insertions were performed in two ex-vivo human livers. Axial forces on the needle were captured during insertion and retraction and characterized by friction along the needle shaft, peak forces, and number of peak forces per unit length. The concentration of PVA and the number of freeze-thaw cycles both influenced the mechanical interaction between needle and specimen. Insertions into 4m% PVA phantoms with 2 freeze-thaw cycles were comparable to human liver in terms of estimated friction along the needle shaft and the number of peak forces. Therefore, these phantoms are considered to be suitable liver mimicking materials for image-guided needle interventions. The mechanical properties of PVA hydrogels can be influenced in a controlled manner by varying the concentration of PVA and the number of freeze-thaw cycles, to mimic liver tissue characteristics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physicochemical properties of marine collagen-alginate biomaterial

Science.gov (United States)

Soon, K. S.; Hii, S. L.; Wong, C. L.; Leong, L. K.; Woo, K. K.

2017-12-01

Collagen base biomaterials are widely applied in the field of tissue engineering. However, these fibrous proteins in animal connective tissues are insufficient to fulfill the mechanical properties for such applications. Therefore, alginate as a natural polysaccharide was incorporated. In this study, Smooth wolf herring skins was collected from the local fish ball processing industry for collagen extraction using acid solubilisation method. On the other hand, alginate from brown seaweed (Sargassum polycystum) was extracted with calcium carbonate at 50 °C. The composite films of different collagen and alginate ratio were prepared by lyophilisation with pure collagen film as control. The effects of alginate on swelling behaviour, porosity, collagenase degradation and tensile strength of the composite films were investigated. Swelling behaviour increased with alginate content, 50 % alginate film achieved 1254.75 % swelling after 24 h. All composite films achieved more than 80 % porosity except the film with 80 % collagen (65.41 %). Porosity was highest in 100 % alginate (94.30 %). Highest tensile strength (1585.87 kPa) and young modulus (27.05 MPa) was found in 50 % alginate film. In addition, resistance to collagenase degradation was improved with alginate content, lowest degradation rate was determined in 80 % alginate film. Results indicated alginate is efficient in improving some mechanical properties of the composite film.

Control of nanostructures in PVA, PVA/chitosan blends and PCL ...

Indian Academy of Sciences (India)

Wintec

viz. chitosan, to PVA solution, an improvement in bio- compatibility of the blend system can be achieved. This can be attributed to the good biocompatibility, antibacte- rial properties, appropriate biodegradability, excellent physicochemical properties, and its commercial availabi- lity at relatively low cost (Huang et al 2005).

A new porous hybrid material derived from silica fume and alginate for sustainable pollutants reduction

Science.gov (United States)

Zanoletti, Alessandra; Vassura, Ivano; Venturini, Elisa; Monai, Matteo; Montini, Tiziano; Federici, Stefania; Zacco, Annalisa; Treccani, Laura; Bontempi, Elza

2018-03-01

In this work a new mesoporous adsorbent material obtained from a natural, high abundant raw material and a high volume industrial by-product is presented. The material is consolidated by the gelling properties of alginate and by decomposition of sodium-bicarbonate controlled porosity at low temperatures (70-80°C) at different scale lengths. The structural, thermal, and morphological characterization shows that the material is a mesoporous organic-inorganic hybrid. The material is tested as adsorbent, showing high performances. Methylene blue, used as model pollutant, can be adsorbed and removed from aqueous solutions even at a high concentration with efficiency up to 94%. By coating the material with a 100 nm thin film of titania, good photodegradation performance (more than 20%) can be imparted. Based on embodied energy and carbon footprint of its primary production, the sustainability of the new obtained material is evaluated and quantified in respect to activated carbon as well. It is shown that the new proposed material has an embodied energy lower than one order of magnitude in respect to the one of activated carbon, which represents the gold standards. The versatility of the new material is also demonstrated in terms of its design and manufacturing possibilities. In addition, this material can be printed in 3D. Finally, preliminary results about its ability to capture diesel exhaust particulate matter are reported. The sample exposed to diesel contains a large amount of carbon in its surface. At the best of our knowledge this is the first time that hybrid porous materials are proposed as a new class of sustainable materials, produced to reduce pollutants in the wastewaters and in the atmosphere.

Self-disinfecting Alginate vs Conventional Alginate: Effect on Surface Hardness of Gypsum Cast-An in vitro Study.

Science.gov (United States)

Madhavan, Ranjith; George, Navia; Thummala, Niharika R; Ravi, S V; Nagpal, Ajay

2017-11-01

For the construction of any dental prosthesis, accurate impressions are necessary. Hence, we undertook the present study to evaluate and compare the surface hardness of gypsum casts poured from impressions made using conventional alginate and self-disinfecting alginate. A total of 30 impressions of stainless steel die were made, out of which 15 impressions were made with conventional alginate and 15 were made with self-disinfecting alginate and poured using Type III dental stone. Thirty stone specimens were subjected for hardness testing. Data were analyzed using independent samples t-test to compare the mean surface hardness. Difference in surface hardness was statistically insignificant (p > 0.05). Surface hardness of gypsum casts poured using impressions made from self-disinfecting alginate and conventional alginates were comparable. Self-disinfecting alginates may be employed in clinical practice as safe and effective materials to overcome the infection control issues without compromising on the properties of the material.

Effects of MWNT nanofillers on structures and properties of PVA electrospun nanofibres

International Nuclear Information System (INIS)

Naebe, Minoo; Lin Tong; Tian, Wendy; Dai Liming; Wang Xungai

2007-01-01

In this study, we have electrospun poly(vinyl alcohol)(PVA) nanofibres and PVA composite nanofibres containing multi-wall carbon nanotubes (MWNTs) (4.5 wt%), and examined the effect of the carbon nanotubes and the PVA morphology change induced by post-spinning treatments on the tensile properties, surface hydrophilicity and thermal stability of the nanofibres. Through differential scanning calorimetry (DSC) and wide-angle x-ray diffraction (WAXD) characterizations, we have observed that the presence of the carbon nanotubes nucleated crystallization of PVA in the MWNTs/PVA composite nanofibres, and hence considerably improved the fibre tensile strength. Also, the presence of carbon nanotubes in PVA reduced the fibre diameter and the surface hydrophilicity of the nanofibre mat. The MWNTs/PVA composite nanofibres and the neat PVA nanofibres responded differently to post-spinning treatments, such as soaking in methanol and crosslinking with glutaric dialdehyde, with the purpose of increasing PVA crystallinity and establishing a crosslinked PVA network, respectively. The presence of carbon nanotubes reduced the PVA crystallization rate during the methanol treatment, but prevented the decrease of crystallinity induced by the crosslinking reaction. In comparison with the crosslinking reaction, the methanol treatment resulted in better improvement in the fibre tensile strength and less reduction in the tensile strain. In addition, the presence of carbon nanotubes reduced the onset decomposition temperature of the composite nanofibres, but stabilized the thermal degradation for the post-spinning treated nanofibres. The MWNTs/PVA composite nanofibres treated by both methanol and crosslinking reaction gave the largest improvement in the fibre tensile strength, water contact angle and thermal stability

Photoluminescence study of CdSe nanorods embedded in a PVA matrix

Energy Technology Data Exchange (ETDEWEB)

Sharma, Mamta [Centre of Advanced Study in Physics, Department of Physics, Panjab University, Chandigarh 160014 (India); Tripathi, S.K., E-mail: surya@pu.ac.in [Centre of Advanced Study in Physics, Department of Physics, Panjab University, Chandigarh 160014 (India)

2013-03-15

Nanometer-sized semiconductor CdSe nanorods have been successfully grown within polyvinyl alcohol (PVA) matrix by in situ technique. PVA:n-CdSe nanorods are characterized by X-ray diffraction, transmission electron microscopy, UV-vis spectrophotometer and photoluminescence spectroscopy. The photoluminescence spectra of PVA:n-CdSe nanorods are studied at different excitation wavelengths. PVA:n-CdSe nanorods have demonstrated to exhibit strong and well-defined green photoluminescence emission. The long-term stability of the PL properties of PVA:n-CdSe nanorods is also investigated in view of possible applications of polymer nanocomposites. The linear optical constants such as the extinction coefficient (k), real ({epsilon}{sub 1}) and imaginary ({epsilon}{sub 2}) dielectric constant, optical conductivity ({sigma}{sub opt}) are calculated for PVA:n-CdSe nanorods. The optical properties i.e. good photostability and larger stokes shift suggesting to apply PVA:n-CdSe nanorods in bioimaging applications. - Highlights: Black-Right-Pointing-Pointer In situ synthesis of PVA:n-CdSe via chemical bath method at room temperature. {open_square} From TEM image, the three arm nanorods morphology of PVA:n-CdSe is obtained. Black-Right-Pointing-Pointer The optical constants i.e. n, k, {epsilon}{sub 1}, {epsilon}{sub 2} and {sigma}{sub opt} are calculated. Black-Right-Pointing-Pointer Exhibiting green band photoemission peak at 540 nm.

A flow cytometric assay technology based on quantum dots-encoded beads

International Nuclear Information System (INIS)

Wang Haiqiao; Liu Tiancai; Cao Yuancheng; Huang Zhenli; Wang Jianhao; Li Xiuqing; Zhao Yuandi

2006-01-01

A flow cytometric detecting technology based on quantum dots (QDs)-encoded beads has been described. Using this technology, several QDs-encoded beads with different code were identified effectively, and the target molecule (DNA sequence) in solution was also detected accurately by coupling to its complementary sequence probed on QDs-encoded beads through DNA hybridization assay. The resolution of this technology for encoded beads is resulted from two longer wavelength fluorescence identification signals (yellow and red fluorescent signals of QDs), and the third shorter wavelength fluorescence signal (green reporting signal of fluorescein isothiocyanate (FITC)) for the determination of reaction between probe and target. In experiment, because of QDs' unique optical character, only one excitation light source was needed to excite the QDs and probe dye FITC synchronously comparing with other flow cytometric assay technology. The results show that this technology has present excellent repeatability and good accuracy. It will become a promising multiple assay platform in various application fields after further improvement

Development of alginate-based aggregate inoculants of Methylobacterium sp. and Azospirillum brasilense tested under in vitro conditions to promote plant growth.

Science.gov (United States)

Joe, M M; Saravanan, V S; Islam, M R; Sa, T

2014-02-01

To develop co-aggregated bacterial inoculant comprising of Methylobacterium oryzae CBMB20/Methylobacterium suomiense CBMB120 strains with Azospirillum brasilense (CW903) strain and testing their efficiency as inoculants for plant growth promotion (PGP). Biofilm formation and co-aggregation efficiency was studied between A. brasilense CW903 and methylobacterial strains M. oryzae CBMB20 and M. suomiense CBMB120. Survival and release of these co-aggregated bacterial strains entrapped in alginate beads were assessed. PGP attributes of the co-aggregated bacterial inoculant were tested in tomato plants under water-stressed conditions. Results suggest that the biofilm formation efficiency of the CBMB20 and CBMB120 strains increased by 15 and 34%, respectively, when co-cultivated with CW903. Co-aggregation with CW903 enhanced the survivability of CBMB20 strain in alginate beads. Water stress index score showed least stress index in plants inoculated with CW903 and CBMB20 strains maintained as a co-aggregated inoculant. This study reports the development of co-aggregated cell inoculants containing M. oryzae CBMB20 and A. brasilense CW903 strains conferred better shelf life and stress abatement in inoculated tomato plants. These findings could be extended to other PGP bacterial species to develop multigeneric bioinoculants with multiple benefits for various crops. © 2013 The Society for Applied Microbiology.

Ultrasonic force microscopy on poly(vinyl alcohol)/SrTiO3 nano-perovskites hybrid films

International Nuclear Information System (INIS)

Marino, Salvatore; Joshi, Girish M.; Lusuardi, Angelo; Cuberes, M. Teresa

2014-01-01

Atomic Force Microscopy (AFM) and Ultrasonic Force Microscopy (UFM) have been applied to the characterization of composite samples formed by SrTiO 3 (STO) nanoparticles (NPs) and polyvinyl alcohol (PVA). The morphological features of the STO NPs were much better resolved using UFM than contact-mode AFM topography. For high STO concentrations the individual STO NPs formed nanoclusters, which gathered in microaggregates. The STO aggregates, covered by PVA, exhibited no AFM frictional contrast, but were clearly distinguished from the PVA matrix using UFM. Similar aggregation was observed for NPs in the composite samples and for NPs deposited on top of a flat silicon substrate from milliQ water solution in the absence of polymer. In the hybrid films, most STO nanoparticles typically presented a lower UFM contrast than the PVA matrix, even though stiffer sample regions such as STO should give rise to a higher UFM contrast. STO NPs with intermediate contrast were characterized by an UFM halo of lower contrast at the PVA/STO interface. The results may be explained by considering that ultrasound is effectively damped on the nanometer scale at PVA/STO interfaces. According to our data, the nanoscale ultrasonic response at the PVA/STO interface plays a fundamental role in the UFM image contrast. - Highlights: • Hybrid films of SrTiO 3 nanoparticles and PVA have been studied using AFM, FFM and UFM. • The SrTiO 3 nanoparticles form nano-clusters from 3 to 5 individuals, which for high concentrations gather in micro-aggregates. • Most SrTiO 3 nanoparticles in the composite samples exhibited a lower (softer) UFM contrast than the PVA matrix. • In the UFM images, SrTiO 3 nanoparticles with intermediate contrast are delimited by a lower-contrast halo at the PVA boundary. • The nanoscale ultrasonic response at the PVA/SrTiO 3 interface plays a fundamental role in the UFM image contrast

Magnetic nanohydroxyapatite/PVA composite hydrogels for promoted osteoblast adhesion and proliferation.

Science.gov (United States)

Hou, Ruixia; Zhang, Guohua; Du, Gaolai; Zhan, Danxia; Cong, Yang; Cheng, Yajun; Fu, Jun

2013-03-01

This paper reports on the systematic investigation of novel magnetic nano-hydroxyapatite/PVA composite hydrogels through cyclic freeze-thawing with controllable structure, mechanical properties, and cell adhesion and proliferation properties. The content of the magnetic nano-hydroxyapatite-coated γ-Fe(2)O(3) (m-nHAP) particles exhibited remarkable influence on the porous structures and compressive strength of the nanocomposite hydrogels. The average pore diameter of the nanocomposite hydrogels exhibited a minimum of 1.6 ± 0.3 μm whereas the compressive strength reached a maximum of about 29.6 ± 6.5 MPa with the m-nHAP content of around 10 wt% in the nanocomposite hydrogels. In order to elucidate the influence of the composite m-nHAP on the cell adhesion and proliferation on the composite hydrogels, the PVA, γ-Fe(2)O(3)/PVA, nHAP/PVA and m-nHAP/PVA hydrogels were seeded and cultured with osteoblasts. The results demonstrated that the osteoblasts preferentially adhered to and proliferated on the m-nHAP/PVA hydrogels, in comparison to the PVA and nHAP/PVA hydrogels, whereas the γ-Fe(2)O(3)/PVA hydrogels appeared most favorable to the osteoblasts. Moreover, with the increasing m-nHAP content in the composite hydrogels, the adhesion density and proliferation of the osteoblasts were significantly promoted, especially at the content of around 50 wt%. Copyright © 2012 Elsevier B.V. All rights reserved.

Immobilization of Electroporated Cells for Fabrication of Cellular Biosensors: Physiological Effects of the Shape of Calcium Alginate Matrices and Foetal Calf Serum

Directory of Open Access Journals (Sweden)

Nikos Katsanakis

2009-01-01

Full Text Available In order to investigate the physiological effect of transfected cell immobilization in calcium alginate gels, we immobilized electroporated Vero cells in gels shaped either as spherical beads or as thin membrane layers. In addition, we investigated whether serum addition had a positive effect on cell proliferation and viability in either gel configuration. The gels were stored for four weeks in a medium supplemented or not with 20% (v/v foetal calf serum. Throughout a culture period of four weeks, cell proliferation and cell viability were assayed by optical microscopy after provision of Trypan Blue. Non-elaborate culture conditions (room temperature, non-CO2 enriched culture atmosphere were applied throughout the experimental period in order to evaluate cell viability under less than optimal storage conditions. Immobilization of electroporated cells was associated with an initially reduced cell viability, which was gradually increased. Immobilization was associated with maintenance of cell growth for the duration of the experimental period, whereas electroporated cells essentially died after a week in suspension culture. Considerable proliferation of immobilized cells was observed in spherical alginate beads. In both gel configurations, addition of serum was associated with increased cell proliferation. The results of the present study could contribute to an improvement of the storability of biosensors based on electroporated, genetically or membrane-engineered cells.

PLGA/alginate composite microspheres for hydrophilic protein delivery

International Nuclear Information System (INIS)

Zhai, Peng; Chen, X.B.; Schreyer, David J.

2015-01-01

Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility

PLGA/alginate composite microspheres for hydrophilic protein delivery

Energy Technology Data Exchange (ETDEWEB)

Zhai, Peng [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Chen, X.B. [Department of Mechanical Engineering, University of Saskatchewan, S7N5A9 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Schreyer, David J., E-mail: david.schreyer@usask.ca [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada)

2015-11-01

Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility.

Graphite coated PVA fibers as the reinforcement for cementitious composites

Science.gov (United States)

Zhang, Yunhua; Zhang, Zhipeng; Liu, Zhichao

2018-02-01

A new preconditioning method was developed to PVA fibers as the reinforcement in cement-based materials. Virgin PVA fibers exhibits limited adhesion to graphite powders due to the presence of oil spots on the surface. Mixing PVA fibers with a moderately concentrated KMnO4-H2SO4 solution can efficiently remove the oil spots by oxidation without creating extra precipitate (MnO2) associated with the reduction reaction. This enhances the coating of graphite powders onto fiber surface and improves the mechanical properties of PVA fiber reinforced concrete (PVA-FRC). Graphite powders yields better fiber distribution in the matrix and reduces the fiber-matrix bonding, which is beneficial in uniformly distributing the stress among embedded fibers and creating steady generation and propagation of tight microcracks. This is evidenced by the significantly enhanced strain hardening behavior and improved flexural strength and toughness.

Effect of polyvinyl alcohol content and after synthesis neutralization on structure, mechanical properties and cytotoxicity of sol-gel derived hybrid foams

Directory of Open Access Journals (Sweden)

Agda Aline Rocha de Oliveira

2009-06-01

Full Text Available Bioactive glass/polymer hybrids are promising materials for biomedical applications because they combine the bioactivity of these glasses with the flexibility of polymers. In this work it was evaluated the effect of increasing the PVA content of the on structural characteristics and mechanical properties of hybrid. The hybrids were prepared with 70 wt. (% SiO2-30 wt. (% CaO and PVA fractions of 20 to 60 wt. (% by the sol-gel method. The structural and mechanical characterization was done by FTIR, SEM and compression tests. To reduce the acidic character of the hybrids due to the catalysts added, different neutralization solutions were tested. The calcium acetate alcoholic solution was the best neutralizing method, resulting in foams with final pH of about 7.0 and small sample contraction. The foams presented porosity of 60-85 wt. (% and pore diameters of 100-500 μm with interconnected structure. An increase of PVA fraction in the hybrids improved their mechanical properties. The scaffolds produced provided a good environment for the adhesion and proliferation of osteoblasts.

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)

Ultrasonic force microscopy on poly(vinyl alcohol)/SrTiO{sub 3} nano-perovskites hybrid films

Energy Technology Data Exchange (ETDEWEB)

Marino, Salvatore, E-mail: smarino71@gmail.com [Laboratory of Nanotechnology, University of Castilla-La Mancha, Plaza Manuel Meca 1, 13400 Almadén (Spain); Joshi, Girish M. [Polymer Nanocomposite Laboratory, Materials Physics Division, School of Advanced Sciences VIT University, Vellore 14, Tamil Nadu (India); Lusuardi, Angelo [Laboratory of Nanotechnology, University of Castilla-La Mancha, Plaza Manuel Meca 1, 13400 Almadén (Spain); Cuberes, M. Teresa, E-mail: teresa.cuberes@uclm.es [Laboratory of Nanotechnology, University of Castilla-La Mancha, Plaza Manuel Meca 1, 13400 Almadén (Spain)

2014-07-01

Atomic Force Microscopy (AFM) and Ultrasonic Force Microscopy (UFM) have been applied to the characterization of composite samples formed by SrTiO{sub 3} (STO) nanoparticles (NPs) and polyvinyl alcohol (PVA). The morphological features of the STO NPs were much better resolved using UFM than contact-mode AFM topography. For high STO concentrations the individual STO NPs formed nanoclusters, which gathered in microaggregates. The STO aggregates, covered by PVA, exhibited no AFM frictional contrast, but were clearly distinguished from the PVA matrix using UFM. Similar aggregation was observed for NPs in the composite samples and for NPs deposited on top of a flat silicon substrate from milliQ water solution in the absence of polymer. In the hybrid films, most STO nanoparticles typically presented a lower UFM contrast than the PVA matrix, even though stiffer sample regions such as STO should give rise to a higher UFM contrast. STO NPs with intermediate contrast were characterized by an UFM halo of lower contrast at the PVA/STO interface. The results may be explained by considering that ultrasound is effectively damped on the nanometer scale at PVA/STO interfaces. According to our data, the nanoscale ultrasonic response at the PVA/STO interface plays a fundamental role in the UFM image contrast. - Highlights: • Hybrid films of SrTiO{sub 3} nanoparticles and PVA have been studied using AFM, FFM and UFM. • The SrTiO{sub 3} nanoparticles form nano-clusters from 3 to 5 individuals, which for high concentrations gather in micro-aggregates. • Most SrTiO{sub 3} nanoparticles in the composite samples exhibited a lower (softer) UFM contrast than the PVA matrix. • In the UFM images, SrTiO{sub 3} nanoparticles with intermediate contrast are delimited by a lower-contrast halo at the PVA boundary. • The nanoscale ultrasonic response at the PVA/SrTiO{sub 3} interface plays a fundamental role in the UFM image contrast.

Design of a Novel Two-Component Hybrid Dermal Scaffold for the Treatment of Pressure Sores.

Science.gov (United States)

Sharma, Vaibhav; Kohli, Nupur; Moulding, Dale; Afolabi, Halimat; Hook, Lilian; Mason, Chris; García-Gareta, Elena

2017-11-01

The aim of this study is to design a novel two-component hybrid scaffold using the fibrin/alginate porous hydrogel Smart Matrix combined to a backing layer of plasma polymerized polydimethylsiloxane (Sil) membrane to make the fibrin-based dermal scaffold more robust for the treatment of the clinically challenging pressure sores. A design criteria are established, according to which the Sil membranes are punched to avoid collection of fluid underneath. Manual peel test shows that native silicone does not attach to the fibrin/alginate component while the plasma polymerized silicone membranes are firmly bound to fibrin/alginate. Structural characterization shows that the fibrin/alginate matrix is intact after the addition of the Sil membrane. By adding a Sil membrane to the original fibrin/alginate scaffold, the resulting two-component scaffolds have a significantly higher shear or storage modulus G'. In vitro cell studies show that dermal fibroblasts remain viable, proliferate, and infiltrate the two-component hybrid scaffolds during the culture period. These results show that the design of a novel two-component hybrid dermal scaffold is successful according to the proposed design criteria. To the best of the authors' knowledge, this is the first study that reports the combination of a fibrin-based scaffold with a plasma-polymerized silicone membrane. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

21 CFR 582.7187 - Calcium alginate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is generally...

Physical Evaluation of PVA/Chitosan Film Blends with Glycerine and Calcium Chloride

Science.gov (United States)

Nugraheni, A. D.; Purnawati, D.; Kusumaatmaja, A.

2018-04-01

PVA/chitosan film has been fabricated by using drop casting method. PVA/chitosan film is produced by dissolving 2% (w/v) PVA solution and 2% (w/v) chitosan solution. PVA/chitosan film is produced with weight ratio variation (w/w) 100/0, 75/25, 50/50 and 0/100. The film is fabricated using drop casting method in Petry dish with diameter 11 cm at room temperature and RH 50%–60% during seven days. The mechanical properties were characterized by using Universal Technical Machine (UTM) and UV-Vis to understand the physical properties of weight ratio (w/w) of PVA/Chitosan film by addition of plasticizer and calcium chloride. The film thickness tends to decrease with PVA content. The addition of chitosan will increase film thickness, and it will decrease swelling index, elongation (%), and transmittance of UV rays. The additions of plasticizer to PVA/Chitosan film will increase film thickness and elongation (%), and it will decrease swelling index, tensile strength and transmittance of UV rays. The crosslink of PVA/Chitosan film with calcium chloride will decrease film thickness, swelling index, elongation (%) and transmittance of UV rays, and increase tensile strength.

Development of Wax-Incorporated Emulsion Gel Beads for the Encapsulation and Intragastric Floating Delivery of the Active Antioxidant from Tamarindus indica L.

Science.gov (United States)

Soradech, Sitthiphong; Petchtubtim, Intira; Thongdon-A, Jeerayu; Muangman, Thanchanok

2016-03-22

In this study, tamarind (Tamarindus indica L.) seed extracts with potential antioxidant activity and toxicity to cancer cells were developed as functional foods and nutraceutical ingredients in the form of emulsion gel beads. Three extracts were obtained from ethanol and water: TSCH50, TSCH95 and TSCH. All extracts exhibited high potential for superoxide anion scavenging activity over the IC50 range emulsion gel beads, which were prepared using a modified ionotropic gelation technique. Tamarind seed extract at 1% (w/w) was used as the active ingredient in all formulations. The effect of the types and amounts of wax on the encapsulation efficiency and percentage of the active release of alginate gel beads was also investigated. The results demonstrated that the incorporation of both waxes into the gel beads had an effect on the percentage of encapsulation efficiency (%) and the percentage of the active ingredient release. Furthermore, the addition of water insoluble waxes (carnauba and bee wax) significantly retarded the release of the active ingredient. The addition of both waxes had a slight effect on drug release behavior. Nevertheless, the increase in incorporated waxes in all formulations could sustain the percentage of active ingredient release. In conclusion, wax-incorporated emulsion gel beads using a modified ionotropic gelation technique could be applied for the intragastric floating delivery and controlled release of functional food and nutraceutical products for their antioxidant and anticancer capacity.

New multifunctional materials obtained by the intercalation of anionic dyes into layered zinc hydroxide nitrate followed by dispersion into poly(vinyl alcohol) (PVA).

Science.gov (United States)

Marangoni, Rafael; Ramos, Luiz Pereira; Wypych, Fernando

2009-02-15

Different anionic blue and orange dyes have been immobilized on a zinc hydroxide nitrate (Zn(5)(OH)(8)(NO(3))(2)nH(2)O--Zn-OH-NO(3)) by anion exchange with interlayer and/or outer surface nitrate ions of the layered matrix. Orange G (OG) was totally intercalated, orange II (OII) was partially intercalated, while Niagara blue 3B (NB) and Evans blue (EV) were only adsorbed at the outer surface. Several composite films of poly(vinyl alcohol)--PVA were prepared by casting through the dispersion of the hybrid material (Zn-OH-OG) into a PVA aqueous solution and evaporation of water in a vacuum oven. The obtained composite films were transparent, colored, and capable of absorbing UV radiation. Improved mechanical properties were also obtained in relation to the nonfilled PVA films. These results demonstrate the onset of a new range of potential applications for layered hydroxide salts in the preparation of polymer composite multifunctional materials.

Chemical synthesis of highly stable PVA/PANI films for supercapacitor application

Energy Technology Data Exchange (ETDEWEB)

Patil, D.S.; Shaikh, J.S.; Dalavi, D.S.; Kalagi, S.S. [Thin Films Materials laboratory, Department of Physics, Shivaji University, Kolhapur 416004, M.S. (India); Patil, P.S., E-mail: psp_phy@unishivaji.ac.in [Thin Films Materials laboratory, Department of Physics, Shivaji University, Kolhapur 416004, M.S. (India)

2011-08-15

Highlights: {yields} Chemical synthesis of PVA/PANI films by spin and dip coating at room temperature. {yields} Thickness dependent supercapacitor behavior of PVA/PANI film. {yields} The synthesized film are highly stable up to 20,000 cycles. - Abstract: Polyvinyl alcohol (PVA)/polyaniline (PANI) thin films were chemically synthesized by adopting two step process: initially a thin layer (200 nm) of PVA was spin coated by using an aqueous PVA solution onto fluorine doped tin oxide (FTO) coated glass substrate, afterwards PANI was chemically polymerized from aniline monomer and dip coated onto the precoated substrate. The thickness of PANI layer was varied from 293 nm to 2367 nm by varying deposition cycles onto the precoated PVA thin film. The resultant PVA/PANI films were characterized for their optical, morphological and electrochemical properties. The FT-IR and Raman spectra revealed characteristic features of the PANI phase. The SEM study showed porous spongy structure. Electrochemical properties were studied by electrochemical impedance measurement and cyclic voltammetry. The electrochemical performance of PVA/PANI thin films was investigated in 1 M H{sub 2}SO{sub 4} aqueous electrolyte. The highest specific capacitance of 571 Fg{sup -1} was observed for the optimized thickness of 880 nm. The film was found to be stable for more than 20,000 cycles. The samples degraded slightly (25% decrement in specific capacitance) for the first 10,000 cycles. The degradation becomes much slower (10.8% decrement in specific capacitance) beyond 10,000 cycles. This dramatic improvement in the electrochemical stability of the PANI samples, without sacrificing specific capacitance was attributed to the optimized PVA layer.

Electromechanical properties of nanotube-PVA composite actuator bimorphs

International Nuclear Information System (INIS)

Bartholome, Christele; Derre, Alain; Roubeau, Olivier; Zakri, Cecile; Poulin, Philippe

2008-01-01

Oxidized multiwalled carbon nanotube (oxidized-MWNT)/polyvinyl alcohol (PVA) composite sheets have been prepared for electromechanical actuator applications. MWNT have been oxidized by nitric acid treatments. They were then dispersed in water and mixed with various amounts of PVA of high molecular weight (198 000 g mol -1 ). The composite sheets were then obtained through a membrane filtration process. The composition of the systems has been optimized to combine suitable mechanical and electrical properties. Thermogravimetric analysis, mechanical tensile tests and conductivity measurements show that the best compromise of mechanical and electrical properties was obtained for a PVA weight fraction of about 30 wt%. In addition, one face of the sheets was coated with gold to increase the conductivity of the sheets and promote uniform actuation. Pseudo-bimorph devices have been realized by subsequently coating the composite sheets with an inert layer of PVA. The devices have been tested electromechanically in a liquid electrolyte (tetrabutylammonium/tetrafluoroborate (TBA/TFB) in acetonitrile) at constant frequency and different applied voltages, from 2 to 10 V. Measurements of the bimorph deflections were used to determine the stress generated by the nanotube-PVA sheets. The results show that the stress generated increases with increasing amplitude of the applied voltage and can reach 1.8 MPa. This value compares well with and even exceeds the stress generated by recently obtained bimorphs made of gold nanoparticles

Novel electroactive PVA-TOCN actuator that is extremely sensitive to low electrical inputs

International Nuclear Information System (INIS)

Wang, Fan; Kim, Si-Seup; Kee, Chang-Doo; Shen, Yun-De; Oh, Il-Kwon

2014-01-01

A novel electroactive biopolymer actuator was developed based on a cross-linked ionic networking membrane of TEMPO-oxidized bacterial cellulose nanofibers (TOCNs) and polyvinyl alcohol (PVA). Ionic liquids were added to develop an air-working artificial muscle and to enhance the performance of the PVA-TOCN actuator. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conducting layers were deposited on the top and bottom surfaces of the PVA-TOCN membrane via a simple dipping and drying method. The electroactive PVA-TOCN actuator under both step and harmonic electrical inputs shows much larger tip displacements and faster bending deformation than the pure TOCN actuator. The cross-linking reaction between PVA and TOCN was observed in the Fourier transform–near-infrared (FT-IR) spectrum of the PVA-TOCN networking membrane. Scanning electron microscopy (SEM), x-ray diffusion (XRD), thermogravimetric analysis (TGA) and tensile and ion conductivity testing results for the PVA-TOCN membrane were compared with those of pristine TOCN. Most important, the PVA-TOCN actuator shows much larger bending deformation under even extremely low input voltages, and this could be attributed to the cross-linking mechanism and the greater flexibility resulting from the synergistic effects between PVA and TOCN. (papers)

Structural Properties of Nanoparticles TiO2/PVA Polymeric Films

Directory of Open Access Journals (Sweden)

Samara A. Madhloom

2018-04-01

Full Text Available In this research, X-ray diffraction of the powder (PVA polymer, titanium dioxide with two parti-cle sizes and (TiO2 (15.7 nm/PVA and TiO2 (45.7 nm/PVA films have been studied,the amount of polymer is (0.5 g and (0.01g from each particle sizes of nanoparticles will be used. Casting method is used to prepare homogeneous films on glass petri dishes. All parameters ac-counted for the X-ray diffraction; full width half maximum (FWHM, Miller indices (hkl, size of crystalline (D, Specific Surface Area (S and Dislocation Density (δ. The nature of the structural of materials and films will be investigated. The XRD pattern of PVA polymer has semi-crystalline nature and the titanium dioxide with two particle sizes have crystalline structure; ana-tase type. While the mixture between these materials led to appearing some crystalline peaks into XRD pattern of PVA polymer

Bioactive polymeric–ceramic hybrid 3D scaffold for application in bone tissue regeneration

Energy Technology Data Exchange (ETDEWEB)

Torres, A.L.; Gaspar, V.M.; Serra, I.R.; Diogo, G.S.; Fradique, R. [CICS-UBI — Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã (Portugal); Silva, A.P. [CAST-UBI — Centre for Aerospace Science and Technologies, University of Beira Interior, Calçada Fonte do Lameiro, 6201-001 Covilhã (Portugal); Correia, I.J., E-mail: icorreia@ubi.pt [CICS-UBI — Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã (Portugal)

2013-10-01

The regeneration of large bone defects remains a challenging scenario from a therapeutic point of view. In fact, the currently available bone substitutes are often limited by poor tissue integration and severe host inflammatory responses, which eventually lead to surgical removal. In an attempt to address these issues, herein we evaluated the importance of alginate incorporation in the production of improved and tunable β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) three-dimensional (3D) porous scaffolds to be used as temporary templates for bone regeneration. Different bioceramic combinations were tested in order to investigate optimal scaffold architectures. Additionally, 3D β-TCP/HA vacuum-coated with alginate, presented improved compressive strength, fracture toughness and Young's modulus, to values similar to those of native bone. The hybrid 3D polymeric–bioceramic scaffolds also supported osteoblast adhesion, maturation and proliferation, as demonstrated by fluorescence microscopy. To the best of our knowledge this is the first time that a 3D scaffold produced with this combination of biomaterials is described. Altogether, our results emphasize that this hybrid scaffold presents promising characteristics for its future application in bone regeneration. - Graphical abstract: B-TCP:HA–alginate hybrid 3D porous scaffolds for application in bone regeneration. - Highlights: • The produced hybrid 3D scaffolds are prone to be applied in bone tissue engineering. • Alginate coated 3D scaffolds present high mechanical and biological properties. • In vitro assays for evaluation of human osteoblast cell attachment in the presence of the scaffolds • The hybrid 3D scaffolds present suitable mechanical and biological properties for use in bone regenerative medicine.

Bioactive polymeric–ceramic hybrid 3D scaffold for application in bone tissue regeneration

International Nuclear Information System (INIS)

Torres, A.L.; Gaspar, V.M.; Serra, I.R.; Diogo, G.S.; Fradique, R.; Silva, A.P.; Correia, I.J.

2013-01-01

The regeneration of large bone defects remains a challenging scenario from a therapeutic point of view. In fact, the currently available bone substitutes are often limited by poor tissue integration and severe host inflammatory responses, which eventually lead to surgical removal. In an attempt to address these issues, herein we evaluated the importance of alginate incorporation in the production of improved and tunable β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) three-dimensional (3D) porous scaffolds to be used as temporary templates for bone regeneration. Different bioceramic combinations were tested in order to investigate optimal scaffold architectures. Additionally, 3D β-TCP/HA vacuum-coated with alginate, presented improved compressive strength, fracture toughness and Young's modulus, to values similar to those of native bone. The hybrid 3D polymeric–bioceramic scaffolds also supported osteoblast adhesion, maturation and proliferation, as demonstrated by fluorescence microscopy. To the best of our knowledge this is the first time that a 3D scaffold produced with this combination of biomaterials is described. Altogether, our results emphasize that this hybrid scaffold presents promising characteristics for its future application in bone regeneration. - Graphical abstract: B-TCP:HA–alginate hybrid 3D porous scaffolds for application in bone regeneration. - Highlights: • The produced hybrid 3D scaffolds are prone to be applied in bone tissue engineering. • Alginate coated 3D scaffolds present high mechanical and biological properties. • In vitro assays for evaluation of human osteoblast cell attachment in the presence of the scaffolds • The hybrid 3D scaffolds present suitable mechanical and biological properties for use in bone regenerative medicine

[The appraisal of mechanical properties and friction coefficient of PVA hydro-gel].

Science.gov (United States)

Chen, Liqi; Zhang, Dekun; Zhang, Jinsong

2009-10-01

Gelatin and hydroxyapatite were introduced to polyvinyl alcohol (PVA) hydrogel with an attempt to enhance the performances of PVA hydrogel. Through a reiterative freezing-thawing methods, three kinds of PVA composite hydrogels were prepared. The mechanical performances of these composite hydrogels with the same PVA and HA content but varying gelatin content, such as tensile strength, elasticity modulus, creep curve, relaxation curve and friction coefficient were evaluated by using a computer-controlled universal electronic mechanical testing machine and a UMT-II frictional testing machine. The additional effects of hydroxylapatite and varying gelatin on the performances of composite PVA hydro-gels were analyzed. It was found that the gelatin content directly influenced the physical performances of PVA composite hydrogels; but no linear relationship was recorded. PVA composite hydrogel containing 2wt-% gelatin gave optimal results, i.e. tensile strength of 5.5MPa, compressive elastical modulus of 1.48MPa, creeping rate of 31% in 45 minutes, stress relaxing rate of 40.3%, and the starting friction coefficient of 0.332.

Novel PVA-DNA nanoparticles prepared by ultra high pressure technology for gene delivery

International Nuclear Information System (INIS)

Kimura, Tsuyoshi; Okuno, Akira; Miyazaki, Kozo; Furuzono, Tsutomu; Ohya, Yuichi; Ouchi, Tatsuro; Mutsuo, Shingo; Yoshizawa, Hidekazu; Kitamura, Yoshiro; Fujisato, Toshiyta; Kishida, Akio

2004-01-01

Polyvinyl alcohol (PVA)-DNA nanoparticles have been developed by ultra high pressure (UHP) technology. Mixture solutions of DNA and PVA having various molecular weights (Mw) and degree of saponifications (DS) were treated under 10,000 atmospheres (981 MPa) condition at 40 deg. C for 10 min. Agarose gel electrophoresis and scanning electron microscope observation revealed that the PVA-DNA nanoparticles with average diameter of about 200 nm were formed. Using PVA of higher Mw and degree of saponifications, the amount of nanoparticles formed increased. The driving force of nanoparticle formation was the hydrogen bonding between DNA and PVA. In order to apply the PVA-DNA nanoparticles for gene delivery, the cytotoxicity and the cellular uptake of them were investigated using Raw264 cell lines. The cell viability was not influenced whether the presence of the PVA-DNA nanoparticles. Further, the nanoparticles internalized into cells were observed by fluorescent microscope. These results indicates that the PVA-DNA nanoparticles prepared by UHP technology showed be useful as drug carrier, especially for gene delivery

Enzymatic transesterification of soybean oil with ethanol using lipases immobilized on highly crystalline PVA microspheres

International Nuclear Information System (INIS)

Bergamasco, Juliana; Araujo, Marcelo V. de; Vasconcellos, Adriano de; Luizon Filho, Roberto A.; Hatanaka, Rafael R.; Giotto, Marcus V.; Aranda, Donato A.G.; Nery, José G.

2013-01-01

Polyvinyl alcohol (PVA) microspheres with different degree of crystallinity were used as solid supports for Rhizomucor miehei lipase immobilization, and the enzyme-PVA complexes were used as biocatalysts for the transesterification of soybean oil to fatty acid ethyl esters (FAEE). The amounts of immobilized enzyme on the polymeric supports were similar for both the amorphous microspheres (PVA4) and the high crystalline microspheres (PVA25). However, the enzymatic activity of the immobilized enzymes was depended on the crystallinity degree of the PVA microspheres: enzymes immobilized on the PVA4 microspheres have shown low enzymatic activity (6.13 U mg −1 ), in comparison with enzymes immobilized on the high crystalline PVA25 microspheres (149.15 U mg −1 ). A synergistic effect was observed for the enzyme-PVA25 complex during the transesterification reaction of soybean oil to FAEE: transesterification reactions with free enzyme with the equivalent amount of enzyme that were immobilized onto the PVA25 microspheres (5.4 U) have yielded only 20% of FAEE, reactions with the pure highly crystalline microsphere PVA25 have not yielded FAEE, however reactions with the enzyme-PVA25 complexes have yielded 66.3% of FAEE. This synergistic effect of an immobilized enzyme on a polymeric support has not been observed before for transesterification reaction of triacylglycerides into FAEE. Based on ATR-FTIR, 23 Na- and 13 C-NMR-MAS spectroscopic data and the interaction of the polymeric network intermolecular hydrogen bonds with the lipases residual amino acids a possible explanation for this synergistic effect is provided. Highlights: • Rhizomucor miehei lipase was immobilized on PVA microspheres (PVA4, PVA12, PVA25). • Polymer-enzyme complex was characterized by XDR, SEM, ATR-FTIR, 13 C-CPMAS-NMR, 23 Na-MAS-NMR. • Polymer-enzymes (PVA12 and PVA25) enzymes yielded considerable amount of ethyl esters. • Synergistic effect was observed for the polymer-enzyme complexes

Optimisation of nutritional requirements for dopamine synthesis by calcium alginate-entrapped mutant strain of Aspergillus oryzae EMS-6.

Science.gov (United States)

Ali, Sikander; Nawaz, Wajeeha

2017-02-01

The optimisation of nutritional requirements for dopamine (DA) synthesis by calcium alginate-entrapped mutant variant of Aspergillus oryzae EMS-6 using submerged fermentation technique was investigated. A total of 13 strains were isolated from soil. Isolate I-2 was selected as a better producer of DA and improved by exposing with ethyl methylsulphonate (EMS). EMS-6 was selected as it exhibited 43 μg/mL DA activity. The mutant variable was further treated with low levels of l-cysteine HCl to make it resistant against diversion and environmental stress. The conidiospores of mutant variant were entrapped in calcium alginate beads for stable product formation. EMS-6 gave maximum DA activity (124 μg/mL) when supplemented with 0.1% peptone and 0.2% sucrose, under optimised parameters viz. pH 3, temperature of 55 °C and incubation time of 70 min. The study involves the high profile of DA activity and is needed, as DA is capable to control numerous neurogenic disorders.

(Zn-doped PVA)/n-4H-SiC (MPS)

Indian Academy of Sciences (India)

2018-05-23

May 23, 2018 ... A comparative study on dielectric behaviours of Au/(Zn-doped. PVA)/n-4H-SiC .... To form MPS structures, the prepared PVA (Zn nanoparticle- doped) ..... 95 2885. [26] MacCallum J R and Vincent C A 1989 Polymer electrolyte.

Optical studies of CdSe/PVA nanocomposite films

Science.gov (United States)

Kushwaha, Kamal Kumar; Ramrakhaini, Meera

2018-05-01

The nanocomposite films of CdSe nanocrystals in polyvinyl alcohol (PVA) matrix were synthesized by environmental friendly chemical method. These composites were characterized by X-ray diffraction which indicates the hexagonal crystalline structure of CdSe with crystal size up to a few nm. The crystal size is found to decrease by increasing PVA Concentration. The photoluminescence (PL) characteristics of these composite films with varying concentration of PVA as well as Cd2+ content have been investigated. The PL peak of CdSe was observed at 510 nm and higher intensity is observed by increasing PVA concentration without any change in position of PL peak. Due to proper passivation of surface states non-radiative transition are reduced which enhance the PL intensity. By increasing concentration of Cd2+ content in the CdSe/PVA nanocomposite films, smaller CdSe nanocrystals were obtained giving higher intensity and blue shift in the PL peak due to enhanced oscillator strength and quantum confinement effect. The PL peak in green and blue region makes these composite films promising materials for optical display devices. The Refractive index of these composites was also measured at sodium line with the help of Abee's refractometer and was found in the range of 2.20-2.45. It is seen that refractive index varies with polymer concentration. This may be useful for their potential application in anti-reflection coating, display devices and optical sensors.

Strength development of high-strength ductile concrete incorporating Metakaolin and PVA fibers.

Science.gov (United States)

Nuruddin, Muhammad Fadhil; Khan, Sadaqat Ullah; Shafiq, Nasir; Ayub, Tehmina

2014-01-01

The mechanical properties of high-strength ductile concrete (HSDC) have been investigated using Metakaolin (MK) as the cement replacing material and PVA fibers. Total twenty-seven (27) mixes of concrete have been examined with varying content of MK and PVA fibers. It has been found that the coarser type PVA fibers provide strengths competitive to control or higher than control. Concrete with coarser type PVA fibers has also refined microstructure, but the microstructure has been undergone with the increase in aspect ratio of fibers. The microstructure of concrete with MK has also more refined and packing of material is much better with MK. PVA fibers not only give higher stiffness but also showed the deflection hardening response. Toughness Index of HSDC reflects the improvement in flexural toughness over the plain concrete and the maximum toughness indices have been observed with 10% MK and 2% volume fraction of PVA fibers.

Synthesis and optical properties of CdS/PVA nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Khanna, P K [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India); Gokhale, R R [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India); Subbarao, V V.V.S. [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India); Singh, Narendra [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India); Jun, K -W [Korea Research Institute of Chemical Technology, P.O. Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of); Das, B K [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India)

2005-12-15

Yellow and orange light emission from nanoparticles of cadmium sulphide embedded in polyvinyl alcohol (PVA) has been observed as thin films. The synthesis of CdS embedded in PVA has been performed via two different routes at room temperature and the composite films have been prepared by vacuum evaporation of solvent on a glass surface. The absorption spectra show a blue shift of more than 80 nm as compared to bulk CdS band-gap. The photoluminescence studies indicate the air stable light emission from the films. Bright light emission at 515 nm (2.41 eV) has been observed without using PVA.

Efficient functionalization of alginate biomaterials.

Science.gov (United States)

Dalheim, Marianne Ø; Vanacker, Julie; Najmi, Maryam A; Aachmann, Finn L; Strand, Berit L; Christensen, Bjørn E

2016-02-01

Peptide coupled alginates obtained by chemical functionalization of alginates are commonly used as scaffold materials for cells in regenerative medicine and tissue engineering. We here present an alternative to the commonly used carbodiimide chemistry, using partial periodate oxidation followed by reductive amination. High and precise degrees of substitution were obtained with high reproducibility, and without formation of by-products. A protocol was established using l-Tyrosine methyl ester as a model compound and the non-toxic pic-BH3 as the reducing agent. DOSY was used to indirectly verify covalent binding and the structure of the product was further elucidated using NMR spectroscopy. The coupling efficiency was to some extent dependent on alginate composition, being most efficient on mannuronan. Three different bioactive peptide sequences (GRGDYP, GRGDSP and KHIFSDDSSE) were coupled to 8% periodate oxidized alginate resulting in degrees of substitution between 3.9 and 6.9%. Cell adhesion studies of mouse myoblasts (C2C12) and human dental stem cells (RP89) to gels containing various amounts of GRGDSP coupled alginate demonstrated the bioactivity of the material where RP89 cells needed higher peptide concentrations to adhere. Copyright © 2015 Elsevier Ltd. All rights reserved.

Structure and sorption properties of CNC reinforced PVA films.

Science.gov (United States)

Popescu, Maria-Cristina

2017-08-01

Bio-nanocomposite films based on cellulose nanocrystals reinforced poly(vinyl alcohol) were obtained by solvent casting method. To assess the structural features of the films, different spectral techniques (FTIR, 2D COS and XRD) have been used. Infrared and 2D correlation spectroscopy evidenced the presence of H-bond interactions between the PVA and CNC, and the variation in the conformational rearrangements, while XRD showed that the crystallite size and the crystallinity degree were affected by the incorporation of CNC. At low content of CNC in the PVA matrix, the crystallinity degree decreased to 29.9%, while at higher CNC content increased to 80.6%, comparing to PVA (35.4%). To evaluate the interaction with water, contact angle measurement, water sorption and NIR spectroscopy were used, respectively. The increase of the CNC content induced a reduction in water sorption ability from 93% for PVA to 75% for PVA/CNC films, indicating the involvement of the hydroxyl groups in new hydrogen bonded interactions. By analyzing the variation of the NIR bands from 1930, 1902 and 1985nm, was observed that the water molecules interact with the polymer matrix through moderate hydrogen bond before diffusing into the free volume of the matrix and form stronger hydrogen bonds. Copyright © 2017 Elsevier B.V. All rights reserved.

Luminescence study of ZnSe/PVA (polyvinyl alcohol) composite film

Energy Technology Data Exchange (ETDEWEB)

Lahariya, Vikas [Amity School of Applied Science, Amity University Haryana Panchgaon, Manesar, Haryana 122413 (India)

2016-05-06

The ZnSe nanocrystals have been prepared into poly vinyl alcohol(PVA) polymer matrix on glass using ZnCl2 and Na2SeSO3 as zinc and selenium source respectively. Poly vinyl Alcohol (PVA) used as polymer matrix cum capping agent due to their high viscosity and water solubility. It is transparent for visible region and prevents Se- ions to photo oxidation. The ZnSe/PVA composite film was deposited on glass substrate. The film was characterized by X Ray Diffraction (XRD) and UV-Visible absorption Spectroscopy and Photoluminescence. The X Ray Diffraction (XRD) study confirms the nanometer size (10 nm) particle formation within PVA matrix with cubic zinc blend crystal structure. The UV-Visible Absorption spectrum of ZnSe/PVA composite film shown blue shift in absorption edge indicating increased band gap due to quantum confinement. The calculated energy band gap from the absorption edge using Tauc relation is 3.4 eV. From the Photoluminescence study a broad peak at 435 nm has been observed in violet blue region due to recombination of surface states.

Preparation and Characterization of Starch-g-PVA/Nano-hydroxyapatite Complex Hydrogel

Institute of Scientific and Technical Information of China (English)

无

2005-01-01

Starch-g-PVA/hydroxyapatite complex hydrogel was prepared with two-repeated freezing/ thawing circles. SEM observation results exhibits that hydroxyapatite is dispersed in starch-g-PVA in nanoscale. Thermogravimetric analysis curves show that the remained fraction keeps the same at the temperatures higher than 490℃ . It was found the dried starch-g- PVA/ hydroxyapatite films could reswell within 12 minutes.

Pseudomonas aeruginosa aggregate formation in an alginate bead model system exhibits In Vivo-like characteristics

DEFF Research Database (Denmark)

Sønderholm, Majken; Kragh, Kasper Nørskov; Koren, Klaus

2017-01-01

similar in size to in vivo aggregates observed ex vivo in cystic fibrosis lungs and chronic wounds. Bacterial aggregates primarily grew in the bead periphery and decreased in size and abundance toward the center of the bead. Microsensor measurements showed that the O2 concentration decreased rapidly...... and flexible in vivo-like biofilm model system, wherein bacterial growth exhibits central features of in vivo biofilms. This was observed by the formation of small cell aggregates in a secondary matrix with O2-limited growth, which was alleviated by the addition of NO3− as an alternative electron acceptor...

Mechanically stable antimicrobial chitosan-PVA-silver nanocomposite coatings deposited on titanium implants.

Science.gov (United States)

Mishra, Sandeep K; Ferreira, J M F; Kannan, S

2015-05-05

Bionanocomposite coatings with antimicrobial activity comprising polyvinyl alcohol (PVA)-capped silver nanoparticles embedded in chitosan (CS) matrix were developed by a green soft chemistry synthesis route. Colloidal sols of PVA-capped silver nanoparticles (AgNPs) were synthesized by microwave irradiating an aqueous solution comprising silver nitrate and PVA. The bionanocomposites were prepared by adding an aqueous solution of chitosan to the synthesized PVA-capped AgNPs sols in appropriate ratios. Uniform bionanocomposite coatings with different contents of PVA-capped AgNPs were deposited onto titanium substrates by "spread casting" followed by solvent evaporation. Nanoindentation and antimicrobial activity tests performed on CS and bionanocomposites revealed that the incorporation of PVA-capped AgNPs enhanced the overall functional properties of the coatings, namely their mechanical stability and bactericidal activity against Escherichia coli and Staphylococcus aureus. The coated specimens maintained their antimicrobial activity for 8h due to the slow sustained release of silver ions. The overall benefits for the relevant functional properties of the coatings were shown increase with increasing contents of PVA-capped AgNPs in the bionanocomposites. Copyright © 2015 Elsevier Ltd. All rights reserved.

Strength Development of High-Strength Ductile Concrete Incorporating Metakaolin and PVA Fibers

Directory of Open Access Journals (Sweden)

Muhammad Fadhil Nuruddin

2014-01-01

Full Text Available The mechanical properties of high-strength ductile concrete (HSDC have been investigated using Metakaolin (MK as the cement replacing material and PVA fibers. Total twenty-seven (27 mixes of concrete have been examined with varying content of MK and PVA fibers. It has been found that the coarser type PVA fibers provide strengths competitive to control or higher than control. Concrete with coarser type PVA fibers has also refined microstructure, but the microstructure has been undergone with the increase in aspect ratio of fibers. The microstructure of concrete with MK has also more refined and packing of material is much better with MK. PVA fibers not only give higher stiffness but also showed the deflection hardening response. Toughness Index of HSDC reflects the improvement in flexural toughness over the plain concrete and the maximum toughness indices have been observed with 10% MK and 2% volume fraction of PVA fibers.

Doxorubicin loaded PVA coated iron oxide nanoparticles for targeted drug delivery

International Nuclear Information System (INIS)

Kayal, S.; Ramanujan, R.V.

2010-01-01

Magnetic drug targeting is a drug delivery system that can be used in locoregional cancer treatment. Coated magnetic particles, called carriers, are very useful for delivering chemotherapeutic drugs. Magnetic carriers were synthesized by coprecipitation of iron oxide followed by coating with polyvinyl alcohol (PVA). Characterization was carried out using X-ray diffraction, TEM, TGA, FTIR and VSM techniques. The magnetic core of the carriers was magnetite (Fe 3 O 4 ), with average size of 10 nm. The room temperature VSM measurements showed that magnetic particles were superparamagnetic. The amount of PVA bound to the iron oxide nanoparticles were estimated by thermogravimetric analysis (TGA) and the attachment of PVA to the iron oxide nanoparticles was confirmed by FTIR analysis. Doxorubicin (DOX) drug loading and release profiles of PVA coated iron oxide nanoparticles showed that up to 45% of adsorbed drug was released in 80 h, the drug release followed the Fickian diffusion-controlled process. The binding of DOX to the PVA was confirmed by FTIR analysis. The present findings show that DOX loaded PVA coated iron oxide nanoparticles are promising for magnetically targeted drug delivery.

Coaxial PCL/PVA electrospun nanofibers: osseointegration enhancer and controlled drug release device

International Nuclear Information System (INIS)

Song, Wei; Shi, Tong; Ren, Weiping; Yu, Xiaowei; Markel, David C

2013-01-01

The failure of prosthesis after total joint replacement is mainly due to dysfunctional osseointegration and implant infection. There is a critical need for orthopedic implants that promote rapid osseointegration and prevent bacterial colonization, particularly when placed in bone compromised by disease or physiology of the patients. The aim of this study was to fabricate a novel coaxial electrospun polycaprolactone (PCL)/polyvinyl alcohol (PVA) core-sheath nanofiber (NF) blended with both hydroxyapatite nanorods (HA) and type I collagen (Col) (PCL Col /PVA HA ). Doxycycline (Doxy) and dexamethasone (Dex) were successfully incorporated into the PCL Col /PVA HA NFs for controlled release. The morphology, surface hydrophilicity and mechanical properties of the PCL/PVA NF mats were analyzed by scanning electron microscopy, water contact angle and atomic force microscopy. The PCL Col /PVA HA NFs are biocompatible and enhance the adhesion and proliferation of murine pre-osteoblastic MC3T3 cells. The release of Doxy and Dex from coaxial PCL Col /PVA HA NFs showed more controlled release compared with the blended NFs. Using an ex vivo porcine bone implantation model we found that the PCL Col /PVA HA NFs bind firmly on the titanium rod surface and the NFs coating remained intact on the surface of titanium rods after pullout. No disruption or delamination was observed after the pullout test. These findings indicate that PCL Col /PVA HA NFs encapsulating drugs have great potential in enhancing implant osseointegration and preventing implant infection. (paper)

Coaxial PCL/PVA electrospun nanofibers: osseointegration enhancer and controlled drug release device.

Science.gov (United States)

Song, Wei; Yu, Xiaowei; Markel, David C; Shi, Tong; Ren, Weiping

2013-09-01

The failure of prosthesis after total joint replacement is mainly due to dysfunctional osseointegration and implant infection. There is a critical need for orthopedic implants that promote rapid osseointegration and prevent bacterial colonization, particularly when placed in bone compromised by disease or physiology of the patients. The aim of this study was to fabricate a novel coaxial electrospun polycaprolactone (PCL)/polyvinyl alcohol (PVA) core-sheath nanofiber (NF) blended with both hydroxyapatite nanorods (HA) and type I collagen (Col) (PCL(Col)/PVA(HA)). Doxycycline (Doxy) and dexamethasone (Dex) were successfully incorporated into the PCL(Col)/PVA(HA) NFs for controlled release. The morphology, surface hydrophilicity and mechanical properties of the PCL/PVA NF mats were analyzed by scanning electron microscopy, water contact angle and atomic force microscopy. The PCL(Col)/PVA(HA) NFs are biocompatible and enhance the adhesion and proliferation of murine pre-osteoblastic MC3T3 cells. The release of Doxy and Dex from coaxial PCL(Col)/PVA(HA) NFs showed more controlled release compared with the blended NFs. Using an ex vivo porcine bone implantation model we found that the PCL(Col)/PVA(HA) NFs bind firmly on the titanium rod surface and the NFs coating remained intact on the surface of titanium rods after pullout. No disruption or delamination was observed after the pullout test. These findings indicate that PCL(Col)/PVA(HA) NFs encapsulating drugs have great potential in enhancing implant osseointegration and preventing implant infection.

Cu nanoparticles induced structural, optical and electrical modification in PVA

DEFF Research Database (Denmark)

Rozra, J.; Saini, I.; Sharma, A.

2012-01-01

Cu nanoparticles were synthesized in PVA matrix by chemical reduction of cupric nitrate with hydrazine hydrate. Structural characterization of synthesized Cu-PVA nanocomposite was carried out using UV-Visible Spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission...... are in agreement with the size obtained using X-ray diffraction. Morphology of Cu-PVA nanocomposite was further confirmed using SEM. Analysis of UV-Visible absorption and reflection data indicates towards the reduction in optical band gap and increase in refractive index of the resulting nanocomposite...

Membranes of polyindene sulfonated and PVA for use as polymer electrolyte; Membranas mistas de poli(indeno) sulfonado e PVA para uso como eletrolito polimerico

Energy Technology Data Exchange (ETDEWEB)

Loser, N.; Silva, B.B.R. da; Brum, F.J.B.; Forte, M.M.C. [Universidade Federal do Rio Grande do Sul - Escola de Engenharia, Porto Alegre, RS (Brazil)

2010-07-01

This study is focused on developing polymer poly electrolytes for fuel cell PEM and aims to evaluate the efficiency of sulfonated polyindene as A polymer electrolyte in blends with poly (vinyl alcohol) (PVA). For this, polyindene synthesized in the lab was functionalized with sulfonic groups (-SO{sub 3}H), using as sulfonation agent acetyl sulfate in 1,2-dichloroethane. The membranes of sulfonated polyindene (SPInd) and PVA were prepared in aqueous medium, using glutaraldehyde as a PVA cross linker. The membranes SPInd/PVA were evaluated on the content of sulfonic groups, ion exchange capacity (IEC), degree of swelling in water and thermal stability (TGA). Electrochemical impedance analysis was used for ionic conductivity evaluation and DMA for the mechanical strength of the membranes. Preliminary results show that the membranes showed ion exchange capacity about 3.2 m equiv/g and degree of swelling in water of 550%. (author)

Fabrication of electrospun almond gum/PVA nanofibers as a thermostable delivery system for vanillin.

Science.gov (United States)

Rezaei, Atefe; Tavanai, Hossein; Nasirpour, Ali

2016-10-01

In this study, the fabrication of vanillin incorporated almond gum/polyvinyl alcohol (PVA) nanofibers through electrospinning has been investigated. Electrospinning of only almond gum was proved impossible. It was found that the aqueous solution of almond gum/PVA (80:20, concentration=7% (w/w)) containing 3% (w/w) vanillin could have successfully electrospun to uniform nanofibers with diameters as low as 77nm. According to the thermal analysis, incorporated vanillin in almond gum/PVA nanofibers showed higher thermal stability than free vanillin, making this composite especially suitable for high temperature applications. XRD and FTIR analyses proved the presence of vanillin in the almond gum/PVA nanofibers. It was also found that vanillin was dispersed as big crystallites in the matrix of almond gum/PVA nanofibers. FTIR analysis showed almond gum and PVA had chemical cross-linking by etheric bonds between COH groups of almond gum and OH groups of PVA. Also, in the nanofibers, there were no major interaction between vanillin and either almond gum or PVA. Copyright © 2016 Elsevier B.V. All rights reserved.