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Sample records for chitosan nanoparticle-based neuronal

  1. Chitosan nanoparticle-based neuronal membrane sealing and neuroprotection following acrolein-induced cell injury

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    Shi Riyi

    2010-01-01

    Full Text Available Abstract Background The highly reactive aldehyde acrolein is a very potent endogenous toxin with a long half-life. Acrolein is produced within cells after insult, and is a central player in slow and progressive "secondary injury" cascades. Indeed, acrolein-biomolecule complexes formed by cross-linking with proteins and DNA are associated with a number of pathologies, especially central nervous system (CNS trauma and neurodegenerative diseases. Hydralazine is capable of inhibiting or reducing acrolein-induced damage. However, since hydralazine's principle activity is to reduce blood pressure as a common anti-hypertension drug, the possible problems encountered when applied to hypotensive trauma victims have led us to explore alternative approaches. This study aims to evaluate such an alternative - a chitosan nanoparticle-based therapeutic system. Results Hydralazine-loaded chitosan nanoparticles were prepared using different types of polyanions and characterized for particle size, morphology, zeta potential value, and the efficiency of hydralazine entrapment and release. Hydralazine-loaded chitosan nanoparticles ranged in size from 300 nm to 350 nm in diameter, and with a tunable, or adjustable, surface charge. Conclusions We evaluated the utility of chitosan nanoparticles with an in-vitro model of acrolein-mediated cell injury using PC -12 cells. The particles effectively, and statistically, reduced damage to membrane integrity, secondary oxidative stress, and lipid peroxidation. This study suggests that a chitosan nanoparticle-based therapy to interfere with "secondary" injury may be possible.

  2. Preparation and Charaterization of Self-assembled Nanoparticles Based on Linolenic-acid Modified Chitosan

    Institute of Scientific and Technical Information of China (English)

    LIU Chenguang; Desai Kashappa Goud H.; CHEN Xiguang; Park Hyun-Jin

    2005-01-01

    Chitosan was modified by conjugating coupling with linolenic acid through the 1-ethyl-3-(3-dimethylaminopropyyl) earbodiimide (EDC)-mediated reaction. The degree of substitution 1.8% (i.e. 1.8 linolenic acid group per 100anhydroglucose units) was measured by 1H NMR. The critical aggregation concentration (CAC) of the self-aggregate of hydrophobically modified chitosan was determined by measuring the fluorescence intensity of the pyrene as a fluorescent probe.The CAC value in phosphate-buffered saline (PBS) solution (pH7.4) was 5 × 10-2 mgmL-1. The average particle size of selfaggregates of hydrophobically modified chitosan in PBS solution (pH7.4) was 210.8 nm with a unimodal size distribution ranging from 100 to 500 nm. Transmission electron microscopy (TEM) study showed that the formation of near spherical shape nanoparticles has enough structural integrity. The loading ability of hydrophibically modified chitosan (LA-chitosan)was investigated by using bovine serum albumin (BSA) as the model. The loading capacity of self-aggregated nanoparticles increases (19.85% ± 0.04% to 37.57% ± 0.25 %) with the concentration of BSA (0.1-0.5 mg mL-1).

  3. Nanoparticles Based on Chitosan as Carriers for the Combined Herbicides Imazapic and Imazapyr

    Science.gov (United States)

    Maruyama, Cintia Rodrigues; Guilger, Mariana; Pascoli, Mônica; Bileshy-José, Natalia; Abhilash, P. C.; Fraceto, Leonardo Fernandes; de Lima, Renata

    2016-01-01

    The use of lower concentrations and fewer applications of herbicides is one of the prime objectives of the sustainable agriculture as it decreases the toxicity to non-targeted organisms and the risk of wider environmental contamination. In the present work, nanoparticles were developed for encapsulation of the herbicides imazapic and imazapyr. Alginate/chitosan and chitosan/tripolyphosphate nanoparticles were manufactured, and their physicochemical stability was evaluated. Determinations were made of the encapsulation efficiency and release kinetics, and the toxicity of the nanoparticles was evaluated using cytotoxicity and genotoxicity assays. The effects of herbicides and herbicide-loaded nanoparticles on soil microorganisms were studied in detail using real-time polymerase chain reactions. The nanoparticles showed an average size of 400 nm and remained stable during 30 days of storage at ambient temperature. Satisfactory encapsulation efficiencies of between 50 and 70% were achieved for both types of particles. Cytotoxicity assays showed that the encapsulated herbicides were less toxic, compared to the free compounds, and genotoxicity was decreased. Analyses of soil microbiota revealed changes in the bacteria of the soils exposed to the different treatments. Our study proves that encapsulation of the herbicides improved their mode of action and reduced their toxicity, indicating their suitability for use in future practical applications.

  4. Immunogenic Properties of a BCG Adjuvanted Chitosan Nanoparticle-Based Dengue Vaccine in Human Dendritic Cells.

    Science.gov (United States)

    Hunsawong, Taweewun; Sunintaboon, Panya; Warit, Saradee; Thaisomboonsuk, Butsaya; Jarman, Richard G; Yoon, In-Kyu; Ubol, Sukathida; Fernandez, Stefan

    2015-09-01

    Dengue viruses (DENVs) are among the most rapidly and efficiently spreading arboviruses. WHO recently estimated that about half of the world's population is now at risk for DENV infection. There is no specific treatment or vaccine available to treat or prevent DENV infections. Here, we report the development of a novel dengue nanovaccine (DNV) composed of UV-inactivated DENV-2 (UVI-DENV) and Mycobacterium bovis Bacillus Calmette-Guerin cell wall components (BCG-CWCs) loaded into chitosan nanoparticles (CS-NPs). CS-NPs were prepared by an emulsion polymerization method prior to loading of the BCG-CWCs and UVI-DENV components. Using a scanning electron microscope and a zetasizer, DNV was determined to be of spherical shape with a diameter of 372.0 ± 11.2 nm in average and cationic surface properties. The loading efficacies of BCG-CWCs and UVI-DENV into the CS-NPs and BCG-CS-NPs were up to 97.2 and 98.4%, respectively. THP-1 cellular uptake of UVI-DENV present in the DNV was higher than soluble UVI-DENV alone. DNV stimulation of immature dendritic cells (iDCs) resulted in a significantly higher expression of DCs maturation markers (CD80, CD86 and HLA-DR) and induction of various cytokine and chemokine productions than in UVI-DENV-treated iDCs, suggesting a potential use of BCG- CS-NPs as adjuvant and delivery system for dengue vaccines. PMID:26394138

  5. Immunogenic Properties of a BCG Adjuvanted Chitosan Nanoparticle-Based Dengue Vaccine in Human Dendritic Cells.

    Directory of Open Access Journals (Sweden)

    Taweewun Hunsawong

    2015-09-01

    Full Text Available Dengue viruses (DENVs are among the most rapidly and efficiently spreading arboviruses. WHO recently estimated that about half of the world's population is now at risk for DENV infection. There is no specific treatment or vaccine available to treat or prevent DENV infections. Here, we report the development of a novel dengue nanovaccine (DNV composed of UV-inactivated DENV-2 (UVI-DENV and Mycobacterium bovis Bacillus Calmette-Guerin cell wall components (BCG-CWCs loaded into chitosan nanoparticles (CS-NPs. CS-NPs were prepared by an emulsion polymerization method prior to loading of the BCG-CWCs and UVI-DENV components. Using a scanning electron microscope and a zetasizer, DNV was determined to be of spherical shape with a diameter of 372.0 ± 11.2 nm in average and cationic surface properties. The loading efficacies of BCG-CWCs and UVI-DENV into the CS-NPs and BCG-CS-NPs were up to 97.2 and 98.4%, respectively. THP-1 cellular uptake of UVI-DENV present in the DNV was higher than soluble UVI-DENV alone. DNV stimulation of immature dendritic cells (iDCs resulted in a significantly higher expression of DCs maturation markers (CD80, CD86 and HLA-DR and induction of various cytokine and chemokine productions than in UVI-DENV-treated iDCs, suggesting a potential use of BCG- CS-NPs as adjuvant and delivery system for dengue vaccines.

  6. Chitosan nanoparticle-based neuronal membrane sealing and neuroprotection following acrolein-induced cell injury

    OpenAIRE

    Shi Riyi; Cho Youngnam; Ben Borgens Richard

    2010-01-01

    Abstract Background The highly reactive aldehyde acrolein is a very potent endogenous toxin with a long half-life. Acrolein is produced within cells after insult, and is a central player in slow and progressive "secondary injury" cascades. Indeed, acrolein-biomolecule complexes formed by cross-linking with proteins and DNA are associated with a number of pathologies, especially central nervous system (CNS) trauma and neurodegenerative diseases. Hydralazine is capable of inhibiting or reducing...

  7. Hair dye-incorporated poly-γ-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation

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    Lee HY

    2011-11-01

    Full Text Available Hye-Young Lee1,*, Young-IL Jeong2,*, Ki-Choon Choi31Anyang Science University, Anyang, Gyeonggi, South Korea; 2Chonnam National University Hwasun Hospital, Jeonnam, South Korea; 3Grassland and Forages Research Center, National Institute of Animal Science, Rural Development Administration, Chungnam, South Korea*These authors contributed equally to this work.Background: p-Phenylenediamine (PDA or its related chemicals are used more extensively than oxidative hair dyes. However, permanent hair dyes such as PDA are known to have potent contact allergy reactions in humans, and severe allergic reactions are problematic.Methods: PDA-incorporated nanoparticles were prepared based on ion-complex formation between the cationic groups of PDA and the anionic groups of poly(γ-glutamic acid (PGA. To reinforce PDA/PGA ion complexes, glycol chitosan (GC was added. PDA-incorporated nanoparticles were characterized using field-emission scanning electron microscopy, Fourier-transform infrared (FT-IR spectroscopy, dynamic light scattering, and powder X-ray diffractometry (XRD.Results: Nanoparticles were formed by ion-complex formation between the amine groups of PDA and the carboxyl groups of PGA. PDA-incorporated nanoparticles are small in size (<100 nm, and morphological observations showed spherical shapes. FT-IR spectra results showed that the carboxylic acid peak of PGA decreased with increasing PDA content, indicating that the ion complexes were formed between the carboxyl groups of PGA and the amine groups of PDA. Furthermore, the intrinsic peak of the carboxyl groups of PGA was also decreased by the addition of GC. Intrinsic crystalline peaks of PDA were observed by XRD. This crystalline peak of PDA was completely nonexistent when nanoparticles were formed by ion complex between PDA, PGA, and GC, indicating that PDA was complexed with PGA and no free drug existed in the formulation. During the drug-release experiment, an initial burst release of PDA was

  8. Neuronal Differentiation of Induced Pluripotent Stem Cells on Surfactant Templated Chitosan Hydrogels.

    Science.gov (United States)

    Worthington, Kristan S; Green, Brian J; Rethwisch, Mary; Wiley, Luke A; Tucker, Budd A; Guymon, C Allan; Salem, Aliasger K

    2016-05-01

    The development of effective tissue engineering materials requires careful consideration of several properties beyond biocompatibility, including permeability and mechanical stiffness. While surfactant templating has been used for over a decade to control the physical properties of photopolymer materials, the potential benefit of this technique with regard to biomaterials has yet to be fully explored. Herein we demonstrate that surfactant templating can be used to tune the water uptake and compressive modulus of photo-cross-linked chitosan hydrogels. Interestingly, templating with quaternary ammonium surfactants also hedges against property fluctuations that occur with changing pH. Further, we demonstrate that, after adequate surfactant removal, these materials are nontoxic, support the attachment of induced pluripotent stem cells and facilitate stem cell differentiation to neuronal phenotypes. These results demonstrate the utility of surfactant templating for optimizing the properties of biomaterials intended for a variety of applications, including retinal regeneration. PMID:27008004

  9. Nanoparticle-based Sensors

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    V.K. Khanna

    2008-09-01

    Full Text Available Nanoparticles exhibit several unique properties that can be applied to develop chemical and biosensorspossessing desirable features like enhanced sensitivity and lower detection limits. Gold nanoparticles arecoated with sugars tailored to recognise different biological substances. When mixed with a weak solution ofthe sugar-coated nanoparticles, the target substance, e.g., ricin or E.coli, attaches to the sugar, thereby alteringits properties and changing the colour. Spores of bacterium labeled with carbon dots have been found to glowupon illumination when viewed with a confocal microscope. Enzyme/nanoparticle-based optical sensors forthe detection of organophosphate (OP compounds employ nanoparticle-modified fluorescence of an inhibitorof the enzyme to generate the signal for the OP compound detection. Nanoparticles shaped as nanoprisms,built of silver atoms, appear red on exposure to light. These nanoparticles are used as diagnostic labels thatglow when target DNA, e.g., those of anthrax or HIV, are present. Of great importance are tools like goldnanoparticle-enhanced surface-plasmon resonance sensor and silver nanoparticle surface-enhanced portableRaman integrated tunable sensor. Nanoparticle metal oxide chemiresistors using micro electro mechanical systemhotplate are very promising devices for toxic gas sensing. Chemiresistors comprising thin films of nanogoldparticles, encapsulated in monomolecular layers of functionalised alkanethiols, deposited on interdigitatedmicroelectrodes, show resistance changes through reversible absorption of vapours of harmful gases. Thispaper reviews the state-of-the-art sensors for chemical and biological terror agents, indicates their capabilitiesand applications, and presents the future scope of these devices.Defence Science Journal, 2008, 58(5, pp.608-616, DOI:http://dx.doi.org/10.14429/dsj.58.1683

  10. Polymeric nanoparticles-based topical delivery systems for the treatment of dermatological diseases.

    Science.gov (United States)

    Zhang, Zheng; Tsai, Pei-Chin; Ramezanli, Tannaz; Michniak-Kohn, Bozena B

    2013-01-01

    Human skin not only functions as a permeation barrier (mainly because of the stratum corneum layer) but also provides a unique delivery pathway for therapeutic and other active agents. These compounds penetrate via intercellular, intracellular, and transappendageal routes, resulting in topical delivery (into skin strata) and transdermal delivery (to subcutaneous tissues and into the systemic circulation). Passive and active permeation enhancement methods have been widely applied to increase the cutaneous penetration. The pathology, pathogenesis, and topical treatment approaches of dermatological diseases, such as psoriasis, contact dermatitis, and skin cancer, are then discussed. Recent literature has demonstrated that nanoparticles-based topical delivery systems can be successful in treating these skin conditions. The studies are reviewed starting with the nanoparticles based on natural polymers especially chitosan, followed by those made of synthetic, degradable (aliphatic polyesters), and nondegradable (polyacrylates) polymers; emphasis is given to nanospheres made of polymers derived from naturally occurring metabolites, the tyrosine-derived nanospheres (TyroSpheres™). In summary, the nanoparticles-based topical delivery systems combine the advantages of both the nanosized drug carriers and the topical approach, and are promising for the treatment of skin diseases. For the perspectives, the penetration of ultra-small nanoparticles (size smaller than 40 nm) into skin strata, the targeted delivery of the encapsulated drugs to hair follicle stem cells, and the combination of nanoparticles and microneedle array technologies for special applications such as vaccine delivery are discussed. PMID:23386536

  11. Nanoparticle Based Surface-Enhanced Raman Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Talley, C E; Huser, T R; Hollars, C W; Jusinski, L; Laurence, T; Lane, S M

    2005-01-03

    Surface-enhanced Raman scattering is a powerful tool for the investigation of biological samples. Following a brief introduction to Raman and surface-enhanced Raman scattering, several examples of biophotonic applications of SERS are discussed. The concept of nanoparticle based sensors using SERS is introduced and the development of these sensors is discussed.

  12. Aqueous Behaviour of Chitosan

    Directory of Open Access Journals (Sweden)

    D. P. Chattopadhyay

    2010-01-01

    Full Text Available Chitosan, a versatile biopolymer, finds numerous applications in textile processing unit operations such as preparation, dyeing, printing, and finishing. However, the accessibility of this biopolymer by the textile material depends on the viscosity of its solution which in turn is a function of its molecular weight. In this work, therefore, the effect of molecular weight, storage life, presence of electrolyte, and particle size of chitosan on its viscosity was investigated. Chitosan of different molecular weights was synthesized by nitrous acid hydrolysis of parent chitosan solution. The synthesized low molecular weight products were analysed by FTIR spectroscopy. Chitosan of nanoconfiguration was prepared by Ionotropic gelation method and characterized by particle size analyzer. The viscosity of different chitosan solutions was determined using Ubbelohde capillary viscometer. As an extension to this study, the chelation property of chitosan was also evaluated.

  13. Chitosan and radiation chemistry

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    Chmielewski, Andrzej G.

    2010-03-01

    Chitosan as a raw material with special properties has drawn attention of scientists working in the field of radiation processing and natural polymer products development, and also of specialists working in the field of radiation protection and oncologists. Especially the applications concern reduced molecular weight chitosan which still retain its chemical structure; such form of the compound is fostering biological, physical and chemical reactivity of the product. Chitosan degrades into fragments under γ-ray or electron beam irradiation. Antibacterial properties of the product are applied in manufacturing hydrogel for wound dressing and additional healing properties can be achieved by incorporating in the hydrogel matrix chitosan bonded silver clusters. Another possible application of chitosan is in reducing radiation damage to the radiation workers or radiation cured patients. In the case of radioisotopes oral or respiratory chitosan-based materials can be applied as chelators. Applications of chitosan in oncology are also reported.

  14. Chitosan and radiation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Chmielewski, Andrzej G., E-mail: a.chmielewski@ichtj.waw.p [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    2010-03-15

    Chitosan as a raw material with special properties has drawn attention of scientists working in the field of radiation processing and natural polymer products development, and also of specialists working in the field of radiation protection and oncologists. Especially the applications concern reduced molecular weight chitosan which still retain its chemical structure; such form of the compound is fostering biological, physical and chemical reactivity of the product. Chitosan degrades into fragments under gamma-ray or electron beam irradiation. Antibacterial properties of the product are applied in manufacturing hydrogel for wound dressing and additional healing properties can be achieved by incorporating in the hydrogel matrix chitosan bonded silver clusters. Another possible application of chitosan is in reducing radiation damage to the radiation workers or radiation cured patients. In the case of radioisotopes oral or respiratory chitosan-based materials can be applied as chelators. Applications of chitosan in oncology are also reported.

  15. Chitosan and radiation chemistry

    International Nuclear Information System (INIS)

    Chitosan as a raw material with special properties has drawn attention of scientists working in the field of radiation processing and natural polymer products development, and also of specialists working in the field of radiation protection and oncologists. Especially the applications concern reduced molecular weight chitosan which still retain its chemical structure; such form of the compound is fostering biological, physical and chemical reactivity of the product. Chitosan degrades into fragments under γ-ray or electron beam irradiation. Antibacterial properties of the product are applied in manufacturing hydrogel for wound dressing and additional healing properties can be achieved by incorporating in the hydrogel matrix chitosan bonded silver clusters. Another possible application of chitosan is in reducing radiation damage to the radiation workers or radiation cured patients. In the case of radioisotopes oral or respiratory chitosan-based materials can be applied as chelators. Applications of chitosan in oncology are also reported.

  16. Preparation of chitosan gel

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    Lagerge S.

    2012-06-01

    Full Text Available Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. The increase in the chitosan concentration or the degree of acetylation decreases the specific surface of the synthesized chitosan gel. Whereas drying with supercritical CO2 more effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying.

  17. Design of chitosan-based nanoparticles functionalized with gallic acid.

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    Lamarra, J; Rivero, S; Pinotti, A

    2016-10-01

    Active nanoparticles based on chitosan could be applied as a support for the modulation of gallic acid delivery. In this sense, these nanostructures could be employed in different fields such as food, packaging, and pharmaceutical areas. The design parameters of chitosan-based nanoparticles functionalized with gallic acid (GA) were optimized through RSM by means of the analysis of zeta potential (ZP) and percentage encapsulation efficiency (PEE). The nanoparticles were prepared by ionotropic gelation using tripolyphosphate (TPP), at different combinations of chitosan (CH) concentration, CH:TPP ratio and GA. Global desirability methodology allowed finding the optimum formulation that included CH 0.76% (w/w), CH:TPP ratio of 5 and 37mgGA/gCH leading to ZP of +50mV and 82% of PEE. Analysis through QuickScan and turbidity demonstrated that the most stable nanoparticle suspensions were achieved combining concentrations of chitosan ranging between 0.5 and 0.75% with CH:TPP ratios higher than 3. These suspensions had high stability confirmed by means ZP and transmittance values which were higher than +25mV and 0.21 on average, respectively, as well as nanoparticle diameters of about 140nm. FTIR revealed the occurrence of both hydrogen bond and ionic interactions of CH-TPP which allowed the encapsulation and the improvement of the stability of the active agent. PMID:27287172

  18. Chitosan supplementation and cholesterol

    Czech Academy of Sciences Publication Activity Database

    Koppová, Ingrid; Fliegerová, Kateřina; Šimůnek, Jiří; Kopečný, Jan

    Ancona : PUM, 2007, s. 6-6. [Application of Chitosan in Medical Sciences. Venezia (IT), 25.01.2007-26.01.2007] R&D Projects: GA AV ČR 1QS500200572 Institutional research plan: CEZ:AV0Z50450515 Keywords : chitosan Subject RIV: EE - Microbiology, Virology

  19. Production of Chitosan by Fungi

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    K. Nadarajah

    2001-01-01

    Full Text Available In this study chitosan was extracted from the mycelia of Rhizopus sp KN01, Rhizopus sp KN02, Mucor sp KN03 and Aspergillus niger with the highest amount of extractable chitosan obtained at the late exponential phase. The amount of chitosan produced varied widely amongst isolates. Mucor sp KN03 produced the highest amount of extractable chitosan per ml of substrate and the highest yield of chitosan per unit mycelia mass.

  20. Modified chitosans for biomedical applications

    OpenAIRE

    Yalınca, Zülal

    2013-01-01

    ABSTRACT: The subject of this thesis is the exploration of the suitability of chitosan and some of its derivatives for some chosen biomedical applications. Chitosan-graft-poly (N-vinyl imidazole), Chitosan-tripolyphosphate and ascorbyl chitosan were synthesized and characterized for specific biomedical applications in line with their chemical functionalities. Chitosan-graft-poly (N-vinyl imidazole), Chi-graft-PNVI, was synthesized by two methods; via an N-protection route and without N-pr...

  1. Gold nanoparticle-based microfluidic sensor for mercury detection

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Jensen, Thomas Glasdam; Kutter, Jörg Peter

    2011-01-01

    The contamination of natural resources by human activity can have severe socio-economical impacts. Conventional methods of environmental analysis can be significantly improved by the development of portable microscale technologies for remote/field sensing. A gold nanoparticle-based lab-on-a-chip ...

  2. Chitosan in Plant Protection

    OpenAIRE

    Abdelbasset El Hadrami; Adam, Lorne R.; Ismail El Hadrami; Fouad Daayf

    2010-01-01

    Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of ph...

  3. Chitosan against cutaneous pathogens

    OpenAIRE

    Champer, Jackson; Patel, Julie; Fernando, Nathalie; Salehi, Elaheh; Wong, Victoria; Kim, Jenny

    2013-01-01

    Propionibacterium acnes and Staphylococcus aureus are cutaneous pathogens that have become increasingly resistant to antibiotics. We sought to determine if chitosan, a polymer of deacetylated chitin, could be used as a potential treatment against these bacteria. We found that higher molecular weight chitosan had superior antimicrobial properties compared to lower molecular weights, and that this activity occurred in a pH dependent manner. Electron and fluorescence microscopy revealed that chi...

  4. Red Fluorescent Carbon Nanoparticle-Based Cell Imaging Probe.

    Science.gov (United States)

    Ali, Haydar; Bhunia, Susanta Kumar; Dalal, Chumki; Jana, Nikhil R

    2016-04-13

    Fluorescent carbon nanoparticle-based probes with tunable visible emission are biocompatible, environment friendly and most suitable for various biomedical applications. However, synthesis of red fluorescent carbon nanoparticles and their transformation into functional nanoparticles are very challenging. Here we report red fluorescent carbon nanoparticle-based nanobioconjugates of carbon nanoparticles are synthesized via high temperature colloid-chemical approach and transformed into water-soluble functional nanoparticles via coating with amphiphilic polymer followed by covalent linking with desired biomolecules. Following this approach, carbon nanoparticles are functionalized with polyethylene glycol, primary amine, glucose, arginine, histidine, biotin and folic acid. These functional nanoparticles can be excited with blue/green light (i.e., 400-550 nm) to capture their emission spanning from 550 to 750 nm. Arginine and folic acid functionalized nanoparticles have been demonstrated as fluorescent cell labels where blue and green excitation has been used for imaging of labeled cells. The presented method can be extended for the development of carbon nanoparticle-based other bioimaging probes. PMID:27011336

  5. Neural Stem Cell Affinity of Chitosan and Feasibility of Chitosan-Based Porous Conduits as Scaffolds for Nerve Tissue Engineering

    Institute of Scientific and Technical Information of China (English)

    WANG Aijun; AO Qiang; HE Qing; GONG Xiaoming; GONG Kai; GONG Yandao; ZHAO Nanming; ZHANG Xiufang

    2006-01-01

    Neural stem cells (NSCs) are currently considered as powerful candidate seeding cells for regeneration of both spinal cords and peripheral nerves. In this study, NSCs derived from fetal rat cortices were co-cultured with chitosan to evaluate the cell affinity of this material. The results showed that NSCs grew and proliferated well on chitosan films and most of them differentiated into neuron-like cells after 4 days of culture. Then, molded and braided chitosan conduits were fabricated and characterized for their cytotoxicity, swelling, and mechanical properties. Both types of conduits had no cytotoxic effects on fibroblasts (L929 cells) or neuroblastoma (Neuro-2a) cells. The molded conduits are much softer and more flexible while the braided conduits possess much better mechanical properties, which suggests different potential applications.

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

    DEFF Research Database (Denmark)

    Gordon, Sarah; Saupe, Anne; McBurney, Warren;

    2008-01-01

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

  7. DNA/chitosan electrostatic complex.

    Science.gov (United States)

    Bravo-Anaya, Lourdes Mónica; Soltero, J F Armando; Rinaudo, Marguerite

    2016-07-01

    Up to now, chitosan and DNA have been investigated for gene delivery due to chitosan advantages. It is recognized that chitosan is a biocompatible and biodegradable non-viral vector that does not produce immunological reactions, contrary to viral vectors. Chitosan has also been used and studied for its ability to protect DNA against nuclease degradation and to transfect DNA into several kinds of cells. In this work, high molecular weight DNA is compacted with chitosan. DNA-chitosan complex stoichiometry, net charge, dimensions, conformation and thermal stability are determined and discussed. The influence of external salt and chitosan molecular weight on the stoichiometry is also discussed. The isoelectric point of the complexes was found to be directly related to the protonation degree of chitosan. It is clearly demonstrated that the net charge of DNA-chitosan complex can be expressed in terms of the ratio [NH3(+)]/[P(-)], showing that the electrostatic interactions between DNA and chitosan are the main phenomena taking place in the solution. Compaction of DNA long chain complexed with low molar mass chitosan gives nanoparticles with an average radius around 150nm. Stable nanoparticles are obtained for a partial neutralization of phosphate ionic sites (i.e.: [NH3(+)]/[P(-)] fraction between 0.35 and 0.80). PMID:27050113

  8. Chitosan in Plant Protection

    Directory of Open Access Journals (Sweden)

    Abdelbasset El Hadrami

    2010-03-01

    Full Text Available Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions.

  9. Tight junction modulation by chitosan nanoparticles: comparison with chitosan solution.

    Science.gov (United States)

    Vllasaliu, Driton; Exposito-Harris, Ruth; Heras, Angeles; Casettari, Luca; Garnett, Martin; Illum, Lisbeth; Stolnik, Snow

    2010-11-15

    Present work investigates the potential of chitosan nanoparticles, formulated by the ionic gelation with tripolyphosphate (TPP), to open the cellular tight junctions and in doing so, improve the permeability of model macromolecules. A comparison is made with chitosan solution at equivalent concentrations. Initial work assessed cytotoxicity (through MTS and LDH assays) of chitosan nanoparticles and solutions on Calu-3 cells. Subsequently, a concentration of chitosan nanoparticles and solution exhibiting minimal toxicity was used to investigate the effect on TEER and macromolecular permeability across filter-cultured Calu-3 monolayer. Chitosan nanoparticles and solution were also tested for their effect on the distribution of the tight junction protein, zonnula occludens-1 (ZO-1). Chitosan nanoparticles produced a sharp and reversible decrease in TEER and increased the permeability of two FITC-dextrans (FDs), FD4 (MW 4 kDa) and FD10 (MW 10 kDa), with effects of a similar magnitude to chitosan solution. Chitosan nanoparticles produced changes in ZO-1 distribution similar to chitosan solution, indicating a tight junction effect. While there was no improvement in permeability with chitosan nanoparticles compared to solution, nanoparticles provide the potential for drug incorporation, and hence the possibility for providing controlled drug release and protection from enzymatic degradation. PMID:20727955

  10. Antitumour Acitivty of Chitosan Hydrogen Selenites

    Institute of Scientific and Technical Information of China (English)

    CaiQinQIN; XiaoHaiGAO; 等

    2002-01-01

    Chitosans reacted with selenious acid to prepare chitosan hydrogen selenites, which were found to be growth-inhibitory against sarcoma 180 solid tumor. The results indicated that the activity also depended on the molecular weight of chitosan supports.

  11. Antitumour Activity of Chitosan Hydrogen Selenites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Chitosans reacted with selenious acid to prepare chitosan hydrogen selenites, which were found to be growth-inhibitory against sarcoma 180 solid tumor. The results indicated that the activity also depended on the molecular weight of chitosan supports.

  12. Fluorescent nanoparticles based on AIE fluorogens for bioimaging

    Science.gov (United States)

    Yan, Lulin; Zhang, Yan; Xu, Bin; Tian, Wenjing

    2016-01-01

    Fluorescent nanoparticles (FNPs) have recently attracted increasing attention in the biomedical field because of their unique optical properties, easy fabrication and outstanding performance in imaging. Compared with conventional molecular probes including small organic dyes and fluorescent proteins, FNPs based on aggregation-induced emission (AIE) fluorogens have shown significant advantages in tunable emission and brightness, good biocompatibility, superb photo- and physical stability, potential biodegradability and facile surface functionalization. In this review, we summarize the latest advances in the development of fluorescent nanoparticles based on AIE fluorogens including polymer nanoparticles and silica nanoparticles over the past few years, and the various biomedical applications based on these fluorescent nanoparticles are also elaborated.

  13. Plastic and paper platforms for nanoparticle based immunosensors

    OpenAIRE

    Parolo, Claudio

    2013-01-01

    La tesis titulada “Plastic and paper platforms for nanoparticle based immunosensors” presentada como compendio de publicaciones, muestra avances significativos en el campo de los biosensores ópticos y electroquímicos. En la introducción (Capítulo 1) se presenta la importancia que tienen tanto los sensores inmunológicos basados en nanopartículas como los biosensores basados en plataformas de papel y nanomateriales para aplicaciones en diagnóstico. Ambas plataformas destacan por la versa...

  14. Characterization and cytocompatibility of an antibiotic/chitosan/cyclodextrins nanocoating on titanium implants.

    Science.gov (United States)

    Mattioli-Belmonte, Monica; Cometa, Stefania; Ferretti, Concetta; Iatta, Roberta; Trapani, Adriana; Ceci, Edmondo; Falconi, Mirella; De Giglio, Elvira

    2014-09-22

    A novel ciprofloxacin loaded chitosan nanoparticle-based coating onto titanium substrates has been developed and characterized to obtain an orthopaedic implant surface able to in situ release the antibiotic for the prevention of post-operative infections. Ciprofloxacin loaded chitosan nanoparticles were obtained using the combination of sulfobutyl ether-beta-cyclodextrin and gamma-cyclodextrin. The resulting nanoparticulate system was characterized by TEM, HPLC and XPS. Particle size was in the range 426-552 nm and zeta potential values were around +30 mV. This antibacterial coating was able to in vitro inhibit two nosocomial Staphylococcus aureus strains growth, with a reduction of about 20 times compared to controls. No impairment in MG63 osteoblast-like cells viability, adhesion and gene expression were detected at 48 h, 7 and 14 days of culture. Overall, the investigated coating represents a promising candidate for the development of a new antibiotic carrier for titanium implants. PMID:24906744

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

    Institute of Scientific and Technical Information of China (English)

    AZLAN Kamari; WAN SAIME Wan Ngah; LAI KEN Liew

    2009-01-01

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

  16. Chitosan: Gels and Interfacial Properties

    Directory of Open Access Journals (Sweden)

    Julie Nilsen-Nygaard

    2015-03-01

    Full Text Available Chitosan is a unique biopolymer in the respect that it is abundant, cationic, low-toxic, non-immunogenic and biodegradable. The relative occurrence of the two monomeric building units (N-acetyl-glucosamine and d-glucosamine is crucial to whether chitosan is predominantly an ampholyte or predominantly a polyelectrolyte at acidic pH-values. The chemical composition is not only crucial to its surface activity properties, but also to whether and why chitosan can undergo a sol–gel transition. This review gives an overview of chitosan hydrogels and their biomedical applications, e.g., in tissue engineering and drug delivery, as well as the chitosan’s surface activity and its role in emulsion formation, stabilization and destabilization. Previously unpublished original data where chitosan acts as an emulsifier and flocculant are presented and discussed, showing that highly-acetylated chitosans can act both as an emulsifier and as a flocculant.

  17. Effects of laminin blended with chitosan on axon guidance on patterned substrates

    International Nuclear Information System (INIS)

    Axon guidance is a crucial consideration in the design of tissue scaffolds used to promote nerve regeneration. Here we investigate the combined use of laminin (a putative axon adhesion and guidance molecule) and chitosan (a leading candidate base material for the construction of scaffolds) for promoting axon guidance in cultured adult dorsal root ganglion (DRG) neurons. Using a dispensing-based rapid prototyping (DBRP) technique, two-dimensional grid patterns were created by dispensing chitosan or laminin-blended chitosan substrate strands oriented in orthogonal directions. In vitro experiments illustrated DRG neurites on these patterns preferentially grew upon and followed the laminin-blended chitosan pathways. These results suggest that an orientation of neurite growth can be achieved in an artificially patterned substrate by creating selectively biofunctional pathways. The DBRP technique may provide improved strategies for the use of biofunctional pathways in the design of three-dimensional scaffolds for guidance of nerve repair.

  18. Effects of laminin blended with chitosan on axon guidance on patterned substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, N; Guan, Y J; Chen, X B [Division of Biomedical Engineering, University of Saskatchewan, Saskatoon S7N 5A9 (Canada); Li, M G [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon S7N 5A9 (Canada); Schreyer, D J, E-mail: niz504@mail.usask.c [Department of Anatomy and Cell Biology, Cameco MS Neuroscience Research Center, University of Saskatchewan, Saskatoon, S7K 0M7 (Canada)

    2010-12-15

    Axon guidance is a crucial consideration in the design of tissue scaffolds used to promote nerve regeneration. Here we investigate the combined use of laminin (a putative axon adhesion and guidance molecule) and chitosan (a leading candidate base material for the construction of scaffolds) for promoting axon guidance in cultured adult dorsal root ganglion (DRG) neurons. Using a dispensing-based rapid prototyping (DBRP) technique, two-dimensional grid patterns were created by dispensing chitosan or laminin-blended chitosan substrate strands oriented in orthogonal directions. In vitro experiments illustrated DRG neurites on these patterns preferentially grew upon and followed the laminin-blended chitosan pathways. These results suggest that an orientation of neurite growth can be achieved in an artificially patterned substrate by creating selectively biofunctional pathways. The DBRP technique may provide improved strategies for the use of biofunctional pathways in the design of three-dimensional scaffolds for guidance of nerve repair.

  19. 季铵盐壳聚糖三维支架复合GNDF载间充质干细胞向神经样细胞分化%Neuron-like differentiation of mesenchymal stem cells induced by quaternary chitosan thermosensitive hydrogel scaffolds combined with glial cell line-derived neurotrophic factor

    Institute of Scientific and Technical Information of China (English)

    黄成; 杨建东; 冯新民; 李广峰; 李艺楠; 肖海祥; 孙钰

    2013-01-01

    chitosan thermosensitive hydrogel scaffold and to look for more ideal tissue engineering materials for the treatment of nervous system damage. METHODS:The thermosensitive hygrogel scaffold was prepared using hydroxypropyltrimethyl ammonium chloride chitosan (HACC) andβ-glycerophosphate (β-GP). The spatial structure of scaffold was observed by scanning electronic microscope. Effect of leaching liquor from the HACC/β-GP scaffold on the viability of bone marrow mesenchymal stem cells was detected by (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The albumin from bovine serum was combined with the scaffold, and the slow-release effect of the scaffold was detected by ultraviolet absorption spectrometry. Bone marrow mesenchymal stem cells were incubated onto the compound scaffold at 3 passages. The adhesion, growth and differentiation of bone marrow mesenchymal stem cells on the compound scaffold were observed by the scanning electron microscope. Neuron-specific enolase was detected by immunofluorescence. RESULTS AND CONCLUSION:The porosity and thermal sensitivity of HACC/β-GP scaffold and slow-release effect of glial cellline-derived neurotrophic factor were apparent. The results of MTT showed that the compound scaffold cannot take apparent negative effects to the proliferation of bone marrow mesenchymal stem cells. After inoculation, bone marrow mesenchymal stem cells permeated the porous structure of the scaffold and adhered to the scaffold. Under the role of glial cellline-derived neurotrophic factor, bone marrow mesenchymal stem cells showed neuron-like cellmorphology and cells co-cultured with the compound scaffold expressed the marker of neurons, neuron-specific enolase. Under the role of slow-release glial cellline-derived neurotrophic factor, bone marrow mesenchymal stem cells can grow wel in vitro and differentiate into neuron-like cells on the HACC/β-GP scaffold.

  20. Nanoparticle-based immunosensors and immunoassays for aflatoxins.

    Science.gov (United States)

    Wang, Xu; Niessner, Reinhard; Tang, Dianping; Knopp, Dietmar

    2016-03-17

    Aflatoxins are naturally existing mycotoxins produced mainly by Aspergillus flavus and Aspergillus parasiticus, present in a wide range of food and feed products. Because of their extremely high toxicity and carcinogenicity, strict control of maximum residue levels of aflatoxins in foodstuff is set by many countries. In daily routine, different chromatographic methods are used almost exclusively. As supplement, in several companies enzyme immunoassay-based sample testing as primary screening is performed. Recently, nanomaterials such as noble metal nanoparticles, magnetic particles, carbon nanomaterials, quantum dots, and silica nanomaterials are increasingly utilized for aflatoxin determination to improve the sensitivity and simplify the detection. They are employed either as supports for the immobilization of biomolecules or as electroactive or optical labels for signal transduction and amplification. Several nanoparticle-based electrochemical, piezoelectric, optical, and immunodipstick assays for aflatoxins have been developed. In this review, we summarize these recent advances and illustrate novel concepts and promising applications in the field of food safety. PMID:26920768

  1. Nanoparticles based DNA conjugates for detection of pathogenic microorganisms

    Science.gov (United States)

    Jamdagni, Pragati; Khatri, Poonam; Rana, J. S.

    2016-01-01

    Infectious diseases have been on rise in the recent past. Early diagnosis plays a role as important as proper treatment and prophylaxis. The current practices of detection are time consuming which may result in unnecessary delays in treatment. Advances in nanodiagnostic approaches have been in focus lately. The rising interest and better understanding of nanoparticles have led to opening up of new frontiers in the concerned area. Optical properties of nanoparticles are being exploited to design detection systems that can provide fast, one-step and reliable results. Based on conserved DNA sequences unique to the target organism, the results offer accuracy comparable to conventional tests. Further, visual or spectrophotometric analysis omits the need of costly apparatus for result interpretation. The present review aims at putting together the information on nanoparticles based DNA conjugate systems for detection of pathogenic microorganisms.

  2. Hyaluronidase To Enhance Nanoparticle-Based Photodynamic Tumor Therapy.

    Science.gov (United States)

    Gong, Hua; Chao, Yu; Xiang, Jian; Han, Xiao; Song, Guosheng; Feng, Liangzhu; Liu, Jingjing; Yang, Guangbao; Chen, Qian; Liu, Zhuang

    2016-04-13

    Photodynamic therapy (PDT) is considered as a safe and selective way to treat a wide range of cancers as well as nononcological disorders. However, as oxygen is required in the process of PDT, the hypoxic tumor microenvironment has largely limited the efficacy of PDT to treat tumors especially those with relatively large sizes. To this end, we uncover that hyaluronidase (HAase), which breaks down hyaluronan, a major component of extracellular matrix (ECM) in tumors, would be able to enhance the efficacy of nanoparticle-based PDT for in vivo cancer treatment. It is found that the administration of HAase would lead to the increase of tumor vessel densities and effective vascular areas, resulting in increased perfusion inside the tumor. As a result, the tumor uptake of nanomicelles covalently linked with chlorine e6 (NM-Ce6) would be increased by ∼2 folds due to the improved "enhanced permeability and retention" (EPR) effect, while the tumor oxygenation level also shows a remarkable increase, effectively relieving the hypoxia state inside the tumor. Those effects taken together offer significant benefits in greatly improving the efficacy of PDT delivered by nanoparticles. Taking advantage of the effective migration of HAase from the primary tumor to its drainage sentinel lymph nodes (SLNs), we further demonstrate that this strategy would be helpful to the treatment of metastatic lymph nodes by nanoparticle-based PDT. Lastly, both enhanced EPR effect of NM-Ce6 and relieved hypoxia state of tumor are also observed after systemic injection of modified HAase, proving its potential for clinical translation. Therefore, our work presents a new concept to improve the efficacy of nanomedicine by modulating the tumor microenvironment. PMID:27022664

  3. Heavy Metal Removal by Chitosan and Chitosan Composite

    International Nuclear Information System (INIS)

    Radiation grafting of diethyl aminoethyl methacrylate (DEAEMA) on chitosan to impart ion exchange properties and to be used for the separation of metal ions from waste water, was carried out. The effect of experimental conditions such as monomer concentration and the radiation dose on grafting were studied. On using chitosan, grafted chitosan and some chitosan composites in metal ion removal they show high up-take capacity for Cu2+ and lower uptake capacities for the other divalent metal ions used (Zn and Co). Competitive study, performed with solutions containing mixture of metal salts, showed high selectivity for Cu2+ than the other metal ion. Limited grafting of DEAEMA polymer -containing specific functional groups-onto the chitosan backbone improves the sorption performance

  4. Vestibular Neuronitis

    Science.gov (United States)

    ... Prevent Painful Swimmer's Ear Additional Content Medical News Vestibular Neuronitis By Lawrence R. Lustig, MD NOTE: This ... Drugs Herpes Zoster Oticus Meniere Disease Purulent Labyrinthitis Vestibular Neuronitis Vestibular neuronitis is a disorder characterized by ...

  5. Chitosan composite films. Biomedical applications.

    Science.gov (United States)

    Cárdenas, Galo; Anaya, Paola; von Plessing, Carlos; Rojas, Carlos; Sepúlveda, Jackeline

    2008-06-01

    Chitosan acetate films have been prepared using chitosans from shrimps (Pleuroncodes monodon) of low and high molecular weight (LMv = 68,000 g/mol and HMv = 232,000 g/mol) and deacetylation degree of 80 and 100%, respectively. The chitosan films were obtained by addition of several additives to acetic acid chitosan solutions, such as: glycerol, oleic acid and linoleic acid in different proportions. The pH of the solutions before casting ranged from 5.0 to 6.0. The composite film thickness are reported. The films have been analyzed by FTIR showing characteristic bands corresponding to the additives. The scanning electron microscopy (SEM) studies reveals the different morphology of the composite films. The films exhibit different physical properties depending upon the additives and/or mixture of them. The addition of glycerol to composite improves the elasticity of the films. The swelling in glucose and saline solutions for several films was evaluated, being higher in the glucose solution. The bactericide test against Staphylococcus aureus, Pseudomona aeruginosa and Acinetobacter baumanii in plates with either blood and or agar tripticase showed that the molecular weight influences on the bactericidal properties of the chitosan composite films and over its effect against gram positive and gram negative bacteria. Medical applications of the composite films were done in patients with burns, ulcers and injuries, the films containing glycerol showed good adhesion in comparison with those without it. The composite films tested were mainly three (1) chitosan acetate with glycerol, (2) chitosan acetate with oleic acid and (3) chitosan acetate with glycerol and oleic acid. Excellent results in the skin recovery were obtained after 7-10 days. Since the chitosan is biodegradable by the body enzymes it does not need to be removed and increases the gradual grows of the damage tissues. PMID:18165888

  6. Nanoparticle-based drug delivery systems: promising approaches against infections

    Energy Technology Data Exchange (ETDEWEB)

    Ranghar, Shweta; Sirohi, Parul [Department of Applied Mechanics, Motilal Nehru National Institute of Technology, Allahabad (India); Verma, Pritam; Agarwal, Vishnu, E-mail: vishnu_agarwal02@rediffmail.com [Department of Biotechnology, Motilal Nehru National Institute of Technology, Allahabad (India)

    2014-03-15

    Despite the fact that many new drugs and technologies have been developed to combat the infectious diseases, these have continued to be global health challenges. The use of conventional antimicrobial agents against these infections is always associated with problems such as the development of multiple drug resistance and adverse side effects. In addition, the inefficient traditional drug delivery system results in inadequate therapeutic index, low bioavailability of drugs and many other limitations. In this regard, antimicrobial nanoparticles and nanosized drug delivery carriers have emerged as potent effective agents against the infections. Nanoparticles have unique properties owing to their ultra small and controllable size such as high surface area, enhanced reactivity, and functionalizable structure. This review focused on different classes of antimicrobial nanoparticles, including metal, metal oxide and others along with their mechanism of action and their potential use against the infections. The review also focused on the development of nanoparticle systems for antimicrobial drug delivery and use of these systems for delivery of various antimicrobial agents, giving an overview about modern nanoparticle based therapeutic strategies against the infections. (author)

  7. Nanoparticle-based drug delivery systems: promising approaches against infections

    International Nuclear Information System (INIS)

    Despite the fact that many new drugs and technologies have been developed to combat the infectious diseases, these have continued to be global health challenges. The use of conventional antimicrobial agents against these infections is always associated with problems such as the development of multiple drug resistance and adverse side effects. In addition, the inefficient traditional drug delivery system results in inadequate therapeutic index, low bioavailability of drugs and many other limitations. In this regard, antimicrobial nanoparticles and nanosized drug delivery carriers have emerged as potent effective agents against the infections. Nanoparticles have unique properties owing to their ultra small and controllable size such as high surface area, enhanced reactivity, and functionalizable structure. This review focused on different classes of antimicrobial nanoparticles, including metal, metal oxide and others along with their mechanism of action and their potential use against the infections. The review also focused on the development of nanoparticle systems for antimicrobial drug delivery and use of these systems for delivery of various antimicrobial agents, giving an overview about modern nanoparticle based therapeutic strategies against the infections. (author)

  8. Chitosan: Gels and Interfacial Properties

    OpenAIRE

    Julie Nilsen-Nygaard; Strand, Sabina P.; Kjell M. Vårum; Kurt I. Draget; Catherine T. Nordgård

    2015-01-01

    Chitosan is a unique biopolymer in the respect that it is abundant, cationic, low-toxic, non-immunogenic and biodegradable. The relative occurrence of the two monomeric building units (N-acetyl-glucosamine and d-glucosamine) is crucial to whether chitosan is predominantly an ampholyte or predominantly a polyelectrolyte at acidic pH-values. The chemical composition is not only crucial to its surface activity properties, but also to whether and why chitosan can undergo a sol–gel transition. T...

  9. Preparation and Characterization of Acylated Chitosan

    Institute of Scientific and Technical Information of China (English)

    LI Ming-chun; LIU Chao; XIN Mei-hua; ZHAO Huang; WANG Min; FENG Zhen; SUN Xiao-li

    2005-01-01

    Fully acylated chitosan and N, N-diacyl chitosan were prepared. The products were characterized by elemental analysis, FTIR and 1H NMR. The experimental results indicate that the average degree of acylation depends on the volume ratio of pyridine to chloroform in the reaction medium, the chain length of the acylation agent used, and the molecular weight of chitosan raw materials. The XRD measurements were carried out for pure chitosan, fully acylated chitosan and N, N-diacyl chitosan to verify the crystallinity change caused by the acylation.

  10. Hair dye-incorporated poly-γ-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation

    OpenAIRE

    Choi, Ki-Choon

    2011-01-01

    Hye-Young Lee1,*, Young-IL Jeong2,*, Ki-Choon Choi31Anyang Science University, Anyang, Gyeonggi, South Korea; 2Chonnam National University Hwasun Hospital, Jeonnam, South Korea; 3Grassland and Forages Research Center, National Institute of Animal Science, Rural Development Administration, Chungnam, South Korea*These authors contributed equally to this work.Background: p-Phenylenediamine (PDA) or its related chemicals are used more extensively than oxidative hair dyes. However, permanent hair ...

  11. Hair dye-incorporated poly-γ-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation

    OpenAIRE

    Lee HY; Jeong YI; Choi KC

    2011-01-01

    Hye-Young Lee1,*, Young-IL Jeong2,*, Ki-Choon Choi31Anyang Science University, Anyang, Gyeonggi, South Korea; 2Chonnam National University Hwasun Hospital, Jeonnam, South Korea; 3Grassland and Forages Research Center, National Institute of Animal Science, Rural Development Administration, Chungnam, South Korea*These authors contributed equally to this work.Background: p-Phenylenediamine (PDA) or its related chemicals are used more extensively than oxidative hair dyes. However, permanent hair ...

  12. Electrochemical detection of short HIV sequences on chitosan/Fe3O4 nanoparticle based screen printed electrodes

    International Nuclear Information System (INIS)

    In this study, a novel CS/Fe3O4 nanobiocomposite-based platform for electrochemical detection of HIV-1 was developed. The most attractive feature of this system is a suitable microenvironment (Fe3O4 nanoparticles) which could contribute to electron transfer and thus sensitivity enhancement when using methylene blue (MB) as an external mediator and Square Wave Voltammetry (SWV), Electrochemical Impedance Spectroscopy (EIS) techniques. The proposed screen printed electrode (SPE) had a low detection limit (as low as 50 pM), acceptable stability and good reproducibility, which would be valuable for clinical diagnosis. In addition, this sensing interface may be feasibly adapted for multiplexed detection of other species of bacterial pathogens.

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

    International Nuclear Information System (INIS)

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

  14. Blood protein adsorption onto chitosan

    OpenAIRE

    Benesch, Johan; Tengvall, P.

    2002-01-01

    Chitosan was recently indicated to enhance osteogenesis, improve wound healing but to activate the coagulation and the complement systems. In the present study approximately 10nm thick chitosan film were prepared on aminopropyltriethoxysilane (APTES) coated silicon. The surfaces were incubated in serum or plasma and subsequently in antibodies towards key complement and contact activation of coagulation proteins. The deposited amounts were compared with those on hydrophilic and hydrop...

  15. Magnetic nanoparticle-based drug delivery for cancer therapy.

    Science.gov (United States)

    Tietze, Rainer; Zaloga, Jan; Unterweger, Harald; Lyer, Stefan; Friedrich, Ralf P; Janko, Christina; Pöttler, Marina; Dürr, Stephan; Alexiou, Christoph

    2015-12-18

    Nanoparticles have belonged to various fields of biomedical research for quite some time. A promising site-directed application in the field of nanomedicine is drug targeting using magnetic nanoparticles which are directed at the target tissue by means of an external magnetic field. Materials most commonly used for magnetic drug delivery contain metal or metal oxide nanoparticles, such as superparamagnetic iron oxide nanoparticles (SPIONs). SPIONs consist of an iron oxide core, often coated with organic materials such as fatty acids, polysaccharides or polymers to improve colloidal stability and to prevent separation into particles and carrier medium [1]. In general, magnetite and maghemite particles are those most commonly used in medicine and are, as a rule, well-tolerated. The magnetic properties of SPIONs allow the remote control of their accumulation by means of an external magnetic field. Conjugation of SPIONs with drugs, in combination with an external magnetic field to target the nanoparticles (so-called "magnetic drug targeting", MDT), has additionally emerged as a promising strategy of drug delivery. Magnetic nanoparticle-based drug delivery is a sophisticated overall concept and a multitude of magnetic delivery vehicles have been developed. Targeting mechanism-exploiting, tumor-specific attributes are becoming more and more sophisticated. The same is true for controlled-release strategies for the diseased site. As it is nearly impossible to record every magnetic nanoparticle system developed so far, this review summarizes interesting approaches which have recently emerged in the field of targeted drug delivery for cancer therapy based on magnetic nanoparticles. PMID:26271592

  16. Nanoparticle-based targeted gene therapy for lung cancer

    Science.gov (United States)

    Lee, Hung-Yen; Mohammed, Kamal A; Nasreen, Najmunnisa

    2016-01-01

    Despite striking insights on lung cancer progression, and cutting-edge therapeutic approaches the survival of patients with lung cancer, remains poor. In recent years, targeted gene therapy with nanoparticles is one of the most rapidly evolving and extensive areas of research for lung cancer. The major goal of targeted gene therapy is to bring forward a safe and efficient treatment to cancer patients via specifically targeting and deterring cancer cells in the body. To achieve high therapeutic efficacy of gene delivery, various carriers have been engineered and developed to provide protection to the genetic materials and efficient delivery to targeted cancer cells. Nanoparticles play an important role in the area of drug delivery and have been widely applied in cancer treatments for the purposes of controlled release and cancer cell targeting. Nanoparticles composed of artificial polymers, proteins, polysaccharides and lipids have been developed for the delivery of therapeutic deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) sequences to target cancer. In addition, the effectiveness of cancer targeting has been enhanced by surface modification or conjugation with biomolecules on the surface of nanoparticles. In this review article we provide an overview on the latest developments in nanoparticle-based targeted gene therapy for lung cancers. Firstly, we outline the conventional therapies and discuss strategies for targeted gene therapy using nanoparticles. Secondly, we provide the most representative and recent researches in lung cancers including malignant pleural mesothelioma, mainly focusing on the application of Polymeric, Lipid-based, and Metal-based nanoparticles. Finally, we discuss current achievements and future challenges. PMID:27294004

  17. Chitosan and lactic acid-grafted chitosan nanoparticles as carriers for prolonged drug delivery

    OpenAIRE

    Bhattarai, Narayan; Ramay, Hassna R; Chou, Shinn-Huey; Zhang, Miqin

    2006-01-01

    Nanoparticles of ~10 nm in diameter made with chitosan or lactic acid-grafted chitosan were developed for high drug loading and prolonged drug release. A drug encapsulation efficiency of 92% and a release rate of 28% from chitosan nanoparticles over a 4-week period were demonstrated with bovine serum protein. To further increase drug encapsulation, prolong drug release, and increase chitosan solubility in solution of neutral pH, chitosan was modified with lactic acid by grafting D,L-lactic ac...

  18. Modeling and optimization of degree of folate grafted on chitosan and carboxymethyl-chitosan

    OpenAIRE

    Esfandiarpour-Boroujeni, S.; Bagheri-Khoulenjani, S.; Mirzadeh, H.

    2015-01-01

    Chitosan is a cationic polysaccharide with great properties and so is considered as an attractive biopolymer. However, chitosan shows its antibacterial activity only in acidic environment and this restricts its uses. So water-soluble chitosan derivatives such as carboxymethyl chitosan could be good candidates for such biomedical applications. Modified chitosan with hydrophobic functional groups such as folate (FA) is able to make self-assembled nanoparticles in aqueous media. One of the most ...

  19. SEM-EDX STUDIES OF CHITOSAN DERIVATIVES-METAL ADDUCTS

    OpenAIRE

    Galo Cárdenas; Edelio Taboada; Armando Bravo; S. Patricia Miranda

    2003-01-01

    Chitosan was obtained from shrimps shells (pleuroncodes monodon) using chemical methods. A series of chitosan (QS)charged with solution of copper, cobalt, nickel and mercury ions were prepared at room temperature using the batch method. N-3,5-diethylamino benzoyl chitosan (QDAB); N,O-dimercapto succinate chitosan (QNOT) and 4-aminobenzoate chitosan (QAB) derivatives were prepared. The chitosan metal adducts with Cu, Co, Ni and Hg ions and derivatives maximum loading is discussed. Chitosan and...

  20. Characterization of Chitosan Nanofiber Sheets for Antifungal Application

    OpenAIRE

    Mayumi Egusa; Ryo Iwamoto; Hironori Izawa; Minoru Morimoto; Hiroyuki Saimoto; Hironori Kaminaka; Shinsuke Ifuku

    2015-01-01

    Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young’s modulus and tensile strength of the chitosan NF sheets were higher than those of the chitosan sheets prepared from dissolving chitosan in acetic acid. The chitosan NF sheets showed strong mycelial growth in...

  1. FK506-loaded chitosan conduit promotes the regeneration of injured sciatic nerves in the rat through the upregulation of brain-derived neurotrophic factor and TrkB.

    Science.gov (United States)

    Zhao, Jia; Zheng, Xifu; Fu, Chongyang; Qu, Wei; Wei, Guoqiang; Zhang, Weiguo

    2014-09-15

    FK506 has been shown to exert neurotrophic and neuroprotective effects, but its long-term application for nerve regeneration is limited. This study evaluated the potential application of a novel FK506-loaded chitosan conduit for peripheral nerve repair, and explored the underlying mechanism. A sciatic nerve injury model was created in male Wistar rats, which were then randomly divided into three treatment groups (n=40, each): chitosan-only, chitosan+FK506 injection, and FK506-loaded chitosan. We found significant recovery of normal morphology of sciatic nerves and higher density of myelinated nerve fibers in rats treated with FK506-loaded chitosan. Similarly, the total number of myelinated nerve fibers, myelin sheath thickness, and axon diameters were significantly higher in this group compared with the others, and the compound muscle action potentials and motor nerve conduction velocity values of sciatic nerves were significantly higher. BDNF and TrkB levels in motor neurons were highest in rats treated with FK506-loaded chitosan. In conclusion, FK506-loaded chitosan promoted peripheral nerve repair and regeneration in a rat model of sciatic nerve injury. These effects are correlated with increased BDNF and TrkB expression in motor neurons. PMID:24954089

  2. Synthesis of Chitosan Quaternary Ammonium Salts

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, 1HNMR and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.

  3. Enhancing Biological Wastewater Treatment with Chitosan

    Institute of Scientific and Technical Information of China (English)

    陈亮; 陈东辉; 朱珺

    2003-01-01

    Chitin and chitosan have been applied to biological wastewater treatment.From a number of parallel comparison experiments,it can be concluded that the application of chitin and chitosan can both enhance the biological treatment,besides which chitosan is more efficient than chitin.The study on the enhancement mechanism reveals the difference between the two additives:chitosan improves the sludge structure and settlibility,while chitin acts as a kind of carrier for microorganism in the biological treatment system.

  4. Application of irradiated chitosan for fruit preservation

    International Nuclear Information System (INIS)

    Preliminary test of mango (Mangifera indica) preservation by irradiated chitosan coating has been investigated. The coating by using irradiated chitosan in 1.5% solution has extended the shelf life of mango from 7 to 15 days. At the 15th day mango coated by irradiated chitosan has been keeping good color, natural ripening, without spoilage, weight loss 10%, whereas the mango without coating was spoiled completely and the coating of fruit with unirradiated chitosan inhibited the ripening. (author)

  5. Application of irradiated chitosan for fruit preservation

    Energy Technology Data Exchange (ETDEWEB)

    Lan, K.N. [Post-harvest Technology Institute, 4, Ngo Quyen-Ha Noi (Viet Nam); Lam, N.D. [Ha Noi Radiation Center, VAEC, 5T-160, Nghiado, Tuliem, Ha Noi (Viet Nam); Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Preliminary test of mango (Mangifera indica) preservation by irradiated chitosan coating has been investigated. The coating by using irradiated chitosan in 1.5% solution has extended the shelf life of mango from 7 to 15 days. At the 15th day mango coated by irradiated chitosan has been keeping good color, natural ripening, without spoilage, weight loss 10%, whereas the mango without coating was spoiled completely and the coating of fruit with unirradiated chitosan inhibited the ripening. (author)

  6. Chitosan-supported Borohydride Reducing Agent

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new chitosan-supported borohydride reducing reagent (CBER) was prepared by treatment of KBH4 with the resin of chitosan derivative, which was first synthesized fiom the reaction of cross-linked chitosan microsphere with glycidyl trimethylammonium chloride. CBER could reduce aromatic carbonyl compound to corresponding alcohol.

  7. Antimicrobial properties of N-carboxybutyl chitosan.

    OpenAIRE

    Muzzarelli, R; Tarsi, R; Filippini, O; Giovanetti, E; G. Biagini; Varaldo, P E

    1990-01-01

    N-Carboxybutyl chitosan, a modified chitin of crustacean origin, displayed inhibitory, bactericidal, and candidacidal activities when tested against 298 cultures of various pathogens. Examination by electron microscopy showed that microbial cells exposed to N-carboxybutyl chitosan underwent marked morphological alterations. The data are of importance in defining the suitability of N-carboxybutyl chitosan as a wound dressing.

  8. A framework for grouping nanoparticles based on their measurable characteristics

    Directory of Open Access Journals (Sweden)

    Sayes CM

    2013-09-01

    Full Text Available Christie M Sayes,1–3 P Alex Smith,2 Ivan V Ivanov3 1Center for Aerosol and Nanomaterials Engineering, RTI International, Research Triangle Park, NC, USA; 2Department of Biomedical Engineering, 3Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA Background: There is a need to take a broader look at nanotoxicological studies. Eventually, the field will demand that some generalizations be made. To begin to address this issue, we posed a question: are metal colloids on the nanometer-size scale a homogeneous group? In general, most people can agree that the physicochemical properties of nanomaterials can be linked and related to their induced toxicological responses. Methods: The focus of this study was to determine how a set of selected physicochemical properties of five specific metal-based colloidal materials on the nanometer-size scale – silver, copper, nickel, iron, and zinc – could be used as nanodescriptors that facilitate the grouping of these metal-based colloids. Results: The example of the framework pipeline processing provided in this paper shows the utility of specific statistical and pattern recognition techniques in grouping nanoparticles based on experimental data about their physicochemical properties. Interestingly, the results of the analyses suggest that a seemingly homogeneous group of nanoparticles could be separated into sub-groups depending on interdependencies observed in their nanodescriptors. Conclusion: These particles represent an important category of nanomaterials that are currently mass produced. Each has been reputed to induce toxicological and/or cytotoxicological effects. Here, we propose an experimental methodology coupled with mathematical and statistical modeling that can serve as a prototype for a rigorous framework that aids in the ability to group nanomaterials together and to facilitate the subsequent analysis of trends in data based on quantitative

  9. LYOTROPIC LIQUID CRYSTALLINE BEHAVIOR OF FIVE CHITOSAN DERIVATIVES

    Institute of Scientific and Technical Information of China (English)

    Yan-ming Dong; Zhi-qiang Li

    1999-01-01

    Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubilitythan chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two Nsubstituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three Osubstituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.

  10. Effects of chitosan/collagen substrates on the behavior of rat neural stem cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Spinal cord and brain injuries usually lead to cavity formation.The transplantation by combining stem cells and tissue engineering scaffolds has the potential to fill the cavities and replace the lost neural cells.Both chitosan and collagen have their unique characteristics.In this study,the effects of chitosan and collagen on the behavior of rat neural stem cells (at the neurosphere level) were tested in vitro in terms of cytotoxicity and supporting ability for stem cell survival,proliferation and differentiation.Under the serum-free condition,both chitosan membranes and collagen gels had low cytotoxicity to neurospheres.That is,cells migrated from neurospheres,and processes extended out from these neurospheres and the differentiated cells.Compared with the above two materials,chitosan-collagen membranes were more suitable for the co-culture with rat neural stem cells,because,except for low cytotoxicity and supporting ability for the cell survival,in this group,a large number of cells were observed to migrate out from neurospheres,and the differentiating percentage from neurospheres into neurons was significantly increased.Further modification of chitosan-collagen membranes may shed light on in vivo nerve regeneration by transplanting neural stem cells.

  11. SYNTHESIS AND PROPERTIES OF SULFHYDRYL CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    杨宇民; 邵健; 姚成

    2001-01-01

    A new adsorbent for heavy metal ions, sulfhydryl chitosan (S-chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confirmed by elemental analysis and FT-IR spectra analysis. The adsorption properties of sulfhydryl chitosan for Cu( Ⅱ ), Cd( Ⅱ ), Pb( Ⅱ ), Cr( Ⅲ ) and Ni( Ⅱ ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S-chitosan has good adsorption for Pb( Ⅱ ), Cu( Ⅱ ) and Cd( Ⅱ ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S-chitosan can be affected by media acidity. The adsorbed Cu( Ⅱ ) Cd ( Ⅱ )and Pb( Ⅱ ) could be eluted by diluted chlorhydric acid.

  12. SYNTHESIS AND PROPERTIES OF SULFHYDRYL CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    杨宇民; 邵健; 姚成

    2001-01-01

    A new adsorbent for heavy metal ions, sulfhydryl chitosan (S-chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confrrmed by elemental analysis and FI'-IR spectra analysis. The adsorption properties of sulthydryl chitosan for Cu(Ⅱ ), Cd(Ⅱ ), Pb(Ⅱ), Cr(Ⅲ) and Ni(Ⅱ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S-chitosan has good adsorption for Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S-chitosan can be affected by media acidity. The adsorbed Cu(Ⅱ) Cd(Ⅱ) and Pb(Ⅱ) could be eluted by diluted chlorhydric acid.

  13. Anti-fungal activity of irradiated chitosan

    International Nuclear Information System (INIS)

    Anti-fungal activity of chitosan induced by irradiation has been investigated. Commercial chitosan samples of 8B (80% deacetylation) and l0B (99% deacetylation) were irradiated by γ-ray in dry condition. Highly deacethylated chitosan (10B) at low dose irradiation (75 kGy) was effective for inhibition of fungal growth. The sensitivities of Exobasidium vexans, Septoria chrysanthemum and Gibberella fujikuroi for the irradiated chitosan were different and the necessary concentrations of chitosan were 550, 350 and 250 μg/ml, respectively. For the plant growth, low deacethylation (chitosan 8B) and high dose (500 kGy) was effective and the growth of chrysanthemum was promoted by spraying the irradiated chitosan. (author)

  14. LOW MOLECULAR WEIGHT O-CARBOXYMETHYLATED CHITOSANS DERIVED FROM IRRADIATED CHITOSAN AND THEIR ANTIBACTERIAL ACTIVITY

    Institute of Scientific and Technical Information of China (English)

    Xu-pin Zhuang; Xiao-fei Liu; Zhi Li; Yun-lin Guan; Kang-de Yao

    2004-01-01

    Original chitosan with My of 2.7 × 10 5 was degraded by irradiation with y-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinetic model of the irradiation of chitosan was put forward. Results show that the irradiation degradation of chitosan obeys the rule of random degradation and the degree of deacetylation of irradiated chitosan is slightly raised. The antibacterial activity of O-CMCh is significantly influenced by its MW, and a suppositional antibacterial peak appears when Mv is equal to 2 × 10 5.

  15. Novel Chitosan-based Biomaterials

    Institute of Scientific and Technical Information of China (English)

    Mingchun Li; Meihua Xin

    2005-01-01

    @@ 1Introduction Chitosan with two long side chains of N-alkyl group is an important amphiphilic material, which has potential application in tissue engineering and drug delivery system. In this paper the amphiphilic N, N-dilauryl chitosan has been prepared by the phase transfer catalysis. The π-A isotherms of the products were measured in order to find some fundamental data for making self-assembled vesicles out of this kind of material. The LB film experiment indicates that N, N-dilauryl chitosan can form ultrathin LB film with highly ordered layer structure and smooth surface. The thickness of each layer of the LB film was measured as 1.74 nm by XRD.

  16. A study on biosorption of copper ions by fungal chitosan: an alternative to shrimp chitosan

    Directory of Open Access Journals (Sweden)

    Sanaz Behnam

    2015-02-01

    Full Text Available   Introduction : One of the main applications of chitosan is for heavy metals removal from waste waters. Industrially, chitosan is produced through deacetylation of chitin present in shellfish waste. Another source of chitosan is the cell wall of zygomycetes fungi with several advantages over shellfish wastes .   Materials and method s: Fungal chitosan purified from biomass of Mucor indicus and shrimp chitosan were applied and compared for removal of copper ions from aqueous solution. The effects of pH (3 to 5.5, copper ion concentration (5 to 52 mg l-1, the amount of chitosan (200 to 3000 mg l-1, adsorption time, temperature, and presence of other metal ions on the biosorption of Cu2+ were investigated .   Results : Maximum adsorption capacities for fungal and shrimp chitosans were 58.5 and 60.7 mg g-1, respectively. T he rate of copper adsorption by the fungal chitosan was significantly higher than that by the shrimp chitosan. Among p seudo-first order, pseudo-second order, intra-particle diffusion, and Elovich models, Ho’s pseudo-second order model was the best model for fitting the kinetic data. The adsorption capacity increased for both types of chitosans by increasing the solution pH. However, temperature and presence of other ions did not show significant effects on the biosorption capacity of copper. The isotherm data were very well described by Langmuir, Freundlich, and Redlich-Peterson models .   Discussion and conclusion : Both fungal and shrimp chitosans can effectively be used for removal of copper ions from aqueous solutions. Adsorption process for fungal chitosan is fast, while the process is slower for the shrimp chitosan. Therefore, from the kinetics point of view, the fungal chitosan is preferable compared with the shrimp chitosan . Key words: Biosorption, Copper, Fungal chitosan, Shrimp chitosan, Water treatment .

  17. Nanoparticle-Based Systems for T1-Weighted Magnetic Resonance Imaging Contrast Agents

    Directory of Open Access Journals (Sweden)

    Dianjun Liu

    2013-05-01

    Full Text Available Because magnetic resonance imaging (MRI contrast agents play a vital role in diagnosing diseases, demand for new MRI contrast agents, with an enhanced sensitivity and advanced functionalities, is very high. During the past decade, various inorganic nanoparticles have been used as MRI contrast agents due to their unique properties, such as large surface area, easy surface functionalization, excellent contrasting effect, and other size-dependent properties. This review provides an overview of recent progress in the development of nanoparticle-based T1-weighted MRI contrast agents. The chemical synthesis of the nanoparticle-based contrast agents and their potential applications were discussed and summarized. In addition, the recent development in nanoparticle-based multimodal contrast agents including T1-weighted MRI/computed X-ray tomography (CT and T1-weighted MRI/optical were also described, since nanoparticles may curtail the shortcomings of single mode contrast agents in diagnostic and clinical settings by synergistically incorporating functionality.

  18. Zwitterionic chitosan derivatives for pH-sensitive stealth coating

    OpenAIRE

    Xu, Peisheng; Bajaj, Gaurav; Shugg, Tyler; Van Alstine, William G.; Yeo, Yoon

    2010-01-01

    Zwitterionic chitosan, a chitosan derivative with a unique pH-dependent charge profile, was employed to create a stealth coating on the cationic surface of drug carriers. Zwitterionic chitosans were synthesized by amidation of chitosan with succinic anhydride. The succinic anhydride-conjugated chitosan had an isoelectric point, which could be easily tuned from pH 4.9 to 7.1, and showed opposite charges below and above the isoelectric point. The succinic anhydride-conjugated chitosan was able ...

  19. Chitosan as a starting material for wound healing applications

    OpenAIRE

    Patrulea, Viorica; Ostafe, V.; Borchard, Gerrit; Jordan, Olivier

    2015-01-01

    Chitosan and its derivatives have attracted great attention due to their properties beneficial for application to wound healing. The main focus of the present review is to summarize studies involving chitosan and its derivatives, especially N,N,N-trimethyl-chitosan (TMC), N,O-carboxymethyl-chitosan (CMC) and O-carboxymethyl-N,N,N-trimethyl-chitosan (CMTMC), used to accelerate wound healing. Moreover, formulation strategies for chitosan and its derivatives, as well as their in vitro, in vivo a...

  20. Chitosan as an adjuvant for poliovaccine.

    Science.gov (United States)

    Ghendon, Y; Markushin, S; Akopova, I; Koptiaeva, I; Krivtsov, G

    2011-05-01

    The use of inactivated poliomyelitis vaccine is very important for eradicating poliomyelitis. However, this vaccine is not available readily in underdeveloped countries due to the high cost. Adjuvants can improve the immunogenicity of a vaccine and reduce the antigen dose required for vaccination, thus lowering the cost of the vaccine. Chitosan glutamate solution and a chitosan sulfate micro/nanoparticle suspension were tested as adjuvants for Imovax-inactivated poliovaccine and for inactivated monovalent poliovirus type 1, 2, and 3 vaccines obtained by inactivation of the attenuated Sabin poliovirus strains. Inactivated vaccines admixed with either chitosan glutamate or chitosan sulfate micro/nanoparticles and administered to mice showed significantly enhanced immunogenicity to poliovirus type 1, 2, and 3 strains compared to the respective vaccines administered without chitosan. Chitosan preparations increased the immunogenicity of 1:2 and 1:4 diluted inactivated Sabin strain preparations in mice 8- to 16-fold, so that the neutralizing antibody titers after vaccination with adjuvanted diluted vaccine were equal to those obtained after vaccination with undiluted vaccine administered without chitosan. Neutralizing antibodies could be detected in sera of rats vaccinated with undiluted, 1:10, and 1:100 diluted Imovax vaccine admixed with chitosan sulfate micro/nanoparticles, although in the control group, vaccination only with the undiluted vaccine resulted in antibody production. These results show that the chitosan glutamate solution and chitosan sulfate micro/nanoparticle suspension can significantly improve the immunogenicity of various poliovaccines, and reduce the effective antigen dose. PMID:21412793

  1. Pharmacokinetics and biodegradation of chitosan in rats

    Science.gov (United States)

    Li, Hui; Jiang, Zhiwen; Han, Baoqin; Niu, Shuyi; Dong, Wen; Liu, Wanshun

    2015-10-01

    Chitosan, an excellent biomedical material, has received a widespread in vivo application. In contrast, its metabolism and distribution once being implanted were less documented. In this study, the pharmacokinetics and biodegradation of fluorescein isothiocyanate (FITC) labeled and muscle implantation administrated chitosan in rats were investigated with fluorescence spectrophotometry, histological assay and gel chromatography. After implantation, chitosan was degraded gradually during its distribution to diverse organs. Among the tested organs, liver and kidney were found to be the first two highest in chitosan content, which was followed by heart, brain and spleen. Urinary excretion was believed to be the major pathway of chitosan elimination, yet 80% of chitosan administered to rats was not trackable in their urine. This indicated that the majority of chitosan was degraded in tissues. In average, the molecular weight of the degradation products of chitosan in diverse organs and urine was found to be <65 kDa. This further confirmed the in vivo degradation of chitosan. Our findings provided new evidences for the intensive and safe application of chitosan as a biomedical material.

  2. Blood contact properties of ascorbyl chitosan.

    Science.gov (United States)

    Yalinca, Z; Yilmaz, E; Taneri, B; Bullici, F; Tuzmen, S

    2013-01-01

    Ascorbyl chitosan was synthesized by heating chitosan with ascorbic acid in isopropanol. The products were characterized by FTIR and C-13 NMR spectroscopies, SEM, and elemental analysis. Blood contact properties of ascorbyl chitosans were evaluated. The ascorbyl chitosans demonstrated to have increased lipid-lowering activity in comparison to chitosan alone upon contact with human blood serum in in vitro conditions. Furthermore, the total cholesterol/HDL ratio was improved towards the desirable ideal values after three hours contact with ascorbyl chitosan samples. The lipid-lowering activity increased with ascorbyl substitution. The inherent nonspecific adsorption capability of chitosan due to its chelating power with several different functional groups was exhibited by ascorbyl chitosans as well. This behavior was exemplified in a simultaneous decrease in the total iron values of the volunteers together with lower lipid levels. Furthermore, ascorbyl chitosans were observed to have less hemocompatibility but increased anticoagulant activity when compared to chitosan alone. Additional in vivo studies are necessary to support these results and to investigate further the advantages and disadvantages of these materials to prove their safety prior to clinical applications. PMID:23862665

  3. Chitosan and chitosan/wheat gluten blends : properties of extrudates, solid films and bio-foams

    OpenAIRE

    Chen, Fei

    2015-01-01

    This thesis presents four different studis describing the characteristics and processing opportunities of two widely available biopolymers: chitosan and wheat gluten. The interest in these materials is mainly because they are bio-based and obtained as co- or by-products in the fuel and food sector In the first study, high solids content chitosan samples (60 wt.%) were successfully extruded. Chitosan extrusion has previously been reported but not chitosan extrusion with a high solids content, ...

  4. Chitin, Chitosan, and Glycated Chitosan Regulate Immune Responses: The Novel Adjuvants for Cancer Vaccine

    OpenAIRE

    Xiaosong Li; Min Min; Nan Du; Ying Gu; Tomas Hode; Mark Naylor; Dianjun Chen; Nordquist, Robert E.; Chen, Wei R.

    2013-01-01

    With the development of cancer immunotherapy, cancer vaccine has become a novel modality for cancer treatment, and the important role of adjuvant has been realized recently. Chitin, chitosan, and their derivatives have shown their advantages as adjuvants for cancer vaccine. In this paper, the adjuvant properties of chitin and chitosan were discussed, and some detailed information about glycated chitosan and chitosan nanoparticles was also presented to illustrate the trend for future development.

  5. Chitosan adsorption to salivary pellicles

    NARCIS (Netherlands)

    van der Mei, Henderina; Engels, Eefje; de Vries, Jacob; Dijkstra, Rene JB; Busscher, Hendrik

    2007-01-01

    The salivary pellicle is a negatively charged protein film, to which oral bacteria readily adhere. Chitosans are cationic biomolecules with known antimicrobial properties that can be modified in different ways to enhance its antimicrobial activity. Here, we determined the changes in surface chemical

  6. Chitosan Modification and Pharmaceutical/Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Jiali Zhang

    2010-06-01

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

  7. Characterization of chitosan composites with various clays.

    Science.gov (United States)

    Lewandowska, Katarzyna; Sionkowska, Alina; Kaczmarek, Beata; Furtos, Gabriel

    2014-04-01

    The structural properties, thermal behaviour and mechanical properties of composites of chitosan (Ch) with nanoclay (montmorillonite, MMT) and/or nanoclays after surface modification have been characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and a tensile tests. The microstructure obtained by SEM and AFM microscopy for unmodified chitosan and its composites showed that particles are relatively well dispersed in the chitosan matrix. However, the increasing concentration of the chitosan solution from 1% to 2% decreases the homogeneity of the surface of the composites. In the case of chitosan composite with modified nanoclay (contains 25-30 wt.% of octadecylamine), the lack of particles aggregates in polymer matrix independent of the concentration of chitosan solution was observed. Generally, addition of nanoclay after its surface modification improved the mechanical and thermal properties of the composite much more than montmorillonite without modification. PMID:24530323

  8. In Vitro Degradation of Polyglycolide/Chitosan Hybrid Braids

    Institute of Scientific and Technical Information of China (English)

    YUAN Xiaoyan; ZHANG Qingwei; WANG Yonglin; YAO Kangde

    2005-01-01

    Hybrid braids of polyglycolide (PGA) and chitosan were prepared by the three-yarn braiding method from PGA and chitosan fiber bundles. These braids were in vitro degraded by incubating them in phosphate buffered saline (PBS) at pH 7.4 and 37 ℃ for 5 weeks. Results suggested that PGA/chitosan hybrid braids degraded significantly. Scanning electron micrographs showed that chitosan fibers in the PGA/chitosan hybrid braid with about 750% PGA in weight (PGA75/chitosan) were shaped into gel-like after 5 weeks, but those in the hybrid braid with about 250% PGA in weight (PGA25/chitosan) did not change. After 5 weeks, the ultimate tensile loads of PGA and PGA75/chitosan braids lost almost completely, but those of chitosan and PGA25/chitosan braids remained around 14 N. The PGA/chitosan hybrid braids with higher initial ultimate tensile load would have potential applications in tendon/ligament tissue reconstruction.

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

    International Nuclear Information System (INIS)

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

  10. Radiation processing of chitosan derivative and its characteristics

    International Nuclear Information System (INIS)

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

  11. ADSORPTION OF LDL ON THE MODIFIED CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    LIUManying; ZHAOLirui; 等

    2000-01-01

    In this paper,the selective adsorption of LDL on chitosan modified with PEG and Asp.was studied.The adsorption rate of LDL and HDL on the double modified chitosan was 57% and 12% respoectively,The results shown that the double modified chitosan can be used a adsorbent for selective binding to LDL,this work may help to develop functional columns for hemoperfusion.

  12. Effect of Chitosan Properties on Immunoreactivity

    OpenAIRE

    Sruthi Ravindranathan; Bhanu prasanth Koppolu; Smith, Sean G.; Zaharoff, David A

    2016-01-01

    Chitosan is a widely investigated biopolymer in drug and gene delivery, tissue engineering and vaccine development. However, the immune response to chitosan is not clearly understood due to contradicting results in literature regarding its immunoreactivity. Thus, in this study, we analyzed effects of various biochemical properties, namely degree of deacetylation (DDA), viscosity/polymer length and endotoxin levels, on immune responses by antigen presenting cells (APCs). Chitosan solutions fro...

  13. Nanoindentation of Chitosan Doped with Silver Nanoparticles

    Science.gov (United States)

    Palumbo, Matthew; Teklu, Alem; Kuthirummal, Narayanan; Levi-Polyachenko, Nicole; Department of Physics; Astronomy, College of Charleston Collaboration; Department of Plastic; Reconstructive Surgery, Wake Forest University Health Sciences Collaboration

    Imaging and spectroscopic analysis via nanoindentation was performed with the Nanosurf EasyScan2 AFM on the pure and silver doped chitosan samples allowing for a more localized determination of their stiffness, hardness, and reduced Young's modulus. The pure chitosan sample was tested to have a stiffness of 0.367 N/m, a hardness of 1.12 GPa, and a reduced Young's modulus of 30.5 MPa. The film with 5mg Ag nanoparticle per gram of chitosan was tested on the boundaries between the chitosan and Ag nanoparticles to show an increase in stiffness of about 4.6% at 0.384 N/m, an increase in hardness of about 5.4% at 1.18 GPa, and an increase in the reduced Young's modulus of about 5.0% at 3.2 MPa in comparison to the pure chitosan sample. On the other hand, upon increasing the doping to 10mg Ag nanoparticle per gram of chitosan showed a decrease in stiffness of about 6.3% at 0.344 N/m, a decrease in hardness of about 27.0% at 0.820 GPa, and a decrease in the reduced Young's modulus of about 6.0% at 28.7 MPa in comparison to the pure chitosan sample. Obviously, films doped with 5mg Ag nanoparicle per gram of chitosan provided the composites with improved mechanical strength compared to chitosan alone.

  14. Specific optical rotation indicatrices of chitosan films

    Science.gov (United States)

    Rudenko, Darya A.; Shipovskaya, Anna B.

    2016-04-01

    The optical activity of chitosan films in the forms of polysalt (chitosan acetate) and polybase was studied. The specific optical rotation [α] of all our films was negative. The absolute values of [α] of polybasic chitosan films was by an order of magnitude higher than that for polysalt films. A dependence of [α] on the orientation angle of the sample relative to the direction of the polarization vector of the incident light beam in the plane perpendicular to this beam was established. Specific optical rotation indicatrices of the chitosan films of both chemical forms were plotted.

  15. A review on chitosan-cellulose blends and nanocellulose reinforced chitosan biocomposites: Properties and their applications.

    Science.gov (United States)

    H P S, Abdul Khalil; Saurabh, Chaturbhuj K; A S, Adnan; Nurul Fazita, M R; Syakir, M I; Davoudpour, Y; Rafatullah, M; Abdullah, C K; M Haafiz, M K; Dungani, R

    2016-10-01

    Chitin is one of the most abundant natural polymers in world and it is used for the production of chitosan by deacetylation. Chitosan is antibacterial in nature, non-toxic, and biodegradable thus it can be used for the production of biodegradable film which is a green alternative to commercially available synthetic counterparts. However, their poor mechanical and thermal properties restricted its wide spread applications. Chitosan is highly compatible with other biopolymers thus its blending with cellulose and/or incorporation of nanofiber isolated from cellulose namely cellulose nanofiber and cellulose nanowhiskers are generally useful. Cellulosic fibers in nano scale are attractive reinforcement in chitosan to produce environmental friendly composite films with improved physical properties. Thus chitosan based composites have wide applicability and potential in the field of biomedical, packaging and water treatment. This review summarises properties and preparation procedure of chitosan-cellulose blends and nano size cellulose reinforcement in chitosan bionanocomposites for different applications. PMID:27312632

  16. Potentiometric urea biosensor utilizing nanobiocomposite of chitosan-iron oxide magnetic nanoparticles

    International Nuclear Information System (INIS)

    The iron oxide (Fe3O4) magnetic nanoparticles have been fabricated through a simple, cheap and reproducible approach. Scanning electron microscope, x-rays powder diffraction of the fabricated nanoparticles. Furthermore, the fabrication of potentiometric urea biosensor is carried out through drop casting the initially prepared isopropanol and chitosan solution, containing Fe3O4 nanoparticles, on the glass fiber filter with a diameter of 2 cm and a copper wire (of thickness −500 μm) has been utilized to extract the voltage signal from the functionalized nanoparticles. The functionalization of surface of the Fe3O4 nanoparticles is obtained by the electrostatically immobilization of urease onto the nanobiocomposite of the chitosan- Fe3O4 in order to enhance the sensitivity, specificity, stability and reusability of urea biosensor. Electrochemical detection procedure has been adopted to measure the potentiometric response over the wide logarithmic concentration range of the 0.1 mM to 80 mM. The Fe3O4 nanoparticles based urea biosensor depicts good sensitivity with ∼42 mV per decade at room temperature. Durability of the biosensor could be considerably enhanced by applying a thin layer of the nafion. In addition, the reasonably stable output response of the biosensor has been found to be around 12 sec.

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

    International Nuclear Information System (INIS)

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

  18. Preparation, characterization, and potential application of chitosan, chitosan derivatives, and chitosan metal nanoparticles in pharmaceutical drug delivery.

    Science.gov (United States)

    Ahmed, Tarek A; Aljaeid, Bader M

    2016-01-01

    Naturally occurring polymers, particularly of the polysaccharide type, have been used pharmaceutically for the delivery of a wide variety of therapeutic agents. Chitosan, the second abundant naturally occurring polysaccharide next to cellulose, is a biocompatible and biodegradable mucoadhesive polymer that has been extensively used in the preparation of micro-as well as nanoparticles. The prepared particles have been exploited as a potential carrier for different therapeutic agents such as peptides, proteins, vaccines, DNA, and drugs for parenteral and nonparenteral administration. Therapeutic agent-loaded chitosan micro- or nanoparticles were found to be more stable, permeable, and bioactive. In this review, we are highlighting the different methods of preparation and characterization of chitosan micro- and nanoparticles, while reviewing the pharmaceutical applications of these particles in drug delivery. Moreover, the roles of chitosan derivatives and chitosan metal nanoparticles in drug delivery have been illustrated. PMID:26869768

  19. Characterization of Chitosan Nanofiber Sheets for Antifungal Application

    Directory of Open Access Journals (Sweden)

    Mayumi Egusa

    2015-11-01

    Full Text Available Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young’s modulus and tensile strength of the chitosan NF sheets were higher than those of the chitosan sheets prepared from dissolving chitosan in acetic acid. The chitosan NF sheets showed strong mycelial growth inhibition against dermatophytes Microsporum and Trichophyton. Moreover, the chitosan NF sheets exhibited resistance to degradation by the fungi, suggesting potentials long-lasting usage. In addition, surface-deacetylated chitin nanofiber (SDCNF sheets were prepared. The SDCNF sheet had a high Young’s modulus and tensile strength and showed antifungal activity to dermatophytes. These data indicate that nanofibrillation improved the properties of chitosan. Thus, chitosan NF and SDCNF sheets are useful candidates for antimicrobial materials.

  20. Chitosan/halloysite nanotubes bionanocomposites: structure, mechanical properties and biocompatibility.

    Science.gov (United States)

    Liu, Mingxian; Zhang, Yun; Wu, Chongchao; Xiong, Sheng; Zhou, Changren

    2012-11-01

    Incorporation of nanosized reinforcements into chitosan usually results in improved properties and changed microstructures. Naturally occurred halloysite nanotubes (HNTs) are incorporated into chitosan for forming bionanocomposite films via solution casting. The electrostatic attraction and hydrogen bonding interactions between HNTs and chitosan are confirmed. HNTs are uniformly dispersed in chitosan matrix. The tensile strength and Young's modulus of chitosan are enhanced by HNTs. The storage modulus and glass transition temperature of chitosan/HNTs films also increase significantly. Blending with HNTs induces changes in surface nanotopography and increase of roughness of chitosan films. In vitro fibroblasts response demonstrates that both chitosan and chitosan/HNTs nanocomposite films are cytocompatibility even when the loading of HNTs is 10%. In summary, these results provide insights into understanding of the structural relationships of chitosan/HNTs bionanocomposite films in potential applications, such as scaffold materials in tissue engineering. PMID:22743347

  1. Synthesis and characterization of chitosan alkyl urea.

    Science.gov (United States)

    Wang, Jing; Jiang, Ji-Zhou; Chen, Wei; Bai, Zheng-Wu

    2016-07-10

    Chitosan is a versatile material employed for various purposes in many fields including the development of chiral stationary phases for enantioseparation. Chitosan alkyl urea is a kind of intermediate used to prepare enantioseparation materials. In order to synthesize the intermediates, in the present work, a new way to prepare chitosan alkyl urea has been established: chitosan was first reacted with methyl chloroformate yielding N-methoxyformylated chitosan, which was then converted to chitosan alkyl urea through amine-ester exchange reaction. With a large excess of methyl chloroformate and primary amine of low stereohindrance, the amino group in chitosan could be almost completely converted to ureido group. The as-prepared chitosan alkyl urea derivatives were characterized by IR, (1)H NMR, (13)C NMR,(1)H-(1)H COSY and (1)H-(13)C HSQC NMR spectra. The chemical shifts of hydrogen and carbon atoms of glucose unit were assigned. It was found that the degree of substitution was obviously lower if cyclopropyl amine, aniline, tert-butyl amine and diethyl amine were used as reactants for the amine-ester exchange reaction. The reason was explained with the aid of theoretical calculations. PMID:27106154

  2. Degradation of chitosan for rice crops application

    International Nuclear Information System (INIS)

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

  3. Application of irradiated chitosan for fruit preservation

    International Nuclear Information System (INIS)

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

  4. Preparation and Blood Compatibility of Oxidized-chitosan Films

    Institute of Scientific and Technical Information of China (English)

    Yue Dong YANG; Jiu Gao YU; Yong Guo ZHOU; Pei Guo LI

    2005-01-01

    Chitosan membrane was modified by the selective oxidization of chitosan molecules on its surface with NO2 gas. FTIR spectra indicated there were plenty of-COOH and -COO- groups on the modified membrane surface. The SEM study showed the modified membrane surface was rough rather than smooth as chitosan membrane. All antithrombosis test, hemolysis test and blood cell morphology observation with SEM revealed that modified chitosan membranes have superior blood compatibility to chitosan.

  5. Application Of Chitosan/Cyclodextrin Nanoparticles for Tissue Glutathione Delivery

    OpenAIRE

    Rotar O.V.; Rotar V.I.

    2013-01-01

    The aim of this study was to investigate an ability of chitosan nanoparticles for tissue delivery of the peptide glutathione. Formulations composed of chitosan or chitosan plus cyclodextrin-beta comlex were prepared. Reduced glutathione was loaded and delivered to mucosal layer of small intestine after ischemia-reperfusion injury more efficiently in chitosan/cyclodextrin-beta nanoparticles. From the data obtained, we believe that chitosan/cyclodextrin nanoparticles can be used for the oral adm...

  6. Chitosan Fibers Modified with HAp/β–TCP Nanoparticles

    OpenAIRE

    Dariusz Wawro; Luciano Pighinelli

    2011-01-01

    This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp), tricalcium phosphate (β-TCP), and HAp/β-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis) and nanoparticles of tricalcium phosphate (β-TCP) and hydroxyapatite (HAp) suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/β-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0...

  7. PHARAMACEUTICAL RELEVANCE OF CROSSLINKED CHITOSAN IN MICROPARTICULATE DRUG DELIVERY

    OpenAIRE

    Pahuja Sonia; Aggarwal Shweta

    2013-01-01

    This review highlights the importance of cross-linking with chitosan. Derivatisation of chitosan leads to the cross-linking of chitosan without changing its fundamental skelton structure. Cross-linking agents are broadly divided into two categories i.e Physical and chemical cross-linking; on the basis of interaction with chitosan. The various cross-linking agents used for the preparation of chitosan microspheres and its mechanism of cross-linking have also been described. This article also re...

  8. Preparation and characterization of magnetic chitosan particles for hyperthermia application

    International Nuclear Information System (INIS)

    The size and shape of magnetic chitosan particles were found to be dependent on both the barium ferrite/chitosan (BF/C) ratio and viscosity of a chitosan solution. The saturation magnetization of magnetic chitosan particles varied directly with the BF/C ratio, while coercivity remained almost constant. Notably, incorporated chitosan was shown to exert substantial activity with regard to low cytotoxicity and high heating rate

  9. Faster chitosan production by mucoralean strains in submerged culture

    OpenAIRE

    Amorim Rosa Valéria da Silva; Souza Wanderley de; Fukushima Kazutaka; Campos-Takaki Galba Maria de

    2001-01-01

    Production of chitosan was conducted using two Mucoralean strains, Mucor racemosus and Cunninghamella elegans. Chitosan was extracted from mycelia of M. racemosus and C. elegans at different growth phases on YPD medium. In both fungi, chitosan was rapidly produced, while highest yield of extractable chitosan was found in 24h of cultivation in submerged culture. The yield of chitosan isolated from dry mycelia of M. racemosus was about 40% higher than from C. elegans. The degree of N-acetylatio...

  10. Preparation of Chitosan-g-HEMA by radiation technique

    International Nuclear Information System (INIS)

    Chitosan-g-HEMA copolymer was prepared by radiation technique. Effects of chitosan and HEMA concentrations, irradiation dose on grafting have been investigated. Results showed that grafting process of HEMA onto chitosan occurred smoothly and achieved high grafting degree, up to 600% at 5 kGy, with 15% HEMA and 1.5% chitosan. The obtained copolymer was characterized by IR spectra, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). These measured parameters proved that HEMA grafted onto chitosan backbone. (author)

  11. Chitosan dan Aplikasi Klinisnya Sebagai Biomaterial

    Directory of Open Access Journals (Sweden)

    Bambang Irawan

    2015-10-01

    Full Text Available The development of new materials with both organic and inorganic structures is of great interest to obtain special material properties. Chitosan [2-amino-2-deoxy-D-glucan] can be obtained by N-deacetylation of chitin. Chitin is the second most abundant biopolymer in nature and the supporting material of crustaceans, insects, fungi etc. Chitosan is unique polysaccharide and has been widely used in various biomedical application due to its biocompatibility, low toxicity, biodegradability, non-immunogenic and non-carcinogenic character. In the past few years, chitosan and some of its modifications have been reported for use in biomedical applications such as artificial skin, wound dressing, anticoagulant, suture, drug delivery, vaccine carrier and dietary fibers. Recently, the use of chitosan and its derivatives has received much attention as temporary scaffolding to promotie mineralization or stimulate endochodral ossification. This article aims to give a broad overview of chitosan and its clinical applications as biomaterial.

  12. Hydrogels made from chitosan and silver nitrate.

    Science.gov (United States)

    Kozicki, Marek; Kołodziejczyk, Marek; Szynkowska, Małgorzata; Pawlaczyk, Aleksandra; Leśniewska, Ewa; Matusiak, Aleksandra; Adamus, Agnieszka; Karolczak, Aleksandra

    2016-04-20

    This work describes a gelation of chitosan solution with silver nitrate. Above the critical concentration of chitosan (c*), continuous hydrogels of chitosan-silver can be formed. At lower concentrations, the formation of nano- and micro-hydrogels is discussed. The sol-gel analysis was performed to characterise the hydrogels' swelling properties. Moreover, the following were employed: (i) mechanical testing of hydrogels, (ii) inductively coupled plasma-optical emission spectroscopy (ICP-OES) for the measurement of silver concentration, (iii) scanning electron microscopy (SEM) to examine the morphology of products obtained, and (iv) dynamic light scattering (DLS) and UV-vis spectrophotometry to examine products formed at low concentration of chitosan (cchitosan used that showed no such activity. PMID:26876830

  13. Antimicrobial and antitumor activities of chitosan from shiitake stipes, compared to commercial chitosan from crab shells.

    Science.gov (United States)

    Chien, Rao-Chi; Yen, Ming-Tsung; Mau, Jeng-Leun

    2016-03-15

    Chitosan was prepared by alkaline N-deacetylation of chitin obtained from shiitake stipes and crab shells and its antimicrobial and antitumor activities were studied. Chitosan from shiitake stipes and crab shells exhibited excellent antimicrobial activities against eight species of Gram positive and negative pathogenic bacteria with inhibition zones of 11.4-26.8mm at 0.5mg/ml. Among chitosan samples, shiitake chitosan C120 was the most effective with inhibition zones of 16.4-26.8mm at 0.5mg/ml. In addition, shiitake and crab chitosan showed a moderate anti-proliferative effect on IMR 32 and Hep G2 cells. At 5mg/ml, the viability of IMR 32 cells incubated with chitosan was 68.8-85.0% whereas that of Hep G2 cells with chitosan was 60.4-82.9%. Overall, shiitake chitosan showed slightly better antimicrobial and antitumor activities than crab chitosan. Based on the results obtained, shiitake and crab chitosan were strong antimicrobial agents and moderate antitumor agents. PMID:26794761

  14. Effects of Chitosan Concentration on the Protein Release Behaviour of Electrospun Poly(ε-caprolactone)/Chitosan Nanofibers

    OpenAIRE

    Fatemeh Roozbahani; Naznin Sultana; Davood Almasi; Farnaz Naghizadeh

    2015-01-01

    Poly(ε-caprolactone)/chitosan (PCL/chitosan) blend nanofibers with different ratios of chitosan were electrospun from a formic acid/acetic acid (FA/AA) solvent system. Bovine serum albumin (BSA) was used as a model protein to incorporate biochemical cues into the nanofibrous scaffolds. The morphological characteristics of PCL/chitosan and PCL/chitosan/BSA Nanofibers were investigated by scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) was used to detect the p...

  15. Fluorescent Nanoparticle-Based Indirect Immunofluorescence Microscopy for Detection of Mycobacterium tuberculosis

    OpenAIRE

    Jiyun Chen; Weihong Tan; Xiaojun Julia Zhao; Kemin Wang; Xiaoxiao He; Dilan Qin

    2007-01-01

    A method of fluorescent nanoparticle-based indirect immunofluorescence microscopy (FNP-IIFM) was developed for the rapid detection of Mycobacterium tuberculosis. An anti-Mycobacterium tuberculosis antibody was used as primary antibody to recognize Mycobacterium tuberculosis, and then an antibody binding protein (Protein A) labeled with Tris(2,2-bipyridyl)dichlororuthenium(II) hexahydrate (RuBpy)-doped silica nanoparticles was used to generate fluorescent signal for microscopic examination. P...

  16. Portable ceria nanoparticle-based assay for rapid detection of food antioxidants (NanoCerac)

    OpenAIRE

    Sharpe, Erica; Frasco, Thalia; Andreescu, Daniel; Andreescu, Silvana

    2012-01-01

    With increased awareness of nutrition and the advocacy for healthier food choices, there exists a great demand for a simple, easy-to-use test that can reliably measure the antioxidant capacity of dietary products. We report development and characterization of a portable nanoparticle based-assay, similar to a small sensor patch, for rapid and sensitive detection of food antioxidants. The assay is based on the use of immobilized ceria nanoparticles, which change color after interaction with ant...

  17. Nanoparticle-Based Drug Delivery for Therapy of Lung Cancer: Progress and Challenges

    OpenAIRE

    Anish Babu; Templeton, Amanda K.; Anupama Munshi; Rajagopal Ramesh

    2013-01-01

    The last decade has witnessed enormous advances in the development and application of nanotechnology in cancer detection, diagnosis, and therapy culminating in the development of the nascent field of “cancer nanomedicine.” A nanoparticle as per the National Institutes of Health (NIH) guidelines is any material that is used in the formulation of a drug resulting in a final product smaller than 1 micron in size. Nanoparticle-based therapeutic systems have gained immense popularity due to their ...

  18. Nanoparticle-based detection and quantification of DNA with single nucleotide polymorphism (SNP) discrimination selectivity

    OpenAIRE

    Qin, Wei Jie; Yung, Lin Yue Lanry

    2007-01-01

    Sequence-specific DNA detection is important in various biomedical applications such as gene expression profiling, disease diagnosis and treatment, drug discovery and forensic analysis. Here we report a gold nanoparticle-based method that allows DNA detection and quantification and is capable of single nucleotide polymorphism (SNP) discrimination. The precise quantification of single-stranded DNA is due to the formation of defined nanoparticle-DNA conjugate groupings in the presence of target...

  19. Environmental applications of chitosan and its derivatives.

    Science.gov (United States)

    Yong, Soon Kong; Shrivastava, Manoj; Srivastava, Prashant; Kunhikrishnan, Anitha; Bolan, Nanthi

    2015-01-01

    Chitosan originates from the seafood processing industry and is one of the most abundant of bio-waste materials. Chitosan is a by-product of the alkaline deacetylation process of chitin. Chemically, chitosan is a polysaccharide that is soluble in acidic solution and precipitates at higher pHs. It has great potential for certain environmental applications, such as remediation of organic and inorganic contaminants, including toxic metals and dyes in soil, sediment and water, and development of contaminant sensors. Traditionally, seafood waste has been the primary source of chitin. More recently, alternative sources have emerged such as fungal mycelium, mushroom and krill wastes, and these new sources of chitin and chitosan may overcome seasonal supply limitations that have existed. The production of chitosan from the above-mentioned waste streams not only reduces waste volume, but alleviates pressure on landfills to which the waste would otherwise go. Chitosan production involves four major steps, viz., deproteination, demineralization, bleaching and deacetylation. These four processes require excessive usage of strong alkali at different stages, and drives chitosan's production cost up, potentially making the application of high-grade chitosan for commercial remediation untenable. Alternate chitosan processing techniques, such as microbial or enzymatic processes, may become more cost-effective due to lower energy consumption and waste generation. Chitosan has proved to be versatile for so many environmental applications, because it possesses certain key functional groups, including - OH and -NH2 . However, the efficacy of chitosan is diminished at low pH because of its increased solubility and instability. These deficiencies can be overcome by modifying chitosan's structure via crosslinking. Such modification not only enhances the structural stability of chitosan under low pH conditions, but also improves its physicochemical characteristics, such as porosity

  20. Nanoparticle-Based Drug Delivery for Therapy of Lung Cancer: Progress and Challenges

    Directory of Open Access Journals (Sweden)

    Anish Babu

    2013-01-01

    Full Text Available The last decade has witnessed enormous advances in the development and application of nanotechnology in cancer detection, diagnosis, and therapy culminating in the development of the nascent field of “cancer nanomedicine.” A nanoparticle as per the National Institutes of Health (NIH guidelines is any material that is used in the formulation of a drug resulting in a final product smaller than 1 micron in size. Nanoparticle-based therapeutic systems have gained immense popularity due to their ability to overcome biological barriers, effectively deliver hydrophobic therapies, and preferentially target disease sites. Currently, many formulations of nanocarriers are utilized including lipid-based, polymeric and branched polymeric, metal-based, magnetic, and mesoporous silica. Innovative strategies have been employed to exploit the multicomponent, three-dimensional constructs imparting multifunctional capabilities. Engineering such designs allows simultaneous drug delivery of chemotherapeutics and anticancer gene therapies to site-specific targets. In lung cancer, nanoparticle-based therapeutics is paving the way in the diagnosis, imaging, screening, and treatment of primary and metastatic tumors. However, translating such advances from the bench to the bedside has been severely hampered by challenges encountered in the areas of pharmacology, toxicology, immunology, large-scale manufacturing, and regulatory issues. This review summarizes current progress and challenges in nanoparticle-based drug delivery systems, citing recent examples targeted at lung cancer treatment.

  1. Functional modification of chitosan for biomedical application

    Science.gov (United States)

    Tang, Ruogu

    Chitosan is a linear polysaccharide. Normally commercial chitosan consists of randomly distributed beta-(1-4)-linked D-glucosamine (deacetylated proportion) and N-acetyl-D-glucosamine (acetylated proportion) together. Chitosan has been proved to be a multifunctional biopolymer that presents several unique properties due to free amino groups in the repeating unit therefore chitosan has been widely applied in various areas. To be specific, provided by the excellent biocompatibility, chitosan is expected to be used in biological and medical applications including wound dressing, implants, drug carrier/delivery, etc. In this thesis, we worked on chitosan functionalization for biomedical application. The thesis are composed of three parts: In the first part, we focused on modifying the chitosan thin film, chemically introducing the nitric oxide functional groups on chitosan film. We covalently bonded small molecule diazeniumdiolates onto the chitosan films and examined the antimicrobial function and biocompatibility. Commercial chitosan was cast into films from acidic aqueous solutions. Glutaraldehyde reacted with the chitosan film to introduce aldehyde groups onto the chitosan film (GA-CS film). GA-CS reacted with a small molecule NO donor, NOC-18, to covalently immobilize NONO groups onto the polymer (NO-CS film). The-CHO and [NONO] group were verified by FT IR, UV and Griess reagent. The NO releasing rate in aqueous solution and and thermal stability were studied quantitatively to prove its effectiveness. A series of antimicrobial tests indicated that NO-CS films have multiple functions: 1. It could inhibit the bacteria growth in nutrient rich environment; 2. It could directly inactivate bacteria and biofilm; 3. It could reduce the bacteria adherence on the film surface as well as inhibit biofilm formation. In addition, the NO-CS film was proved to be biocompatible with cell and it was also compatible with other antibiotics like Amoxicillin. In the second part, we

  2. Synthesis of raloxifene-chitosan conjugate: A novel chitosan derivative as a potential targeting vehicle.

    Science.gov (United States)

    Samadi, Fatemeh Yazdi; Mohammadi, Zohreh; Yousefi, Maryam; Majdejabbari, Sara

    2016-01-01

    Chitosan is a biocompatible, non-toxic and biodegradable biopolymer. Due to the presence of functional groups on its surface, it can be modified and used as a carrier in targeted drug/gene delivery systems. In this study, raloxifene (a selective estrogen receptor ligand) was conjugated to chitosan using different methods. The conjugates were investigated by means of FTIR, TGA and physical properties assessments. Cell viability was evaluated by XTT assay. FTIR and TGA results confirmed that the conjugation between chitosan and raloxifene occurred more efficiently when trimethyl chitosan in the presence of triethylamine and excess amount of linker was used. XTT assay on MCF-7 cell line illustrated that more than 80% of cells were viable after 24h exposure to selected molecules. These findings confirm that the conjugation of raloxifene-chitosan can occur successfully using special synthesis condition and this novel chitosan derivative can be introduced as a potential drug/gene targeting agent. PMID:26552018

  3. The effect of chitosan concentration on the electrical property of chitosan-blended cellulose electroactive paper

    International Nuclear Information System (INIS)

    We studied the effect of chitosan blending on the electrical property of chitosan-blended cellulose electroactive paper (EAPap) under different humidity conditions. As the chitosan blending ratio increased, the real part of the dielectric constant of chitosan-blended cellulose EAPap increased while the dielectric loss factor decreased. From the curve fitting of the measured data using an electrode polarization model, it was found that increasing the chitosan ratio in the EAPap might promote a decrease in the relaxation time of the EAPap, resulting in an increase of the ion mobility and dc conductivity. Over 30% of the chitosan blending ratio, a gradual increment of the ion mobility of the EAPap was observed at 40% relative humidity, while a quadratic increment of the mobility was found at 60% relative humidity condition. This kind of ion-mobility-enhanced cellulose EAPap can be used not only for bending actuators but also for medical applications such as blood clotting patches

  4. Chitosan-collagen porous scaffold and bone marrow mesenchymal stem cell transplantation for ischemic stroke

    Directory of Open Access Journals (Sweden)

    Feng Yan

    2015-01-01

    Full Text Available In this study, we successfully constructed a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffold in vitro, transplanted either the composite or bone marrow mesenchymal stem cells alone into the ischemic area in animal models, and compared their effects. At 14 days after co-transplantation of bone marrow mesenchymal stem cells and the hitosan-collagen scaffold, neurological function recovered noticeably. Vascular endothelial growth factor expression and nestin-labeled neural precursor cells were detected in the ischemic area, surrounding tissue, hippocampal dentate gyrus and subventricular zone. Simultaneously, a high level of expression of glial fibrillary acidic protein and a low level of expression of neuron-specific enolase were visible in BrdU-labeled bone marrow mesenchymal stem cells. These findings suggest that transplantation of a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffold has a neuroprotective effect following ischemic stroke.

  5. Experimental Study and Stabilization Mechanisms of Silica Nanoparticles Based Brine Mud with High Temperature Resistance for Horizontal Shale Gas Wells

    OpenAIRE

    Xian-yu Yang; Ye Yue; Ji-hua Cai; Yue Liu; Xiao-ming Wu

    2015-01-01

    Previous studies showed that silica nanoparticles based fresh water drilling muds had good thermal stability up to 160°C; however its performance at high salt concentration was rather poor. Therefore, high performance silica nanoparticles based brine mud (NPBMs) with high temperature resistance for horizontal shale gas wells was proposed. Thermal stability tests from ambient temperature to 180°C, along with pressure transmission tests and rheology analysis, were performed to evaluate comprehe...

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

    OpenAIRE

    Yolanda Osuna; Karla M. Gregorio-Jauregui; J. Gerardo Gaona-Lozano; de la Garza-Rodríguez, Iliana M.; Anna Ilyna; Enrique Díaz Barriga-Castro; Hened Saade; López, Raúl G.

    2012-01-01

    Chitosan-coated magnetic nanoparticles (CMNP) were obtained at 50°C in a one-step method comprising coprecipitation in the presence of low chitosan content. CMNP showed high magnetization and superparamagnetism. They were composed of a core of 9.5 nm in average diameter and a very thin chitosan layer in accordance with electron microscopy measurements. The results from Fourier transform infrared spectrometry demonstrated that CMNP were obtained and those from thermogravimetric analysis allowe...

  7. Adsorption of fucoidan and chitosan sulfate on chitosan modified PET films monitored by QCM-D

    OpenAIRE

    Indest, Tea; Laine, Janne; Johansson, Leena Sisko; Stana-Kleinschek, Karin; Strnad, Simona; Dworczak, Renate; Ribitsch, Volker

    2012-01-01

    The adsorption behavior of fucoidan as well as chitosan derivatives (chitosan sulfate) on poly(ethylene terephthalate) (PET) model film surface was studied using the quartz crystal microbalance technique. These systems were chosen for this study due to their promising biocompatible properties. Moreover, fucoidan and chitosan sulfate have promising anticoagulant properties and represent an alternative to heparin treatment of vascular grafts. As a first step, PET foils were activated by alkalin...

  8. Structure and Function of Chitosan (V). Conformations of Ethylene Glycol Derivatives of Chitin and Chitosan

    OpenAIRE

    YUI, Toshifumi; NAKATA, Kunihiko; OGAWA, Kozo

    1996-01-01

    Molecular structures of ethylene glycol derivatives of chitin and chitosan, where 0-6 of chitin chain was etherified and both 0-3 and 0-6 of chitosan were substituted, were studied by X-ray fiber diffraction methods coupled with conformational analyses. The extended two-fold helical conformations of both chitin and chitosan chains were retained even by the etherifications. Possible molecular conformations of these derivatives were proposed.

  9. Chitosan: a propitious biopolymer for drug delivery.

    Science.gov (United States)

    Duttagupta, Dibyangana S; Jadhav, Varsha M; Kadam, Vilasrao J

    2015-01-01

    Scientists have always been interested in the use of natural polymers for drug delivery. Chitosan, being a natural cationic polysaccharide has received a great deal of attention in the past few years. It is obtained by deacetylation of chitin and is regarded as the second most ubiquitous polymer subsequent to cellulose on earth. Unlike other natural polymers, the cationic charge possessed by chitosan is accountable for imparting interesting physical and chemical properties. Chitosan has been widely exploited for its mucoadhesive character, permeation enhancing properties and controlled release of drugs. Moreover it's non-toxic, biocompatible and biodegradable properties make it a good candidate for novel drug delivery system. This review provides an insight on various chitosan based formulations for drug delivery. Some of the current applications of chitosan in areas like ophthalmic, nasal, buccal, sublingual, gastro-retentive, pulmonary, transdermal, colon-specific and vaginal drug delivery have been discussed. In addition, active targeting of drugs to tumor cells using chitosan has been described. Lastly a brief section covering the safety aspects of chitosan has also been reviewed. PMID:25761010

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

    Directory of Open Access Journals (Sweden)

    Ligia L. Fernandes

    2011-01-01

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

  11. Small angle Neutron Scatteringanalysis of chitosan in different phases

    International Nuclear Information System (INIS)

    Biopolymers are studied extensively due to its wide applications in the field of bio-technology, micro fluidics and lab on chip devices. Chitosan is natural biopolymer derived from chitin. It has wide applications in bio-medical engineering because of its biocompatibility and biodegradability. Also, chitosan act as reducing and stabilizing agent for the metal ions. Chitosan is also a good candidate in batteries as membranes. It is therefore important to study the conformational changes of chitosan. In this research work, we used SANS to understand the modifications in the radius of gyration (Rg) values of chitosan polymer in solution and in presence of HAuCl4 and LiClO4. Chitosan solution became a gel in the presence of HAuCl4 enabling to study the associated conformational change in chitosan in gels. We have also made films of chitosan, chitosan- Au and Chitosan- LiClO4 and studied the associated conformational changes in chitosan. Gels and films were formed by varying the concentration of HAuCl4. Lower concentration of HAuCl4 gave films while higher concentration of HAuCl4 gave gels. The Imaging was carried out for the samples using TEM and SEM. SANS shows that the chitosan solution (liquid) had greater Rg value than the chitosan film. The Rg value did not change in gels from that of solution. There was no correlation length for the fitting for chitosan in solution, however there was correlation length observed in the gels. This indicates that in gels the chitosan units are more localized than in solution phase. Interestingly, chitosan-Au-Li film shows the formation of star like structures which are not observed in case of gels. Hence we conclude that the presence of Lithium can induce conformational changes in chitosan films while HAuCl4 can localize chitosan units in solution leading to formation of gels.

  12. Chitosan-Pectin Synergistic Interaction and Gelation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Mixed gels of chitosan-pectin were prepared by varying the ratio of constituents in the presence of NaCl. Mixed gel at 3% of total polysaccharide concentration with addtion of 12% NaCl showed a synergistic maximum when the ratio of chitosan to pectin was 60 : 40. The effect of the polysaccharide concentration,the preparation temperature(Tp), the time of incubation, balk salt concentration, the molecular weight and the degree of deacetylation of chitosan on gelation have been studied. Interaction mechanism between molecules of both polysaccharides was investigated by FT-IR spectrometry.

  13. Adsorption of Cadmium By Silica Chitosan

    OpenAIRE

    Moftah Ali; Ani Mulyasuryani; Akhmad Sabarudin

    2013-01-01

    The adsorption process depends on initial concentration of Cd2+ and ratio of  chitosan in adsorbent. The present study deals with the competitive adsorption of Cd2+ ion onto silica graft with chitosan. Batch adsorption experiments were performed at five different initial Cd2+ concentrations (5, 10, 15, 20 and 25 ppm), on five different proportion from silica to chitosan (100%, 95%, 85%, 75% and 65%) as adsorbent at pH 5. In the recovery process, the high recovery at 0.5 mg and observed the re...

  14. Chitosan Conduit for Peripheral Nerve Regeneration

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Chitosan, the N-deacetylated form of chitin, has good biocompatibility and biodegradability.This paper investigates the feasibility of using chitosan conduits for peripheral nerve regeneration.Cell culture experiments were used to test the material's cytotoxicity and affinity to nerve cells.Conduit implantation experiments were used to study the degradation of the material and the regeneration of injured sciatic nerves.The primary results indicate that chitosan has good mechanical properties, biocompatibility, and biodegradability and it may be a promising biomaterial for peripheral nerve regeneration.

  15. Viscometric studies of chitosan radiation degradation

    International Nuclear Information System (INIS)

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

  16. nanocomposites chitosan /clay for electrochemical sensors

    International Nuclear Information System (INIS)

    This study was performed to obtain films of nanocomposites chitosan/bentonite and chitosan/montmorillonite intercalation by the technique of solution in the proportions of 5:1 and 10:1. The nanocomposites were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and the nanocomposites Chitosan/montmorillonite also were characterized by thermogravimetric analysis (TG). The results indicated that the feasibility of obtaining films of nanocomposites exfoliate. Among the suggested applications for films developed in this study includes them use for electrochemical sensors. (author)

  17. Rheological study of chitosan in solution

    International Nuclear Information System (INIS)

    Chitosan is an abundant biopolymer with remarkable physicochemical and biological properties, usually employed in a wide range of applications. It acts as a cationic polyelectrolyte in aqueous acid solutions, leading to unique characteristics. In this work, chitosan was characterized by 1H NMR and its rheological behavior were studied as function of chitosan sample, shear rate, polymer concentration, ionic strength, time and temperature. In order to calculate rheological parameters and to understand the macromolecular dynamic in solution, the Otswald-de Waele model was fitted. (author)

  18. Chitosan as a starting material for wound healing applications.

    Science.gov (United States)

    Patrulea, V; Ostafe, V; Borchard, G; Jordan, O

    2015-11-01

    Chitosan and its derivatives have attracted great attention due to their properties beneficial for application to wound healing. The main focus of the present review is to summarize studies involving chitosan and its derivatives, especially N,N,N-trimethyl-chitosan (TMC), N,O-carboxymethyl-chitosan (CMC) and O-carboxymethyl-N,N,N-trimethyl-chitosan (CMTMC), used to accelerate wound healing. Moreover, formulation strategies for chitosan and its derivatives, as well as their in vitro, in vivo and clinical applications in wound healing are described. PMID:26614560

  19. Some features of irradiated chitosan and its biological effect

    International Nuclear Information System (INIS)

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

  20. Some features of irradiated chitosan and its biological effect

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-03-01

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

  1. Progress of research on the adsorption of chitosan and its derivatives to uranium

    International Nuclear Information System (INIS)

    This paper has summarized the study on the adsorption of chitosan and its derivatives to uranium in recent years at home and abroad. It was found that the derivatives can be serine-type chitosan, methyl phosphoric acid modified chitosan, 3,4-dihydroxy benzoic acid-type chitosan, chitosan with 3,4-dihydroxybenzoic acid moiety, chitosan resin possessing a phenylarsonic acid moiety, quadrol modified chitosan, chitosan modified with molecular imprinting technique, polyacrylamide hydrogel, chitosan-coated perlite and so on. The application vista of chitosan and its derivatives to Absorpt uranium in water has been prospected. (authors)

  2. Effects of carboxymethyl chitosan on the blood system of rats

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Dawei [College of Marine Life Sciences, Ocean University of China, Qingdao 266003 (China); Han, Baoqin, E-mail: baoqinh@ouc.edu.cn [College of Marine Life Sciences, Ocean University of China, Qingdao 266003 (China); Dong, Wen; Yang, Zhao; Lv, You; Liu, Wanshun [College of Marine Life Sciences, Ocean University of China, Qingdao 266003 (China)

    2011-04-29

    Highlights: {yields} We report, for the first time, the safety of carboxymethyl chitosan in blood system. {yields} CM-Chitosan has no significant effects on coagulation function of rats. {yields} CM-Chitosan has no significant effects on anticoagulation performance of rats. {yields} CM-Chitosan has no significant effects on fibrinolytic function of rats. {yields} CM-Chitosan has no significant effects on hemorheology of rats. -- Abstract: Carboxymethyl chitosan (CM-chitosan), a derivative of chitosan, was extensively studied in the biomedical materials field for its beneficial biological properties of hemostasis and stimulation of healing. However, studies examining the safety of CM-chitosan in the blood system are lacking. In this study CM-chitosan was implanted into the abdominal cavity of rats to determine blood indexes at different times and to evaluate the effects of CM-chitosan on the blood system of rats. Coagulation function was reflected by thrombin time (TT), prothrombin time (PT), activated partial thromboplatin time (APTT), fibrinogen (FIB) and platelet factor 4 (PF4) indexes; anti-coagulation performance was assessed by the index of antithrombinIII (ATIII); fibrinolytic function was reflected by plasminogen (PLG) and fibrin degradation product (FDP) indexes; and blood viscosity (BV) and plasma viscosity (PV) indexes reflected hemorheology. Results showed that CM-chitosan has no significant effects on the blood system of rats, and provides experimental basis for CM-chitosan to be applied in the field of biomedical materials.

  3. Electrochemical and Thermal Studies of Prepared Conducting Chitosan Biopolymer Film

    International Nuclear Information System (INIS)

    In this paper, chitosan based conducting bipolymer films were prepared by casting and solvent evaporating technique. All prepared chitosan films were of pale yellow colour, transparent, and smooth. Sulphuric acid was chosen as the cross-linking agent. It enhanced conduction pathway in cross-linked chitosan films. Mechanical properties, solid-state, and thermal behavior of prepared chitosan fimls were studied by means of a material testing machine, powder X-ray diffractometry (XRD), thermogravimetric analysis (TG-DTG), and differential scanning calorimetry (DSC). By the XRD diffraction pattern, high molecular weight of chitosan product indicates the semi-crystalline nature, but the prepared chitosan film and doped chitosan film indicate significantly lower in crystallinity prove which of the amorphous characteristics. In addition, DSC thermogram of pure chitosan film exhibited exothermic peak around at 300 C, indicating polymer decomposition of chitosan molecules in chitosan films. Furthermore, these DSC thermograms clearly showed that while pure chitosan film display exothermal decomposition, the doped chitosan films mainly endothermic characteristics. The ionic conductivity of doped chitosan films were in the order of 10 to 10 S cm , which is in the range of semi-conductor. These results showed that cross-linked chitoson films may be used as polymer electrolyte film to fabricate solid state electrochemical cells

  4. Effects of carboxymethyl chitosan on the blood system of rats

    International Nuclear Information System (INIS)

    Highlights: → We report, for the first time, the safety of carboxymethyl chitosan in blood system. → CM-Chitosan has no significant effects on coagulation function of rats. → CM-Chitosan has no significant effects on anticoagulation performance of rats. → CM-Chitosan has no significant effects on fibrinolytic function of rats. → CM-Chitosan has no significant effects on hemorheology of rats. -- Abstract: Carboxymethyl chitosan (CM-chitosan), a derivative of chitosan, was extensively studied in the biomedical materials field for its beneficial biological properties of hemostasis and stimulation of healing. However, studies examining the safety of CM-chitosan in the blood system are lacking. In this study CM-chitosan was implanted into the abdominal cavity of rats to determine blood indexes at different times and to evaluate the effects of CM-chitosan on the blood system of rats. Coagulation function was reflected by thrombin time (TT), prothrombin time (PT), activated partial thromboplatin time (APTT), fibrinogen (FIB) and platelet factor 4 (PF4) indexes; anti-coagulation performance was assessed by the index of antithrombinIII (ATIII); fibrinolytic function was reflected by plasminogen (PLG) and fibrin degradation product (FDP) indexes; and blood viscosity (BV) and plasma viscosity (PV) indexes reflected hemorheology. Results showed that CM-chitosan has no significant effects on the blood system of rats, and provides experimental basis for CM-chitosan to be applied in the field of biomedical materials.

  5. Application of chitin/chitosan in agriculture

    International Nuclear Information System (INIS)

    Chitosan is the deacetylated derivative of chitin and deacetylation degree is an important chemical characteristic which could be determined by HNMR or IR. spectroscopy. Chitosan of high deacetylation degree (87.37%) was oxidized by hydrogen peroxide at 0.6M concentration for 4 hours to obtain low molecular weight ∼ 6.0 x 104, further degradation was carried out by irradiation of chitosan in solution (4%, w/v) with gamma Co-60 rays, in the dose range from 10 kGy to 70 kGy. The test in the field for antifungus of Rhizoctonia Solani on rice plants was investigated. The antifungal effect of resultant chitosan at dose of 50 kGy and concentration of 80 ppm was most effective. (author)

  6. The development of a silica nanoparticle-based label-free DNA biosensor

    Science.gov (United States)

    Kell, Arnold J.; Pagé, Lilianne; Tan, Sophie; Charlebois, Isabelle; Boissinot, Maurice; Leclerc, Mario; Simard, Benoit

    2011-09-01

    A silica nanoparticle-based DNA biosensor capable of detecting Bacillus anthracis bacteria through the use of unlabelled ss-oligonucleotides has been developed. The biosensor makes use of the optical changes that accompany a nanoparticle-immobilized cationic conjugated polymer (polythiophene) interacting with single-stranded vs. hybridized oligonucleotides, where a fluorescence signal appears only when hybridized DNA is present (i.e. only when the ss-oligonucleotide interacting with the polymer has hybridized with its complement). In order to enhance the sensitivity of the biosensor, two different nanoparticle architectures were developed and used to elucidate how the presence of neighboring fluorophores on the nanoparticle surface affects Förster-resonant energy transfer (FRET) between the polythiophene/oligonucleotide complex (FRET donor) and the fluorophores (FRET acceptors). We demonstrate that the silica nanoparticle-based FRET platform lowers the limit of detection at least 10-fold in comparison to the polythiophene itself, and allows the detection of ~2 × 10-12 moles of ss-oligonucleotide in a 100 μL sample with a standard fluorimeter (i.e. has a limit of detection of ~2 nM ssDNA). Such nanoparticle-based biosensor platforms are beneficial because of the robustness and stability inherent to their covalent assembly and they provide a valuable new tool that may allow for the sensitive, label-free detection (the target DNA that produces the fluorescence signal is unlabelled) without the use of polymerase chain reaction.A silica nanoparticle-based DNA biosensor capable of detecting Bacillus anthracis bacteria through the use of unlabelled ss-oligonucleotides has been developed. The biosensor makes use of the optical changes that accompany a nanoparticle-immobilized cationic conjugated polymer (polythiophene) interacting with single-stranded vs. hybridized oligonucleotides, where a fluorescence signal appears only when hybridized DNA is present (i.e. only when

  7. Quantum dot/glycol chitosan fluorescent nanoconjugates

    OpenAIRE

    Mansur, Alexandra AP; Mansur, Herman S.

    2015-01-01

    In this study, novel carbohydrate-based nanoconjugates combining chemically modified chitosan with semiconductor quantum dots (QDs) were designed and synthesised via single-step aqueous route at room temperature. Glycol chitosan (G-CHI) was used as the capping ligand aiming to improve the water solubility of the nanoconjugates to produce stable and biocompatible colloidal systems. UV-visible (UV–vis) spectroscopy, photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR) spec...

  8. Biophysical studies on chitosan-coated liposomes.

    Science.gov (United States)

    Mady, Mohsen M; Darwish, Mirhane M; Khalil, Safaa; Khalil, Wafaa M

    2009-10-01

    Liposomes have been used as delivery vehicles for stabilizing drugs, overcoming barriers to cellular and tissue uptake, and for directing their contents toward specific sites in vivo. Chitosan is a biological macromolecule derived from crustacean shells and has several emerging applications in drug development, obesity control, and tissue engineering. In the present work, the interaction between chitosan and dipalmitoyl phosphatidylcholine (DPPC) liposomes was studied by transmission electron microscopy (TEM), zeta potential, solubilization using the nonionic detergent octylglucoside (OG), as well as Fourier transform infrared (FTIR) spectroscopy and viscosity measurements. The coating of DPPC liposomes by a chitosan layer was confirmed by electron microscope images and the zeta potential of liposomes. Coating of liposome by chitosan resulted in an increase in liposomal size by addition of a layer of 92 +/- 27.1 nm. The liposomal zeta potential became increasingly positive as chitosan concentration increased from 0.1 to 0.3% w/v, then it held at a relatively constant value. The amount of detergent needed to completely solubilize the liposomal membrane was increased after coating of liposomes with chitosan, indicating an increased membrane resistance to the detergent and hence a change in the natural membrane permeation properties. In the analysis of FTIR spectra of DPPC, the symmetric and antisymmetric CH(2) (at 2,800-3,000 cm(-1)) bands and the C=O (at 1,740 cm(-1)) stretching band were investigated in the absence and presence of the chitosan. It was concluded that appropriate combining of the liposomal and chitosan characteristics might be utilized for the improvement of the therapeutic efficacy of liposomes as a drug delivery system. PMID:19649627

  9. Nanoparticle-Based Topical Ophthalmic Gel Formulation for Sustained Release of Hydrocortisone Butyrate.

    Science.gov (United States)

    Yang, Xiaoyan; Trinh, Hoang M; Agrahari, Vibhuti; Sheng, Ye; Pal, Dhananjay; Mitra, Ashim K

    2016-04-01

    This study was conducted to develop formulations of hydrocortisone butyrate (HB)-loaded poly(D,L-lactic-co-glycolic acid) nanoparticles (PLGA NP) suspended in thermosensitive gel to improve ocular bioavailability of HB for the treatment of bacterial corneal keratitis. PLGA NP with different surfactants such as polyvinyl alcohol (PVA), pluronic F-108, and chitosan were prepared using oil-in-water (O/W) emulsion evaporation technique. NP were characterized with respect to particle size, entrapment efficiency, polydispersity, drug loading, surface morphology, zeta potential, and crystallinity. In vitro release of HB from NP showed a biphasic release pattern with an initial burst phase followed by a sustained phase. Such burst effect was completely eliminated when nanoparticles were suspended in thermosensitive gels and zero-order release kinetics was observed. In HCEC cell line, chitosan-emulsified NP showed the highest cellular uptake efficiency over PVA- and pluronic-emulsified NP (59.09 ± 6.21%, 55.74 ± 6.26%, and 62.54 ± 3.30%, respectively) after 4 h. However, chitosan-emulsified NP indicated significant cytotoxicity of 200 and 500 μg/mL after 48 h, while PVA- and pluronic-emulsified NP exhibited no significant cytotoxicity. PLGA NP dispersed in thermosensitive gels can be considered as a promising drug delivery system for the treatment of anterior eye diseases. PMID:26085051

  10. Plasmonic Nanoparticle-based Protein Detection by Optical Shift of a Resonant Microcavity

    CERN Document Server

    Santiago-Cordoba, Miguel A; Vollmer, Frank; Demirel, Melik C

    2011-01-01

    We demonstrated a biosensing approach which, for the first time, combines the high-sensitivity of whispering gallery modes (WGM) with a metallic nanoparticle based assay. We provided a computational model based on generalized Mie theory to explain the higher sensitivity of protein detection through Plasmonic enhancement. We quantitatively analyzed the binding of a model protein (i.e., BSA) to gold nanoparticles from high-Q WGM resonance frequency shifts, and fit the results to an adsorption isotherm, which agrees with the theoretical predictions of a two-component adsorption model.

  11. Manipulating fluorescence color and intensity with regular metal nanoparticle-based composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, Andrey G., E-mail: nikitin@cinam.univ-mrs.fr [Centre Interdisciplinaire de Nanoscience de Marseille (CINaM, UPR 3118 CNRS), Aix-Marseille University, Campus de Luminy, Case 913, 13288 Marseille, France and Faculty of Physics and Technology, Al-Farabi Kazakh National University, 71 Al-Farabi Ave., 050040 Almaty (Kazakhstan)

    2016-02-01

    This paper first studies the role of structural parameters of ordered metal nanoparticle-based composites in the modification of the spectra and intensity of directional emission from organic molecules. It then investigates the possibilities of white light generation via color conversion using two materials, one emitting in the green and the other one in the red spectral region. The structures under study exhibit enhanced emission within small solid angle in the forward direction due to excitation of the quasiguided modes. These modes modify the angle-dependent local photon density of states and, thus, result in efficient directional outcoupling of radiation.

  12. Gold nanoparticle-based fluorescent sensor for the analysis of dithiocarbamate pesticides in water

    DEFF Research Database (Denmark)

    Senkbeil, Silja; Lafleur, Josiane P.; Jensen, Thomas G.;

    2012-01-01

    Pesticides play a key role in the high yields achieved in modern agricultural food production. Besides their positive effect on increasing productivity they are intentionally toxic, often towards non-target organisms and contaminated food products can have a serious impact on human...... and environmental health. This paper demonstrates the potential of a gold nanoparticle-based microfluidic sensor for in field detection of dithiocarbamate pesticides at remote locations. Combining the attractive optical properties of gold nanoparticles with on chip mixing and detection, using a simple digital...... camera, a detection limit of 16 μg L-1 for Ziram, a dithiocarbamate pesticide, was obtained....

  13. Gold nanoparticle-based fluorescent sensor for the analysis of dithiocarbamate pesticides in water

    DEFF Research Database (Denmark)

    Senkbeil, Silja; Lafleur, Josiane P.; Jensen, Thomas Glasdam; Kutter, Jörg Peter

    2012-01-01

    Pesticides play a key role in the high yields achieved in modern agricultural food production. Besides their positive effect on increasing productivity they are intentionally toxic, often towards non-target organisms and contaminated food products can have a serious impact on human and...... environmental health. This paper demonstrates the potential of a gold nanoparticle-based microfluidic sensor for in field detection of dithiocarbamate pesticides at remote locations. Combining the attractive optical properties of gold nanoparticles with on chip mixing and detection, using a simple digital...... camera, a detection limit of 16 μg L-1 for Ziram, a dithiocarbamate pesticide, was obtained....

  14. Manipulating fluorescence color and intensity with regular metal nanoparticle-based composite materials

    International Nuclear Information System (INIS)

    This paper first studies the role of structural parameters of ordered metal nanoparticle-based composites in the modification of the spectra and intensity of directional emission from organic molecules. It then investigates the possibilities of white light generation via color conversion using two materials, one emitting in the green and the other one in the red spectral region. The structures under study exhibit enhanced emission within small solid angle in the forward direction due to excitation of the quasiguided modes. These modes modify the angle-dependent local photon density of states and, thus, result in efficient directional outcoupling of radiation

  15. The effect of chitosan derivatives and chitosan oligosaccharides on bacterial growth: I. Human colonic bacteria

    Czech Academy of Sciences Publication Activity Database

    Šimůnek, Jiří; Lukáš, Filip; Kopečný, Jan

    Ancona: PUM, 2007, s. 7-7. [Application of Chitosan in Medical Sciences. Venezia (IT), 25.01.2007-26.01.2007] R&D Projects: GA AV ČR 1QS500200572 Institutional research plan: CEZ:AV0Z50450515 Keywords : chitosan Subject RIV: EE - Microbiology, Virology

  16. The effect of chitosan derivates and chitosan oligosacharides on bacterial growth: II. Intestinal bifidobacteria

    Czech Academy of Sciences Publication Activity Database

    Lukáš, Filip; Kopečný, Jan; Šimůnek, Jiří

    Ancona : PUM, 2007, s. 9-9. [Application of Chitosan in Medical Sciences. Venezia (IT), 25.01.2007-26.01.2007] R&D Projects: GA AV ČR 1QS500200572 Institutional research plan: CEZ:AV0Z50450515 Keywords : chitosan Subject RIV: EE - Microbiology, Virology

  17. Irradiating or autoclaving chitosan/polyol solutions. Effect on thermogelling chitosan-β-glycerophosphate systems

    International Nuclear Information System (INIS)

    The effects of steam sterilization and γ-irradiation on chitosan and thermogelling chitosan-βglycerophosphate (GP) solutions containing polyol additives were investigated. The selected polyols were triethylene glycol, glycerol, sorbitol, glucose and poly(ethylene glycol) (PEG). They were incorporated to chitosan solutions prior to sterilization in a proportion ranging from 1 to 5% (w/v). The solutions were characterized with respect to their viscosity, thermogelling properties, compressive stress relaxation behavior and chitosan degradation. All polyols reduced the autoclaving-induced viscosity loss and had a positive impact on the solution thermogelling properties and compressive performance of the gels. Steam sterilization in the presence of glucose resulted in a substantial increase in the solution viscosity and gel strength. This was associated with a strong discoloration suggesting chemical alteration of the system. PEG was the most effective agent in preventing hydrolytic degradation of chitosan chains. Gamma-irradiation strongly decreased the chitosan solution viscosity regardless of the presence of additives, even when sterilization was carried out at -80 deg C. Moreover, the thermogelling properties were dramatically altered, and thus, γ-irradiation would not be an appropriate method to sterilize chitosan solutions. In conclusion, polyols are potentially useful additive to maximise the viscoelastic and mechanical properties of chitosan-GP after steam sterilization. (author)

  18. Effect of chitosan molecular weight on rheological behavious of chitosan modified nanoclay at highly hydrated state

    Science.gov (United States)

    Effect of chitosan molecular weight (M(cs)) on the rheological properties of chitosan modified clay (CMCs) at highly hydrated state was investigated. With special emphasis on its effect on the thixotropy of CMCs, the structure recovery at rest after underwent a pre-shearing process was further perfo...

  19. Clarification Effects of Chitosan on Apple Fruit Juice

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-fei; LI He-sheng; ZHANG Xiao-ping; HUANG Xiao-chun

    2003-01-01

    Chitosan is a good flocculant. The paper deals with the clarification of apple juice by means of chitosan. The results showed that the transmittance was over 97% and soluble solid content was stable basically, under the technological condition of chitosan of 0.5 - 1.2 g L-1 , temperature of 45 - 55℃ and pH 4.5. After the orthogonal trial, the optimum technological conditions of apple juice clarification by using chitosan were 0.3 g L-1 chitosan, 45℃C and pH 4.5. The research of the apple juice clarification with chitosan made a basis of the application of chitosan and provided the theoretical basis for the clarification of apple juice with chitosan.

  20. Dyeing Characteristics of Chitosan Biguanidine Hydrochloride Treated Wool Fabrics

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xue; HE JIN-xin

    2010-01-01

    @@ Chitosan biguanidine hydrochloride(CGH)has been synthesized by the guanidineylation reaction of chitosan with dicyandiamide.The structures of CGH were characterized by Fourier transform infrared spectroscopy and 13CNMR spectra.

  1. SEM-EDX STUDIES OF CHITOSAN DERIVATIVES-METAL ADDUCTS

    Directory of Open Access Journals (Sweden)

    Galo Cárdenas

    2003-12-01

    Full Text Available Chitosan was obtained from shrimps shells (pleuroncodes monodon using chemical methods. A series of chitosan (QScharged with solution of copper, cobalt, nickel and mercury ions were prepared at room temperature using the batch method. N-3,5-diethylamino benzoyl chitosan (QDAB; N,O-dimercapto succinate chitosan (QNOT and 4-aminobenzoate chitosan (QAB derivatives were prepared. The chitosan metal adducts with Cu, Co, Ni and Hg ions and derivatives maximum loading is discussed. Chitosan and derivatives containing copper were analyzed by SEM to find out the morphology of the polymers. Chitosan-Cu and derivatives charged, QDAB-Ni and QDAB-Hg were analyzed by EDX to verify the presence of the metal in the polymeric chain

  2. Enhancement of antimicrobial activity of chitosan by irradiation

    International Nuclear Information System (INIS)

    Antimicrobial activity of irradiated chitosan was studied against Escherichia coli B/r. Irradiation of chitosan at 100 kGy under dry conditions was effective in increasing the activity, and inhibited the growth of E. coli completely. The molecular weight of chitosan significantly decreased with the increase in irradiation dose, whereas the relative surface charge of chitosan was decreased only 3% by 100 kGy irradiation. Antimicrobial activity assay of chitosan fractionated according to molecular weight showed that 1 x 105-3 x 105 fraction was most effective in suppressing the growth of E coli. This fraction comprised only 8% of the 100 kGy irradiated chitosan. On the other hand, chitosan whose molecular weight was less than 1 x 105 had no activity. The results show that low dose irradiation, specifically 100 kGy, of chitosan gives enough degradation to increase its antimicrobial activity as a result of a change in molecular weight. (Author)

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

    Directory of Open Access Journals (Sweden)

    Yolanda Osuna

    2012-01-01

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

  4. The effect of andiroba oil and chitosan concentration on the physical properties of chitosan emulsion film

    Directory of Open Access Journals (Sweden)

    Vanessa Tiemi Kimura

    2016-01-01

    Full Text Available Abstract Chitosan film is used as a dressing to heal burns. The physical and biological properties of the film can be modified by the addition of phytotherapic compounds. This work used the casting -solvent evaporation technique to prepare chitosan film containing andiroba oil (Carapa guianensis which has anti-inflammatory, antibiotic, and healing properties. The objective of this study was to determine the effect of the concentrations of chitosan and andiroba oil on the physical properties of chitosan films. The emulsion films were evaluated concerning the mechanical properties and fluid handling capacity. Additionally, scanning electron microscopy and thermal analysis were performed. The results showed that the barrier and mechanical properties were affected by the addition of andiroba oil, and these may be modulated as a function of the concentration of oil added to the film. The thermal analysis showed no evidence of chemical interactions between the oil and chitosan.

  5. Preparations, Characterizations and Applications of Chitosan-based Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chitosan is a natural polysaccharide prepared by the N-deacetylation of chitin. In this paper we have reviewed the methods of preparation of chitosan-based nanoparticles and their pharmaceutical applications. There are five methods of their preparations: emulsion cross-linking, emulsion-droplet coalescence, ionic gelation, reverse micellar method and chemically modified chitosan method. Chitosan nanoparticles are used as carriers for low molecular weight drug, vaccines and DNA. Releasing characteristics, biodistribution and applications are also summarized.

  6. Chitosan: An Update on Potential Biomedical and Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    Randy Chi Fai Cheung

    2015-08-01

    Full Text Available Chitosan is a natural polycationic linear polysaccharide derived from chitin. The low solubility of chitosan in neutral and alkaline solution limits its application. Nevertheless, chemical modification into composites or hydrogels brings to it new functional properties for different applications. Chitosans are recognized as versatile biomaterials because of their non-toxicity, low allergenicity, biocompatibility and biodegradability. This review presents the recent research, trends and prospects in chitosan. Some special pharmaceutical and biomedical applications are also highlighted.

  7. PREPARATION OF CHITOSAN COATED METAL AFFINITY CHROMATOGRAPHY ADSORBENT

    Institute of Scientific and Technical Information of China (English)

    AanTianwei; XuWeijiang; 等

    1998-01-01

    A new and an inexpensive adsorbent of chitosan coated silica for immobilized metal affinity chromatography(IMAC) was studied.After a double coating,the chitosan coated on silica beads could be up to 53.4mg/g silica beads.When pH>3.8,the metal ligand Cu2+ was chelated on the coated chitosan with a bound capacity of 14.6mg/g chitosan without introducing iminodiacetic acid(IDA).

  8. Chitosan-based nanoparticles prepared by template polymerization

    OpenAIRE

    Pereira, Paula; Gama, F. M.

    2010-01-01

    INTRODUCTION: Chitosan (CS) /poly(acrylic acid) (PAA) nanoparticles (NPs) have recently been obtained by template polymerization1. In this technique, the NPs are produced upon polymerization of an acrylic monomer next to the chitosan backbone. Due to the electrostatic interaction, the negatively charged acrylic monomers align along the chitosan molecules. These physic interactions leads to self-assembled particles. The molecular weight and deacetylation degree of chitosan affect the solubili...

  9. Chitosan in Molecularly-Imprinted Polymers: Current and Future Prospects

    OpenAIRE

    Long Xu; Yun-An Huang; Qiu-Jin Zhu; Chun Ye

    2015-01-01

    Chitosan is widely used in molecular imprinting technology (MIT) as a functional monomer or supporting matrix because of its low cost and high contents of amino and hydroxyl functional groups. The various excellent properties of chitosan, which include nontoxicity, biodegradability, biocompatibility, and attractive physical and mechanical performances, make chitosan a promising alternative to conventional functional monomers. Recently, chitosan molecularly-imprinted polymers have gained consi...

  10. Chitosan as a MAMP, searching for a PRR

    OpenAIRE

    Iriti, Marcello; Faoro, Franco

    2009-01-01

    Chitosan, a deacetylated chitin derivative, behaves like a general elicitor, inducing a non-host resistance and priming a systemic acquired immunity. The defence responses elicited by chitosan include rising of cytosolic H+ and Ca2+, activation of MAP-kinases, callose apposition, oxidative burst, hypersensitive response (HR), synthesis of abscissic acid (ABA), jasmonate, phytoalexins and pathogenesis related (PR) proteins. Putative receptors for chitosan are a chitosan-binding protein, recent...

  11. Removal of azo dye from aqueous solutions using chitosan

    OpenAIRE

    Zuhair Jabbar; G. Hadi Ferdoos Sami; A , Angham

    2014-01-01

    Adsorption of Congo Red (CR) from aqueous solution onto chitosan was investigated in a batch system. The effects of solution pH, initial dye concentration, and temperature were studied. Results indicated that chitosan could be used as a biosorbent to remove the azo dyes from contaminated water. Synthesize of chitosan involved three main stages as preconditioning, demineralization, deproteinization and deacetylation. Chitosan was characterized using Fourier Transform Infrared Spectroscopy (FTI...

  12. Effect of chitosan coating on the characteristics of DPPC liposomes

    OpenAIRE

    Mady, Mohsen M; Mirhane M. Darwish

    2010-01-01

    Because it is both biocompatible and biodegradable, chitosan has been used to provide a protective capsule in new drug formulations. The present work reports on investigations into some of the physicochemical properties of chitosan-coated liposomes, including drug release rate, transmission electron microscopy (TEM), zeta potential and turbidity measurement. It was found that chitosan increases liposome stability during drug release. The coating of DPPC liposomes with a chitosan layer was con...

  13. Adhesion and viability of two enterococcal strains on covalently grafted chitosan and chitosan/kappa-carrageenan multilayers

    NARCIS (Netherlands)

    Bratskaya, S.; Marinin, D.; Simon, F.; Synytska, A.; Zschoche, S.; Busscher, H. J.; Jager, D.; van der Mei, H. C.

    2007-01-01

    Chitosans are natural aminopolysaccharides, whose low cytotoxicity suggests their potential use for nonadhesive, antibacterial coatings on biomaterials implant surfaces. Here, the antiadhesive behavior and ability to kill bacteria upon adhesion ("contact killing") of chitosan coatings were evaluated

  14. Perspectives of Chitin and Chitosan Nanofibrous Scaffolds in Tissue Engineering

    OpenAIRE

    Jayakumar, R.; Nair, S. V.; Furuike, T.; Tamura, H.

    2010-01-01

    This review summarized the preparation and tissue engineering applications of chitin and chitosan based nanofibers. Additional studies are necessary before clinical applications and for commercialization of the chitin and chitosan based nanofibers. We hope that this review article will bring new innovative types of chitin and chitosan nanofibers for tissue engineering applications in the future.

  15. Interactions between chitosan and cells measured by AFM

    International Nuclear Information System (INIS)

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

  16. Interactions between chitosan and cells measured by AFM

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-10-01

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

  17. Pyridine-grafted chitosan derivative as an antifungal agent.

    Science.gov (United States)

    Jia, Ruixiu; Duan, Yunfei; Fang, Qiang; Wang, Xiangyang; Huang, Jianying

    2016-04-01

    Pyridine moieties were introduced into chitosan by nucleophilic substitution to afford N-(1-carboxybutyl-4-pyridinium) chitosan chloride (pyridine chitosan). The resulting chitosan derivative was well characterized, and its antifungal activity was examined, based on the inhibition of mycelial growth and spore germination. The results indicated that pyridine chitosan exhibited enhanced antifungal activity by comparison with pristine chitosan. The values of the minimum inhibitory concentration and the minimal fungicidal concentration of pyridine chitosan against Fulvia fulva were 0.13 mg/ml and 1 mg/ml, respectively, while the corresponding values against Botrytis cinerea were 0.13 mg/ml and 4 mg/ml, respectively. Severe morphological changes of pyridine chitosan-treated B. cinerea were observed, indicative that pyridine chitosan could damage and deform the structure of fungal hyphae and subsequently inhibit strain growth. Non-toxicity of pyridine chitosan was demonstrated by an acute toxicity study. These results are beneficial for assessing the potential utilization of this chitosan derivative and for exploring new functional antifungal agents with chitosan in the food industry. PMID:26593505

  18. Optical and rheological study of gamma irradiated rare-earth nanoparticle based ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Nibedita [Nanoscience and Soft Matter Laboratory, Department of Physics, Tezpur University, PO Napaam, Tezpur 784 028, Assam (India); Mohanta, Dambarudhar, E-mail: best@tezu.ernet.in [Nanoscience and Soft Matter Laboratory, Department of Physics, Tezpur University, PO Napaam, Tezpur 784 028, Assam (India); Department of Physics, School of Engineering and Applied Sciences, Harvard University, MA 02138 (United States); Saha, Abhijit [UGC-DAE Consortium for Scientific Research, Kolkata Centre, III/LB-8 Bidhannagar, Kolkata 700 098 (India)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer Gd{sub 2}O{sub 3} nanoparticle based ferrofluids have been produced with ethanol as carrier medium. Black-Right-Pointing-Pointer PL emission show improvement in defect related emission with {gamma}-irradiation dose. Black-Right-Pointing-Pointer The ferrofluids show shear thinning behavior with bi-exponential decay characteristics. Black-Right-Pointing-Pointer Fast and slow components are found to increase with irradiation dose. - Abstract: The present work reports on the optical and rheological properties of unexposed and gamma irradiated rare-earth (RE) oxide nanoparticle-based ferrofluids (FF). The ferrofluids were prepared by dispersing surfactant coated gadolinium oxide (Gd{sub 2}O{sub 3}) nanoparticles in ethanol medium and later on subjected to energetic gamma irradiation (1.25 MeV) at select doses. As predicted from transmission electron microscopy and X-ray diffraction (XRD) studies, the synthesized nanoparticles are of {approx}7 nm size which crystallize into cubic crystal structure. The photoluminescence response reveals creation of defect states on nanoparticle surfaces when FFs are subjected to gamma irradiation. Whereas, rheology measurements showed unusual shear thinning behavior of the ferrofluids. The flow behavior of all the samples can be correlated to the bi-exponential decay curve fitting which reveals that decay phenomenon is governed by two independent mechanism: fast and slow events. The variation of the decay parameter with irradiation dose is attributed to the creation of point defects and weakening of inter nanoparticle bonding.

  19. Preparation, characterization and antibacterial activity of chitosan and phosphorylated chitosan from cuttlebone of Sepia kobiensis (Hoyle, 1885)

    OpenAIRE

    Annaian Shanmugam; Kandasamy Kathiresan; Lakshman Nayak

    2016-01-01

    Chitosan is a commercially available derivative of chitin that has been extensively studied for its antimicrobial properties. In order to improve the water solubility and its biological activity, the chemical modification or derivatisation is attempted. In the present investigation, the chitosan prepared from the cuttlebone of Sepia kobiensis was being chemically modified by reacting it with orthophosphoric acid so as to obtain phosphorylated chitosan. Then the chitosan and phosphorylated chi...

  20. Preparation, characterization and in vitro evaluation of nanostructured chitosan/apatite and chitosan/Si-doped apatite composites

    OpenAIRE

    Solis, Yaimara; Davidenko, Natalia; Carrodeguas, Raul G.; Cruz, Jeny; Hernandez, Andy; Tomas, Miriela; Cameron, Ruth Elizabeth; Peniche, Carlos

    2013-01-01

    Chitosan/apatite composites are attracting great attention as biomaterials for bone repair and regeneration procedures. The reason is their unique set of properties: bioactivity and osteoconductivity provided by apatite and resorbability supplied by chitosan among others. Thus, in this work chitosan/apatite and chitosan/Si-doped apatite composites were prepared and characterized. Particle size, surface area, in vitro physiological stability, enzymatic biodegradation and bioactivity were evalu...

  1. Preparation and Characterization of Chitosan Hydrochloride

    Institute of Scientific and Technical Information of China (English)

    FENG; HuiXia

    2001-01-01

    Chitin 1 is a biodegradable and nontoxic polysaccharide widely spread among marine and terrestrial invertebrates and fungi. It is usually obtained from waste materials of the sea food-processing industry, mainly shells of crab, shrimp, prawn and krill. Native chitin occurs in such natural composite materials usually combined with inorganics, proteins, lipids and pigments. Its isolation calls for chemical treatments to eliminate these contaminants, some of which maybe coimmercially explored. By treating crude chitin with aqueous 40~50% sodium hydroxide at 110~115℃ chitosan is obtained. However, the fully deacetylated product is rarely obtained due to the risks of side reactions and chain deplolymerization. Chitosan and chitin are closely related since both are linear polysaccharides containing 2-acetamido-2-deoxy-D-glucopyranose and 2-amino-2-deoxy-D-glucopyranose units joined by β (1→4) glycosidic bonds. They can be distinguished by their contents of the above-mentioned units and by their solubilities in aqueous media. The acetylated units predominate in chitin while chitosan chains contain mostly deacetylated units. Chitin is soluble in a very limited number of solvents while chitosan is soluble in aqueous dilute solutions of a number of mineral and organic acids, being the most common ones, the hydrochloric and acetic acids. In aqueous dilute acid media chitosan forms salts, producing polyelectrolyte chains bearing positive charges on the nitrogen atoms of their amine groups. In fact the salt of chitosan may be formed in a separate step or as a consequence of the presence of acid in the water suspension of the neutralized form of chitosan.  ……

  2. Nuclear imaging evaluation of galactosylation of chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hwan Jeong; Kim, Eun Mi; Kim, Chang Guhn [School of Medicine, Wonkwang Univ., Iksan (Korea, Republic of); Park, In Kyu; Cho, Chong Su [Seoul National Univ., Seoul (Korea, Republic of); Bom, Hee Seung [School of Medicine, Chonnam National Univ., Gwangju (Korea, Republic of)

    2004-06-01

    Chitosan has been studied as a non-viral gene delivery vector, drug delivery carrier, metal chelater, food additive, and radiopharmaceutical, among other things. Recently, galactose-graft chitosan was studied as a non-viral gene and drug delivery vector to target hepatocytes. The aim of this study was to investigate the usefulness of nuclear imaging for in vivo evaluation of targeting the hepatocyte by galactose grafting. Galactosyl methylated chitosan (GMC) was produced by methylation to lactobionic acid coupled chitosan Cytotoxicity of {sup 99}mTc-GMC was determined by MTT assay. Rabbits were injected via their auricular vein with {sup 99}mTc-GMC and {sup 99}mTc-methylated chitosan (MC), the latter of which does not contain a galactose group, and images were acquired with a gamma camera equipped with a parallel hole collimator. The composition of the galactose group in galactosylated chitosan (GC), as well as the tri-, di-, or mono-methylation of GMC, was confirmed by NMR spectroscopy. The results of MTT assay indicated that {sup 99}mTc-GMC was non-toxic. {sup 99}mTc-GMC specifically accumulated in the liver within 10 minutes of injection and maintained high hepatic uptake. In contrast, {sup 99}mTc-MC showed faint liver uptake. {sup 99}mTc-GMC scintigraphy of rabbits showed that the galactose ligand principally targeted the liver while the chitosan functionalities led to excretion through the urinary system. Bioconjugation with a specific ligand endows some degree of targetability to an administered molecule or drug, as in the case of galactose for hepatocyte in vivo, and evaluating said targetability is a clear example of the great benefit proffered by nuclear imaging.

  3. Preparation and Characterization of Chitosan Hydrochloride

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Chitin 1 is a biodegradable and nontoxic polysaccharide widely spread among marine and terrestrial invertebrates and fungi. It is usually obtained from waste materials of the sea food-processing industry, mainly shells of crab, shrimp, prawn and krill. Native chitin occurs in such natural composite materials usually combined with inorganics, proteins, lipids and pigments. Its isolation calls for chemical treatments to eliminate these contaminants, some of which maybe coimmercially explored. By treating crude chitin with aqueous 40~50% sodium hydroxide at 110~115℃ chitosan is obtained. However, the fully deacetylated product is rarely obtained due to the risks of side reactions and chain deplolymerization. Chitosan and chitin are closely related since both are linear polysaccharides containing 2-acetamido-2-deoxy-D-glucopyranose and 2-amino-2-deoxy-D-glucopyranose units joined by β (1→4) glycosidic bonds. They can be distinguished by their contents of the above-mentioned units and by their solubilities in aqueous media. The acetylated units predominate in chitin while chitosan chains contain mostly deacetylated units. Chitin is soluble in a very limited number of solvents while chitosan is soluble in aqueous dilute solutions of a number of mineral and organic acids, being the most common ones, the hydrochloric and acetic acids. In aqueous dilute acid media chitosan forms salts, producing polyelectrolyte chains bearing positive charges on the nitrogen atoms of their amine groups. In fact the salt of chitosan may be formed in a separate step or as a consequence of the presence of acid in the water suspension of the neutralized form of chitosan.

  4. Probing cellular behaviors through nanopatterned chitosan membranes

    International Nuclear Information System (INIS)

    This paper describes a high-throughput method for developing physically modified chitosan membranes to probe the cellular behavior of MDCK epithelial cells and HIG-82 fibroblasts adhered onto these modified membranes. To prepare chitosan membranes with micro/nanoscaled features, we have demonstrated an easy-to-handle, facile approach that could be easily integrated with IC-based manufacturing processes with mass production potential. These physically modified chitosan membranes were observed by scanning electron microscopy to gain a better understanding of chitosan membrane surface morphology. After MDCK cells and HIG-82 fibroblasts were cultured on these modified chitosan membranes for various culture durations (i.e. 1, 2, 4, 12 and 24 h), they were investigated to decipher cellular behavior. We found that both cells preferred to adhere onto a flat surface rather than on a nanopatterned surface. However, most (> 80%) of the MDCK cells showed rounded morphology and would suspend in the cultured medium instead of adhering onto the planar surface of negatively nanopatterned chitosan membranes. This means different cell types (e.g. fibroblasts versus epithelia) showed distinct capabilities/preferences of adherence for materials of varying surface roughness. We also showed that chitosan membranes could be re-used at least nine times without significant contamination and would provide us consistency for probing cell–material interactions by permitting reuse of the same substrate. We believe these results would provide us better insight into cellular behavior, specifically, microscopic properties and characteristics of cells grown under unique, nanopatterned cell-interface conditions. (paper)

  5. Nuclear imaging evaluation of galactosylation of chitosan

    International Nuclear Information System (INIS)

    Chitosan has been studied as a non-viral gene delivery vector, drug delivery carrier, metal chelater, food additive, and radiopharmaceutical, among other things. Recently, galactose-graft chitosan was studied as a non-viral gene and drug delivery vector to target hepatocytes. The aim of this study was to investigate the usefulness of nuclear imaging for in vivo evaluation of targeting the hepatocyte by galactose grafting. Galactosyl methylated chitosan (GMC) was produced by methylation to lactobionic acid coupled chitosan Cytotoxicity of 99mTc-GMC was determined by MTT assay. Rabbits were injected via their auricular vein with 99mTc-GMC and 99mTc-methylated chitosan (MC), the latter of which does not contain a galactose group, and images were acquired with a gamma camera equipped with a parallel hole collimator. The composition of the galactose group in galactosylated chitosan (GC), as well as the tri-, di-, or mono-methylation of GMC, was confirmed by NMR spectroscopy. The results of MTT assay indicated that 99mTc-GMC was non-toxic. 99mTc-GMC specifically accumulated in the liver within 10 minutes of injection and maintained high hepatic uptake. In contrast, 99mTc-MC showed faint liver uptake. 99mTc-GMC scintigraphy of rabbits showed that the galactose ligand principally targeted the liver while the chitosan functionalities led to excretion through the urinary system. Bioconjugation with a specific ligand endows some degree of targetability to an administered molecule or drug, as in the case of galactose for hepatocyte in vivo, and evaluating said targetability is a clear example of the great benefit proffered by nuclear imaging

  6. In vitro treatments of Echinococcus granulosus with fungal chitosan, as a novel biomolecule

    Institute of Scientific and Technical Information of China (English)

    Bahman Rahimi-Esboei; Mahdi Fakhar; Aroona Chabra; Mahboobeh Hosseini

    2013-01-01

    Objective: To determined the antiparasitic activity of the isolated chitosan from Penicillium viridicatum, Penicillium aurantiogriseum and commercial chitosan against protoscolicidal of hydatid cysts were determined. Methods:After isolating chitosan from fungal cell walls, four concentrations (50, 100, 200, 400μg/mL) of each type of prepared chitosan and commercial chitosan were used for 10, 30, 60, and 180 min, respectively. Results: Among different type of chitosan, commercial chitosan with the highest degree of deacetylation showed high scolicidal activity in vitro. Fungal chitosan could be recommended, as good as commercial chitosan, for hydatic cysts control. Conclusions:It seems to be a good alternative to synthetic and chemical scolicidal.

  7. Neuronal Migration Disorders

    Science.gov (United States)

    ... Enhancing Diversity Find People About NINDS NINDS Neuronal Migration Disorders Information Page Table of Contents (click to ... being done? Clinical Trials Organizations What are Neuronal Migration Disorders? Neuronal migration disorders (NMDs) are a group ...

  8. Motor Neuron Diseases

    Science.gov (United States)

    ... Awards Enhancing Diversity Find People About NINDS Motor Neuron Diseases Fact Sheet See a list of all ... can I get more information? What are motor neuron diseases? The motor neuron diseases (MNDs) are a ...

  9. Sorption of technetium on chitosan from aqueous solutions

    International Nuclear Information System (INIS)

    This work was aimed to study influence of the contact time, effect of pH and effect of foreign ions on sorption of pertechnetate anions on chitosan and crosslinked chitosan. Sorption of technetium on chitosan was studied using batch techniques in static arrangement of experiment under aerobic conditions at laboratory temperature. The influence of contact time, effect of pH and effect of foreign ions on sorption of pertechnetate anions on chitosan and crosslinked chitosan was studied. The adsorption of technetium on these sorbents was rapid and the percentage of the technetium sorption was > 80 % for chitosan and > 98 % for crosslinked chitosan. The highest value of the percentage technetium sorption on chitosan was observed at pH value near 3. The adsorption capacity of crosslinked chitosan was increased with increasing pH values. In the pH range of 3-11 adsorption of technetium on crosslinked chitosan was > 98 %. The competition effect of Fe3+ towards TcO4 - sorption on crosslinked chitosan is stronger than the competition effect of other observed cations. The selectivity of chitosan and crosslinked chitosan for these cations in solution with the concentration above 1· 10-3 mol dm-3 was in the order Na+ > Ca2+ > Fe2+ and Ca2+ > Na+ > Fe2+, respectively. From these results it can be expected that crosslinked chitosan could be a suitable sorbent for the immobilization of technetium in the liquid radioactive waste. Further work is necessary to investigate the influence of some anions on technetium sorption on crosslinked chitosan. (authors)

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

    International Nuclear Information System (INIS)

    Cast films of chitosan and chitosan containing LiClO4 were characterized using Fourier transform infrared spectroscopy and the thermogravimetric technique. The electric properties of hydrated and dehydrated films were investigated with impedance spectroscopy in the frequency range from 0.1 Hz to 1 MHz, at temperatures varying from 30 to 110 oC. The frequency dependence of the impedance for dehydrated chitosan and chitosan containing LiClO4 films indicated ionic conduction. Two relaxation peaks were evident on the imaginary curve of the electric modulus, which were assigned to ionic conduction. The peak at higher frequency was found for chitosan and chitosan containing LiClO4 films. The peak at lower frequency was attributed to Li+ conduction since it appeared only for the chitosan containing LiClO4. The peak frequency varied with the temperature according to an Arrhenius process with activation energies of circa of 0.6 and 0.45 eV, for H+ and Li+ conduction, respectively.

  11. Targeted delivery of small interfering RNA to colon cancer cells using chitosan and PEGylated chitosan nanoparticles.

    Science.gov (United States)

    Rudzinski, Walter E; Palacios, Adriana; Ahmed, Abuzar; Lane, Michelle A; Aminabhavi, Tejraj M

    2016-08-20

    Small interfering RNA (siRNA) molecules specifically target messenger RNA species, decreasing intracellular protein levels. β-Catenin protein concentrations are increased in 70-80% of colon tumors, promoting tumor progression. Chitosan exhibits low levels of toxicity and can be transported across mucosal membranes; therefore, our objective was to develop chitosan and poly(ethylene glycol)-grafted (PEGylated) chitosan nanoparticles, 100-150nm in diameter, encapsulating anti-β-catenin siRNA for transfection into colon cancer cells. Encapsulation efficiencies up to 97% were observed. Confocal microscopy visualized the entry of fluorescently-tagged siRNA into cells. Western blot analysis showed that both chitosan and PEGylated chitosan nanoparticles containing anti-β-catenin siRNA decreased β-catenin protein levels in cultured colon cancer cells. These results indicate that nanoparticles made with chitosan and PEGylated chitosan can successfully enter colon cancer cells and decrease the level of a protein that promotes tumor progression. These or similar nanoparticles may prove beneficial for the treatment of colon cancer in humans. PMID:27178938

  12. Radiation Synthesis and Application of Carboxymethylated Chitosan Hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Young Chang

    2007-08-15

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

  13. Preparation of ultrafine chitosan particles by reverse microemulsion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ultrafine chitosan particles were prepared by reverse microemulsion consisting of water, Triton X-100, octanol and cyclohexane. Two methods of preparing ultrafine chitosan particles were adopted and compared using TEM and IR, and possible mechanisms for the formation of ultrafine chitosan particles were proposed. Experimental results show that the method which combined ionic gelation and cross-linking gave uniformly sized chitosan nanoparticles with an average diameter of 92 nm, while the cross-linking without ionic gelation produced spindly chitosan particles with an average length of 943 nm and width of 188 nm.

  14. Removal of Petroleum Spill in Water by Chitin and Chitosan

    OpenAIRE

    Francisco Cláudio de Freitas Barros; Luiz Constantino Grombone Vasconcellos; Técia Vieira Carvalho; Ronaldo Ferreira do Nascimento

    2014-01-01

    The present study was undertaken to evaluate the capacity of adsorption of crude oil spilled in seawater by chitin flakes, chitin powder, chitosan flakes, chitosan powder, and chitosan solution. The results showed that, although chitosan flakes had a better adsorption capacity by oil (0.379 ± 0.030 grams oil per gram of adsorbent), the biopolymer was sinking after adsorbing oil. Chitosan solution did not present such inconvenience, despite its lower adsorption capacity (0.013 ± 0.001 grams oi...

  15. Gd-DTPA Adsorption on Chitosan/Magnetite Nanocomposites

    OpenAIRE

    Pylypchuk, Ie. V.; Kołodyńska, D.; Kozioł, M.; Gorbyk, P. P.

    2016-01-01

    The synthesis of the chitosan/magnetite nanocomposites is presented. Composites were prepared by co-precipitation of iron(II) and iron(III) salts by aqueous ammonia in the 0.1 % chitosan solution. It was shown that magnetite synthesis in the chitosan medium does not affect the magnetite crystal structure. The thermal analysis data showed 4.6 % of mass concentration of chitosan in the hybrid chitosan/magnetite composite. In the concentration range of initial Gd-DTPA solution up to 0.4 mmol/L, ...

  16. Electrical Signal Guided Ibuprofen Release from Electrodeposited Chitosan Hydrogel

    Directory of Open Access Journals (Sweden)

    Youyu Liu

    2014-01-01

    Full Text Available Electrical signal guided drug release from conductive surface provides a simple and straightforward way for advanced drug delivery. In this study, we investigated the ibuprofen release from electrodeposited chitosan hydrogel by applying electrical signals. Specifically, chitosan hydrogel was electrodeposited on titanium plate and used as a matrix for ibuprofen load and release. The release of ibuprofen from the chitosan hydrogel on titanium plate was pH sensitive. By applying a positive or negative electrical potential, the release rate of ibuprofen from the electrodeposited chitosan can be facilely controlled. Thus, coupling chitosan electrodeposition and electrical signal control spurs new possibilities for biopolymeric coating and drug elution on conductive implants.

  17. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Marc in het Panhuis

    2011-04-01

    Full Text Available The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that the electrical response upon exposure to humid atmosphere is influenced by clay-chitosan interactions, i.e., the resistance of clay–CNT materials decreases, whereas that of clay–CNT–chitosan increases.

  18. Hg(II) removal from water by chitosan and chitosan derivatives: A review

    International Nuclear Information System (INIS)

    Mercury (Hg) is one of the most toxic heavy metals commonly found in the global environment. Its toxicity is related to the capacity of its compounds to bioconcentrate in organisms and to biomagnifie through food chain. A wide range of adsorbents has been used for removing Hg(II) from contaminated water. Chitosan is obtained by alkaline deacetylation of chitin. The adsorption capacity of chitosan depends on the origin of the polysaccharide, and on the experimental conditions in the preparation, that determine the degree of deacetylation. A great number of chitosan derivatives have been obtained by crosslinking with glutaraldehyde or epichlorohydrin among others or by grafting new functional groups on the chitosan backbone with the aim of adsorbing Hg(II). The new functional groups are incorporated to change the pH range for Hg(II) sorption and/or to change the sorption sites in order to increase sorption selectivity. The chemical modification affords a wide range of derivatives with modified properties for specific applications. Hg(II) adsorption on chitosan or chitosan derivatives is now assumed to occur through several single or mixed interactions: chelation or coordination on amino groups in a pendant fashion or in combination with vicinal hydroxyl groups, electrostatic attraction in acidic media or ion exchange with protonated amino groups. This review reports the recent developments in the Hg(II) removal in waste water treatment, using chitosan and its derivatives in order to provide useful information about the different technologies. When possibly the adsorption capacity of chitosan and chitosan derivatives under different experimental conditions is reported to help to compare the efficacy of the Hg(II) removal process. A comparison with the adsorption capacity of other low-cost adsorbents is also tabled.

  19. TRANSPORT MECHANISM STUDIES OF CHITOSAN ELECTROLYTE SYSTEMS

    International Nuclear Information System (INIS)

    ABSTRACT: Knowledge of ion-conduction mechanisms in polymers is important for designing better polymer electrolytes for electrochemical devices. In this work, chitosan-ethylene carbonate/propylene carbonate (chitosan-EC/PC) system with lithium acetate (LiCH3COO) and lithium triflate (LiCF3SO3) as salts were prepared and characterized using electrochemical impedance spectroscopy to study the ion-conduction mechanism. It was found that the electrolyte system using LiCF3SO3 salt had a higher ionic conductivity, greater dielectric constant and dielectric loss value compared to system using LiCH3COO at room temperature. Hence, it may be inferred that the system incorporated with LiCF3SO3 dissociated more readily than LiCH3COO. Conductivity mechanism for the systems, 42 wt.% chitosan- 28 wt.% LiCF3SO3-30 wt.% EC/PC (CLT) and 42 wt.% chitosan-28 wt.% LiCH3COO-30 wt.% EC/PC (CLA) follows the overlapping large polaron tunneling (OLPT) model. Results show that the nature of anion size influences the ionic conduction of chitosan based polymer electrolytes. The conductivity values of the CLA system are found to be higher than that of CLT system at higher temperatures. This may be due to the vibration of bigger triflate anions would have hindered the lithium ion movements. FTIR results show that lithium ions can form complexation with polymer host which would provide a platform for ion hopping

  20. Flocculation efficiency of chitosan for papermaking applications

    Directory of Open Access Journals (Sweden)

    Raluca Nicu

    2013-02-01

    Full Text Available There is a large interest in bio-polymers as environment-friendly alternatives to synthetic additives in papermaking. In this work, the behavior of three chitosans with different molecular weights and cationic charges were investigated as flocculation additives in papermaking on two systems: calcium carbonate (GCC and pulp/GCC suspension. Comparison was made with two traditional cationic polymers used in wet end chemistry (poly-diallyldimethyl-ammonium chloride (PDADMAC and poly-ethylene imine (PEI. Flocculation efficiency was evaluated by flocculation parameters (mean floc size and number of counts and by floc behavior under shear conditions, using a focused beam reflectance measurement (FBRM technique. Results indicated different behaviors between the three chitosans when they were used for the flocculation of GCC and pulp/GCC suspensions. Chitosans were found to be more efficient over PDADMAC and PEI for flocculating small particles of the GCC suspension, but less efficient for increasing floc sizes, regardless of their MW or CCD. Flocculation parameters for pulp/GCC suspensions suggested the flocculation behavior of chitosan was close to that of PEI, but chitosan had higher efficiency and affinity towards cellulose fibers.

  1. Adsorption of Cadmium By Silica Chitosan

    Directory of Open Access Journals (Sweden)

    Moftah Ali

    2013-03-01

    Full Text Available The adsorption process depends on initial concentration of Cd2+ and ratio of  chitosan in adsorbent. The present study deals with the competitive adsorption of Cd2+ ion onto silica graft with chitosan. Batch adsorption experiments were performed at five different initial Cd2+ concentrations (5, 10, 15, 20 and 25 ppm, on five different proportion from silica to chitosan (100%, 95%, 85%, 75% and 65% as adsorbent at pH 5. In the recovery process, the high recovery at 0.5 mg and observed the recovery decrease with increasing the initial concentration of Cd2+, and the low recovery at 0.25 mg from Cd2+. In this study, the adsorption capacity of Cd2+ in regard to the ratio of silica and chitosan hybrid adsorbents are examined in detail. The aim of this study to explore effects of initial concentrations of Cd2+, and the ratio of silica to chitosan on the adsorption and recovery of Cd2+.

  2. ADSORPTION OF Mg(II) ION FROM AQUEOUS SOLUTION ON CHITOSAN BEADS AND CHITOSAN POWDER

    OpenAIRE

    Sari Edi Cahyaningrum

    2010-01-01

    A basic investigation on the removal of Mg(II) ion from aqueous solution by chitosan beads wasconducted in a batch adsorption system. The influence of different experimental parameters; pH,agitation period and different concentration of Mg(II) ion was evaluated. A pH 7.0 was found to be anoptimum pH for Mg(II) adsorption onto chitosan powder and chitosan beads. The Langmuir andFreundlich adsorption isotherm models were applied to describe the isotherms and isotherm constantsfor the adsorption...

  3. Effects of sulfate chitosan derivatives on nonalcoholic fatty liver disease

    Science.gov (United States)

    Yu, Mingming; Wang, Yuanhong; Jiang, Tingfu; Lv, Zhihua

    2014-06-01

    Sulfate chitosan derivatives have good solubility and therapeutic effect on the cell model of NAFLD. The aim of this study was to examine the therapeutic effect of sulfate chitosan derivatives on NAFLD. The male Wistar rats were orally fed high fat emulsion and received sulfate chitosan derivatives for 5 weeks to determine the pre-treatment effect of sulfate chitosan derivatives on NAFLD. To evaluate the therapeutic effect of sulfate chitosan derivatives on NAFLD, the rats were orally fed with high concentration emulsion for 5 weeks, followed by sulfate chitosan derivatives for 3 weeks. Histological analysis and biomedical assays showed that sulfate chitosan derivatives can dramatically prevent the development of hepatic steatosis in hepatocyte cells. In animal studies, pre-treatment and treatment with sulfate chitosan derivatives significantly protected against hepatic steatohepatitis induced by high fat diet according to histological analysis. Furthermore, increased TC, ALT, MDA, and LEP in NAFLD were significantly ameliorated by pre-treatment and treatment with sulfate chitosan derivatives. Furthermore, increased TG, AST, and TNF-α in NAFLD were significantly ameliorated by treatment with sulfate chitosan derivatives. Sulfate chitosan derivatives have good pre-treatment and therapeutic effect on NAFLD.

  4. Chitosan in Mucoadhesive Drug Delivery: Focus on Local Vaginal Therapy

    Directory of Open Access Journals (Sweden)

    Toril Andersen

    2015-01-01

    Full Text Available Mucoadhesive drug therapy destined for localized drug treatment is gaining increasing importance in today’s drug development. Chitosan, due to its known biodegradability, bioadhesiveness and excellent safety profile offers means to improve mucosal drug therapy. We have used chitosan as mucoadhesive polymer to develop liposomes able to ensure prolonged residence time at vaginal site. Two types of mucoadhesive liposomes, namely the chitosan-coated liposomes and chitosan-containing liposomes, where chitosan is both embedded and surface-available, were made of soy phosphatidylcholine with entrapped fluorescence markers of two molecular weights, FITC-dextran 4000 and 20,000, respectively. Both liposomal types were characterized for their size distribution, zeta potential, entrapment efficiency and the in vitro release profile, and compared to plain liposomes. The proof of chitosan being both surface-available as well as embedded into the liposomes in the chitosan-containing liposomes was found. The capability of the surface-available chitosan to interact with the model porcine mucin was confirmed for both chitosan-containing and chitosan-coated liposomes implying potential mucoadhesive behavior. Chitosan-containing liposomes were shown to be superior in respect to the simplicity of preparation, FITC-dextran load, mucoadhesiveness and in vitro release and are expected to ensure prolonged residence time on the vaginal mucosa providing localized sustained release of entrapped model substances.

  5. ALTERED ENZYMATIC ACTIVITY OF LYSOZYMES BOUND TO VARIOUSLY SULFATED CHITOSANS

    Institute of Scientific and Technical Information of China (English)

    Hong-wei Wang; Lin Yuan; Tie-liang Zhao; He Huang; Hong Chen; Di Wu

    2012-01-01

    The purpose of this research is to investigate the effects of the variously sulfated chitosans on lysozyme activity and structure.It was shown that the specific enzymatic activity of lysozyme remained almost similar to the native protein after being bound to 6-O-sulfated chitosan (6S-chitosan) and 3,6-O-sulfated chitosan (3,6S-chitosan),but decreased greatly after being bound to 2-N-6-O-sulfated chitosan (2,6S-chitosan).Meanwhile,among these sulfated chitosans,2,6S-chitosan induced the greatest conformational change in lysozyme as indicated by the fluorescence spectra.These findings demonstrated that when sulfated chitosans of different structures bind to lysozyme,lysozyme undergoes conformational change of different magnitudes,which results in corresponding levels of lysozyme activity.Further study on the interaction of sulfated chitosans with lysozyme by surface plasmon resonance (SPR) suggested that their affinities might be determined by their molecular structures.

  6. Determination of the optimum conditions for production of chitosan nanoparticles

    International Nuclear Information System (INIS)

    Biodegradable nanoparticles are intensively investigated for their potential applications in drug delivery systems. Being a biocompatible and biodegradable polymer, chitosan holds great promise for use in this area. This investigation was concerned with determination and optimization of the effective parameters involved in the production of chitosan nanoparticles using ionic gelation method. Studied variables were concentration and p H of the chitosan solution, the ratio of chitosan to sodium tripolyphosphate therein and the molecular weight of chitosan. For this purpose, Taguchi statistical method was used for design of experiments in three levels. The size of chitosan nanoparticle was determined using laser light scattering. The experimental results showed that concentration of chitosan solution was the most important parameter and chitosan molecular weight the least effective parameter. The optimum conditions for preparation of nanoparticles were found to be 1 mg/ml chitosan solution with p H=5, chitosan to sodium tripolyphosphate ratio of 3 and chitosan molecular weight of 200,000 daltons. The average nanoparticle size at optimum conditions was found to be about 150 nm

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2012-02-01

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

  9. Suppression of Zn stress on barley by irradiated chitosan

    International Nuclear Information System (INIS)

    Chitosan was irradiated up to 1000 kGy in solid state. Irradiation of chitosan caused the reduction of molecular weight. The molecular weight of the chitosan reduced from ca. 4 x 105 to ca. 6 x 103 by irradiation at 1000 kGy. For the barley growth promotion, irradiated chitosan showed the significant effect and 1000 kGy irradiated chitosan improved 20% of growth. Using the positron emitting tracer imaging system (PETIS), the effect of chitosan on uptake and transportation of 62Zn in barley were investigated. It was found that the transportation of Zn from root to shoot and the damage of plant by Zn were suppressed with irradiated chitosan. (author)

  10. Suppression of Zn stress on barley by irradiated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, N.; Mitomo, H. [Gunma Univ., Faculty of Engineering, Department of Biological and Chemical Engineering, Kiryu, Gunma (Japan); Ha, P.T.L. [Nuclear Research Institute, Dalat (Viet Nam); Watanabe, S.; Ito, T.; Takeshita, H.; Yoshii, F.; Kume, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Chitosan was irradiated up to 1000 kGy in solid state. Irradiation of chitosan caused the reduction of molecular weight. The molecular weight of the chitosan reduced from ca. 4 x 10{sup 5} to ca. 6 x 10{sup 3} by irradiation at 1000 kGy. For the barley growth promotion, irradiated chitosan showed the significant effect and 1000 kGy irradiated chitosan improved 20% of growth. Using the positron emitting tracer imaging system (PETIS), the effect of chitosan on uptake and transportation of {sup 62}Zn in barley were investigated. It was found that the transportation of Zn from root to shoot and the damage of plant by Zn were suppressed with irradiated chitosan. (author)

  11. Chitosan nanoparticles conjugate with trypsin and trypsin inhibitor.

    Science.gov (United States)

    Chanphai, P; Tajmir-Riahi, H A

    2016-06-25

    Chitosan-protein conjugates are widely used in therapeutic drug delivery. We report the bindings of chitosan nanoparticles with trypsin (try) and trypsin inhibitor (tryi), using thermodynamic analysis and multiple spectroscopic methods. Thermodynamic parameters ΔS, ΔH and ΔG showed chitosan-protein bindings occur mainly via H-bonding and van der Waals contacts with trypsin inhibitor forming more stable conjugate than trypsin. As chitosan size increased more stable polymer-protein conjugate was formed. Chitosan complexation induces more perturbations of trypsin inhibitor structure than trypsin with reduction of protein alpha-helix and major increase of random structure. The negative value of ΔG indicates spontaneous protein-chitosan complexation at room temperature. Chitosan nanoparticles can be used to transport trypsin and trypsin inhibitor. PMID:27083826

  12. Interaction between cholesterol and chitosan in Langmuir monolayers

    Directory of Open Access Journals (Sweden)

    Felippe J. Pavinatto

    2005-06-01

    Full Text Available Chitosan incorporated in the aqueous subphase is found to affect the Langmuir monolayers of cholesterol, causing the surface pressure and the surface potential isotherms to become more expanded. The mean molecular area per cholesterol molecule in the condensed monolayer increases from 53 Ų in the absence of chitosan to 61 Ų for a concentration of 0.100 mg/mL of chitosan in the subphase. If additional chitosan is incorporated in the subphase, no change is noted, which points to saturation in the effects from chitosan. The interaction between chitosan and cholesterol probably occurs via hydrogen bonding. The monolayer expansion is also manifested in the monolayer morphology, as indicated by Brewster angle microscopy measurements, where larger cholesterol domains are visualized when chitosan is present in the subphase.

  13. Growth rate inhibition of phytopathogenic fungi by characterized chitosans

    Directory of Open Access Journals (Sweden)

    Enio N. Oliveira Junior

    2012-06-01

    Full Text Available The inhibitory effects of fifteen chitosans with different degrees of polymerization (DP and different degrees of acetylation (F A on the growth rates (GR of four phytopathogenic fungi (Alternaria alternata, Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer were examined using a 96-well microtiter plate and a microplate reader. The minimum inhibitory concentrations (MICs of the chitosans ranged from 100 µg × mL-1 to 1,000 µg × mL-1 depending on the fungus tested and the DP and F A of the chitosan. The antifungal activity of the chitosans increased with decreasing F A. Chitosans with low F A and high DP showed the highest inhibitory activity against all four fungi. P. expansum and B. cinerea were relatively less susceptible while A. alternata and R. stolonifer were relatively more sensitive to the chitosan polymers. Scanning electron microscopy of fungi grown on culture media amended with chitosan revealed morphological changes.

  14. Electrochemical detection of short HIV sequences on chitosan/Fe{sub 3}O{sub 4} nanoparticle based screen printed electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Lam Dai, E-mail: lamtd@ims.vast.ac.vn [Institute of Materials Science, Vietnamese Academy of Science and Technology, 18, Hoang Quoc Viet Road (Viet Nam); Nguyen, Binh Hai [Institute of Materials Science, Vietnamese Academy of Science and Technology, 18, Hoang Quoc Viet Road (Viet Nam); Van Hieu, Nguyen [International Training Institute for Materials Science, Hanoi University of Science and Technology, 1, Dai Co Viet Road, Hanoi (Viet Nam); Tran, Hoang Vinh; Nguyen, Huy Le [Faculty of Chemical Technology, Hanoi University of Science and Technology, 1, Dai Co Viet Road, Hanoi (Viet Nam); Nguyen, Phuc Xuan [Institute of Materials Science, Vietnamese Academy of Science and Technology, 18, Hoang Quoc Viet Road (Viet Nam)

    2011-03-12

    In this study, a novel CS/Fe{sub 3}O{sub 4} nanobiocomposite-based platform for electrochemical detection of HIV-1 was developed. The most attractive feature of this system is a suitable microenvironment (Fe{sub 3}O{sub 4} nanoparticles) which could contribute to electron transfer and thus sensitivity enhancement when using methylene blue (MB) as an external mediator and Square Wave Voltammetry (SWV), Electrochemical Impedance Spectroscopy (EIS) techniques. The proposed screen printed electrode (SPE) had a low detection limit (as low as 50 pM), acceptable stability and good reproducibility, which would be valuable for clinical diagnosis. In addition, this sensing interface may be feasibly adapted for multiplexed detection of other species of bacterial pathogens.

  15. Chromium (VI) ion adsorption features of chitosan film and its chitosan/zeolite conjugate 13X film

    OpenAIRE

    Maria Teresa Tavares; Galba M. de Campos-Takaki; Villanueva, Emílio R.; Rosa Valéria S. Amorim; Anabelle C. L. Batista

    2011-01-01

    This research evaluated the importance of the adsorption properties of chitosan a chitosan/zeolite conjugate film for the removal of Cr(VI) ions from solutions in the 5–260 mg/L concentration range, when the pH was adjusted to 4.0 and 6.0. The uptake capacities of the films formed by chitosan and by the chitosan/zeolite conjugate were calculated by mass balance. The equilibrium isotherms were fitted to the Langmuir, Freundlich and Redlich-Peterson models. The chitosan film seems to be a good ...

  16. Synthesis and characterisation of highly fluorescent core–shell nanoparticles based on Alexa dyes

    International Nuclear Information System (INIS)

    Current and future developments in the emerging field of nanobiotechnology are closely linked to the rational design of novel fluorescent nanomaterials, e.g. for biosensing and imaging applications. Here, the synthesis of bright near infrared (NIR)-emissive nanoparticles based on the grafting of silica nanoparticles (SNPs) with 3-aminopropyl triethoxysilane (APTES) followed by covalent attachment of Alexa dyes and their subsequent shielding by an additional silica shell are presented. These nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. TEM studies revealed the monodispersity of the initially prepared and fluorophore-labelled silica particles and the subsequent formation of raspberry-like structures after addition of a silica precursor. Measurements of absolute fluorescence quantum yields of these scattering particle suspensions with an integrating sphere setup demonstrated the influence of dye labelling density-dependent fluorophore aggregation on the signaling behaviour of such nanoparticles.

  17. Efficient Electrochemical Water Splitting Catalyzed by Electrodeposited Nickel Diselenide Nanoparticles Based Film.

    Science.gov (United States)

    Pu, Zonghua; Luo, Yonglan; Asiri, Abdullah M; Sun, Xuping

    2016-02-01

    In this contribution, we demonstrate that electrodeposited nickel diselenide nanoparticles based film on conductive Ti plate (NiSe2/Ti) is an efficient and robust electrode to catalyze both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in basic media. Electrochemical experiments show this electrode affords 10 mA cm(-2) at HER overpotential of 96 mV and 20 mA cm(-2) at OER overpotential of 295 mV with strong durability in 1.0 M KOH. The corresponding two-electrode alkaline water electrolyzer requires a cell voltage of only 1.66 V to achieve 10 mA cm(-2) water-splitting current. This development provides us an attractive non-noble-metal catalyst toward overall water splitting applications. PMID:26824878

  18. Nanoparticle-based capillary electroseparation of proteins in polymer capillaries under physiological conditions

    DEFF Research Database (Denmark)

    Nilsson, C.; Harwigsson, I.; Becker, K.;

    2010-01-01

    of nanoparticles, i.e. in CE mode, the protein samples adsorbed completely to the capillary walls and could not be recovered. In contrast, nanoparticle-based capillary electroseparation resolved green fluorescent protein from several of its impurities within I min. Furthermore, a mixture of native green...... fluorescent protein and two of its single-amino-acid-substituted variants was separated within 2.5 min with efficiencies of 400 000 plates/m. The nanoparticles prevent adsorption by introducing a large interacting surface and by obstructing the attachment of the protein to the capillary wall. A one......Totally porous lipid-based liquid crystalline nanoparticles were used as pseudostationary phase for capillary electroseparation with LIF detection of proteins at physiological conditions using unmodified cyclic olefin copolymer capillaries (Topas (R), 6.7 cm effective length). In the absence...

  19. Durable superhydrophobic and antireflective surfaces by trimethylsilanized silica nanoparticles-based sol-gel processing.

    Science.gov (United States)

    Manca, Michele; Cannavale, Alessandro; De Marco, Luisa; Aricò, Antonino S; Cingolani, Roberto; Gigli, Giuseppe

    2009-06-01

    We present a robust and cost-effective coating method to fabricate long-term durable superhydrophobic andsimultaneouslyantireflective surfaces by a double-layer coating comprising trimethylsiloxane (TMS) surface-functionalized silica nanoparticles partially embedded into an organosilica binder matrix produced through a sol-gel process. A dense and homogeneous organosilica gel layer was first coated onto a glass substrate, and then, a trimethylsilanized nanospheres-based superhydrophobic layer was deposited onto it. After thermal curing, the two layers turned into a monolithic film, and the hydrophobic nanoparticles were permanently fixed to the glass substrate. Such treated surfaces showed a tremendous water repellency (contact angle = 168 degrees ) and stable self-cleaning effect during 2000 h of outdoor exposure. Besides this, nanotextured topology generated by the self-assembled nanoparticles-based top layer produced a fair antireflection effect consisting of more than a 3% increase in optical transmittance. PMID:19466786

  20. Synthesis and characterisation of highly fluorescent core-shell nanoparticles based on Alexa dyes

    Energy Technology Data Exchange (ETDEWEB)

    Natte, Kishore; Behnke, Thomas; Orts-Gil, Guillermo, E-mail: guillermo.orts-gil@bam.de; Wuerth, Christian; Friedrich, Joerg F.; Oesterle, Werner; Resch-Genger, Ute, E-mail: ute.resch@bam.de [BAM Federal Institute for Materials Research and Testing (Germany)

    2012-02-15

    Current and future developments in the emerging field of nanobiotechnology are closely linked to the rational design of novel fluorescent nanomaterials, e.g. for biosensing and imaging applications. Here, the synthesis of bright near infrared (NIR)-emissive nanoparticles based on the grafting of silica nanoparticles (SNPs) with 3-aminopropyl triethoxysilane (APTES) followed by covalent attachment of Alexa dyes and their subsequent shielding by an additional silica shell are presented. These nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. TEM studies revealed the monodispersity of the initially prepared and fluorophore-labelled silica particles and the subsequent formation of raspberry-like structures after addition of a silica precursor. Measurements of absolute fluorescence quantum yields of these scattering particle suspensions with an integrating sphere setup demonstrated the influence of dye labelling density-dependent fluorophore aggregation on the signaling behaviour of such nanoparticles.

  1. Magnetically induced optical activity and dichroism of gadolinium oxide nanoparticle-based ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Nibedita; Devi, Manasi; Mohanta, Dambarudhar [Nanoscience and Soft Matter Laboratory, Department of Physics, Tezpur University, PO Napaam, Tezpur 784 028, Assam (India); Saha, Abhijit [UGC-DAE Consortium for Scientific Research, Kolkata Centre, III/LB-8 Bidhannagar, Kolkata 700 098 (India)

    2012-02-15

    The present work reports on magnetically induced optical activity (such as Faraday rotation and linear dichroism) of pristine and gamma-irradiated gadolinium oxide (Gd{sub 2}O{sub 3}) nanoparticle-based ferrofluids. The ferrofluids were produced by dispersing N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB)-coated {approx}9-nm-sized Gd{sub 2}O{sub 3} particles in a carrier fluid of ethanol. The ferrofluids were then irradiated with 1.25 MeV energetic gamma rays (dose: 868 Gy and 2.635 kGy). Irradiation-led formation of a number of point defects was revealed through high resolution electron microscopy. The interaction of light with the ionized point defects is believed to have caused substantial improvement in the magneto-optic response of irradiated magnetic fluids.

  2. A sight on the current nanoparticle-based gene delivery vectors

    Science.gov (United States)

    Dizaj, Solmaz Maleki; Jafari, Samira; Khosroushahi, Ahmad Yari

    2014-05-01

    Nowadays, gene delivery for therapeutic objects is considered one of the most promising strategies to cure both the genetic and acquired diseases of human. The design of efficient gene delivery vectors possessing the high transfection efficiencies and low cytotoxicity is considered the major challenge for delivering a target gene to specific tissues or cells. On this base, the investigations on non-viral gene vectors with the ability to overcome physiological barriers are increasing. Among the non-viral vectors, nanoparticles showed remarkable properties regarding gene delivery such as the ability to target the specific tissue or cells, protect target gene against nuclease degradation, improve DNA stability, and increase the transformation efficiency or safety. This review attempts to represent a current nanoparticle based on its lipid, polymer, hybrid, and inorganic properties. Among them, hybrids, as efficient vectors, are utilized in gene delivery in terms of materials (synthetic or natural), design, and in vitro/ in vivo transformation efficiency.

  3. Simulations of the structure and dynamics of nanoparticle-based ionic liquids

    KAUST Repository

    Hong, Bingbing

    2012-01-01

    We use molecular dynamics simulations over microsecond time scales to study the structure and dynamics of coarse-grained models for nanoparticle-based ionic liquids. The systems of interest consist of particles with charged surface groups and linear or three-arm counterions, which also act as the solvent. A comparable uncharged model of nanoparticles with tethered chains is also studied. The pair correlation functions display a rich structure resulting from the packing of cores and chains, as well as electrostatic effects. Even though electrostatic interactions between oppositely charged ions at contact are much greater than the thermal energy, we find that chain dynamics at intermediate time scales are dominated by chain hopping between core particles. The uncharged core particles with tethered chains diffuse faster than the ionic core particles. © 2012 The Royal Society of Chemistry.

  4. Quantum dot/glycol chitosan fluorescent nanoconjugates

    Science.gov (United States)

    Mansur, Alexandra AP; Mansur, Herman S.

    2015-04-01

    In this study, novel carbohydrate-based nanoconjugates combining chemically modified chitosan with semiconductor quantum dots (QDs) were designed and synthesised via single-step aqueous route at room temperature. Glycol chitosan (G-CHI) was used as the capping ligand aiming to improve the water solubility of the nanoconjugates to produce stable and biocompatible colloidal systems. UV-visible (UV-vis) spectroscopy, photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were used to characterise the synthesis and the relative stability of biopolymer-capped semiconductor nanocrystals. The results clearly demonstrated that the glycol chitosan derivative was remarkably effective at nucleating and stabilising semiconductor CdS quantum dots in aqueous suspensions under acidic, neutral, and alkaline media with an average size of approximately 2.5 nm and a fluorescent activity in the visible range of the spectra.

  5. Herstellung von Chitosan und einige Anwendungen

    Science.gov (United States)

    Struszczyk, Marcin Henryk

    2001-05-01

    1. Die Deacetylierung von crabshell - Chitosan führte gleichzeitig zu einem drastischen Abfall der mittleren viscosimetrischen Molmasse ( Mv), insbesondere wenn die Temperatur und die Konzentration an NaOH erhöht werden. Diese Parameter beeinflussten jedoch nicht den Grad der Deacetylierung (DD). Wichtig ist jedoch die Quelle des Ausgangsmaterials: Chitin aus Pandalus borealis ist ein guter Rohstoff für die Herstellung von Chitosan mit niedrigem DD und gleichzeitig hoher mittlerer Mv, während Krill-Chitin (Euphausia superba) ein gutes Ausgangsmaterial zur Herstellung von Chitosan mit hohem DD und niedrigem Mv ist. Chitosan, das aus Insekten (Calliphora erythrocephala), unter milden Bedingungen (Temperatur: 100°C, NaOH-Konzentration: 40 %, Zeit: 1-2h ) hergestellt wurde, hatte die gleichen Eigenschaften hinsichtlich DD und Mv wie das aus Krill hergestellte Chitosan. Der Bedarf an Zeit, Energie und NaOH ist für die Herstellung von Insekten-Chitosan geringer als für crabshell-Chitosan vergleichbare Resultaten für DD und Mv. 2. Chitosan wurde durch den Schimmelpilz Aspergillus fumigatus zu Chitooligomeren fermentiert. Die Ausbeute beträgt 25%. Die Chitooligomere wurden mit Hilfe von HPLC und MALDI-TOF-Massenspektrmetrie identifiziert. Die Fermentationsmischung fördert die Immunität von Pflanzen gegen Bakterien und Virusinfektion. Die Zunahme der Immunität schwankt jedoch je nach System Pflanze-Pathogen. Die Fermentation von Chitosan durch Aspergillus fumigatus könnte eine schnelle und billige Methode zur Herstellung von Chitooligomeren mit guter Reinheit und Ausbeute sein. Eine partiell aufgereinigte Fermentationsmischung dieser Art könnte in der Landwirtschaft als Pathogeninhibitor genutzt werden. Durch kontrollierte Fermentation, die Chitooligomere in definierter Zusammensetzung (d.h. definierter Verteilung des Depolymerisationsgrades) liefert, könnte man zu Mischungen kommen, die für die jeweilige Anwendung eine optimale Bioaktivität besitzen. 3

  6. Solid polymer electrolyte from phosphorylated chitosan

    International Nuclear Information System (INIS)

    Recently, the need of secondary battery application continues to increase. The secondary battery which using a liquid electrolyte was indicated had some weakness. A solid polymer electrolyte is an alternative electrolytes membrane which developed in order to replace the liquid electrolyte type. In the present study, the effect of phosphorylation on to polymer electrolyte membrane which synthesized from chitosan and lithium perchlorate salts was investigated. The effect of the component’s composition respectively on the properties of polymer electrolyte, was carried out by analyzed of it’s characterization such as functional groups, ion conductivity, and thermal properties. The mechanical properties i.e tensile resistance and the morphology structure of membrane surface were determined. The phosphorylation processing of polymer electrolyte membrane of chitosan and lithium perchlorate was conducted by immersing with phosphoric acid for 2 hours, and then irradiated on a microwave for 60 seconds. The degree of deacetylation of chitosan derived from shrimp shells was obtained around 75.4%. Relative molecular mass of chitosan was obtained by viscometry method is 796,792 g/mol. The ionic conductivity of chitosan membrane was increase from 6.33 × 10−6 S/cm up to 6.01 × 10−4 S/cm after adding by 15 % solution of lithium perchlorate. After phosphorylation, the ionic conductivity of phosphorylated lithium chitosan membrane was observed 1.37 × 10−3 S/cm, while the tensile resistance of 40.2 MPa with a better thermal resistance. On the strength of electrolyte membrane properties, this polymer electrolyte membrane was suggested had one potential used for polymer electrolyte in field of lithium battery applications

  7. Solid polymer electrolyte from phosphorylated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Fauzi, Iqbal, E-mail: arcana@chem.itb.ac.id; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Groups, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24

    Recently, the need of secondary battery application continues to increase. The secondary battery which using a liquid electrolyte was indicated had some weakness. A solid polymer electrolyte is an alternative electrolytes membrane which developed in order to replace the liquid electrolyte type. In the present study, the effect of phosphorylation on to polymer electrolyte membrane which synthesized from chitosan and lithium perchlorate salts was investigated. The effect of the component’s composition respectively on the properties of polymer electrolyte, was carried out by analyzed of it’s characterization such as functional groups, ion conductivity, and thermal properties. The mechanical properties i.e tensile resistance and the morphology structure of membrane surface were determined. The phosphorylation processing of polymer electrolyte membrane of chitosan and lithium perchlorate was conducted by immersing with phosphoric acid for 2 hours, and then irradiated on a microwave for 60 seconds. The degree of deacetylation of chitosan derived from shrimp shells was obtained around 75.4%. Relative molecular mass of chitosan was obtained by viscometry method is 796,792 g/mol. The ionic conductivity of chitosan membrane was increase from 6.33 × 10{sup −6} S/cm up to 6.01 × 10{sup −4} S/cm after adding by 15 % solution of lithium perchlorate. After phosphorylation, the ionic conductivity of phosphorylated lithium chitosan membrane was observed 1.37 × 10{sup −3} S/cm, while the tensile resistance of 40.2 MPa with a better thermal resistance. On the strength of electrolyte membrane properties, this polymer electrolyte membrane was suggested had one potential used for polymer electrolyte in field of lithium battery applications.

  8. Preparations, properties and applications of chitosan based nanofibers fabricated by electrospinning

    Directory of Open Access Journals (Sweden)

    2011-04-01

    Full Text Available Chitosan is soluble in most acids. The protonation of the amino groups on the chitosan backbone inhibits the electrospinnability of pure chitosan. Recently, electrospinning of nanofibers based on chitosan has been widely researched and numerous nanofibers containing chitosan have been prepared by decreasing the number of the free amino groups of chitosan as the nanofibiers have enormous possibilities for better utilization in various areas. This article reviews the preparations and properties of the nanofibers which were electrospun from pure chitosan, blends of chitosan and synthetic polymers, blends of chitosan and protein, chitosan derivatives, as well as blends of chitosan and inorganic nanoparticles, respectively. The applications of the nanofibers containing chitosan such as enzyme immobilization, filtration, wound dressing, tissue engineering, drug delivery and catalysis are also summarized in detail.

  9. Photoelectrochemical Solar Cells Based on Chitosan Electroylte

    Institute of Scientific and Technical Information of China (English)

    M.H.A.Buraidah; A.K.Arof

    2007-01-01

    1 Results ITO-ZnTe/Chitosan-NH4I-I2/ITO photoelectrochemical solar cells have been fabricated and characterized by current-voltage characteristics.In this work,the ZnTe thin film was prepared by electrodeposition on indium-tin-oxide coated glass.The chitosan electrolyte consists of NH4I salt and iodine.Iodine was added to provide the I3-/I- redox couple.The PEC solar cell was fabricated by sandwiching an electrolyte film between the ZnTe semiconductor and ITO conducting glass.The area of the solar cell...

  10. Chitosan Effects on Plant Systems

    Directory of Open Access Journals (Sweden)

    Massimo Malerba

    2016-06-01

    Full Text Available Chitosan (CHT is a natural, safe, and cheap product of chitin deacetylation, widely used by several industries because of its interesting features. The availability of industrial quantities of CHT in the late 1980s enabled it to be tested in agriculture. CHT has been proven to stimulate plant growth, to protect the safety of edible products, and to induce abiotic and biotic stress tolerance in various horticultural commodities. The stimulating effect of different enzyme activities to detoxify reactive oxygen species suggests the involvement of hydrogen peroxide and nitric oxide in CHT signaling. CHT could also interact with chromatin and directly affect gene expression. Recent innovative uses of CHT include synthesis of CHT nanoparticles as a valuable delivery system for fertilizers, herbicides, pesticides, and micronutrients for crop growth promotion by a balanced and sustained nutrition. In addition, CHT nanoparticles can safely deliver genetic material for plant transformation. This review presents an overview on the status of the use of CHT in plant systems. Attention was given to the research that suggested the use of CHT for sustainable crop productivity.

  11. Chitosan Effects on Plant Systems.

    Science.gov (United States)

    Malerba, Massimo; Cerana, Raffaella

    2016-01-01

    Chitosan (CHT) is a natural, safe, and cheap product of chitin deacetylation, widely used by several industries because of its interesting features. The availability of industrial quantities of CHT in the late 1980s enabled it to be tested in agriculture. CHT has been proven to stimulate plant growth, to protect the safety of edible products, and to induce abiotic and biotic stress tolerance in various horticultural commodities. The stimulating effect of different enzyme activities to detoxify reactive oxygen species suggests the involvement of hydrogen peroxide and nitric oxide in CHT signaling. CHT could also interact with chromatin and directly affect gene expression. Recent innovative uses of CHT include synthesis of CHT nanoparticles as a valuable delivery system for fertilizers, herbicides, pesticides, and micronutrients for crop growth promotion by a balanced and sustained nutrition. In addition, CHT nanoparticles can safely deliver genetic material for plant transformation. This review presents an overview on the status of the use of CHT in plant systems. Attention was given to the research that suggested the use of CHT for sustainable crop productivity. PMID:27347928

  12. Ursolic acid-loaded chitosan nanoparticles induce potent anti-angiogenesis in tumor.

    Science.gov (United States)

    Jin, Hua; Pi, Jiang; Yang, Fen; Wu, Chaomin; Cheng, Xueli; Bai, Haihua; Huang, Dan; Jiang, Jinhuan; Cai, Jiye; Chen, Zheng W

    2016-08-01

    Angiogenesis provides necessary nutrients and oxygen for tumor growth and metastasis; thus, every stage of angiogenesis process is the potential target for cancer therapies. Ursolic acid (UA) is reported to decrease tumor burden through anti-angiogenesis pathway, but its poor water solubility greatly limits its efficiency and clinical application. Here, a simple method for preparing UA-loaded chitosan nanoparticles (CH-UA-NPs) with anti-angiogenesis and anti-tumor activity was demonstrated. In vitro, CH-UA-NPs could significantly inhibit the proliferation, migration, and tube formation of human umbilical vascular endothelial cells (HUVECs). After uptake by HUVECs, CH-UA-NPs were mainly localized in lysosomes and mitochondria, but not nuclei. CH-UA-NPs induced the destruction of lysosome membrane integrity, collapse of mitochondrial membrane potential, and reorganization of cell cytoskeleton. All these changes led to the apoptosis or necrosis in HUVECs. In vivo, CH-UA-NPs could inhibit the angiogenesis in chicken chorioallantoic membrane (CAM) model and H22 xenograft model. Notably, comparing with free UA, such synthesized CH-UA-NPs could save about tenfold of UA doses, implying that this could significantly decrease the side effects induced by high doses of UA in biological organism. Our data showed that CH-UA-NPs and this nanoparticle-based drug delivery system could be as a potential drug candidate for anti-angiogenesis treatment. PMID:26883344

  13. Chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol

    Directory of Open Access Journals (Sweden)

    Shete Amol S

    2012-12-01

    Full Text Available Abstract Background and the purpose of the study Carvedilol nonselective β-adrenoreceptor blocker, chemically (±-1-(Carbazol-4-yloxy-3-[[2-(o-methoxypHenoxy ethyl] amino]-2-propanol, slightly soluble in ethyl ether; and practically insoluble in water, gastric fluid (simulated, TS, pH 1.1, and intestinal fluid (simulated, TS without pancreatin, pH 7.5 Compounds with aqueous solubility less than 1% W/V often represents dissolution rate limited absorption. There is need to enhance the dissolution rate of carvedilol. The objective of our present investigation was to compare chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol. Methods The different formulations were prepared by different methods like solvent change approach to prepare hydrosols, solvent evaporation technique to form solid dispersions and cogrind mixtures. The prepared formulations were characterized in terms of saturation solubility, drug content, infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, powder X-ray diffraction (PXRD, electron microscopy, in vitro dissolution studies and stability studies. Results The practical yield in case of hydrosols was ranged from 59.76 to 92.32%. The drug content was found to uniform among the different batches of hydrosols, cogrind mixture and solid dispersions ranged from 98.24 to 99.89%. There was significant improvement in dissolution rate of carvedilol with chitosan chlorhdyrate as compare to chitosan and explanation to this behavior was found in the differences in the wetting, solubilities and swelling capacity of the chitosan and chitosan salts, chitosan chlorhydrate rapidly wet and dissolve upon its incorporation into the dissolution medium, whereas the chitosan base, less water soluble, would take more time to dissolve. Conclusion This technique is scalable and valuable in manufacturing process in future for enhancement of dissolution of poorly water soluble

  14. Grafting of Chitosan and Chitosantrimethoxylsilylpropyl Methacrylate on Single Walled Carbon Nanotubes-Synthesis and Characterization

    OpenAIRE

    Carson, Laura; Kelly-Brown, Cordella; Stewart, Melisa; Oki, Aderemi; Regisford, Gloria; Stone, Julia; Traisawatwong, Pasakorn; Durand-Rougely, Clarissa; Luo, Zhiping

    2010-01-01

    Acid functionalized single walled carbon nanotubes (CNTs) were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate (TMSPM), hereafter referred to as CNT-chitosan-...

  15. Does the Use of Chitosan Contribute to Oxalate Kidney Stone Formation?

    OpenAIRE

    Moacir Fernandes Queiroz; Karoline Rachel Teodosio Melo; Diego Araujo Sabry; Guilherme Lanzi Sassaki; Hugo Alexandre Oliveira Rocha

    2014-01-01

    Chitosan is widely used in the biomedical field due its chemical and pharmacological properties. However, intake of chitosan results in renal tissue accumulation of chitosan and promotes an increase in calcium excretion. On the other hand, the effect of chitosan on the formation of calcium oxalate crystals (CaOx) has not been described. In this work, we evaluated the antioxidant capacity of chitosan and its interference in the formation of CaOx crystals in vitro. Here, the chitosan obtained c...

  16. Starch-chitosan hydrogels prepared by reductive alkylation cross-linking

    OpenAIRE

    Baran, E. T.; Mano, J. F.; Reis, R. L.

    2004-01-01

    Starch–chitosan hydrogels were produced by oxidation of soluble starch to produce polyaldehyde and subsequently cross-linked with chitosan via reductive alkylation. The swelling ratio of starch–chitosan membranes was increased gradually with increasing starch ratio, but it was always lower than the native chitosan. In dry state, starch–chitosan membranes with low starch ratio (0.16, 0.38) showed similar tensile strength values to those of native chitosan while these values decreased with incr...

  17. Effects of Dietary Chitosan on Hormone Level in Dairy Calves

    Directory of Open Access Journals (Sweden)

    Dong Li

    2012-01-01

    Full Text Available The objective of the present study was to evaluate the effects of chitosan on serum GH, T3 and T4 in and to determine the appropriate supplemental dosage level of chitosan in dairy calves diet. A 30 days trial of dietary chitosan supplementation was reported. Twenty dairy calves were allotted at random to four groups at 10 days of age. Calves in the control group were fed the basal diet alone and calves in treatment groups I-III were fed the basal diet supplemented with 200, 400, 600 mg/day/h Chitosan (CTS, respectively for 30 days. The trial demonstrated that dietary chitosan supplementation significantly increased serum T3 level (p<0.05, when comparing chitosan groups I, II with the control group. Dietary supplementation of chitosan at 400 mg/day/h significantly increased serum T3 (p<0.05. Treatments with various levels of chitosan supplementation showed a tendency of increase in serum T4 and GH levels. So, the appropriate supplemental dosage of chitosan in the diets of dairy calves was 400 mg/day/h Chitosan (CTS.

  18. Effects of Chitosan Alkali Pretreatment on the Preparation of Electrospun PCL/Chitosan Blend Nanofibrous Scaffolds for Tissue Engineering Application

    Directory of Open Access Journals (Sweden)

    Fatemeh Roozbahani

    2013-01-01

    Full Text Available Recently, nanofibrous scaffolds have been used in the field of biomedical engineering as wound dressings, tissue engineering scaffolds, and drug delivery applications. The electrospun nanofibrous scaffolds can be used as carriers for several types of drugs, genes, and growth factors. PCL is one of the most commonly applied synthetic polymers for medical use because of its biocompatibility and slow biodegradability. PCL is hydrophobic and has no cell recognition sites on its structure. Electrospinning of chitosan and PCL blend was investigated in formic acid/acetic acid as the solvent with different PCL/chitosan ratios. High viscosity of chitosan solutions makes difficulties in the electrospinning process. Strong hydrogen bonds in a 3D network in acidic condition prevent the movement of polymeric chains exposed to the electrical field. Consequently, the amount of chitosan in PCL/chitosan blend was limited and more challenging when the concentration of PCL increases. The treatment of chitosan in alkali condition under high temperature reduced its molecular weight. Longer treatment time further decreased the molecular weight of chitosan and hence its viscosity. Electrospinning of PCL/chitosan blend was possible at higher chitosan ratio, and SEM images showed a decrease in fiber diameter and narrower distribution with increase in the chitosan ratio.

  19. Chitosan-based nanocarriers for antimalarials

    Science.gov (United States)

    Dreve, Simina; Kacso, Iren; Popa, Adriana; Raita, Oana; Bende, A.; Borodi, Gh.; Bratu, I.

    2012-02-01

    The objective of this research was to synthesize and characterize chitosan-based liquid and solid materials with unique absorptive and mechanical properties as carriers for quinine - one of the most used antimalarial drug. The use of chitosan (CTS) as base in polyelectrolyte complex systems, to prepare solid release systems as sponges is presented. The preparation by double emulsification of CTS hydrogels carrying quinine as anti-malarial drug is reported. The concentration of quinine in the CTS hydrogel was 0.08 mmol. Chitosan - drug loaded hydrogel was used to generate solid sponges by freeze-drying at -610°C and 0.09 atm. Structural investigations of the solid formulations were done by Fourier-transformed infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-VIS), spectrofluorimetry, differential scanning calorimetry (DSC) and X-ray diffractometry. The results indicated that the drug molecule is forming temporary chelates in CTS hydrogels and sponges. Electron paramagnetic resonance (EPR) demonstrates the presence of free radicals in a wide range and the antioxidant activity for chitosan - drug supramolecular cross-linked assemblies.

  20. Chitosan application in food preparation and digestion

    Czech Academy of Sciences Publication Activity Database

    Kopečný, Jan

    Antalya : Hacettepe University, 2007, s. 47-47. [International Conference of European Chitin Society /8./. Antalya (TR), 08.09.2007-11.09.2007] R&D Projects: GA AV ČR 1QS500200572 Institutional research plan: CEZ:AV0Z50450515 Keywords : chitosan Subject RIV: GM - Food Processing

  1. Chitosan catalyzes hydrogen evolution at mercury electrodes

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Římánková, Ludmila

    2014-01-01

    Roč. 44, JUL2014 (2014), s. 59-62. ISSN 1388-2481 R&D Projects: GA ČR(CZ) GAP301/11/2055 Institutional support: RVO:68081707 Keywords : Chitosan * Glucosamine-containing polymers * Catalytic hydrogen evolution Subject RIV: BO - Biophysics Impact factor: 4.847, year: 2014

  2. Application of mushroom chitosans in medical biomaterials

    Czech Academy of Sciences Publication Activity Database

    Beran, M.; Urban, M.; Adámek, L.; Jandušík, L.; Spěváček, Jiří

    Snowbird, Utah : Keystone Symposia, 2007. s. 49. [Keystone Symposia: Tissue Engineering and Development Biology. 12.04.2007-17.04.2007, Snowbird] R&D Projects: GA MŠk 2B06173 Institutional research plan: CEZ:AV0Z40500505 Keywords : mushrooms * chitosan * biomaterials Subject RIV: EI - Biotechnology ; Bionics

  3. Reinforcing of chitosan phase with chitin nanofibrils

    Czech Academy of Sciences Publication Activity Database

    Tishchenko, Galina; Kelnar, Ivan; Kaprálková, Ludmila; Pavlova, Ewa; Vacková, Taťana; Brožová, Libuše; Strachota, Adam; Špírková, Milena; Bastl, Zdeněk; Carezzi, F.; Morganti, P.

    Roma : AIRI/Nanotec IT, 2013. s. 105. ISBN 978-88-6140-152-5. [NanotechItaly 2013 - Key Enabling Technologies for Responsible Innovation. 27.11.2013-29.11.2013, Venice] EU Projects: European Commission(XE) 315233 - N-CHITOPACK Institutional support: RVO:61389013 ; RVO:61388955 Keywords : chitin nanofibers * chitosan * reinforcing effect Subject RIV: CD - Macromolecular Chemistry

  4. Conjugation of kojic acid with chitosan

    Czech Academy of Sciences Publication Activity Database

    Synytsya, Andriy.; Blafková, P.; Synytsya, A.; Čopíková, J.; Spěváček, Jiří; Uher, M.

    2008-01-01

    Roč. 72, č. 1 (2008), s. 21-31. ISSN 0144-8617 R&D Projects: GA ČR GA525/05/0273 Institutional research plan: CEZ:AV0Z40500505 Keywords : kojic acid * chitosan * iron(III) * chlorokojic acid Subject RIV: GM - Food Processing Impact factor: 2.644, year: 2008

  5. Thermochemical characteristics of chitosan-polylactide copolymers

    Science.gov (United States)

    Goruynova, P. E.; Larina, V. N.; Smirnova, N. N.; Tsverova, N. E.; Smirnova, L. A.

    2016-05-01

    The energies of combustion of chitosan and its block-copolymers with different polylactide contents are determined in a static bomb calorimeter. Standard enthalpies of combustion and formation are calculated for these substances. The dependences of the thermochemical characteristics on block-copolymer composition are determined and discussed.

  6. TRACTION RESISTANCE IN CHITOSAN TREATED COTTON

    Directory of Open Access Journals (Sweden)

    LOX Wouter

    2015-05-01

    Full Text Available Nowadays natural products interest has increased. However, when some products are included on textile fibers, they have no affinity and need some binders or other kind of auxiliaries to improve the yeld of the process, and some of them are not so natural as the product which are binding and consequently the “bio” definition is missed as some of them can be considered as highly pollutant. Chitosan is a common used bonding agent for cotton. It improves the antimicrobial and antifungal activity, improves wound healing and is a non-toxic bonding agent. The biopolymer used in this work is chitosan, which is a deacetylated derivative of chitin. These properties depend on the amount of deacetylation (DD and the Molecular weight (MW. Along with these improving properties, as it requires some acid pH to ve solved the treatment with chitosan can have some decreasing mechanical properties. The aim of that paper is to evaluate the change in breaking force of the treated samples and a change in elongation of those samples. It compared different amounts of concentration of chitosan with non treated cotton. The traction resistance test were performed on a dynamometer. The test was conducted according to the UNE EN ISO 13934-1 standard.

  7. The Mechanical and Biological Properties of Chitosan Scaffolds for Tissue Regeneration Templates Are Significantly Enhanced by Chitosan from Gongronella butleri

    Directory of Open Access Journals (Sweden)

    Hiroshi Tamura

    2009-04-01

    Full Text Available Chitosan with a molecular weight (MW of 104 Da and 13% degree of acetylation (DA was extracted from the mycelia of the fungus Gongronella butleri USDB 0201 grown in solid substrate fermentation and used to prepare scaffolds by the freeze-drying method. The mechanical and biological properties of the fungal chitosan scaffolds were evaluated and compared with those of scaffolds prepared using chitosans obtained from shrimp and crab shells and squid bone plates (MW 105-106 Da and DA 10-20%. Under scanning electron microscopy, it was observed that all scaffolds had average pore sizes of approximately 60-90 mm in diameter. Elongated pores were observed in shrimp chitosan scaffolds and polygonal pores were found in crab, squid and fungal chitosan scaffolds. The physico-chemical properties of the chitosans had an effect on the formation of pores in the scaffolds, that consequently influenced the mechanical and biological properties of the scaffolds. Fungal chitosan scaffolds showed excellent mechanical, water absorption and lysozyme degradation properties, whereas shrimp chitosan scaffolds (MW 106Da and DA 12% exhibited the lowest water absorption properties and lysozyme degradation rate. In the evaluation of biocompatibility of chitosan scaffolds, the ability of fibroblast NIH/3T3 cells to attach on all chitosan scaffolds was similar, but the proliferation of cells with polygonal morphology was faster on crab, squid and fungal chitosan scaffolds than on shrimp chitosan scaffolds. Therefore fungal chitosan scaffold, which has excellent mechanical and biological properties, is the most suitable scaffold to use as a template for tissue regeneration.

  8. The Use of chitosan in The Formation of Silver Nanoparticles, Chitosanic Nanoparticles and Fibrous Structures

    Science.gov (United States)

    Abdelgawad, Abdelrahman Mohamed

    Nanoscale materials have attracted much attention in the last two decades due to their unique properties. The size effect attains new chemical and physical properties to these materials. Nanoparticles and nanofiber are major component of nanomaterials and they have heavily investigated in the literature for different applications. Nanoparticles could be produced from both metals as well as polymers. Chitosan, which is a natural polymer, can be used as capping agent in the preparation of metallic nanoparticles and itself, can produce nanoparticles. The utilization of nanoparticles and nanofibers for wound dressing materials is a very popular approach. Acquiring antibacterial properties to the wound dressing materials could be obtained either by formulation of nanomaterials composites or direct chemical modification of the substance. To improve the antibacterial properties of chitosan two approaches were applied. First, is through the formulation of chitosan with silver nanoparticles and the formation of nanofiber mats. In this study, the concepts of green chemistry were applied and silver nanoparticles were prepared in high concentration using chitosan as a capping polymer and glucose as a reducing agent. Nanofiber mats of polyvinyl alcohol/chitosan/silvernanoparticles were produced via electrospinning. The antibacterial activity of these fibers shows bactericidal effect against E. coli at low concentrations of Ag-NPs. In the second approach, direct chemical modification of chitosan was performed by grafting of Iodoacetic acid to the amino group at carbon-2. The chemical structure of chitosan Iodoacetamide derivative (CIA) was confirmed by FTIR and H1-NMR. The derivative was amorphous and water soluble at neutral pH. The minimum inhibitory concentration of CIA, against E. coli, was 400ig/mL and the derivative was bacteriostatic after 4h of treatment. Nanofiber mats of polyvinyl alcohol/chitosan/chitosan Iodoacetamide were produced via electrospinning. The

  9. Recent advances in chitosan-based nanoparticulate pulmonary drug delivery.

    Science.gov (United States)

    Islam, Nazrul; Ferro, Vito

    2016-08-14

    The advent of biodegradable polymer-encapsulated drug nanoparticles has made the pulmonary route of administration an exciting area of drug delivery research. Chitosan, a natural biodegradable and biocompatible polysaccharide has received enormous attention as a carrier for drug delivery. Recently, nanoparticles of chitosan (CS) and its synthetic derivatives have been investigated for the encapsulation and delivery of many drugs with improved targeting and controlled release. Herein, recent advances in the preparation and use of micro-/nanoparticles of chitosan and its derivatives for pulmonary delivery of various therapeutic agents (drugs, genes, vaccines) are reviewed. Although chitosan has wide applications in terms of formulations and routes of drug delivery, this review is focused on pulmonary delivery of drug-encapsulated nanoparticles of chitosan and its derivatives. In addition, the controversial toxicological effects of chitosan nanoparticles for lung delivery will also be discussed. PMID:27439116

  10. Antimicrobial Activity of Chitosan-Carbon Nanotube Hydrogels

    Directory of Open Access Journals (Sweden)

    Jayachandran Venkatesan

    2014-05-01

    Full Text Available In the present study, we have prepared chitosan-carbon nanotube (Chitosan-CNT hydrogels by the freeze-lyophilization method and examined their antimicrobial activity. Different concentrations of CNT were used in the preparation of Chitosan-CNT hydrogels. These differently concentrated CNT hydrogels were chemically characterized using Fourier Transform-Infrared Spectroscopy, Scanning Electron Microscopy and Optical microscopy. The porosity of the hydrogels were found to be >94%. Dispersion of chitosan was observed in the CNT matrix by normal photography and optical microscopy. The addition of CNT in the composite scaffold significantly reduced the water uptake ability. In order to evaluate antimicrobial activity, the serial dilution method was used towards Staphylococcus aureus, Escherichia coli and Candida tropicalis. The composite Chitosan-CNT hydrogel showed greater antimicrobial activity with increasing CNT concentration, suggesting that Chitosan-CNT hydrogel scaffold will be a promising biomaterial in biomedical applications.

  11. Gd-DTPA Adsorption on Chitosan/Magnetite Nanocomposites

    Science.gov (United States)

    Pylypchuk, Ie. V.; Kołodyńska, D.; Kozioł, M.; Gorbyk, P. P.

    2016-03-01

    The synthesis of the chitosan/magnetite nanocomposites is presented. Composites were prepared by co-precipitation of iron(II) and iron(III) salts by aqueous ammonia in the 0.1 % chitosan solution. It was shown that magnetite synthesis in the chitosan medium does not affect the magnetite crystal structure. The thermal analysis data showed 4.6 % of mass concentration of chitosan in the hybrid chitosan/magnetite composite. In the concentration range of initial Gd-DTPA solution up to 0.4 mmol/L, addition of chitosan to magnetite increases the adsorption capacity and affinity to Gd-DTPA complex. The Langmuir and Freundlich adsorption models were applied to describe adsorption processes. Nanocomposites were characterized by scanning electron microscopy (SEM), differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and specific surface area determination (ASAP) methods.

  12. Gd-DTPA Adsorption on Chitosan/Magnetite Nanocomposites.

    Science.gov (United States)

    Pylypchuk, Ie V; Kołodyńska, D; Kozioł, M; Gorbyk, P P

    2016-12-01

    The synthesis of the chitosan/magnetite nanocomposites is presented. Composites were prepared by co-precipitation of iron(II) and iron(III) salts by aqueous ammonia in the 0.1 % chitosan solution. It was shown that magnetite synthesis in the chitosan medium does not affect the magnetite crystal structure. The thermal analysis data showed 4.6 % of mass concentration of chitosan in the hybrid chitosan/magnetite composite. In the concentration range of initial Gd-DTPA solution up to 0.4 mmol/L, addition of chitosan to magnetite increases the adsorption capacity and affinity to Gd-DTPA complex. The Langmuir and Freundlich adsorption models were applied to describe adsorption processes. Nanocomposites were characterized by scanning electron microscopy (SEM), differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and specific surface area determination (ASAP) methods. PMID:27030468

  13. Structural evaluation of phospholipidic nanovesicles containing small amounts of chitosan.

    Science.gov (United States)

    Mertins, Omar; Cardoso, Mateus Borba; Pohlmann, Adriana Raffin; da Silveira, Nádya Pesce

    2006-08-01

    In this study we present a full characterization of nanovesicles containing soybean phosphatidylcholine and polysaccharide chitosan. The nanovesicles were prepared by the reverse phase evaporation method, including the preparation of reverse micelles followed by the formation of an organogel, which is dispersed in water to yield the final liposomal particles. Structural changes as a function of the chitosan amount and the filter porosity used in the nanovesicles preparation were studied employing Static and Dynamic Light Scattering as well as Small Angle X-ray Scattering. The hydrodynamic radius of the nanovesicles ranged between 106 and 287 nm, depending on the chitosan contents and the filter porosity. A comparison with nanovesicles free of chitosan indicates the existence of higher contents of multilamellar structures that depends on the chitosan concentration in the vesicles containing chitosan. Typical spherical vesicles having nanometric diameters with polydispersity mostly desired in the biomedical area could only be achieved by filtration through a 0.45 microm porous filter. PMID:17037851

  14. Removal of Petroleum Spill in Water by Chitin and Chitosan

    Directory of Open Access Journals (Sweden)

    Francisco Cláudio de Freitas Barros

    2014-05-01

    Full Text Available The present study was undertaken to evaluate the capacity of adsorption of crude oil spilled in seawater by chitin flakes, chitin powder, chitosan flakes, chitosan powder, and chitosan solution. The results showed that, although chitosan flakes had a better adsorption capacity by oil (0.379 ± 0.030 grams oil per gram of adsorbent, the biopolymer was sinking after adsorbing oil. Chitosan solution did not present such inconvenience, despite its lower adsorption capacity (0.013 ± 0.001 grams oil per gram of adsorbent. It was able to form a polymeric film on the oil slick, which allowed to restrain and to remove the oil from the samples of sea water. The study also suggests that chitosan solution 0.5% has greater efficiency against oil spills in alkaline medium than acidic medium.

  15. Use of the montmorillonite as crosslink agents for chitosan

    International Nuclear Information System (INIS)

    The montmorillonite (the main constituent of bentonite) has been the most commonly used inorganic load in the formation of nanocomposites chitosan / layered silicate. To evaluate its effect as an agent for the reticulation of chitosan, a sodium montmorillonite, Cloisite Na+, supplied by Southern Clay Products, Texas, USA, was used. For the reticulation of chitosan dispersions of chitosan / Cloisite Na+ were prepared in different proportions and the obtained films characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TG). The results indicated that the Cloisite Na+ was for efficient and the reticulation of the chitosan and can be used in place of sulfuric acid, which is one of the most common reticulants for chitosan. (author)

  16. Antibacterial activity of chitosan and the interpolyelectrolyte complexes of poly(acrylic acid-chitosan

    Directory of Open Access Journals (Sweden)

    Hortensia Ortega-Ortiz

    2010-06-01

    Full Text Available The antimicrobial activity of chitosan and water soluble interpolyelectrolyte complexes of poly(acrylic acid-chitosan was studied. Chitosans of two different molecular weights were tested at different concentration for 0.5 to 5 g·L-1 as antimicrobial agents against P. aeruginosa and P. oleovorans. In both cases, the best microbial inhibition was obtained with the concentration of 5 g·L-1. However, the interpolyelectrolyte complexes of poly(acrylic acid-chitosan with composition φ =2 produced higher antibacterial activity than the two chitosans at the concentration of 0.5 g·L-1. The NPEC2 complex was more effective than chitosans. This could be attributed to the number of moles of the amino groups of chitosan and the carboxylic acid groups of the interpolyelectrolyte complexes poly(acrylic acid.A atividade antimicrobiana de quitosana e complexos interpolieletrolíticos hidrossoluvéis de poli(ácido acrílico-quitosana foi estudada. Quitosanas de dois diferentes pesos moleculares foram testados em diferentes concentrações, 0,5 a 5 g • L-1, como agentes antimicrobianos nas P. aeruginosa e P. oleovorans. Em ambos os casos, obteu-se a melhor inibição microbiana com a concentração de 5 g • L-1, no entanto os complexos interpolieletrolíticos de poli (ácido acrílico-quitosana com composição φ = 2 apresentaram maior atividade antibacteriana do que os dois quitosans na concentração de 0,5 g • L-1. O complexo NPEC2 foi mais eficaz do que as quitosanas, sendo que o resultado pode ser atribuído ao número de moles dos grupos aminos da quitosana e aos grupos carboxílicos dos complexos de poli(ácido acrílico.

  17. Combining Hyaluronic Acid with Chitosan Enhances Gene Delivery

    OpenAIRE

    2014-01-01

    The low gene transfer efficiency of chitosan-DNA polyplexes is a consequence of their high stability and consequent slow DNA release. The incorporation of an anionic polymer is believed to loosen chitosan interactions with DNA and thus promote higher transfection efficiencies. In this work, several formulations of chitosan-DNA polyplexes incorporating hyaluronic acid were prepared and characterized for their gene transfection efficiency on both HEK293 and retinal pigment epithelial cells. The...

  18. Chitin and Chitosan as Direct Compression Excipients in Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    Adnan A. Badwan

    2015-03-01

    Full Text Available Despite the numerous uses of chitin and chitosan as new functional materials of high potential in various fields, they are still behind several directly compressible excipients already dominating pharmaceutical applications. There are, however, new attempts to exploit chitin and chitosan in co-processing techniques that provide a product with potential to act as a direct compression (DC excipient. This review outlines the compression properties of chitin and chitosan in the context of DC pharmaceutical applications.

  19. Preparation and Characterization of Chitosan /Ethylcellulose Complex Microcapsule

    Institute of Scientific and Technical Information of China (English)

    史新元; 谭天伟

    2003-01-01

    In this work a system which consists of chitosan microcores entrapped in ethylcellulose is presented.Vitamin D2 was eficiently entrapped in chitosan microcores with spray-drying method and was microencapsulated by coating of ethylcellulose.The average size of chitosan microspheres was 6.06μm.The morphology and release properties of microcapsules were tested.The results of release in vitro showed that the microcapsule could realize sustained release for 12h in artificial intestinal juice.

  20. The Adsorption Effect of Quaternized Chitosan Derivatives on Bile Acid

    Institute of Scientific and Technical Information of China (English)

    Shu Xian MENG; Ya Qing FENG; Wen Jin LI; Cai Xia YIN; Jin Ping DENG

    2006-01-01

    Three quaternized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quaternized chitosan derivatives were evaluated. The kinetic experimental data properly correlated with the second-order kinetic model, which indicated that the chemical sorption is the rate-limiting step. The results showed that the quaternized chitosan derivatives are favorable adsorbents for bile acid.

  1. Ionic Conductivity of Chitosan Membrane and Application for Electrochemical Devices

    Institute of Scientific and Technical Information of China (English)

    A. K. Arof

    2005-01-01

    @@ 1Introduction The product that is able to dissolve in dilute acetic acid when chitin is deacetylated is generally referred to as chitosan. Chitosan is well known for its aptitude to generate thin films[1]. The oxygen and nitrogen atoms of chitosan, in particular, have lone pair electrons that can form complexes with inorganic salts. However,the NH2 groups react much more rapidly than OH moieties towards salt[1-3].

  2. Chitosan-Based Nanoparticles for Mucosal Delivery of RNAi Therapeutics

    DEFF Research Database (Denmark)

    Martirosyan, Alina; Olesen, Morten Jarlstad; Howard, Kenneth A.

    2014-01-01

    polysaccharide chitosan have been used to facilitate delivery of siRNA across mucosal surfaces following local administration. This chapter describes the mucosal barriers that need to be addressed in order to design an effective mucosal delivery strategy and the utilization of the mucoadhesive properties of...... chitosan. Focus is given to preparation methods and the preclinical application of chitosan nanoparticles for respiratory and oral delivery of siRNA....

  3. Permeability Evaluation Through Chitosan Membranes Using Taguchi Design

    OpenAIRE

    Sharma, Vipin; Marwaha, Rakesh Kumar; Dureja, Harish

    2010-01-01

    In the present study, chitosan membranes capable of imitating permeation characteristics of diclofenac diethylamine across animal skin were prepared using cast drying method. The effect of concentration of chitosan, concentration of cross-linking agent (NaTPP), crosslinking time was studied using Taguchi design. Taguchi design ranked concentration of chitosan as the most important factor influencing the permeation parameters of diclofenac diethylamine. The flux of the diclofenac diethylamine ...

  4. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    OpenAIRE

    Marc in het Panhuis; Holly Warren; Higgins, Thomas M.

    2011-01-01

    The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs) and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that ...

  5. Optimizing Conditions to Cholesterol Adsorbed with Carboxymethyl Chitosan

    OpenAIRE

    Mardiyah Kurniasih; Dwi Kartika; Riyanti Riyanti

    2016-01-01

    A research on optimizing conditions to cholesterol adsorbed have been performed. Optimization was performed by varying: contact time, adsorbent weight and temperature of the system's. A full factorial experimental design was used in this study. Characterization performed on the synthesized chitosan and carboxymethyl chitosan including FTIR, water content, ash content, solubility, porosity, and swelling effect. The results showed that carboxymethyl chitosan able to adsorb cholesterol under con...

  6. The production of fully deacetylated chitosan by compression method

    OpenAIRE

    Xiaofei He; Kecheng Li; Ronge Xing; Song Liu; Linfeng Hu; Pengcheng Li

    2016-01-01

    Chitosan’s activities are significantly affected by degree of deacetylation (DDA), while fully deacetylated chitosan is difficult to produce in a large scale. Therefore, this paper introduces a compression method for preparing 100% deacetylated chitosan with less environmental pollution. The product is characterized by XRD, FT-IR, UV and HPLC. The 100% fully deacetylated chitosan is produced in low-concentration alkali and high-pressure conditions, which only requires 15% alkali solution and ...

  7. Biodegradation and biocompatibility of a degradable chitosan vascular prosthesis

    OpenAIRE

    Kong, Xiaoying; Xu, Wenhua

    2015-01-01

    An instrument made by ourselves was used to fabricate biodegradable chitosan-heparin artificial vascular prosthesis with small internal diameter (2 mm) and different crosslinking degree from biodegradable chitosan, chitosan derivates and heparin. In vivo and in vitro degradation studies, inflammatory analysis and electron microscope scanning of this artificial vascular prosthesis were performed. It was observed that 50% of the prosthesis decomposed in vivo and was replaced by natural tissues....

  8. Extraction of Copper(I Thiosulfate by Modified Chitosan

    Directory of Open Access Journals (Sweden)

    Okky Anggraito

    2013-12-01

    Full Text Available Chitosan is one of non-toxic natural biopolymer and abundance in nature. Chitosan have two active sites such as amine and hydroxyl groups. Amine groups (-NH2 in chitosan can be modified into secondary amine (-NHR. In this research, copper was dissolved as copper(I thiosulfate as anion complex (Cu(S2O323- and chitosan was modified by trimethylamine sulfur trioxide (TMAS. One of hydrogen atom in –NH2 was substituted by –SO3Na. The result of this research, the modified chitosan was identified by FT-IR. FT-IR spectra gave characteristic band at 3600-3200 cm-1 (O-H and N-H; 1648 cm-1 (C=O; 1115,74 cm-1 (S=O and 617,18 cm-1 (N-S. The result of surface analysis using SEM and TEM showed that the surface morphology of sulfated chitosan as a result of modification is different in comparison with chitosan. Based on chitosan, pH extraction was adjusted to pH 3 until 8. After optimum pH of extraction was obtained then re-extraction was done by using thiosulfate solution at 0.05 ; 0.10 ; 0.50 ; and 1.00 M. Extraction and re-extraction of copper(I thiosulfate was analyzed by Atomic Absorption Spectrophotometer (AAS. The highest efficiency extraction using modified chitosan and chitosan respectively at pH 3 and 6. The efficiency re-extraction using modified chitosan and chitosan respectively 100% and below 100%.

  9. Novel transparent nanocomposite films based on chitosan and bacterial cellulose

    OpenAIRE

    Fernandes, Susana C. M.; Oliveira, Lúcia; Freire, Carmen S. R.; Silvestre, Armando J. D.; Neto, Carlos Pascoal; Gandini, Alessandro; Desbriéres, Jacques

    2009-01-01

    New nanocomposite films based on different chitosan matrices (two chitosans with different DPs and one water soluble derivative) and bacterial cellulose were prepared by a fully green procedure by casting a water based suspension of chitosan and bacterial cellulose nanofibrils. The films were characterized by several techniques, namely SEM, AFM, X-ray diffraction, TGA, tensile assays and visible spectroscopy. They were highly transparent, flexible and displayed better mechanical properties th...

  10. In Situ Mineralization of Magnetite Nanoparticles in Chitosan Hydrogel

    OpenAIRE

    Wang Yongliang; Li Baoqiang; Zhou Yu; Jia Dechang

    2009-01-01

    Abstract Based on chelation effect between iron ions and amino groups of chitosan, in situ mineralization of magnetite nanoparticles in chitosan hydrogel under ambient conditions was proposed. The chelation effect between iron ions and amino groups in CS–Fe complex, which led to that chitosan hydrogel exerted a crucial control on the magnetite mineralization, was proved by X-ray photoelectron spectrum. The composition, morphology and size of the mineralized magnetite nanoparticles were ...

  11. Surface grafted chitosan gels. Part I. Molecular insight into the formation of chitosan and poly(acrylic acid) multilayers

    DEFF Research Database (Denmark)

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

    2014-01-01

    Composite polyelectrolyte multilayers of chitosan and low molecular weight poly(acrylic acid) (PAA) have been assembled by sequential adsorption as a first step toward building a surface anchored chitosan gel. Silane chemistry was used to graft the first chitosan layer to prevent film detachment...... and decomposition. The assembly process is characterized by nonlinear growth behavior, with different adsorption kinetics for chitosan and PAA. In situ analysis of the multilayer by means of surface sensitive total internal reflection Raman (TIRR) spectroscopy, combined with target factor analysis of...... steps. The higher molecular weight chitosan shows a similar behavior, although to a much lower extent. Our data demonstrate that the charged monomeric units of chitosan are mainly compensated by carboxylate ions from PAA. Furthermore, the morphology and mechanical properties of the multilayers were...

  12. Research of the Mechanism of Enhancing Biological Treatment by Chitosan

    Institute of Scientific and Technical Information of China (English)

    CHEN Liang; QIN Bing; CHEN Dong-hui

    2006-01-01

    Chitosan of different molecular weight (M. W. ) was added into SBR bioreactor to treat domestic wastewater. From comparison of treatment efficiency, sludge activity, sludge structure etc., we revealed the mechanism that chitosan enhanced the biological treatment function of activated sludge. The results proved that, chitosan is certain to restrain the reaction of activated sludge, but it do improve the structure of sludge fiocs and increase the treatment efficiency of activated sludge. The bigger the M. W. of chitosan is, the better the efficiency of enhancing biological treatment can be.

  13. DILUTE SOLUTION BEHAVIOR OF CHITOSAN IN DIFFERENT ACID SOLVENTS

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; WANG Lihua; QIN Wen

    1994-01-01

    Dilute solution behavior of chitosan was studied in formic acid, acetic acid,lactic acid and hydrochloric acid aqueous solution under different pH values. The reduced viscosities, ηsp/C,of chitosan solutions were dependent on the properties of acid and pH value of solvents. For a given chitosan concentration, ηsp/C decreased with the increase of acid concentration, or decreasing pH of solvent, indicating shielding effect of excessive acid similar to adding salt into solution. The stabilities of dilute chitosan solution in formic acid and lactic acid were better than that in acetic acid and hydrochloric acid.

  14. Chitosan grafted monomethyl fumaric acid as a potential food preservative.

    Science.gov (United States)

    Khan, Imran; Ullah, Shafi; Oh, Deog-Hwan

    2016-11-01

    The present study aims at in vitro antibacterial and antioxidant activity evaluation of chitosan modified with monomethyl fumaric acid (MFA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as mediator. Three different kinds of chitosan derivatives Ch-Ds-1,Ch-Ds-2 and Ch-Ds-3 were synthesized by feeding different concentration of MFA. The chemical structures of resulting materials were characterized by (1)H NMR, (13)C NMR, HR-XRD, FT-IR and TNBS assay. The results showed that Ch-Ds-1, Ch-Ds-2 and Ch-Ds-3 were successfully synthesized. The % amino groups of chitosan modified by MFA were evaluated by TNBS assay and ranging from 1.82±0.05% to 7.88±0.04%. All the chitosan derivatives are readily soluble in water and swelled by dimethyl sulfoxide (DMSO), toluene and dimethyl formamide (DMF). The antioxidant activity for all the chitosan derivatives have been significantly improved (P<0.05) compared to the chitosan. Upon antibacterial activity at pH 4.0, all the chitosan derivatives showed significant (P<0.05) antibacterial activity against Gram positive Staphylococcus aureus, Listeria monocytogenes strains and Gram negative Escherichia coli and Salmonella enteritidis strains compared to chitosan. In conclusion, MFA modified chitosan has shown enhanced activities along with solubility, and could be used as a novel food preservative and packaging material for long time food safety and security. PMID:27516253

  15. Pharmacokinetics and biodegradation performance of a hydroxypropyl chitosan derivative

    Science.gov (United States)

    Shao, Kai; Han, Baoqin; Dong, Wen; Song, Fulai; Liu, Weizhi; Liu, Wanshun

    2015-10-01

    Hydroxypropyl chitosan (HP-chitosan) has been shown to have promising applications in a wide range of areas due to its biocompatibility, biodegradability and various biological activities, especially in the biomedical and pharmaceutical fields. However, it is not yet known about its pharmacokinetics and biodegradation performance, which are crucial for its clinical applications. In order to lay a foundation for its further applications and exploitations, here we carried out fluorescence intensity and GPC analyses to determine the pharmacokinetics mode of fluorescein isothiocyanate-labeled HP-chitosan (FITC-HP-chitosan) and its biodegradability. The results showed that after intraperitoneal administration at a dose of 10 mg per rat, FITC-HP-chitosan could be absorbed rapidly and distributed to liver, kidney and spleen through blood. It was indicated that FITC-HP-chitosan could be utilized effectively, and 88.47% of the FITC-HP-chitosan could be excreted by urine within 11 days with a molecular weight less than 10 kDa. Moreover, our data indicated that there was an obvious degradation process occurred in liver (chitosan has excellent bioavailability and biodegradability, suggesting the potential applications of hydroxypropyl-modified chitosan as materials in drug delivery, tissue engineering and biomedical area.

  16. FUNGICIDAL POTENTIAL OF CHITOSAN AGAINST PHYTOPATHOGENIC Fusarium Solani

    Directory of Open Access Journals (Sweden)

    Anirban Bhattacharya

    2013-09-01

    Full Text Available nhibitory effects of chitosan (CHN on colony growth, sporulation, spore germination and germ tube elongation of phytopathogenic fungus Fusarium solani (Mart. Sacc. was reported under in vitro condition. Inhibition caused by chitosan was concentration dependent and maximum inhibition was on 0.20% chitosan dose, that led to the highest growth inhibition of fungal colony development (76.0%, lowest spore production (9 x 104 /ml culture filtrate and complete cessation of spore germination and germ tube emergence. Findings of the present study show that chitosan may be an alternative control agent against the pathogenic fungus, replacing the harmful chemical fungicides

  17. Supercritical solvent impregnation of ophthalmic drugs on chitosan derivatives

    OpenAIRE

    Braga, Mara E. M.; Pato, Maria T. Vaz; Silva, Hélio S. R. Costa; Ferreira, Elisabeth I.; Gil, Maria H.; Duarte, Catarina M. M.; Sousa, Hermínio C. de

    2008-01-01

    In this work, three chitosan derivatives (N-carboxymethyl chitosan (CMC), N-carboxybutyl chitosan (CBC) and N-succinyl chitosan (SCC)) were impregnated with flurbiprofen (an anti-inflammatory drug) and timolol maleate (an anti-glaucoma drug), using a supercritical solvent impregnation (SSI) technique (and employing high pressure CO2 and CO2 + EtOH mixtures) in order to develop hydrogel-type ophthalmic drug delivery applications. Impregnation experiments were carried out from 9.0 up to 14.0 MP...

  18. Adsorptive separation of rare earths by using chelating chitosan

    International Nuclear Information System (INIS)

    Two kinds of chelating chitosan were prepared by chemically modifying chitosan with functional groups of EDTA or DTPA, abbreviated as EDTA- and DTPA-chitosan hereafter, respectively, to investigate the adsorption behaviour for rare earths the mutual separation of which is the most difficult among metal ions on these chelating chitosan from dilute hydrochloric or sulfuric acid solution. The plots of the distribution ratio of a series of rare earths against equilibrium pH lay on different straight lines with slope of 3 corresponding to each earth for both of two chelating chitosan, suggesting that 3 hydrogen ions are released for the adsorption of unit ion of each rare earth by chelate formation with the functional group of EDTA or DTPA and that mutual adsorptive separation between adjacent rare earth is possible with these chelating chitosan. Apparent equilibrium constants of the adsorption were evaluated from the intercepts of these straight lines with the ordinate for each rare earth and for both chelating chitosan. It was found that the equilibrium constants of adsorption on EDTA- or DTPA-chitosan are quite analogous to those of chelate formation with EDTA or DTPA themselves, suggesting that chelating characteristics of these complexones is still maintained after their immobilization on polymer matrices of chitosan. (author)

  19. Synthesis and Characterization of Oil-Chitosan Composite Spheres

    OpenAIRE

    Huang, Keng-Shiang; Wang, Chih-Yu; Yang, Chih-Hui; Grumezescu, Alexandru; Lin, Yung-Sheng; Kung, Chao-Pin; Lin, I-Yin; Chang, Yi-Ching; Weng, Wei-Jie; Wang, Wei-Ting

    2013-01-01

    Oil-chitosan composite spheres were synthesized by encapsulation of sunflower seed oil in chitosan droplets, dropping into NaOH solution and in situ solidification. Hydrophilic materials (i.e., iron oxide nanoparticles) and lipophilic materials (i.e., rhodamine B or epirubicin) could be encapsulated simultaneously in the spheres in a one step process. The diameters of the prepared spheres were 2.48 ± 0.11 mm (pure chitosan spheres), 2.31 ± 0.08 mm (oil-chitosan composites), 1.49 ± 0.15 mm (ir...

  20. Viscometric and Rheological Behaviour of Chitosan-Hydrophilic Polymer Blends

    OpenAIRE

    R. K. Wanchoo; Thakur, Anupama; Sweta, A.

    2008-01-01

    Blends of chitosan with hydrophilic polymers were investigated for miscibility. Chitosan/poly (vinyl alcohol) (CS/PVA), chitosan/poly vinylpyrollidone (CS/PVP) and chitosan/poly (ethylene oxide) (CS/PEO) blends were prepared in dilute aqueous acetic acid ( = 1 %) and found to be miscible over the entire composition range by dilute solution viscosity and rheological measurements. The miscibility of blends by viscosity measurements at 25 ± 0.1 C was estimated on the basis of experimental and ...

  1. Effect of chitosan coating on the characteristics of DPPC liposomes

    Directory of Open Access Journals (Sweden)

    Mohsen M. Mady

    2010-07-01

    Full Text Available Because it is both biocompatible and biodegradable, chitosan has been used to provide a protective capsule in new drug formulations. The present work reports on investigations into some of the physicochemical properties of chitosan-coated liposomes, including drug release rate, transmission electron microscopy (TEM, zeta potential and turbidity measurement. It was found that chitosan increases liposome stability during drug release. The coating of DPPC liposomes with a chitosan layer was confirmed by electron microscopy and the zeta potential of liposomes. The coating of liposomes by chitosan resulted in a marginal increase in the size of the liposomes, adding a layer of (92 ± 27.1 nm. The liposomal zeta potential was found to be increasingly positive as chitosan concentration increased from 0.1% to 0.3% (w/v, before stabilising at a relatively constant value. Turbidity studies revealed that the coating of DPPC liposomes with chitosan did not significantly modify the main phase transition temperature of DPPC at examined chitosan concentrations. The appropriate combination of liposomal and chitosan characteristics may produce liposomes with specific, prolonged and controlled release.

  2. New antimicrobial chitosan derivatives for wound dressing applications.

    Science.gov (United States)

    Dragostin, Oana Maria; Samal, Sangram Keshari; Dash, Mamoni; Lupascu, Florentina; Pânzariu, Andreea; Tuchilus, Cristina; Ghetu, Nicolae; Danciu, Mihai; Dubruel, Peter; Pieptu, Dragos; Vasile, Cornelia; Tatia, Rodica; Profire, Lenuta

    2016-05-01

    Chitosan is a non-toxic, biocompatible, biodegradable natural cationic polymer known for its low imunogenicity, antimicrobial, antioxidant effects and wound-healing activity. To improve its therapeutic potential, new chitosan-sulfonamide derivatives have been designed to develop new wound dressing biomaterials. The structural, morphological and physico-chemical properties of synthesized chitosan derivatives were analyzed by FT-IR, (1)H NMR spectroscopy, scanning electron microscopy, swelling ability and porosity. Antimicrobial, in vivo testing and biodegradation behavior have been also performed. The chitosan derivative membranes showed improved swelling and biodegradation rate, which are important characteristics required for the wound healing process. The antimicrobial assay evidenced that chitosan-based sulfadiazine, sulfadimethoxine and sulfamethoxazole derivatives were the most active. The MTT assay showed that some of chitosan derivatives are nontoxic. Furthermore, the in vivo study on burn wound model induced in Wistar rats demonstrated an improved healing effect and enhanced epithelialization of chitosan-sulfonamide derivatives compared to neat chitosan. The obtained results strongly recommend the use of some of the newly developed chitosan derivatives as antimicrobial wound dressing biomaterials. PMID:26876993

  3. Fluorescent Nanoparticle-Based Indirect Immunofluorescence Microscopy for Detection of Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Jiyun Chen

    2007-11-01

    Full Text Available A method of fluorescent nanoparticle-based indirect immunofluorescence microscopy (FNP-IIFM was developed for the rapid detection of Mycobacterium tuberculosis. An anti-Mycobacterium tuberculosis antibody was used as primary antibody to recognize Mycobacterium tuberculosis, and then an antibody binding protein (Protein A labeled with Tris(2,2-bipyridyldichlororuthenium(II hexahydrate (RuBpy-doped silica nanoparticles was used to generate fluorescent signal for microscopic examination. Prior to the detection, Protein A was immobilized on RuBpy-doped silica nanoparticles with a coverage of ∼5.1×102 molecules/nanoparticle. With this method, Mycobacterium tuberculosis in bacterial mixture as well as in spiked sputum was detected. The use of the fluorescent nanoparticles reveals amplified signal intensity and higher photostability than the direct use of conventional fluorescent dye as label. Our preliminary studies have demonstrated the potential application of the FNP-IIFM method for rapid detection of Mycobacterium tuberculosis in clinical samples.

  4. Inverse I-V Injection Characteristics of ZnO Nanoparticle-Based Diodes.

    Science.gov (United States)

    Mundt, Paul; Vogel, Stefan; Bonrad, Klaus; von Seggern, Heinz

    2016-08-10

    Simple Al/ZnO(NP)/Au diodes produced by spin coating of ZnO nanoparticle dispersions (ZnO(NP)) on Al/Al2O3 and Au substrates and subsequent Au deposition have been investigated to understand electron injection properties of more complex devices, incorporating ZnO(NP) as injection layer. Inverse I-V characteristics have been observed compared to conventional Al/ZnO(SP)/Au diodes produced by reactive ion sputtering of ZnO. SEM micrographs reveal that the void-containing contact of ZnO(NP) with the bottom Al electrode and the rough morphology of the top Au electrode are likely to be responsible for the observed injection and ejection probabilities of electrons. A simple tunneling model, incorporating the voids, explains the strongly reduced injection currents from Al whereas the top electrode fabricated by vapor deposition of Au onto the nanoparticle topology adopts the inverse ZnO(NP) morphology leading to enlarged injection areas combined with Au-tip landscapes. These tips in contrast to the smooth sputtered ZnO(SP) lead to electric field enhancement and strongly increased injection of electrons in reverse direction. The injected charge piles up at the barrier generated by voids between ZnO(NP) and the bottom electrode forcing a change in the barrier shape and therefore allowing for higher ejection rates. Both effects in combination explain the inverse I-V characteristic of nanoparticle based diodes. PMID:27443793

  5. Experimental investigation of a silver nanoparticle-based direct absorption solar thermal system

    International Nuclear Information System (INIS)

    Highlights: • Pilot study of photothermal conversion of Ag nanoparticle under realistic conditions. • Tests were performed under direct sunlight continuously for ∼10 h. • Silver nanoparticle improves remarkably the photothermal conversion efficiency. • Bulk temperature rise of Ag nanofluids can be 10 times higher than the base fluid. • The specific absorption rate of silver reaches ∼0.6 kW/g initially. - Abstract: A nanoparticle-based direct absorption system provides a promising alternative to conventional solar collectors. This work investigates experimentally the photothermal conversion characteristics of one of the plasmonic nanoparticles, i.e., silver, under realistic conditions. Stable silver nanofluids are formulated through a high-pressure homogenizer and the experiments are conducted under sunlight on a rooftop with tests running continuously for ∼10 h. The results show that silver particles have excellent photothermal conversion capability even under very low concentrations. Up to 144% enhancement in the stored thermal energy can be obtained at the peak temperature for a particle concentration of 6.5 ppm. The photothermal conversion performance shows a transient behavior and is best achieved at the initial radiation period due to the low heat loss and strong surface plasmon resonance effect of silver nanofluids. Nearly constant initial specific absorption rate (SAR), ∼0.6 kW/g, is obtained for nanoparticle concentrations up to 6.5 ppm, but it decreases significantly at higher concentrations, which is associated with increased particle–particle interactions

  6. Self-organized nanoparticles based on drug-interpolyelectrolyte complexes as drug carriers

    Energy Technology Data Exchange (ETDEWEB)

    Palena, M. C.; Manzo, R. H.; Jimenez-Kairuz, A. F., E-mail: alvaro@fcq.unc.edu.ar [Universidad Nacional de Cordoba, UNITEFA-CONICET, Departamento de Farmacia, Facultad de Ciencias Quimicas (Argentina)

    2012-06-15

    Potential applications in drug delivery from nanostructures composed of two oppositely charged polymethacrylates, eudragit{sup Registered-Sign} L100 (EL) and eudragit{sup Registered-Sign} EPO (EE), loaded with three model basic drugs (D), atenolol, propranolol, and metroclopramide were evaluated. The self-organized nanoparticles based on drug-interpolyelectrolyte complexes (DIPEC), (EL-D{sub 50})-EE{sub X}, were obtained by mixing the aqueous dispersions of both polyelectrolytes at room temperature in an ultrasound bath. Dispersions of (EL-D{sub 50}) neutralized with increasing proportions of EE exhibited a rise of turbidity, particle sizes in the range of 150-400 nm, and high negative zeta potential. The sign of zeta potential was shifted from negative to positive by changes in composition of DIPEC. Freeze dried DIPEC were easily redispersed in water yielding nearly the same parameters of fresh dispersions. In vitro release experiments using Franz cells showed that DIPEC systems behave as a drug reservoir that slowly releases the drug as water is placed in the receptor compartment. The release rate was raised by ionic exchange with counterions present in simulated physiological fluids placed in the receptor media. Delivery of D from DIPEC exhibited a remarkable robustness toward simulated physiological media of different pH. The DIPEC systems exhibit interesting properties to design nanoparticulate drug delivery systems for oral and/or topical routes.

  7. Biomolecules Detection Using a Silver-Enhanced Gold Nanoparticle-Based Biochip

    Science.gov (United States)

    Liu, Yang; Zhang, Deng; Alocilja, Evangelyn C.; Chakrabartty, Shantanu

    2010-03-01

    Silver-enhanced labeling method has been employed in immunochromatographic assays for improving the sensitivity of detecting pathogens. In this paper, we apply the silver enhancement technique for biomolecular signal amplification in a gold nanoparticle-based conductimetric biochip. We show that the response of the silver-enhanced biochip comprises two distinct regions namely: (a) a sub-threshold region where conduction occurs due to electron hopping between silver islands and the electrolyte and (b) an above-threshold region where the conduction is due to a direct flow of electrons. These two regions are characterized by different conduction slopes, and we show that combining the information from both these regions can improve the sensitivity of the biochip. Results from fabricated prototypes show a dynamic range of more than 40 dB and with a detection limit less than 240 pg/mL. The fabrication of the biochip is compatible with standard complementary metal-oxide-semiconductor (CMOS) processes making it ideal for integration in next-generation CMOS biosensors.

  8. Nanoparticle-based immunosensor with apoferritin templated metallic phosphate label for quantification of phosphorylated acetylcholinesterase

    Energy Technology Data Exchange (ETDEWEB)

    Du, Dan; Chen, Aiqiong; Xie, Yunying; Zhang, Aidong; Lin, Yuehe

    2011-05-15

    A new sandwich-like electrochemical immunosensor has been developed for quantification of organophosphorylated acetylcholinesterase (OP-AChE), an exposure biomarker of organophosphate pesticides and nerve agents. Zirconia nanoparticles (ZrO2 NPs) were anchored on a screen printed electrode (SPE) to preferably capture OP-AChE adducts by metal chelation with phospho-moieties, which was selectively recognized by lead phosphate-apoferritin labeled anti-AChE antibody (LPA-anti-AChE). The sandwich-like immunoreactions were performed among ZrO2 NPs, OP-AChE and LPA-anti-AChE to form ZrO2/OP-AChE/LPA-anti-AChE complex and the released lead ions were detected on a disposable SPE. The binding affinity was investigated by both square wave voltammetry (SWV) and quartz crystal microbalance (QCM) measurements. The proposed immunosensor yielded a linear response current over a broad OP-AChE concentrations range from 0.05 nM to 10 nM, with detection limit of 0.02 nM, which has enough sensitivity for monitoring of low-dose exposure to OPs. This method avoids the drawback of unavailability of commercial OP-specific antibody as well as amplifies detection signal by using apoferritin encoded metallic phosphate nanoparticle tags. This nanoparticle-based immunosensor offers a new method for rapid, sensitive, selective and inexpensive quantification of phosphorylated adducts for monitoring of OP pesticides and nerve agents exposures.

  9. Biomolecules Detection Using a Silver-Enhanced Gold Nanoparticle-Based Biochip

    Directory of Open Access Journals (Sweden)

    Zhang Deng

    2010-01-01

    Full Text Available Abstract Silver-enhanced labeling method has been employed in immunochromatographic assays for improving the sensitivity of detecting pathogens. In this paper, we apply the silver enhancement technique for biomolecular signal amplification in a gold nanoparticle-based conductimetric biochip. We show that the response of the silver-enhanced biochip comprises two distinct regions namely: (a a sub-threshold region where conduction occurs due to electron hopping between silver islands and the electrolyte and (b an above-threshold region where the conduction is due to a direct flow of electrons. These two regions are characterized by different conduction slopes, and we show that combining the information from both these regions can improve the sensitivity of the biochip. Results from fabricated prototypes show a dynamic range of more than 40 dB and with a detection limit less than 240 pg/mL. The fabrication of the biochip is compatible with standard complementary metal–oxide–semiconductor (CMOS processes making it ideal for integration in next-generation CMOS biosensors.

  10. Polyurethane and polyurea nanoparticles based on polyoxyethylene castor oil derivative surfactant suitable for endovascular applications.

    Science.gov (United States)

    Morral-Ruíz, Genoveva; Melgar-Lesmes, Pedro; García, María Luísa; Solans, Conxita; García-Celma, María José

    2014-01-30

    The design of new, safe and effective nanotherapeutic systems is an important challenge for the researchers in the nanotechnology area. This study describes the formation of biocompatible polyurethane and polyurea nanoparticles based on polyoxyethylene castor oil derivative surfactant formed from O/W nano-emulsions by polymerization at the droplet interfaces in systems composed by aqueous solution/Kolliphor(®) ELP/medium chain triglyceride suitable for intravenous administration. Initial nano-emulsions incorporating highly hydrophilic materials were prepared by the phase inversion composition (PIC) method. After polymerization, nanoparticles with a small particle diameter (25-55 nm) and low polydispersity index were obtained. Parameters such as concentration of monomer, O/S weight ratio as well as the polymerization temperature were crucial to achieve a correct formation of these nanoparticles. Moreover, FT-IR studies showed the full conversion of the monomer to polyurethane and polyurea polymers. Likewise the involvement of the surfactant in the polymerization process through their nucleophilic groups to form the polymeric matrix was demonstrated. This could mean a first step in the development of biocompatible systems formulated with polyoxyethylene castor oil derivative surfactants. In addition, haemolysis and cell viability assays evidenced the good biocompatibility of KELP polyurethane and polyurea nanoparticles thus indicating the potential of these nanosystems as promising drug carriers. PMID:24275445

  11. A novel nanoparticle-based disposable electrochemical immunosensor for diagnosis of exposure to toxic organophosphorus agents

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Donglai; Wang, Jun; Wang, Limin; Du, Dan; Timchalk, Charles; Barry, Richard C.; Lin, Yuehe

    2011-11-15

    We present a novel disposable electrochemical immunosensor for highly selective and sensitive detection of organophosphorylated butyrylcholinesterase (OP-BChE), a specific biomarker for exposure to toxic organophosphorus agents. In our new approach, the zirconia nanoparticles (ZrO-2) were employed to selectively capture the OP moiety of OP-BChE adducts, and followed by quantum dot (QD)-tagged anti-BChE antibodies for amplified quantification. The captured CdSe-QD tags can be sensitively detected by stripping voltammetry using in situ bismuth-plating method. The OP agent, diisopropylfluorophosphate (DFP), was selected to prepare OP-BChE adducts in various matrices. The formation of OP-BChE adducts in plasma sample was confirmed using mass spectroscopy. The developed electrochemical immunosensor demonstrates a highly linear voltammetric response over the range of 0.1 to 30 nM OP-BChE. Moreover, the immunosensor has been successfully applied for the detection of OP-BChE adducts in the plasma samples. This novel nanoparticle-based electrochemical immunosensor thus provides an alternative way for designing simple, fast, sensitive, and cost-effective sensing platform for on-site screening/evaluating exposure to a variety of OP agents.

  12. Nanoparticle-based highly sensitive MRI contrast agents with enhanced relaxivity in reductive milieu.

    Science.gov (United States)

    Sigg, Severin J; Santini, Francesco; Najer, Adrian; Richard, Pascal U; Meier, Wolfgang P; Palivan, Cornelia G

    2016-08-01

    Current magnetic resonance imaging (MRI) contrast agents often produce insufficient contrast for diagnosis of early disease stages, and do not sense their biochemical environments. Herein, we report a highly sensitive nanoparticle-based MRI probe with r1 relaxivity up to 51.7 ± 1.2 mM(-1) s(-1) (3T). Nanoparticles were co-assembled from Gd(3+) complexed to heparin-poly(dimethylsiloxane) copolymer, and a reduction-sensitive amphiphilic peptide serving to induce responsiveness to environmental changes. The release of the peptide components leads to a r1 relaxivity increase under reducing conditions and increases the MRI contrast. In addition, this MRI probe has several advantages, such as a low cellular uptake, no apparent cellular toxicity (tested up to 1 mM Gd(3+)), absence of an anticoagulation property, and a high shelf stability (no increase in free Gd(3+) over 7 months). Thus, this highly sensitive T1 MRI contrast nanoparticle system represents a promising probe for early diagnosis through possible accumulation and contrast enhancement within reductive extracellular tumour tissue. PMID:27435820

  13. Detection of liver cancer tissue using silver nanoparticles-based surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Lin, Juqiang; Liao, Fadian; Ruan, Qiuyong; Zeng, Yongyi; Li, Ling; Huang, Zufang; Lu, Peng; Chen, Rong

    2014-11-01

    Early detection of hepatocellular carcinoma is difficult due to the absence of recognizable physical symptoms. In this study, Raman spectra of liver normal tissues and hepatocellular carcinoma tissues were measured by using silver nanoparticles based surface enhanced Raman spectroscopy (SERS), respectively. The mean Raman spectra of two groups are roughly similar. But the peaks intensity of hepatocellular carcinoma tissues at 722 cm-1 and 1049 cm-1 are obviously higher than those of normal tissues. Some peaks of hepatocellular carcinoma tissues have shifted by different degree. Besides, Raman peaks at 1004cm-1 had disappeared in normal tissue. The result suggested that SERS spectra can feature liver normal tissue and hepatocellular carcinoma tissue. Principal component analysis (PCA) coupled with linear discriminant analysis (LDA) was performed on the measured spectra. There were three most diagnostically significant PCs (PC3, PC9, and PC15, p<0.05) for discriminating these two groups. The diagnostic sensitivity and specificity both were 84.6%. The whole analysis of each sample needs less time-consumed and cost than other traditional methods in detecting and diagnosing HCC. The preliminary result suggests that SERS spectra can be a potential medical technology to detect and diagnose HCC.

  14. Self-organized nanoparticles based on drug-interpolyelectrolyte complexes as drug carriers

    International Nuclear Information System (INIS)

    Potential applications in drug delivery from nanostructures composed of two oppositely charged polymethacrylates, eudragit® L100 (EL) and eudragit® EPO (EE), loaded with three model basic drugs (D), atenolol, propranolol, and metroclopramide were evaluated. The self-organized nanoparticles based on drug-interpolyelectrolyte complexes (DIPEC), (EL-D50)–EEX, were obtained by mixing the aqueous dispersions of both polyelectrolytes at room temperature in an ultrasound bath. Dispersions of (EL-D50) neutralized with increasing proportions of EE exhibited a rise of turbidity, particle sizes in the range of 150–400 nm, and high negative zeta potential. The sign of zeta potential was shifted from negative to positive by changes in composition of DIPEC. Freeze dried DIPEC were easily redispersed in water yielding nearly the same parameters of fresh dispersions. In vitro release experiments using Franz cells showed that DIPEC systems behave as a drug reservoir that slowly releases the drug as water is placed in the receptor compartment. The release rate was raised by ionic exchange with counterions present in simulated physiological fluids placed in the receptor media. Delivery of D from DIPEC exhibited a remarkable robustness toward simulated physiological media of different pH. The DIPEC systems exhibit interesting properties to design nanoparticulate drug delivery systems for oral and/or topical routes.

  15. Fabrication of semi-transparent superoleophobic thin film from fabrics and nanoparticle-based hierarchical structure

    Directory of Open Access Journals (Sweden)

    Nishizawa S.

    2013-08-01

    Full Text Available Superoleophobic thin films have many potential applications including fluid transfer, fluid power systems, stain resistant and antifouling materials, and microfluidics among others. Transparency is also desired with superhydrophobicity for their numerous applications; however transparency and oleophobicity are almost incompatible relationship with each other in the point of surface structure. Because oleophobicity required rougher structure at nano-micro scale than hydrophobicity, and these rough structure brings light scattering. So far, there is very few report of the compatible of transparency and superoleophobicity. In this report, we proposed the see-through type fabrics using the nanoparticle-based hierarchical structure thin film for improving both of oleophobicity and transparency. The vacant space between fibrils of fabrics has two important roles: the one is to through the light, another one is to introduce air layer to realize Cassie state of liquid droplet on thin film. To realize the low surface energy and nanoscale rough structure surface on fibrils, we used the spray method with perfluoroalkyl methacrylic copolymer (PMC, silica nano particles and volatile solvent. From the SEM image, the hierarchical structures of nanoparticle were formed uniformly on the fabrics. The transparency of thin film obtained was approximately 61% and the change of transparency between pre-coated fabrics and coated was 11%. From investigation of the surface wettability, the contact angles of oils (rapeseed oil and hexadecane and water droplet on the fabricated film were over 150 degree.

  16. Enhancing magnetic nanoparticle-based DNA transfection: Intracellular-active cassette features

    Science.gov (United States)

    Vernon, Matthew Martin

    Efficient plasmid DNA transfection of embryonic stem cells, mesenchymal stem cells, neural cell lines and the majority of primary cell lines is a current challenge in gene therapy research. Magnetic nanoparticle-based DNA transfection is a gene vectoring technique that is promising because it is capable of outperforming most other non-viral transfection methods in terms of both transfection efficiency and cell viability. The nature of the DNA vector implemented depends on the target cell phenotype, where the particle surface chemistry and DNA binding/unbinding kinetics of the DNA carrier molecule play a critical role in the many steps required for successful gene transfection. Accordingly, Neuromag, an iron oxide/polymer nanoparticle optimized for transfection of neural phenotypes, outperforms many other nanoparticles and lipidbased DNA carriers. Up to now, improvements to nanomagnetic transfection techniques have focused mostly on particle functionalization and transfection parameter optimization (cell confluence, growth media, serum starvation, magnet oscillation parameters, etc.). None of these parameters are capable of assisting the nuclear translocation of delivered plasmid DNA once the particle-DNA complex is released from the endosome and dissociates in the cell's cytoplasm. In this study, incorporation of a DNA targeting sequence (DTS) feature in the transfecting plasmid DNA confers improved nuclear translocation, demonstrating significant improvement in nanomagnetic transfection efficiency in differentiated SH-SY5Y neuroblastoma cells. Other parameters, such as days in vitro, are also found to play a role and represent potential targets for further optimization.

  17. Nanoparticle-mediated conversion of primary human astrocytes into neurons and oligodendrocytes†

    Science.gov (United States)

    Li, Xiaowei; Kozielski, Kristen; Cheng, Yu-Hao; Liu, Huanhuan; Zamboni, Camila Gadens; Green, Jordan

    2016-01-01

    Central nervous system (CNS) diseases and injuries are accompanied by reactive gliosis and scarring involving the activation and proliferation of astrocytes to form hypertrophic and dense structures, which present a significant barrier to neural regeneration. Engineering astrocytes to functional neurons or oligodendrocytes may constitute a novel therapeutic strategy for CNS diseases and injuries. Such direct cellular programming has been successfully demonstrated using viral vectors via the transduction of transcriptional factors, such as Sox2, which could program resident astrocytes into neurons in the adult brain and spinal cord, albeit the efficiency was low. Here we report a non-viral nanoparticle-based transfection method to deliver Sox2 or Olig2 into primary human astrocytes and demonstrate the effective conversion of the astrocytes into neurons and oligodendrocyte progenitors following the transgene expression of Sox2 and Olig2, respectively. This approach is highly translatable for engineering astrocytes to repair injured CNS tissues. PMID:27328202

  18. Thermodynamic study on adsorption of Copper Formaldehyde, Chitosan immobilised on Red Soil, Chitosan reinforced by Banana stem fibre

    OpenAIRE

    J. Thilagan, Prof. S. Gopalakrishnan,; Dr. T. Kannadasan

    2013-01-01

    The effective and economic removal of heavy metals from industrial effluents is one of the important issues globally. Batch adsorption experiments were carried to fix the adsorption dosage and also to find the optimum pH. A thermodynamic study was made on the adsorption of Cu +2 ions in aqueous solution distinctly by the adsorbents such as Chitosan blended with Cellulose and cross linked by Formaldehyde, Chitosan immobilised on Red Soil and Chitosan reinforced...

  19. Comparison and Characterisation of Regenerated Chitosan from 1-Butyl-3-methylimidazolium Chloride and Chitosan from Crab Shells

    OpenAIRE

    Saniyat Islam; Lyndon Arnold; Rajiv Padhye

    2015-01-01

    Chitosan is a biopolymer derived from chitin which is naturally occurring in the exoskeleton of crustaceans. This paper reports dissolution and regeneration of chitosan by directly dissolving in an ionic liquid solvent, 1-butyl-3-methylimidazolium chloride (BMIMCl). This will provide an ideal platform to solubilise these kinds of polymers to achieve the dissolution. The current study dissolved chitosan from crab shell utilising BMIMCl as a solvent and characterised the resultant regenerated p...

  20. Detection of chlorine-labelled chitosan in Scots pine by energy-dispersive X-ray spectroscopy

    OpenAIRE

    Larnøy, Erik; Eikenes, Morten; Militz, Holger

    2011-01-01

    The aim of this study was to use energy-dispersive X-ray spectroscopy (EDX) to localize chitosan in the cell wall of chitosan-impregnated Scots pine. It was of interest to investigate the concentration of chitosan in wood to gain further knowledge and understanding of the distribution of chitosan in the wooden matrix. After deacetylation, chitosan was re-acetylated with chloroacetic anhydride to achieve a covalent bonding of chloride to the chitosan polymer. Chloride-labelled chitosan was mea...

  1. Juvenil neuronal ceroid lipofuscinosis

    DEFF Research Database (Denmark)

    Ostergaard, J R; Hertz, Jens Michael

    1998-01-01

    Neuronal ceroid-lipofuscinosis is a group of neurodegenerative diseases which are characterized by an abnormal accumulation of lipopigment in neuronal and extraneuronal cells. The diseases can be differentiated into several subgroups according to age of onset, the clinical picture...

  2. Chitosan-film enhanced chitosan nerve guides for long-distance regeneration of peripheral nerves.

    Science.gov (United States)

    Meyer, Cora; Stenberg, Lena; Gonzalez-Perez, Francisco; Wrobel, Sandra; Ronchi, Giulia; Udina, Esther; Suganuma, Seigo; Geuna, Stefano; Navarro, Xavier; Dahlin, Lars B; Grothe, Claudia; Haastert-Talini, Kirsten

    2016-01-01

    Biosynthetic nerve grafts are developed in order to complement or replace autologous nerve grafts for peripheral nerve reconstruction. Artificial nerve guides currently approved for clinical use are not widely applied in reconstructive surgery as they still have limitations especially when it comes to critical distance repair. Here we report a comprehensive analysis of fine-tuned chitosan nerve guides (CNGs) enhanced by introduction of a longitudinal chitosan film to reconstruct critical length 15 mm sciatic nerve defects in adult healthy Wistar or diabetic Goto-Kakizaki rats. Short and long term investigations demonstrated that the CNGs enhanced by the guiding structure of the introduced chitosan film significantly improved functional and morphological results of nerve regeneration in comparison to simple hollow CNGs. Importantly, this was detectable both in healthy and in diabetic rats (short term) and the regeneration outcome almost reached the outcome after autologous nerve grafting (long term). Hollow CNGs provide properties likely leading to a wider clinical acceptance than other artificial nerve guides and their performance can be increased by simple introduction of a chitosan film with the same advantageous properties. Therefore, the chitosan film enhanced CNGs represent a new generation medical device for peripheral nerve reconstruction. PMID:26517563

  3. Preparation, characterization and antibacterial activity of chitosan and phosphorylated chitosan from cuttlebone of Sepia kobiensis (Hoyle, 1885

    Directory of Open Access Journals (Sweden)

    Annaian Shanmugam

    2016-03-01

    Full Text Available Chitosan is a commercially available derivative of chitin that has been extensively studied for its antimicrobial properties. In order to improve the water solubility and its biological activity, the chemical modification or derivatisation is attempted. In the present investigation, the chitosan prepared from the cuttlebone of Sepia kobiensis was being chemically modified by reacting it with orthophosphoric acid so as to obtain phosphorylated chitosan. Then the chitosan and phosphorylated chitosan were structurally characterized through FT-IR spectroscopy. Further the antibacterial activity of chitosan and phosphorylated chitosan was tested against clinically isolated human pathogens (Gram-positive: Streptococcus sp., Streptococcus pneumoniae and Staphylococcus aureus and Gram-negative: Escherichia coli, Vibrio cholerae, V. alginolyticus, Vibrio parahaemolyticus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella sp. and Proteus vulgaris by well diffusion method and the Minimum Inhibitory Concentration (MIC was also calculated. The results of the present study suggests that the chitosan and phosphorylated chitosan has concentration dependent antibacterial activity with variation against several pathogenic human pathogenic bacterial strains which indicates their possible use as antibacterial agents.

  4. Refractory Neuron Circuits

    OpenAIRE

    Sarpeshkar, Rahul; Watts, Lloyd; Mead, Carver

    1992-01-01

    Neural networks typically use an abstraction of the behaviour of a biological neuron, in which the continuously varying mean firing rate of the neuron is presumed to carry information about the neuron's time-varying state of excitation. However, the detailed timing of action potentials is known to be important in many biological systems. To build electronic models of such systems, one must have well-characterized neuron circuits that capture the essential behaviour of real neur...

  5. NEURON and Python

    OpenAIRE

    Michael Hines; Davison, Andrew P.; Eilif Muller

    2009-01-01

    The NEURON simulation program now allows Python to be used, alone or in combination with NEURON's traditional Hoc interpreter. Adding Python to NEURON has the immediate benefit of making available a very extensive suite of analysis tools written for engineering and science. It also catalyzes NEURON software development by offering users a modern programming tool that is recognized for its flexibility and power to create and maintain complex programs. At the same time, nothing is lost because ...

  6. Motor Neurons that Multitask

    OpenAIRE

    Goulding, Martyn

    2012-01-01

    Animals use a form of sensory feedback termed proprioception to monitor their body position and modify the motor programs that control movement. In this issue of Neuron, Wen et al. (2012) provide evidence that a subset of motor neurons function as proprioceptors in C. elegans, where B-type motor neurons sense body curvature to control the bending movements that drive forward locomotion.

  7. Preparation, characterization, and potential application of chitosan, chitosan derivatives, and chitosan metal nanoparticles in pharmaceutical drug delivery

    OpenAIRE

    Ahmed TA; Aljaeid BM

    2016-01-01

    Tarek A Ahmed1,2 Bader M Aljaeid11Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Al-Azhar University, Cairo, EgyptAbstract: Naturally occurring polymers, particularly of the polysaccharide type, have been used pharmaceutically for the delivery of a wide variety of therapeutic agents. Chitosan, the second abundant naturally o...

  8. Synthesis and Characterization of a Novel Soluble Diethoxy Phosphoryl Chitosan%Synthesis and Characterization of a Novel Soluble Diethoxy Phosphoryl Chitosan

    Institute of Scientific and Technical Information of China (English)

    Ma, Li; Li, Kerang; Li, Limin; Liu, Pu

    2012-01-01

    A simple and efficient method for the preparation of a novel soluble chitosan derivative, diethoxy phosphoryl chitosan (PH-chitosan), has been developed. Ph-chitosan was characterized by elemental analysis, FT-IR, NMR, ICP, XRD, TG and SEM, respectively. The chemical identity of PH-chitosan was determined by FT-IR and confirmed by NMR, and those results unequivocally demonstrated that diethoxy phosphoryl groups were grafted onto the amino and hydroxyl groups of chitosan. The results of XRD indicated that the crystalline structure of chitosan was destroyed due to the incorporation of diethoxy phosphoryl group resulting in loss of hydrogen bond. The analysis of TG demonstrated that PH-chitosan was less thermal stable than chitosan. This simple synthetic method provided a new and available approach to prepare a soluble high molecule weight chitosan derivative.

  9. New sizing agents and flocculants derived from chitosan

    International Nuclear Information System (INIS)

    Novel approaches for development of new textile sizing agents and flocculants were undertaken. One of these approaches is based on acid hydrolysis of chitosan and the other involves its carboxy methylation. Characterization of the hydrolyzed chitosan was performed through monitoring nitrogen content and apparent viscosity, while carboxymethyl chitosan was analyzed for degree of substitution (DS) along with apparent viscosity. Factors affecting both hydrolysis and carboxy methylation were investigated. The nitrogen content and apparent viscosity of chitosan decrease variably by increasing HCl concentration as well as time and temperature of hydrolysis. On the other hand, the DS of carboxymethyl chitosan increases by increasing the concentration of both sodium hydroxide and monochloroacetic acid and similarly increases by prolonging the duration and raising the temperature of carboxy methylation; in contrast with apparent viscosity which is inversely related to these parameters. Aqueous solutions of hydrolyzed chitosan or carboxymethyl chitosan were applied to light cotton fabric with a view to envision the technical feasibility of such water soluble chitosan for textile sizing. The size add-on on the light fabric is directly related to the concentration of the hydrolyzed or carboxymethyl chitosan in the sizing solution and so does the apparent viscosity of the latter. Hundred percent size removals could be achieved with the hydrolyzed chitosan irrespective or the size solution concentration provided that the latter is not less than 8%. Different situation is encountered with carboxymethyl chitosan where the percent size removal increase from 81% to 95% by increasing its concentration in the sizing solution from 5 % to 15%. Drying the sized fabric at 80 degree C for 5 minutes or 120 degree C for 3 minutes has practically no effect on percent size removal. The same holds true for heat treatment of the sized fabric at higher temperatures (up to 160 degree C) for longer

  10. Synthesis and Adsorption Property of Dihydroxyl Azacrown Ether—Grafted Chitosan

    Institute of Scientific and Technical Information of China (English)

    ZhiKuanYANG; LiZHUANG; 等

    2002-01-01

    A novel dihydroxyl azacrown ether chitosan was synthesized by reacting dihydroxyl azacrown ether with epoxy activated chitosan. The adsorption property of the azacrown ether chitosan for Pb2+, Cr3+, and Ag+, were determined. The experimental results showed that the dihydroxyl azacrown ether grafted chitosan has high adsorption capacity and high selectivity for some metal ions.

  11. Synthesis and Adsorption Property of Dihydroxyl Azacrown Ether-Grafted Chitosan

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel dihydroxyl azacrown ether chitosan was synthesized by reacting dihydroxyl azacrown ether with epoxy activated chitosan. The adsorption property of the azacrown ether chitosan for Pb2+, Cr3+, and Ag+, were determined. The experimental results showed that the dihydroxyl azacrown ether grafted chitosan has high adsorption capacity and high selectivity for some metal ions.

  12. An investigation into the digestibility of chitosan by human colonic bacteria.

    OpenAIRE

    McConnell, E. L.; Basit, A. W.; Murdan, S.

    2006-01-01

    The suitability of chitosan (non-crosslinked and crosslinked by glutaraldehyde) for colonic drug delivery was assessed by incubation of chitosan films in human faecal slurry and assessment of the film’s disappearance with time. It was found that non-crosslinked chitosan, was digested by colonic bacteria, but crosslinked chitosan was not.

  13. MUCOADHESIVE MICROPARTICLES OF CARBOXYMETHYL CHITOSAN FOR SITE SPECIFIC DELIVERY OF PANTOPRAZOLE: FORMULATION AND IN VITRO CHARACTERIZATION

    OpenAIRE

    N.A. Gujarathi*, B.R. Rane and J.K. Patel

    2012-01-01

    Carboxymethyl chitosan, a water soluble modified carboxymethyl substituted chitosan derivative have distinct and unique properties, rendering them effective to form selective permeable mucoadhesive film or membranes. In the formulation of chitosan microsphere an acidic environment is essentially required that may degrade acid sensitive moiety, peptide or protein drugs. Mucoadhesive microparticle of carboxymethyl chitosan was designed and developed for site specific sustained release of Pantop...

  14. Solubility, viscosity and rheological properties of water-soluble chitosan derivatives

    Directory of Open Access Journals (Sweden)

    Songwut Yotsawimonwat

    2012-08-01

    Full Text Available An investigation and comparison of solubility, viscosity and rheological properties under neutral, acidic and alkaline conditions of water-soluble chitosan derivatives, viz. O-carboxymethyl chitosan, N,O-carboxymethyl chitosan, N-[(2-hydroxy-3-trimethylammoniumpropyl] chitosanchloride and O-carboxymethyl-N-[(2-hydroxy-3-trimethylammoniumpropyl] chitosan chloride, was undertaken.

  15. Solubility, viscosity and rheological properties of water-soluble chitosan derivatives

    OpenAIRE

    Songwut Yotsawimonwat

    2012-01-01

    An investigation and comparison of solubility, viscosity and rheological properties under neutral, acidic and alkaline conditions of water-soluble chitosan derivatives, viz. O-carboxymethyl chitosan, N,O-carboxymethyl chitosan, N-[(2-hydroxy-3-trimethylammonium)propyl] chitosanchloride and O-carboxymethyl-N-[(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride, was undertaken.

  16. Biodegradation Study of Microcrystalline Chitosan and Microcrystalline Chitosan/β-TCP Complex Composites

    Directory of Open Access Journals (Sweden)

    Kinga Brzoza-Malczewska

    2012-06-01

    Full Text Available Bone repair or regeneration is a common and complicated clinical problem in orthopedic surgery. The importance of natural polymers, such as microcrystalline chitosan, and minerals such as HAp and β-TCP, has grown significantly over the last two decades due to their renewable and biodegradable source, increasing the knowledge and functionality of composites in technological and biomedical applications. This study compares the biodegradation process, bioactivity, structure, morphology, and mechanical properties of microcrystalline chitosan and microcrystalline chitosan/β-TCP complex; the latter according to the new method of preparation. The complex showed a homogeneous network structure with regular pores, good bioactivity, even after 60 days of conducting the hydrolytic and enzymatic degradation process, showing a bacteriostatic and bactericidal activity. The complex indicates that it could be used successfully as a base for implants and scaffolds production in orthopedic surgery.

  17. Application of Chitosan Flocculant to Conditioning Sludge

    Institute of Scientific and Technical Information of China (English)

    李步祥; 陈亮; 陈东辉; 张印堂

    2003-01-01

    The dewaterability of activated sludge conditioned by chitosan fiocculant was studied. The effects of chitasan characteristics such as molecular weight,degree of deacetylation, and dose on the dewaterability were investigated. The sludge dewaterability is evaluated in terms of specific resistance to filtration, residual turbidity of supernatant, moisture content of cake, and settling rate. Sludge dehydrating behaviors conditioned with CTS, PAM and PAC fiocculants were compared. The conditioning was also carried out with dual flocculants in two stages. It is found that the sludge conditioned with CTS has better dewaterability than that with PAC. The optimum conditions with chitosan are: dose 0.8~1.2 g per 100 g dry cake, molecular weight 300,000, and degree of deacetylation 70%. The conditioning in two stages with dual flocculants is found to be more effective than that with single flocculant.

  18. Insights into and relative effect of chitosan-krill oil, chitosan-H-aspirin, chitosan-H-krill oil-nystatin and chitosan-H-krill oil-aspirin-nystatin on dentin bond strength and functional drug delivery capacity: In-vitro studies

    OpenAIRE

    Victoria Tamara Perchyonok; Shengmiao Zhang; Grobler, Sias R; Oberholzer, Theunis G.; Ward Massey

    2014-01-01

    Background: Restorative materials in the new era aim to be "bio-active" and long-lasting. The purpose of this study was to design and to evaluate a novel chitosan hydrogels containing krill oil (antioxidant containing material), nystatin (antifungal), aspirin (pain relieve medication and free radical scavengers) and combinations thereof (chitosan-H-krill oil, chitosan-H-krill oil-nystatin and chitosan-H-aspirin, chitosan-H-aspirin-nystatin, chitosan-H-krill oil-aspirin and chitosan-H-krill oi...

  19. Die Chitosan-induzierte Abwehrreaktion des Weizens

    OpenAIRE

    Kohlhoff, M.

    2003-01-01

    Eine Inokulation anfälliger Weizensorten mit dem phytopathogenen Rostpilz Puccinia graminis f.sp. tritici (Pgt) führt zur Erkrankung der Pflanze an Schwarzrost. In hochresistenten Weizensorten kann die Pflanze eine Infektion durch den obligat biotrophen Pilz abwehren, indem infizierte Zellen lignifizieren und absterben. Substanzen, die bei Applikation ähnliche Abwehrreaktionen induzieren können, werden Elicitoren genannt. In Blätter infiltriertes polymeres Chitosan wirkt in Weizen als Elic...

  20. Viscometric Studies in Dilute Solution Mixtures of Chitosan and Microcrystalline Chitosan with Poly(vinyl alcohol)

    OpenAIRE

    Lewandowska, Katarzyna

    2013-01-01

    The viscosity behavior of aqueous mixtures formed by a polyelectrolyte (A) and a neutral polymer (B), such as chitosan/poly(vinyl alcohol) (Ch/PVA) and microcrystalline chitosan/poly(vinyl alcohol) (MCCh/PVA), have been investigated at 25 °C. The intrinsic viscosity and the viscosity interaction parameter of each polymer in 0.1 mol·dm−3 CH3COOH/0.2 mol·dm−3 NaCl solution as well as the ternary systems (polymer A/polymer B/solvent) have been determined and have served for estimation of the mis...

  1. Niche nanoparticle-based FRET assay for bleomycin detection via DNA scission.

    Science.gov (United States)

    Pei, Haimeng; Zheng, Yiqun; Kong, Rongmei; Xia, Lian; Qu, Fengli

    2016-11-15

    We describe a highly sensitive nanoparticle-based fluorescence resonance energy transfer (FRET) probe developed without using molecular fluorophores as donors and acceptors. The success of this work relies on the strategy that DNA scission was designed to occur to the probe when target presented, which enabled the fluorescence signal "turn-on" of graphene quantum dots (GQDs) and thus quantitative analysis. In particular, amino-modified SiO2 NPs were initially coated by GQDs to form highly emitting SiO2/GQDs, followed by conjunction with DNA functionalized gold nanoparticles (Au NPs-DNA) to form SiO2/GQDs-DNA-Au NPs composite. Owing to the FRET interactions between the GQDs and Au NPs, the fluorescence of GQDs was effectively quenched by Au NPs. When bleomycin (BLM), a model analyte, was mixed with the probe, the fluorescence signal of GQDs would be restored due to the removal of Au NPs from the SiO2/GQDs surface by DNA scission treatment with BLM in the presence of Fe (II). The current FRET probe shows a good linear relationship between the fluorescence intensity and the concentration of BLM in the range from 0.5nM to 1μM with a detection limit of 0.2nM. The probe also shows satisfactory results for the analysis of clinical serum samples. This method provides versatility to the application of GQDs in FRET biosensing and could be potentially extended to other similar systems by replacing the linker between the GQDs and Au NPs. PMID:27155119

  2. Nanoparticle-based optical biosensors for the direct detection of organophosphate chemical warfare agents and pesticides

    International Nuclear Information System (INIS)

    Neurotoxic organophosphates (OP) have found widespread use in the environment for insect control. In addition, there is the increasing threat of use of OP based chemical warfare agents in both ground based warfare and terrorist attacks. Together, these trends necessitate the development of simple and specific methods for discriminative detection of ultra low quantities of OP neurotoxins. In our previous investigations a new biosensor for the direct detection of organophosphorus neurotoxins was pioneered. In this system, the enzymatic hydrolysis of OP neurotoxins by organophosphate hydrolase (OPH) generated two protons in each hydrolytic turnover through reactions in which P-X bonds are cleaved. The sensitivity of this biosensor was limited due to the potentiometric method of detection. Recently, it was reported that a change in fluorescence properties of a fluorophore in the vicinity of gold nanoparticles might be used for detection of nanomolar concentrations of DNA oligonucleotides. The detection strategy was based on the fact that an enhancement or quenching of fluorescence intensity is a function of the distances between the gold nanoparticle and fluorophore. While these reports have demonstrated the use of nanoparticle-based sensors for the detection of target DNA, we observed that the specificity of enzyme-substrate interactions could be exploited in similar systems. To test the feasibility of this approach, OPH-gold nanoparticle conjugates were prepared, then incubated with a fluorescent enzyme inhibitor or decoy. The fluorescence intensity of the decoy was sensitive to the proximity of the gold nanoparticle, and thus could be used to indicate that the decoy was bound to the OPH. Then different paraoxon concentrations were introduced to the OPH-nanoparticle-conjugate-decoy mixtures, and normalized ratio of fluorescence intensities were measured. The greatest sensitivity to paraoxon was obtained when decoys and OPH-gold nanoparticle conjugates were present at

  3. In vitro osteoclastogenesis on textile chitosan scaffold

    Directory of Open Access Journals (Sweden)

    C Heinemann

    2010-02-01

    Full Text Available Textile chitosan fibre scaffolds were evaluated in terms of interaction with osteoclast-like cells, derived from human primary monocytes. Part of the scaffolds was further modified by coating with fibrillar collagen type I in order to make the surface biocompatible. Monocytes were cultured directly on the scaffolds in the presence of macrophage colony stimulating factor (M-CSF and receptor activator of nuclear factor kappaB ligand (RANKL for up to 18 days. Confocal laser scanning microscopy (CLSM as well as scanning electron microscopy (SEM revealed the formation of multinuclear osteoclast-like cells on both the raw chitosan fibres and the collagen-coated scaffolds. The modified surface supported the osteoclastogenesis. Differentiation towards the osteoclastic lineage was confirmed by the microscopic detection of cathepsin K, tartrate resistant acid phosphatase (TRAP, acidic compartments using 3-(2,4-dinitroanillino-3’-amino-N-methyldipropylamine (DAMP, immunological detection of TRAP isoform 5b, and analysis of gene expression of the osteoclastic markers TRAP, cathepsin K, vitronectin receptor, and calcitonin receptor using reverse transcription-polymerase chain reaction (RT-PCR. The feature of the collagen-coated but also of the raw chitosan fibre scaffolds to support attachment and differentiation of human monocytes facilitates cell-induced material resorption – one main requirement for successful bone tissue engineering.

  4. Preparation and properties of polyvinyl acetal sponge modified by chitosan

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The polyvinyl acetal sponge modified by chitosan was prepared by adding chitosan/polyvinyl alcohol (PVA) solution during the acetalation reaction of PVA and formaldehyde.The effect of vesicant and chitosan to the pore morphology,water absorption ratio,water absorption rate,expansion time and mechanical properties were studied.The polyvinyl acetal sponge modified by chitosan was used as a hemostatic packing material for the injured rabbit nasal tissue.The hemostatic effect and the healing effect of the modified sponge on the nasal mucosa after nasal surgery were studied.The results indicated that the polyvinyl acetal sponge modified by chitosan has an interconnected pore structure and the wall between large pores also has small pores.The chitosan adhered on the inner surface of the pores.The increased content of vesicant led to an increase in pore diameter,in the water absorption ratio and in expansion time.However,there was only a small change in the water absorption rate and a decrease in tensile strength and compression strength were noted.With an increase in chitosan content,the pore diameter and interconnection of the sponge was reduced.Water absorption ratio,expansion time and water absorption rate decreased,but tensile strength and compression strength improved.Observation of the rabbit nasal tissue after surgical operation suggested that polyvinyl acetal sponge modified by chitosan has an anti-inflammatory,hemostatic and antiadherent characteristic and could promote the healing and functional recovery of rabbit nasal mucosa.

  5. Crosslinked collagen/chitosan matrix for artificial livers

    NARCIS (Netherlands)

    Wang, X.H.; Li, D.P.; Wang, W.J.; Feng, Q.L.; Cui, F.Z.; Xu, Y.X.; Song, X.H.; Werf, van der Mark

    2003-01-01

    Matrices composed of collagen and chitosan may create an appropriate environment for the regeneration of livers. In this study, we have prepared, characterized and evaluated a new collagen/chitosan matrix (CCM). The CCM was made by using crosslinking agent 1-ethyl-3-(3-dimethylaminopropyl)-carbodiim

  6. Thermal decomposition of natural polysaccharides: Chitin and chitosan

    Directory of Open Access Journals (Sweden)

    Kuchina Yu.A.

    2015-03-01

    Full Text Available The results of the thermal analysis of shrimp’s chitin and chitosan have been presented (samples of polysaccharide differed by the deacetylation degree have been studied. The thermal analysis has been carried out by differential thermogravimetry and differential scanning calorimetry. Activation energy of process of chitin and chitosan thermal destruction has been calculated

  7. Chitosan in food additives and digestive dysfunction treatment

    Czech Academy of Sciences Publication Activity Database

    Kopečný, Jan

    Ancona: PUM, 2007, s. 1-3. [Application of Chitosan in Medical Sciences. Venezia (IT), 25.01.2007-26.01.2007] R&D Projects: GA AV ČR 1QS500200572 Institutional research plan: CEZ:AV0Z50450515 Keywords : chitosan Subject RIV: EE - Microbiology, Virology

  8. Mucoadhesive 4-carboxybenzenesulfonamide-chitosan with antibacterial properties.

    Science.gov (United States)

    Suvannasara, Phruetchika; Juntapram, Kotchakorn; Praphairaksit, Nalena; Siralertmukul, Krisana; Muangsin, Nongnuj

    2013-04-15

    The mucoadhesive property of chitosan, especially in an acidic (chitosan. Four different feeding ratios of 4-carboxybenzensulfonamide (4-CBS) to chitosan in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride as a coupling agent were investigated. The 0.2:1 (w/w) ratio 4-CBS:chitosan revealed a 20-fold stronger mucoadhesion to mucin type II than the native chitosan in the simulated gastric fluid (SGF; pH 1.2), and a swelling ratio after 1 h in water, SGF and simulated intestinal fluid (pH 7.4) of about 2.9-, 3.0- and 3.4-fold higher than that of chitosan, respectively. In tissue culture, the 4-CBS-chitosan, like chitosan, were found to be non-cytotoxic to the Vero, KB, MCF-7 and NCI-H187 cell lines but showed potential antibacterial activity against Escherichia coli and Staphlyococcus aureus as model gram-negative and gram-positive bacteria, respectively. PMID:23544535

  9. Electrosprayed 4-carboxybenzenesulfonamide-chitosan microspheres for acetazolamide delivery.

    Science.gov (United States)

    Suvannasara, Phruetchika; Siralertmukul, Krisana; Muangsin, Nongnuj

    2014-03-01

    4-Carboxybenzensulfonamide-chitosan (4-CBS-chitosan) microspheres were prepared by electrospraying with acetazolamide (ACZ) as a model drug. The obtained 4-CBS-chitosan microspheres with or without ACZ-loading were characterized by Fourier transform infrared spectroscopy, differential scanning colorimetry, scanning electron microscopy and particle size analyses. The crystalline form and the stability of ACZ in a basic solution was determined using X-ray single crystal analysis. 4-CBS-chitosan had 90% encapsulation efficiency for ACZ compared to 47% of encapsulation efficiency (EE) obtained from native chitosan, forming 3.1 μm diameter microspheres with a low polydispersity index (0.4). After an initial burst release (58% in 5 min), ACZ-loaded 4-CBS-chitosan gave a sustained release of ACZ (∼ 100% over 3h) in simulated gastric fluid (0.1N HCl; pH 1.2), which was better than that seen for the release from ACZ-loaded chitosan (44% over 1.5h). Thus, 4-CBS-chitosan microspheres are a possible drug carrier in acidic conditions, such as at the gastric mucosal wall. PMID:24360896

  10. SYNTHESIS AND CHARACTERIZATION OF NEW CHITOSAN-O-ETHYL PHOSPHONATE

    Directory of Open Access Journals (Sweden)

    GLORIA PALMA

    2005-12-01

    Full Text Available The chitin is a natural polymer that is extracted commercially from the shells of crustaceans generated as raw material from the fishing industry. Their chemical structure is constituted by residual units of N-acetyl glucosamine linked by b (1 ® 4 and its derivatives can be obtained from alkaline chitosan. The chitin, chitosan and their derivatives present very good perspectives to be used in agriculture. These derivatives are biodegradable and they exhibit fungicides, germicides, nemacides properties and natural defensive mechanisms of the plants. The chlorophosphonic-2-acid (Ethephon® is a commercial product employed for the early maturation of fruits. The objective of the present work is the synthesis and characterization of chitosan-O-ethyl phosphonate chitosan to obtain a controlled released system with potential plant growth regulation properties. Alkaline chitosan was obtained; and then reacted with the 2-chlorophosphonic acid. The synthesis of new chitosan derivatives and its complete characterization by FT-IR, 13C, ¹H and 31P NMR is described and gas chromatographic, the effects on field blueberries are also tested. A chitosan 99 % deacetylated and Mv = 89,000 g/mol is prepared. The O-(ethyl phosphonic chitosan (QOEP with a degree of substitution of 58% is obtained

  11. The influence of chitosan dietary supplements on fecal microbial population

    Czech Academy of Sciences Publication Activity Database

    Mrázek, Jakub; Fliegerová, Kateřina; Koppová, Ingrid; Šimůnek, Jiří; Kopečný, Jan

    Ancona : PUM, 2007, s. 5-5. [Application of Chitosan in Medical Sciences. Venezia (IT), 25.01.2007-26.01.2007] R&D Projects: GA AV ČR 1QS500200572 Institutional research plan: CEZ:AV0Z50450515 Keywords : chitosan Subject RIV: EE - Microbiology, Virology

  12. Fabrication of chitosan-magnetite nanocomposite strip for chromium removal

    Science.gov (United States)

    Sureshkumar, Vaishnavi; Kiruba Daniel, S. C. G.; Ruckmani, K.; Sivakumar, M.

    2016-02-01

    Environmental pollution caused by heavy metals is a serious threat. In the present work, removal of chromium was carried out using chitosan-magnetite nanocomposite strip. Magnetite nanoparticles (Fe3O4) were synthesized using chemical co-precipitation method at 80 °C. The nanoparticles were characterized using UV-visible spectroscopy, fourier transform infrared spectroscopy, X-ray diffraction spectrometer, atomic force microscope, dynamic light scattering and vibrating sample magnetometer, which confirm the size, shape, crystalline nature and magnetic behaviour of nanoparticles. Atomic force microscope revealed that the particle size was 15-30 nm and spherical in shape. The magnetite nanoparticles were mixed with chitosan solution to form hybrid nanocomposite. Chitosan strip was casted with and without nanoparticle. The affinity of hybrid nanocomposite for chromium was studied using K2Cr2O7 (potassium dichromate) solution as the heavy metal solution containing Cr(VI) ions. Adsorption tests were carried out using chitosan strip and hybrid nanocomposite strip at different time intervals. Amount of chromium adsorbed by chitosan strip and chitosan-magnetite nanocomposite strip from aqueous solution was evaluated using UV-visible spectroscopy. The results confirm that the heavy metal removal efficiency of chitosan-magnetite nanocomposite strip is 92.33 %, which is higher when compared to chitosan strip, which is 29.39 %.

  13. Characterisation of chitosan solubilised in aqueous formic and acetic acids

    OpenAIRE

    Esam A. El-Hefian

    2009-01-01

    The intrinsic viscosity of chitosan (MW 7.9 x 105 g mol-1) having a high degree of deacetylation and solubilised in aqueous formic and acetic acids was determined at room temperature. Contact angle and conductivity of the chitosan solutions were also studied. The values of critical coagulation concentration (CCC) were then obtained from the plots of contact angle or conductivity versus concentration.

  14. Migration of canine neutrophils to chitin and chitosan.

    Science.gov (United States)

    Usami, Y; Okamoto, Y; Minami, S; Matsuhashi, A; Kumazawa, N H; Tanioka, S; Shigemasa, Y

    1994-12-01

    Suspension of chitin and chitosan particles (mean size of 1 micron) were found to attract canine neutrophils chemotactically as determined by a checkerboard assay through polycarbonate filter with 5 microns pore size in Blind well chamber. Suspension of chitin induced chemokinetic migrations of the neutrophils. These evidences might reflect accumulation of neutrophils to chitin- and chitosan-implanted regions in dogs. PMID:7696425

  15. Studies on electrospun nylon-6/chitosan complex nanofiber interactions

    International Nuclear Information System (INIS)

    Composite membranes of nylon-6/chitosan nanofibers with different weight ratio of nylon-6 to chitosan were fabricated successfully using electrospinning. Morphologies of the nanofibers were investigated by scanning electron microscopy (SEM) and the intermolecular interactions of the nylon-6/chitosan complex were evaluated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) as well as mechanical testing. We found that morphology and diameter of the nanofibers were influenced by the concentration of the solution and weight ratio of the blending component materials. Furthermore FT-IR analyses on interactions between components demonstrated an IR band frequency shift that appeared to be dependent on the amount of chitosan in the complex. Observations from XRD and DSC suggested that a new fraction of γ phase crystals appeared and increased with the increasing content of chitosan in blends, this indicated that intermolecular interactions occurred between nylon-6 and chitosan. Results from performance data in mechanical showed that intermolecular interactions varied with varying chitosan content in the fibers. It was concluded that a new composite product was created and the stability of this system was attributed to strong new interactions such as hydrogen bond formation between the nylon-6 polymers and chitosan structures.

  16. Antimicrobial and physicochemical properties of chitosan-HPMC-based films.

    Science.gov (United States)

    Möller, Heike; Grelier, Stéphane; Pardon, Patrick; Coma, Véronique

    2004-10-20

    To prepare composite films from biopolymers with anti-listerial activity and moisture barrier properties, the antimicrobial efficiency of chitosan-hydroxy propyl methyl cellulose (HPMC) films, chitosan-HPMC films associated with lipid, and chitosan-HPMC films chemically modified by cross-linking were evaluated. In addition, the physicochemical properties of composite films were evaluated to determine their potential for food applications. The incorporation of stearic acid into the composite chitosan-HPMC film formulation decreased water sensitivity such as initial solubility in water and water drop angle. Thus, cross-linking of composite chitosan-HPMC, using citric acid as the cross-linking agent, led to a 40% reduction in solubility in water. The water vapor transfer rate of HPMC film, approximately 270 g x m(-2) x day(-1) x atm(-1), was improved by incorporating chitosan and was further reduced 40% by the addition of stearic acid and/or cross-linking. Anti-listerial activity of films was determined on solid medium by a numeration technique. Chitosan-HPMC-based films, with and without stearic acid, inhibited the growth of Listeria monocytogenes completely. On the other hand, a loss of antimicrobial activity after chemical cross-linking modification was observed. FTIR and 13C NMR analyses were then conducted in order to study a potential chemical modification of biopolymers such as a chemical reaction with the amino group of chitosan. To complete the study, the mechanical properties of composite films were determined from tensile strength assays. PMID:15479027

  17. Air plasma treated chitosan fibers-stacked scaffolds

    International Nuclear Information System (INIS)

    Chitosan is a nontoxic, biodegradable and biocompatible polymer. Rapid prototyped chitosan scaffolds were manufactured by liquid-frozen deposition of chitosan fibers in this study. To investigate if the air plasma (AP) treatment could be used to improve the surface properties of these scaffolds for cell attachment, chitosan films were first prepared and treated with AP under different conditions. Under the optimized condition, the water contact angle of chitosan films was significantly reduced from 90 ± 1° to 19 ± 1° after AP treatment. On the other hand, the surface charge and nanometric roughness of chitosan films increased after AP treatment. X-ray photoelectron spectroscopy measurement on AP-treated three-dimensional chitosan scaffolds showed that nitrogen and oxygen increased at each location inside the scaffolds as compared to the untreated ones, which indicated that AP could permeate through the fibrous stacks of the scaffolds and effectively modify the interior (visible) surface of the scaffolds. Moreover, AP treatment enabled the migration of MC3T3-E1 cells into the scaffolds, facilitated their proliferation and promoted the bone mineral deposition. These results suggested that fibers-stacked chitosan scaffolds may be produced by liquid-frozen deposition and treated with AP for bone tissue engineering applications. (paper)

  18. Synthesis and Characterization of Oil-Chitosan Composite Spheres

    Directory of Open Access Journals (Sweden)

    Wei-Ting Wang

    2013-05-01

    Full Text Available Oil-chitosan composite spheres were synthesized by encapsulation of sunflower seed oil in chitosan droplets, dropping into NaOH solution and in situ solidification. Hydrophilic materials (i.e., iron oxide nanoparticles and lipophilic materials (i.e., rhodamine B or epirubicin could be encapsulated simultaneously in the spheres in a one step process. The diameters of the prepared spheres were 2.48 ± 0.11 mm (pure chitosan spheres, 2.31 ± 0.08 mm (oil-chitosan composites, 1.49 ± 0.15 mm (iron-oxide embedded oil-chitosan composites, and 1.69 ± 0.1 mm (epirubicin and iron oxide encapsulated oil-chitosan composites, respectively. Due to their superparamagnetic properties, the iron-oxide embedded oil-chitosan composites could be guided by a magnet. A lipophilic drug (epirubicin could be loaded in the spheres with encapsulation rate measured to be 72.25%. The lipophilic fluorescent dye rhodamine B was also loadable in the spheres with red fluorescence being observed under a fluorescence microscope. We have developed a novel approach to an in situ process for fabricating oil-chitosan composite spheres with dual encapsulation properties, which are potential multifunctional drug carriers.

  19. Synthesis and characterization of oil-chitosan composite spheres.

    Science.gov (United States)

    Huang, Keng-Shiang; Wang, Chih-Yu; Yang, Chih-Hui; Grumezescu, Alexandru Mihai; Lin, Yung-Sheng; Kung, Chao-Pin; Lin, I-Yin; Chang, Yi-Ching; Weng, Wei-Jie; Wang, Wei-Ting

    2013-01-01

    Oil-chitosan composite spheres were synthesized by encapsulation of sunflower seed oil in chitosan droplets, dropping into NaOH solution and in situ solidification. Hydrophilic materials (i.e., iron oxide nanoparticles) and lipophilic materials (i.e., rhodamine B or epirubicin) could be encapsulated simultaneously in the spheres in a one step process. The diameters of the prepared spheres were 2.48 ± 0.11 mm (pure chitosan spheres), 2.31 ± 0.08 mm (oil-chitosan composites), 1.49 ± 0.15 mm (iron-oxide embedded oil-chitosan composites), and 1.69 ± 0.1 mm (epirubicin and iron oxide encapsulated oil-chitosan composites), respectively. Due to their superparamagnetic properties, the iron-oxide embedded oil-chitosan composites could be guided by a magnet. A lipophilic drug (epirubicin) could be loaded in the spheres with encapsulation rate measured to be 72.25%. The lipophilic fluorescent dye rhodamine B was also loadable in the spheres with red fluorescence being observed under a fluorescence microscope. We have developed a novel approach to an in situ process for fabricating oil-chitosan composite spheres with dual encapsulation properties, which are potential multifunctional drug carriers. PMID:23681059

  20. Biopolymers produced from gelatin and chitosan using polyphenols

    Science.gov (United States)

    Chitin, and its derivative chitosan, is an abundant waste product derived from crustaceans (e.g. crab). It has unique properties which enable its use in, but not limited to, cosmetic, medical, and food applications. Chitosan has recently been studied, in conjunction with other waste carbohydrates ...

  1. The effect of chitosan on blood parameters of healthy humans

    Czech Academy of Sciences Publication Activity Database

    Fliegerová, Kateřina; Šimůnek, Jiří; Koppová, Ingrid; Mrázek, Jakub; Kopečný, Jan

    Ancona : PUM, 2007, s. 8-8. [Application of Chitosan in Medical Sciences. Venezia (IT), 25.01.2007-26.01.2007] R&D Projects: GA AV ČR 1QS500200572 Institutional research plan: CEZ:AV0Z50450515 Keywords : chitosan Subject RIV: EE - Microbiology, Virology

  2. Some biomedical applications of chitosan-based hybrid nanomaterials

    International Nuclear Information System (INIS)

    Being naturally abundant resources and having many interesting physicochemical and biological properties, chitin/chitosan have been found to be useful in many fields, especially biomedical ones. This paper describes the strategy to design multifunctional, hybrid chitosan-based nanomaterials and test them in some typical biomedical applications

  3. Physicochemical characterisation of β-chitosan from Sepioteuthis lessoniana gladius.

    Science.gov (United States)

    Subhapradha, Namasivayam; Ramasamy, Pasiyappazham; Shanmugam, Vairamani; Madeswaran, Perumal; Srinivasan, Alagiri; Shanmugam, Annaian

    2013-11-15

    β-Chitin and its chitosan from the gladius of Sepioteuthis lessoniana have been isolated, purified, characterised and compared with the commercial chitosan. Ash, moisture, mineral, metal and elemental content were analyzed using standard techniques. The optical activity of chitin was found to be levorotatory. The degree of deacetylation was calculated by potentiometric titration and (1)H NMR. Viscosity average molecular weight of β-chitosan was calculated by viscometry and size average molecular weight by GPC. The structure of β-chitosan was elucidated with FT-IR and NMR. Thermal nature, crystalline structure and morphology of β-chitosan were characterised through DSC, XRD and SEM, respectively. The water and fat binding capacity of β-chitosan presently studied was significantly higher than that of the commercial chitosan. The result of the present study adds that S. lessoniana gladius is also an additional source of β-chitin and chitosan of higher yield, lower molecular weight and higher degree of deacetylation. PMID:23790866

  4. Preparation and Characterization of Chitosan/Agar Blended Films: Part 2. Thermal, Mechanical, and Surface Properties

    OpenAIRE

    Elhefian, Esam. A.; Mohamed Mahmoud NASEF; Yahaya, Abdul Hamid

    2012-01-01

    Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar (considering chitosan as the major component) in solution forms. The thermal stability of the blended films was studied using thermal gravimetric analysis (TGA). It was revealed that chitosan and agar form a compatible blend. Studying the mechanical properties of the films showed a decrease in the tensile strength and elongation at break with increasing agar content. Blending of agar with chitosan...

  5. In Vivo Biocompatibility Study of Electrospun Chitosan Microfiber for Tissue Engineering

    OpenAIRE

    Moon Suk Kim; Young Hwan Park; Chun Ho Kim; Heung Jae Chun; Jae Ho Kim; Da Yeon Kim; Kkot Nim Kang; Gyeong Hae Kim; Jae Hoon Ko; Bit Na Lee; Yun Mi Kang

    2010-01-01

    In this work, we examined the biocompatibility of electrospun chitosan microfibers as a scaffold. The chitosan microfibers showed a three-dimensional pore structure by SEM. The chitosan microfibers supported attachment and viability of rat muscle-derived stem cells (rMDSCs). Subcutaneous implantation of the chitosan microfibers demonstrated that implantation of rMDSCs containing chitosan microfibers induced lower host tissue responses with decreased macrophage accumulation than did the chitos...

  6. Incorporation of copper into chitosan scaffolds promotes bone regeneration in rat calvarial defects

    OpenAIRE

    D'Mello, Sheetal; Elangovan, Satheesh; Hong, Liu; Ross, Ryan D.; Sumner, D. Rick; Salem, Aliasger K.

    2014-01-01

    The objective of this study was to investigate the effects of a copper loaded chitosan scaffold on bone regeneration in critical-sized calvarial defects in rats. Chitosan scaffolds and copper-chitosan scaffolds were fabricated and characterized by scanning electron microscopy (SEM). Chitosan and copper-chitosan scaffolds were implanted into 5 mm diameter critical-sized calvarial defects in Fisher 344 male rats. Empty defects (no scaffolds) were included as a control. After 4 weeks, the rats w...

  7. Biomedical-Grade Chitosan in Wound Management and Its Biocompatibility In Vitro

    OpenAIRE

    Halim, Ahmad Sukari; Lim, Chin Keong

    2010-01-01

    Chitosan and chitosan-based derivatives have various medical applications. It is wellknown that chitosan possesses medicinal properties that accelerate wound healing and tissue regeneration. Chitosan is a natural product. It is biocompatible and biodegradable, enabling it to be used for wound dressing material. However, the practical use of chitosan is restricted to the unmodified forms, as these are water-insoluble and have high viscosity and the tendency to coagulate with proteins at high p...

  8. Antimicrobial Actions of Degraded and Native Chitosan against Spoilage Organisms in Laboratory Media and Foods

    OpenAIRE

    Rhoades, J.; Roller, S

    2000-01-01

    The objective of this study was to determine whether chitosan (poly-β-1,4-glucosamine) and hydrolysates of chitosan can be used as novel preservatives in foods. Chitosan was hydrolyzed by using oxidative-reductive degradation, crude papaya latex, and lysozyme. Mild hydrolysis of chitosan resulted in improved microbial inactivation in saline and greater inhibition of growth of several spoilage yeasts in laboratory media, but highly degraded products of chitosan exhibited no antimicrobial activ...

  9. Mechanism Study on Flocculating Organnic Pollutants By Chitosan with Different Molecular In Wastewater

    OpenAIRE

    Zeng De-fang

    2013-01-01

    This paper presents the effect of the molecular weight of chitosan on flocculation of simulation sewage. The flocculation process of different chitosan samples were analyzed in different deacetylation degree, dosage and pH. The different molecular weight of chitosan samples and simulation sewage were all laboratories homemade. The flocculating effects of chitosan increases with the increase of deacetylation degree; the flocculating effects of chitosan decreases with the increase of viscosity-...

  10. Development and Characterization of Novel Films Based on Sulfonamide-Chitosan Derivatives for Potential Wound Dressing

    OpenAIRE

    Oana Maria Dragostin; Sangram Keshari Samal; Florentina Lupascu; Andreea Pânzariu; Peter Dubruel; Dan Lupascu; Cristina Tuchilus; Cornelia Vasile; Lenuta Profire

    2015-01-01

    The objective of this study was to develop new films based on chitosan functionalized with sulfonamide drugs (sulfametoxydiazine, sulfadiazine, sulfadimetho-xine, sulfamethoxazol, sulfamerazine, sulfizoxazol) in order to enhance the biological effects of chitosan. The morphology and physical properties of functionalized chitosan films as well the antioxidant effects of sulfonamide-chitosan derivatives were investigated. The chitosan-derivative films showed a rough surface and hydrophilic prop...

  11. Kinetic of Th ions adsorption process in the magnetic chitosan

    International Nuclear Information System (INIS)

    A magnetic bio absorbent called chitosan was prepared and it potentiality for removal Th ions in nitric medium was verified. The chitosan is a derivative processed from crustacean shells which is a fishing residue. The adsorption studies were accomplished by essays in batch. The equilibrium time was determined for the concentration of Th 101,4 mg L-1 and the kinetic of equilibrium was analysed according to the pseudo-first order, pseudo-second order and intra particle diffusion models. A removal of 35 % by adsorption was observed to confirm that the magnetic chitosan posses a considerable potential as Th absorbent. The magnetic use of chitosan can contribute in the economic and environmental aspects, viewing the low cost of chitosan and the strategies application of control of fishing activity residues and radionuclides with development of a sustainable technology

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  13. A mechanistic based approach for enhancing buccal mucoadhesion of chitosan

    DEFF Research Database (Denmark)

    Meng-Lund, Emil; Muff-Westergaard, Christian; Sander, Camilla;

    2014-01-01

    Mucoadhesive buccal drug delivery systems can enhance rapid drug absorption by providing an increased retention time at the site of absorption and a steep concentration gradient. An understanding of the mechanisms behind mucoadhesion of polymers, e.g. chitosan, is necessary for improving the...... mucoadhesiveness of buccal formulations. The interaction between chitosan of different chain lengths and porcine gastric mucin (PGM) was studied using a complex coacervation model (CCM), isothermal titration calorimetry (ITC) and a tensile detachment model (TDM). The effect of pH was assessed in all three models...... and the approach to add a buffer to chitosan based drug delivery systems is a means to optimize and enhance buccal drug absorption. The CCM demonstrated optimal interactions between chitosan and PGM at pH 5.2. The ITC experiments showed a significantly increase in affinity between chitosan and PGM at...

  14. PREPARATION AND PROPERTIES OF CHITOSAN/LIGNIN COMPOSITE FILMS

    Institute of Scientific and Technical Information of China (English)

    Long Chen; Chang-yu Tang; Nan-ying Ning; Chao-yu Wang; Qiang Fu; Qin Zhang

    2009-01-01

    Biodegradable composite films based on chitosan and lignin with various composition were prepared via the solution-casting technique.FT-IR results indicate the existence of hydrogen bonding between chitosan and lignin,and SEM images show that lignin could be well dispersed in chitosan when the content of lignin is below 20 wt% due to the strong interfacial interaction.As a result of strong interaction and good dispersion,the tensile strength,storage modulus,thermal degradation temperature and glass transition temperature of chitosan have been largely improved by adding lignin.Our work provides a simple and cheap way to prepare fully biodegradable chitosan/lignin composites,which could be used as packaging films or wound dressings.

  15. A Coarse-Grained Model for Simulating Chitosan Hydrogels

    Science.gov (United States)

    Xu, Hongcheng; Matysiak, Silvina

    Hydrogels are biologically-derived materials composed of water-filled cross-linking polymer chains. It has widely been used as biodegradable material and has many applications in medical devices. The chitosan hydrogel is stimuli-responsive for undergoing pH-sensitive self-assembly process, allowing programmable tuning of the chitosan deposition through electric pulse. To explore the self-assembly mechanism of chitosan hydroge, we have developed an explicit-solvent coarse-grained chitosan model that has roots in the MARTINI force field, and the pH change is modeled by protonating chitosan chains using the Henderson-Hasselbalch equation. The mechanism of hydrogel network formation will be presented. The self-assembled polymer network qualitatively reproduce many experimental observables such as the pH-dependent strain-stress curve, bulk moduli, and structure factor. Our model is also capable of simulating other similar polyelectrolyte polymer systems.

  16. Antimicrobial coating of modified chitosan onto cotton fabrics

    Science.gov (United States)

    Cheng, Xiaoli; Ma, Kaikai; Li, Rong; Ren, Xuehong; Huang, T. S.

    2014-08-01

    Chitosan has been applied as an antibacterial agent to provide biocidal function for textiles but has limitations of application condition and durability. In this study, a new N-halamine chitosan derivative was synthesized by introducing N-halamine hydantoin precursor. The synthesized chitosan derivative 1-Hydroxymethyl-5,5-dimethylhydantoin chitosan (chitosan-HDH) was coated onto cotton fabric with 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent. The coatings were characterized and confirmed by FT-IR and SEM. The treated cotton fabrics can be rendered excellent antimicrobial activity upon exposure to dilute household bleach. The chlorinated coated swatches can inactivate 100% of the Staphylococcus aureus and E. coli O157:H7 with a contact time of 5 min. Almost all the lost chlorine after a month of storage could be recharged upon rechlorination. The crease recovery property of the treated swatches improved while the breaking strength decreased compared with uncoated cotton.

  17. Characterization and bacterial adhesion of chitosan-perfluorinated acid films.

    Science.gov (United States)

    Bierbrauer, Karina L; Alasino, Roxana V; Muñoz, Adrián; Beltramo, Dante M; Strumia, Miriam C

    2014-02-01

    We reported herein the study and characterization of films obtained by casting of chitosan solutions in perfluorinated acids, trifluoroacetic (TFA), perfluoropropionic (PFPA), and perfluorooctanoic (PFOA). The films were characterized by FTIR, solid state (13)C NMR, X-ray, AFM, contact angle, thermogravimetric effluent analysis by mass spectrometry, and rheology. The results showed a marked influence of chain length of the perfluorinated acids on the hydrophobic/hydrophilic ratio of the modified chitosan films which was evidenced by the different characteristics observed. The material that showed greater surface stability was chitosan-PFOA. Chitosan film with the addition of PFOA modifier became more hydrophobic, thus water vapor permeability diminished compared to chitosan films alone, this new material also depicted bacterial adhesion which, together with the features already described, proves its potential in applications for bioreactor coating. PMID:24189195

  18. The production of fully deacetylated chitosan by compression method

    Directory of Open Access Journals (Sweden)

    Xiaofei He

    2016-03-01

    Full Text Available Chitosan’s activities are significantly affected by degree of deacetylation (DDA, while fully deacetylated chitosan is difficult to produce in a large scale. Therefore, this paper introduces a compression method for preparing 100% deacetylated chitosan with less environmental pollution. The product is characterized by XRD, FT-IR, UV and HPLC. The 100% fully deacetylated chitosan is produced in low-concentration alkali and high-pressure conditions, which only requires 15% alkali solution and 1:10 chitosan powder to NaOH solution ratio under 0.11–0.12 MPa for 120 min. When the alkali concentration varied from 5% to 15%, the chitosan with ultra-high DDA value (up to 95% is produced.

  19. Degradation of chitosan by synergetic treatment of irradiation and chemical

    International Nuclear Information System (INIS)

    The degradation of solid state chitosan by irradiation at solid state and synergetic method were investigated in this paper. Four factors which affect the degradation effect of chitosan: irradiation, H2O2 concentration, the ratio of solvent and solute (volum/weight), acetic acid were analyzed. The first three were measured by multiple comparisons of the different level and variance analysis, and infrared spectroscopy was employed to analyze check the degradation products. It is concluded that chitosan's viscosity, and average molecular weight was decreased from 8.7 x 105 to 104 at the condition of 15% H2O2, HAc1.5%, 4:1 H2O2 solution/chitosan, 110 kGy irradiation, and the chemical structure of treat chitosan products was almost no changed. (authors)

  20. Preparation and mechanical properties of chitosan/carbon nanotubes composites.

    Science.gov (United States)

    Wang, Shao-Feng; Shen, Lu; Zhang, Wei-De; Tong, Yue-Jin

    2005-01-01

    Biopolymer chitosan/multiwalled carbon nanotubes (MWNTs) nanocomposites have been successfully prepared by a simple solution-evaporation method. The morphology and mechanical properties of the chitosan/MWNTs nanocomposites have been characterized with field emission scanning electron microscopy (SEM), bright field transmission electron microscopy (TEM), optical microscopy (OM), wide-angle X-ray diffraction (XRD), and tensile as well as nanoindentation tests. The MWNTs were observed to be homogeneously dispersed throughout the chitosan matrix. When compared with neat chitosan, the mechanical properties, including the tensile modulus and strength, of the nanocomposites are greatly improved by about 93% and 99%, respectively, with incorporation of only 0.8 wt % of MWNTs into the chitosan matrix. PMID:16283728

  1. Dairy Wastewater Treatment Using Low Molecular Weight Crab Shell Chitosan

    Science.gov (United States)

    Geetha Devi, M.; Dumaran, Joefel Jessica; Feroz, S.

    2012-08-01

    The investigation of possible use of low molecular weight crab shell chitosan (MW 20 kDa) in the treatment of dairy waste water was studied. Various experiments have been carried out using batch adsorption technique to study the effects of the process variables, which include contact time, stirring speed, pH and adsorbent dosage. Treated effluent characteristics at optimum condition showed that chitosan can be effectively used as adsorbent in the treatment of dairy wastewater. The optimum conditions for this study were at 150 mg/l of chitosan, pH 5 and 50 min of mixing time with 50 rpm of mixing speed. Chitosan showed the highest performance under these conditions with 79 % COD, 93 % turbidity and 73 % TSS reduction. The result showed that chitosan is an effective coagulant, which can reduce the level of COD, TSS and turbidity in dairy industry wastewater.

  2. Chitosan as flocculant agent for clarification of stevia extract

    Directory of Open Access Journals (Sweden)

    Silvia P. D. de Oliveira

    2012-01-01

    Full Text Available Stevia is used as a sweetener due to its low calorific value and its taste, which is very similar to that of sucrose. After extraction from dried leaves, stevia extract is dark in colour, and therefore needs to be whitened to increase acceptance by consumers. In this study we tested chitosan, a cationic polyelectrolyte, as flocculant agent for the whitening of the Stevia extract. Positive charges of chitosan can interact electrostatically with a counter-ion, sodium tripolyphosphate (TPP, and then chitosan precipitates. A factorial design was used to study the whitening process, in which Glycosides Removal, Colour Removal, Turbidity Removal and Soluble Solids Removal were evaluated. The studied factors were Chitosan Mass and pH of the TPP solution. The results showed that chitosan is a good flocculant agent, being able to flocculate both the glycosides and the pigments that make the extract coloured.

  3. Chitosan magnetic microspheres for technological applications: Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Podzus, P.E. [Grupo de Aplicaciones de Materiales Biocompatibles, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires. Paseo Colon 850, C1063ACV Buenos Aires (Argentina); LAFMACEL, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires. Paseo Colon 850, C1063ACV Buenos Aires (Argentina); Daraio, M.E., E-mail: medit@fi.uba.a [Grupo de Aplicaciones de Materiales Biocompatibles, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires. Paseo Colon 850, C1063ACV Buenos Aires (Argentina); Jacobo, S.E., E-mail: sjacobo@fi.uba.a [LAFMACEL, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires. Paseo Colon 850, C1063ACV Buenos Aires (Argentina)

    2009-10-01

    One of the major applications of chitosan and its many derivatives are based on its ability to bind strongly heavy and toxic metal ions. In this study chitosan magnetic microspheres have been synthesized. Acetic acid (1%w/v) solution was used as solvent for the chitosan polymer solution (2%w/v) where magnetite nanoparticles were suspended in order to obtain a stable ferrofluid. Glutaraldehyde was used as cross-linker. The magnetic characteristic of these materials allows an easy removal after use if is necessary. The morphological characterization of the microspheres shows that they can be produced in the size range 800-1100 mum. The adsorption of Cu(II) onto chitosan-magnetite nanoparticles was studied in batch system. A second-order kinetic model was used to fit the kinetic data, leading to an equilibrium adsorption capacity of 19 mg Cu/g chitosan.

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

    International Nuclear Information System (INIS)

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

  5. Antifungal Effect of Chitosan as Ca(2+) Channel Blocker.

    Science.gov (United States)

    Lee, Choon Geun; Koo, Ja Choon; Park, Jae Kweon

    2016-06-01

    The aim of this study was to investigate antifungal activity of a range of different molecular weight (MW) chitosan against Penicillium italicum. Our results demonstrate that the antifungal activity was dependent both the MW and concentration of the chitosan. Among a series of chitosan derived from the hydrolysis of high MW chitosan, the fractions containing various sizes of chitosan ranging from 3 to 15 glucosamine units named as chitooligomers-F2 (CO-F2) was found to show the highest antifungal activity against P. italicum. Furthermore, the effect of CO-F2 toward this fungus was significantly reduced in the presence of Ca(2+), whereas its effect was recovered by ethylenediaminetetraacetic acid, suggesting that the CO-F2 acts via disruption of Ca(2+) gradient required for survival of the fungus. Our results suggest that CO-F2 may serve as potential compounds to develop alternatives to synthetic fungicides for the control of the postharvest diseases. PMID:27298599

  6. Antifungal Effect of Chitosan as Ca2+ Channel Blocker

    Science.gov (United States)

    Lee, Choon Geun; Koo, Ja Choon; Park, Jae Kweon

    2016-01-01

    The aim of this study was to investigate antifungal activity of a range of different molecular weight (MW) chitosan against Penicillium italicum. Our results demonstrate that the antifungal activity was dependent both the MW and concentration of the chitosan. Among a series of chitosan derived from the hydrolysis of high MW chitosan, the fractions containing various sizes of chitosan ranging from 3 to 15 glucosamine units named as chitooligomers-F2 (CO-F2) was found to show the highest antifungal activity against P. italicum. Furthermore, the effect of CO-F2 toward this fungus was significantly reduced in the presence of Ca2+, whereas its effect was recovered by ethylenediaminetetraacetic acid, suggesting that the CO-F2 acts via disruption of Ca2+ gradient required for survival of the fungus. Our results suggest that CO-F2 may serve as potential compounds to develop alternatives to synthetic fungicides for the control of the postharvest diseases. PMID:27298599

  7. Chitosan magnetic microspheres for technological applications: Preparation and characterization

    International Nuclear Information System (INIS)

    One of the major applications of chitosan and its many derivatives are based on its ability to bind strongly heavy and toxic metal ions. In this study chitosan magnetic microspheres have been synthesized. Acetic acid (1%w/v) solution was used as solvent for the chitosan polymer solution (2%w/v) where magnetite nanoparticles were suspended in order to obtain a stable ferrofluid. Glutaraldehyde was used as cross-linker. The magnetic characteristic of these materials allows an easy removal after use if is necessary. The morphological characterization of the microspheres shows that they can be produced in the size range 800-1100 μm. The adsorption of Cu(II) onto chitosan-magnetite nanoparticles was studied in batch system. A second-order kinetic model was used to fit the kinetic data, leading to an equilibrium adsorption capacity of 19 mg Cu/g chitosan.

  8. Synthesis, characterization, and antifungal activity of novel quaternary chitosan derivatives.

    Science.gov (United States)

    Li, Rongchun; Guo, Zhanyong; Jiang, Pingan

    2010-09-01

    Three novel quaternary chitosan derivatives were successfully synthesized by reaction of chloracetyl chitosan (CACS) with pyridine (PACS), 4-(5-chloro-2-hydroxybenzylideneamino)-pyridine (CHPACS), and 4-(5-bromo-2-hydroxybenzylideneamino)-pyridine (BHPACS). The chemical structure of the prepared chitosan derivatives was confirmed by Fourier transform infrared (FT-IR) and (13)C nuclear magnetic resonance ((13)C NMR) and their antifungal activity against Cladosporium cucumerinum, Monilinia fructicola, Colletotrichum lagenarium, and Fusarium oxysporum was assessed. Comparing with the antifungal activity of chitosan, CACS, and PACS, CHPACS and BHPACS exhibited obviously better inhibitory effects, which should be related to the synergistic reaction of chitosan itself with the grafted 2-[4-(5-chloro-2-hydroxybenzylideneamino)-pyridyl]acetyl and 2-[4-(5-bromo-2-hydroxybenzylideneamino)-pyridyl]acetyl. PMID:20615498

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

    Directory of Open Access Journals (Sweden)

    Abu Bakar Mohd Hilmi

    2013-01-01

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

  10. Chitosan and reinforced Chitosan films for the removal of Cr(VI heavy metal from synthetic aqueous solution

    Directory of Open Access Journals (Sweden)

    Sibi Srinivasan

    2016-05-01

    Full Text Available Cr(VI is removed efficiently from aqueous solution using Chitosan made films as the adsorbent. The efficiency of free Chitosan films is compared with the Chitosan-Silica and Chitosan-Carbon, which are reinforced with biogenic Silica and Carbon obtained from Panicum miliare husk ashes, respectively. All the films were prepared by simple ageing method and swelling index was determined for all the three adsorbents independently. Adsorption studies of Cr(VI heavy metal were carried out by varying pH, temperature, initial concentration of the adsorbate and quantity of adsorbent. On the otherhand, Cr(VI was removed from the solution by Chitosan-Silica film better than free Chitosan and Chitosan-Carbon films. The optimum pH was found to be 3.0 and optimum temperature was 30°C. Thermodynamic, equilibrium and kinetic studies were carried out for all the three adsorbents, independently. Langmuir adsorption isotherm and Pseudo First Order kinetics were followed for the adsorption process. Concentration of metal ions was determined using a spectrophotometer. Oxidation states of the adsorbed Cr were determined by ESR. It was found that Chitosan-Silica film reduced Cr(VI to Cr(III almost completely in the aqueous solution.

  11. Effect of the incorporation of sulfonated chitosan/sulfonated graphene oxide on the proton conductivity of chitosan membranes

    Science.gov (United States)

    Shirdast, Abbas; Sharif, Alireza; Abdollahi, Mahdi

    2016-02-01

    Chitosan biopolymer (CS) has been attracting considerable interest as polymer electrolyte in fuel cells. However, proton conductivity of chitosan is low and it is necessary to enhance its conductivity. In this work, 10 wt% sulfonated chitosan (SCS) and different amounts of sulfonated graphene oxide (SGO) nanosheets are incorporated into a chitosan membrane to investigate their effects on the electrochemical properties of the membrane. The proton conductivity and methanol permeability tests conducted on the CS/SCS/SGO membranes show that the conductivity is increased by 454%, the permeability is reduced by 23% and hence the selectivity is increased by 650%, relative to the neat chitosan, at SGO content of 5 wt%. Furthermore, combined addition of SCS and SGO to chitosan causes much more proton conductivity enhancement than the individual additives due to the synergistic effect of SCS and SGO. The observed synergistic effect reveals the importance of the chemical functionality of chitosan and nanofillers in the formation of ionic cluster domains with enhanced size within the membranes for proton transport. Finally, a Nernst-Planck based model is applied to the experimental proton conductivity data in order to shed more light on the role of GOs in the proton conductivity mechanism of chitosan.

  12. SOLID-STATE FERMENTATIVE PRODUCTION AND BIOACTIVITY OF FUNGAL CHITOSAN

    Directory of Open Access Journals (Sweden)

    Barry Aigbodion Omogbai

    2013-10-01

    Full Text Available Chitosan production was investigated using a laboratory-scale solid substrate fermentation (SSF technique with four species of fungi: Penicillium expansum, Aspergillus niger, Rhizopus oryzae and Fusarium moniliforme.The peak growth for the organisms was after 16 days. Aspergillus niger had the highest growth with a maximal dry cell biomass of 15.8g/kg after 16 days cultivation on corn straw under solid substrate fermentation. This was closely followed by Rhizopus oryzae (14.6g/kg, Penicillium expansum (13.8g/kg and Fusarium moniliforme (10.6g/kg respectively. The fungus Rhizopus oryzae had the highest chitosan production with a maximum of 8.57g/kg in 16 days under solid substrate fermentation (SSF with a medium containing corn straw. Aspergillus niger showed a modest chitosan yield of 6.8g/kg. Penicillium expansum and Fusarium moniliforme had low chitosan yields of 4.31g/kg and 3.1g/kg respectively. The degree of deacetylation of fungal chitosans ranged between 75.3-91.5% with a viscosity of 3.6-7.2 centipoises (Cp.Chitosan extracted from Rhizopus oryzae was found to have antibacterial activity on some bacterial isolates. At a concentration of 50mg/L, Rhizopus oryzae chitosan paralleled crab chitosan in susceptibility testing against some food-borne bacterial pathogens. Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and Bacillus subtilis showed inhibition rates of 83.2%, 67.9%, 63.8% and 62.4% respectively in response to 50mg/l Rhizopus oryzae chitosan in 24 h. The rate of inhibition (% increased with increase in chitosan concentration.

  13. Characterization and electrical properties of chitosan for waste water treatment

    Science.gov (United States)

    Saengkaew, Phannee; Chantanachai, Kanittha; Cheewajaroen, Kulthawat; Nimsiri, Woraporn

    2016-05-01

    Chitosan extracted from shrimp shell waste was characterized in order to use for the industrial wastewater treatment. By XRF technique, the qualitative and semi-quantitative analyses of pure chitosan were performed with the relative compositions of Ca, Mg, Si, Fe, Al, and Na of 0.321%, 0.738%, 0.713%, 0.363%, 0.338%, and 3.858%, respectively. In the case of two types of the contaminated chitosan from the wastewater treatment before and after a process of a primary H2O2-treatment, the relative compositions of Ca, Mg, Si and Fe were obtained with an increasing of 0.356%, 1.321%, 1.536%, 0.451% and 0.406%, 1.105%, 1.178%, 0.591%, respectively. This shows that the suspended materials in the wastewater were absorbed by chitosan. By I-V Measurements, the across-through voltage of the pure chitosan disc was 0.245V±0.053 at the applied voltage of 17V, and resistance of 53.9MΩ ±10.3 at the applied voltage of 590V. After the utilization for the wastewater treatment, the across voltage of chitosan discs from two cases were 0.133V±0.047 and 0.223V±0.063, and the resistance of 122.8MΩ ±16.1 and 24.8MΩ ±5.1. The used chitosan has a lower conductivity because of a decreasing in the chitosan's electrical dipoles by combining with the suspended ions in the wastewater. Moreover, the adsorption efficiencies of chitosan for formaldehyde in the wastewater of two cases were 31.08% and 25.40%. In summary, chitosan is efficiently utilized in the wastewater treatment by absorption of the suspended materials and formaldehyde due to its molecular structure providing a good electrical property.

  14. Chitosan-collagen porous scaffold and bone marrow mesenchymal stem cell transplantation for ischemic stroke

    Institute of Scientific and Technical Information of China (English)

    Feng Yan; Wei Yue; Yue-lin Zhang; Guo-chao Mao; Ke Gao; Zhen-xing Zuo; Ya-jing Zhang; Hui Lu

    2015-01-01

    In this study, we successfully constructed a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffoldin vitro, transplanted either the composite or bone marrow mesenchymal stem cells alone into the ischemic area in animal models, and compared their effects. At 14 days after co-transplantation of bone marrow mesenchymal stem cells and the hi-tosan-collagen scaffold, neurological function recovered noticeably. Vascular endothelial growth factor expression and nestin-labeled neural precursor cells were detected in the ischemic area, surrounding tissue, hippocampal dentate gyrus and subventricular zone. Simultaneously, a high level of expression of glial ifbrillary acidic protein and a low level of expression of neuron-spe-ciifc enolase were visible in BrdU-labeled bone marrow mesenchymal stem cells. These ifndings suggest that transplantation of a composite of bone marrow mesenchymal stem cells and a chi-tosan-collagen scaffold has a neuroprotective effect following ischemic stroke.

  15. Study of a New Neuron

    OpenAIRE

    Adler, S. L.; Bhanot, G. V.; Weckel, J. D.

    1994-01-01

    We study a modular neuron alternative to the McCulloch-Pitts neuron that arises naturally in analog devices in which the neuron inputs are represented as coherent oscillatory wave signals. Although the modular neuron can compute $XOR$ at the one neuron level, it is still characterized by the same Vapnik-Chervonenkis dimension as the standard neuron. We give the formulas needed for constructing networks using the new neuron and training them using back-propagation. A numerical study of the mod...

  16. The antimicrobial action of low-molar-mass chitosan, chitosan derivates and chitooligosaccharides on bifidobacteria

    Czech Academy of Sciences Publication Activity Database

    Šimůnek, Jiří; Koppová, Ingrid; Lukáš, Filip; Tishchenko, Galina; Belzecki, G.

    2010-01-01

    Roč. 55, č. 4 (2010), s. 379-382. ISSN 0015-5632 R&D Projects: GA ČR(CZ) GA525/08/0803 Institutional research plan: CEZ:AV0Z50450515; CEZ:AV0Z40500505 Keywords : chitooligosaccharides * low-molar-mass chitosan Subject RIV: EE - Microbiology, Virology Impact factor: 0.977, year: 2010

  17. Nanoparticle-based delivery of small interfering RNA: challenges for cancer therapy

    Directory of Open Access Journals (Sweden)

    Miele E

    2012-07-01

    treatment regimens in a substantial way. These nanoparticles could be designed to surmount one or more of the barriers encountered by siRNA. Nanoparticle drug formulations afford the chance to improve drug bioavailability, exploiting superior tissue permeability, payload protection, and the “stealth” features of these entities. The main aims of this review are: to explain the siRNA mechanism with regard to potential applications in siRNA-based cancer therapy; to discuss the possible usefulness of nanoparticle-based delivery of certain molecules for overcoming present therapeutic limitations; to review the ongoing relevant clinical research with its pitfalls and promises; and to evaluate critically future perspectives and challenges in siRNA-based cancer therapy.Keywords: small interfering RNA, nanoparticles, cancer therapy, delivery strategies, biological barriers, clinical trials

  18. Mesmerising mirror neurons.

    Science.gov (United States)

    Heyes, Cecilia

    2010-06-01

    Mirror neurons have been hailed as the key to understanding social cognition. I argue that three currents of thought-relating to evolution, atomism and telepathy-have magnified the perceived importance of mirror neurons. When they are understood to be a product of associative learning, rather than an adaptation for social cognition, mirror neurons are no longer mesmerising, but they continue to raise important questions about both the psychology of science and the neural bases of social cognition. PMID:20167276

  19. Kalman Filter Neuron Training

    OpenAIRE

    Murase, Haruhiko; KOYAMA, Shuhei; HONAMI, Nobuo; Kuwabara, Takao

    1991-01-01

    An attempt of implementing Kalman filter algorithm in the procedure for training the neural network was made and evaluated. The Kalman filter neuron training program (KNT) was coded. The performance of Kalman filter in KNT was compared to commonly used neuron training algorithm. The study revealed that KNT requires much less calculation time to accomplish neuron training than commonly used other algorithms do. KNT also gave much smaller final error than any other algorithms tested in this study.

  20. Folate-Chitosan Nanoparticles Loaded with Ursolic Acid Confer Anti-Breast Cancer Activities in vitro and in vivo

    Science.gov (United States)

    Jin, Hua; Pi, Jiang; Yang, Fen; Jiang, Jinhuan; Wang, Xiaoping; Bai, Haihua; Shao, Mingtao; Huang, Lei; Zhu, Haiyan; Yang, Peihui; Li, Lihua; Li, Ting; Cai, Jiye; Chen, Zheng W.

    2016-01-01

    Ursolic acid (UA) has proved to have broad-spectrum anti-tumor effects, but its poor water solubility and incompetent targeting property largely limit its clinical application and efficiency. Here, we synthesized a nanoparticle-based drug carrier composed of chitosan, UA and folate (FA-CS-UA-NPs) and demonstrated that FA-CS-UA-NPs could effectively diminish off-target effects and increase local drug concentrations of UA. Using MCF-7 cells as in vitro model for anti-cancer mechanistic studies, we found that FA-CS-UA-NPs could be easily internalized by cancer cells through a folate receptor-mediated endocytic pathway. FA-CS-UA-NPs entered into lysosome, destructed the permeability of lysosomal membrane, and then got released from lysosomes. Subsequently, FA-CS-UA-NPs localized into mitochondria but not nuclei. The prolonged retention of FA-CS-UA-NPs in mitochondria induced overproduction of ROS and destruction of mitochondrial membrane potential, and resulted in the irreversible apoptosis in cancer cells. In vivo experiments showed that FA-CS-UA-NPs could significantly reduce breast cancer burden in MCF-7 xenograft mouse model. These results suggested that FA-CS-UA-NPs could further be explored as an anti-cancer drug candidate and that our approach might provide a platform to develop novel anti-cancer drug delivery system. PMID:27469490

  1. Folate-Chitosan Nanoparticles Loaded with Ursolic Acid Confer Anti-Breast Cancer Activities in vitro and in vivo

    Science.gov (United States)

    Jin, Hua; Pi, Jiang; Yang, Fen; Jiang, Jinhuan; Wang, Xiaoping; Bai, Haihua; Shao, Mingtao; Huang, Lei; Zhu, Haiyan; Yang, Peihui; Li, Lihua; Li, Ting; Cai, Jiye; Chen, Zheng W.

    2016-07-01

    Ursolic acid (UA) has proved to have broad-spectrum anti-tumor effects, but its poor water solubility and incompetent targeting property largely limit its clinical application and efficiency. Here, we synthesized a nanoparticle-based drug carrier composed of chitosan, UA and folate (FA-CS-UA-NPs) and demonstrated that FA-CS-UA-NPs could effectively diminish off-target effects and increase local drug concentrations of UA. Using MCF-7 cells as in vitro model for anti-cancer mechanistic studies, we found that FA-CS-UA-NPs could be easily internalized by cancer cells through a folate receptor-mediated endocytic pathway. FA-CS-UA-NPs entered into lysosome, destructed the permeability of lysosomal membrane, and then got released from lysosomes. Subsequently, FA-CS-UA-NPs localized into mitochondria but not nuclei. The prolonged retention of FA-CS-UA-NPs in mitochondria induced overproduction of ROS and destruction of mitochondrial membrane potential, and resulted in the irreversible apoptosis in cancer cells. In vivo experiments showed that FA-CS-UA-NPs could significantly reduce breast cancer burden in MCF-7 xenograft mouse model. These results suggested that FA-CS-UA-NPs could further be explored as an anti-cancer drug candidate and that our approach might provide a platform to develop novel anti-cancer drug delivery system.

  2. Effects of Partially N-acetylated Chitosans to Elicit Resistance Reaction on Brassica napus L.

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue-kun; TANG Zhang-lin; CHEN Li; GUO Yi-hong; CHEN Yun-ping; LI Jia-na

    2002-01-01

    The effects to elicit resistance reaction on oilseed rape (Brassica napus L. cv Xinongchangjiao )by four partially N-acetylated chitosan 7B, 8B, 9B and 10B (Degree of acetylation (D. A. ) is 30%, 20%,10%, 0%, respectively) and Glycol chitosan (GC, D.A. is 0%) were investigated and compared. Results showed that chitosan were similar to salicylic acid (SA), and could induce resistance reaction, but the reaction was influenced by the degree of acetylation of chitosan. Fully deacetylated chitosans, 10B and GC, elicited chitinase activity, but partially acetylated chitosan, 7B, 8B and 9B, inhibited chitinase activity. Phenyalanine ammonia-lyase (PAL) was also elicited. Elicitor activity increased with on increasing degree of acetylation, 7B induced highest PAL activity among all chitosans. All chitosans induced peroxidase (POD) in a similar level.After elicited by glycol chitosan, like SA treatment, the seedlings increased disease resistance to Sclerotinia sclerotiorum significantly.

  3. Biological preparation of chitosan nanoparticles and its in vitro antifungal efficacy against some phytopathogenic fungi.

    Science.gov (United States)

    Sathiyabama, M; Parthasarathy, R

    2016-10-20

    The aim of the present study was to prepare Chitosan nanoparticles through biological method with high antifungal activities. Chitosan nanoparticles were prepared by the addition of anionic proteins isolated from Penicillium oxalicum culture to chitosan solutions. The formation of chitosan nanoparticles was preliminary confirmed by UV-vis spectrophotometric analysis. The physico-chemical properties of the chitosan nanoparticles were determined by size and zeta potential analysis, FTIR analysis, HRTEM and XRD pattern. The chitosan nanoparticles were evaluated for its potential to inhibit the growth of phytopathogens viz., Pyricularia grisea, Alternaria solani, Fusarium oxysporum. It is evident from our results that chitosan nanoparticles inhibit the growth of phytopathogens tested. Chitosan nanoparticle treated chickpea seeds showed positive morphological effects such as enhanced germination%, seed vigor index and vegetative biomass of seedlings. All these results indicate that chitosan nanoparticle can be used further under field condition to protect various crops from the devastating fungal pathogens as well as growth promoters. PMID:27474573

  4. Preparation of a silver nanoparticle-based dual-functional sensor using a complexation-reduction method.

    Science.gov (United States)

    Mi, Fwu-Long; Wu, Shao-Jung; Zhong, Wen-Qi; Huang, Cheng-Yu

    2015-09-01

    A dual-functional sensor based on silver nanoparticles was synthesized by a two-stage procedure consisting of a low-temperature chitosan-Ag(+) complexation followed by a high-temperature reduction of the complex to form chitosan-capped silver nanoparticles (CS-capped Ag NPs). The surface plasmon resonance (SPR) absorption and fluorescence emission of the silver nanoparticles were influenced by the concentration and degradation time of chitosan, and the temperatures of the complexation and reduction reactions. The SPR absorption band was blue-shifted while the intensities of emission and absorption were decreased after reacting the silver nanoparticles with Hg(2+) ions. The silver nanoparticles reacted with Hg(2+) were characterized by high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and surface-enhanced Raman scattering spectroscopy (SERS). The results suggested that the particle growth and aggregation of the silver nanoparticles were caused by the adsorption of Hg(2+) and deposition of Hg(0) on the nanoparticle surface. Direct correlations of the SPR absorption and fluorescence emission with the concentration of Hg(2+) were useful for quantitative analysis of Hg(2+). It was possible to use the dual-functional silver nanoparticles as a colorimetric and fluorescent sensor for sensitive and selective detection of Hg(2+) ions. PMID:25619929

  5. Synthesis and application of magnetic chitosan nanoparticles in oilfield

    Science.gov (United States)

    Lian, Qi; Zheng, Xuefang

    2016-01-01

    The novel magnetic Co0.5Mn0.5Fe2O4-chitosan nanoparticles has the advantage of excellent biodegradation and a high level of controllability. The Co0.5Mn0.5Fe2O4-chitosan nanoparticles was prepared successfully. The size of the Co0.5Mn0.5Fe2O4-chitosan nanoparticles were all below 100 nm. The saturated magnetization of the Co0.5Mn0.5Fe2O4-chitosan nanoparticles could reach 80 emu/g and showed the characteristics of superparamagnetism at the same time. The image of TEM and SEM electron microscopy showed that the cubic-shape magnetic Co0.5Mn0.5Fe2O4 particles were encapsulated by the spherical chitosan nanoparticles. The evaluation on the interfacial properties of the product showed that the interfacial tension between crude oil and water could be reduce to ultra-low values as low as 10-3 mN/m when the magnetic Co0.5Mn0.5Fe2O4-chitosan nanoparticle was used in several blocks in Shengli Oilfield without other additives. Meanwhile, the magnetic Co0.5Mn0.5Fe2O4-chitosan nanoparticles possessed good salt-resisting capacity.

  6. Thermal and magnetic properties of chitosan-iron oxide nanoparticles.

    Science.gov (United States)

    Soares, Paula I P; Machado, Diana; Laia, César; Pereira, Laura C J; Coutinho, Joana T; Ferreira, Isabel M M; Novo, Carlos M M; Borges, João Paulo

    2016-09-20

    Chitosan is a biopolymer widely used for biomedical applications such as drug delivery systems, wound healing, and tissue engineering. Chitosan can be used as coating for other types of materials such as iron oxide nanoparticles, improving its biocompatibility while extending its range of applications. In this work iron oxide nanoparticles (Fe3O4 NPs) produced by chemical precipitation and thermal decomposition and coated with chitosan with different molecular weights were studied. Basic characterization on bare and chitosan-Fe3O4 NPs was performed demonstrating that chitosan does not affect the crystallinity, chemical composition, and superparamagnetic properties of the Fe3O4 NPs, and also the incorporation of Fe3O4 NPs into chitosan nanoparticles increases the later hydrodynamic diameter without compromising its physical and chemical properties. The nano-composite was tested for magnetic hyperthermia by applying an alternating current magnetic field to the samples demonstrating that the heating ability of the Fe3O4 NPs was not significantly affected by chitosan. PMID:27261762

  7. "The Good, the Bad and the Ugly" of Chitosans.

    Science.gov (United States)

    Bellich, Barbara; D'Agostino, Ilenia; Semeraro, Sabrina; Gamini, Amelia; Cesàro, Attilio

    2016-05-01

    The objective of this paper is to emphasize the fact that while consistent interest has been paid to the industrial use of chitosan, minor attention has been devoted to spread the knowledge of a good characterization of its physico-chemical properties. Therefore, the paper attempts to critically comment on the conflicting experimental results, highlighting the facts, the myths and the controversies. The goal is to indicate how to take advantage of chitosan versatility, to learn how to manage its variability and show how to properly tackle some unexpected undesirable features. In the sections of the paper various issues that relate chitosan properties to some basic features and to advanced solutions and applications are presented. The introduction outlines some historical pioneering works, where the chemistry of chitosan was originally explored. Thereafter, particular reference is made to analytical purity, characterization and chain modifications. The macromolecular characterization is mostly related to molecular weight and to degree of acetylation, but also refers to the conformational and rheological properties and solution stability. Then, the antimicrobial activity of chitosan in relation with its solubility is reviewed. A section is dedicated to the formulation of chitosan biomaterials, from gel to nanobeads, exploring their innovative application as active carrier nanoparticles. Finally, the toxicity issue of chitosan as a polymer and as a constructed nanomaterial is briefly commented in the conclusions. PMID:27196916

  8. Rheological and structural studies of carboxymethyl derivatives of chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Winstead, Cherese; Katagumpola, Pushpika [Delaware State University, Department of Chemistry, 1200 N. Dupont Highway, Dover, DE 19901 (United States)

    2014-05-15

    The degrees of substitution of chitosan derivatives were varied and the viscoelastic behavior of these biopolymer solutions was studied using rheology. Chitosan is a cationic copolymer of glucosamine and N-acetylglucosamine obtained by alkaline deacetylation of chitin. Due to its inherent non-toxicity, biocompatibility, and biodegradability, chitosan has gained much interest. However, the poor solubility of the biopolymer in water and most common organic solvents limits its applications. Therefore, the focus of this work is the chemical modification of chitosan via carboxymethylation as well as studying the viscoelastic behavior of these polymer solutions. Varying degrees of substitution (DS) of carboxymethyl chitosan derivatives were synthesized by treating chitosan with monochloroacetic acid under alkylated medium varying the reaction time and temperature. The effect of degree of substitution on the rheology of these polymer solutions was studied as a function of concentration. The viscosity of chitosan derivatives sharply increased with increase in degree of substitution. G' and G' dependence on strain and angular frequency were studied and were found to exhibit predominantly viscous behavior. Additional characterization of the derivatized products were further studied using Fourier transform infrared (FT-IR), {sup 1}H Nuclear Magnetic Resonance ({sup 1}H NMR) spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis as well as differential scanning calorimetry (DSC). Degree of substitution (DS) was calculated by titrimetric method.

  9. Bromine pretreated chitosan for adsorption of lead (II) from water

    Indian Academy of Sciences (India)

    Rajendra Dongre; Minakshi Thakur; Dinesh Ghugal; Jostna Meshram

    2012-10-01

    Pollution by heavy metals like lead (II) is responsible for health hazards and environmental degradation. Adsorption is a prevalent method applied for removal of heavy metal pollutants from water. This study explored adsorption performances of 30% bromine pretreated chitosan for lead (II) abatement from water. Bromine pretreatment alters porosity and specific surface area of chitosan by means of physicochemical interaction with cationic sites of chitosan skeleton, besides imparting anionic alteration at amino linkages of chitosan, to remove lead (II) by chemical interactions on superfluous active sites as characterized by FTIR, SEM, DTA and elemental analysis. Lead adsorptions were studied in batch mode by varying parameters viz. pH, bromine loading, sorbent dosage, initial lead concentration, contact time and temperature. The adsorption equilibrium data was well fitted to Freundlich isotherm and maximum sorption capacity of 30% bromine pretreated chitosan sorbent was 1.755 g/kg with 85–90% lead removal efficiency. Though cost and applicability of sorbent is unproven, yet contrast to raw chitosan derivatives, activated carbons and some resins, 30% bromine pretreated chitosan endow benign and efficient lead abatement technique.

  10. Chitosan-based nanofibrous membranes for antibacterial filter applications.

    Science.gov (United States)

    Cooper, Ashleigh; Oldinski, Rachael; Ma, Hongyan; Bryers, James D; Zhang, Miqin

    2013-01-30

    Nanofibrous membranes have drawn considerable interest for filtration applications due to their ability to withstand high fluid flux while removing micro- and nano-sized particulates from solution. The desire to introduce an antibacterial function into water filter applications presents a challenge to widespread application of fibrous membranes because the addition of chemicals or biocides may produce harmful byproducts downstream. Here, we report the development of chitosan-polycaprolactone (PCL) nanofibrous membranes to utilize the natural antibacterial property of chitosan for antibacterial water filtration. Chitosan-PCL fibers with diameters of 200-400 nm and chitosan contents of 25, 50 and 75 wt% were prepared by electrospinning. In a series of bacterial challenge tests, chitosan-PCL fibrous membranes significantly reduced Staphylococcus aureus adhesion compared to PCL fibrous membranes. In water permeability and particulate size removal tests, fibrous membranes with 25% chitosan supported the greatest water flux (∼7000 L/h/m(2)) with 100% removal of 300-nm particulates, while maintaining the membrane integrity. This study demonstrates the potential of chitosan-PCL nanofibrous membranes as pre-filters for water filtration systems that demonstrate combinatorial filtration and intrinsic antibacterial advantages. PMID:23218292

  11. Functional gene silencing mediated by chitosan/siRNA nanocomplexes

    International Nuclear Information System (INIS)

    Chitosan/siRNA nanoparticles to knock down FHL2 gene expression were reported in this work. The physicochemical properties such as particle size, surface charge, morphology and complex stability of chitosan nanoparticle-incorporated siRNA were evaluated. Nanoparticles which were formulated with chitosan/siRNA exhibited irregular, lamellar and dendritic structures with a hydrodynamic radius size of about 148 nm and net positive charges with zeta-potential value of 58.5 mV. The knockdown effect of the chitosan/siRNA nanoparticles on gene expression in FHL2 over-expressed human colorectal cancer Lovo cells was investigated. The result showed that FHL2 siRNA formulated within chitosan nanoparticles could knock down about 69.6% FHL2 gene expression, which is very similar to the 68.8% reduced gene expression when siRNA was transfected with liposome Lipofectamine. Western analysis further showed significant FHL-2 protein expression reduced by the chitosan/siRNA nanoparticles. The results also showed that blocking FHL2 expression by siRNA could also inhibit the growth and proliferation of human colorectal cancer Lovo cells. The current results demonstrated that chitosan-based siRNA nanoparticles were a very efficient delivery system for siRNA in vivo as previously reported.

  12. Rheological and structural studies of carboxymethyl derivatives of chitosan

    International Nuclear Information System (INIS)

    The degrees of substitution of chitosan derivatives were varied and the viscoelastic behavior of these biopolymer solutions was studied using rheology. Chitosan is a cationic copolymer of glucosamine and N-acetylglucosamine obtained by alkaline deacetylation of chitin. Due to its inherent non-toxicity, biocompatibility, and biodegradability, chitosan has gained much interest. However, the poor solubility of the biopolymer in water and most common organic solvents limits its applications. Therefore, the focus of this work is the chemical modification of chitosan via carboxymethylation as well as studying the viscoelastic behavior of these polymer solutions. Varying degrees of substitution (DS) of carboxymethyl chitosan derivatives were synthesized by treating chitosan with monochloroacetic acid under alkylated medium varying the reaction time and temperature. The effect of degree of substitution on the rheology of these polymer solutions was studied as a function of concentration. The viscosity of chitosan derivatives sharply increased with increase in degree of substitution. G' and G' dependence on strain and angular frequency were studied and were found to exhibit predominantly viscous behavior. Additional characterization of the derivatized products were further studied using Fourier transform infrared (FT-IR), 1H Nuclear Magnetic Resonance (1H NMR) spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis as well as differential scanning calorimetry (DSC). Degree of substitution (DS) was calculated by titrimetric method

  13. Remediation of coal mining wastewaters using chitosan microspheres.

    Science.gov (United States)

    Geremias, R; Pedrosa, R C; Benassi, J C; Fávere, V T; Stolberg, J; Menezes, C T B; Laranjeira, M C M

    2003-12-01

    This study aimed to evaluate the potential use of chitosan and chitosan/poly(vinylalcohol) microspheres incorporating with tetrasulphonated copper (II) phthalocyanine (CTS/PVA/TCP) in the remediation of coal mining wastewaters. The process was monitored by toxicity tests both before and after adsorption treatments with chitosan and microspheres. Physicochemical parameters, including pH and trace-metal concentration, as well as bioindicators of water pollution were used to that end. Wastewater samples colleted from drainage of underground coal mines, decantation pools, and contaminated rivers were scrutinized. Acute toxicity tests were performed using the Brine Shrimp Test (BST) in order to evaluate the remediation efficiency of different treatments. The results showed that the pH of treated wastewater samples were improved to values close to neutrality. Chitosan treatments were also effective in removing trace-metals. Pre-treatment with chitosan followed by microsphere treatment (CTS/PVA/TCP) was more effective in decreasing toxicity than the treatment using only chitosan. This was probably due to the elimination of pollutants other than trace-metals. Thus, the use of chitosan and microspheres is an adequate alternative towards remediation of water pollution from coal mining. PMID:14977147

  14. Evaluation of hemagglutination activity of chitosan nanoparticles using human erythrocytes.

    Science.gov (United States)

    de Lima, Jefferson Muniz; Sarmento, Ronaldo Rodrigues; de Souza, Joelma Rodrigues; Brayner, Fábio André; Feitosa, Ana Paula Sampaio; Padilha, Rafael; Alves, Luiz Carlos; Porto, Isaque Jerônimo; Batista, Roberta Ferreti Bonan Dantas; de Oliveira, Juliano Elvis; de Medeiros, Eliton Souto; Bonan, Paulo Rogério Ferreti; Castellano, Lúcio Roberto

    2015-01-01

    Chitosan is a polysaccharide composed of randomly distributed chains of β-(1-4) D-glucosamine and N-acetyl-D-glucosamine. This compound is obtained by partial or total deacetylation of chitin in acidic solution. The chitosan-based hemostatic agents have been gaining much attention in the management of bleeding. The aim of this study was to evaluate in vitro hemagglutination activity of chitosan nanoparticles using human erythrocytes. The preparation of nanoparticles was achieved by ionotropic gelification technique followed by neutralization with NaOH 1 mol/L(-1). The hemagglutination activity was performed on a solution of 2% erythrocytes (pH 7.4 on PBS) collected from five healthy volunteers. The hemolysis determination was made by spectrophotometric analysis. Chitosan nanoparticle solutions without NaOH addition changed the reddish colour of the wells into brown, suggesting an oxidative reaction of hemoglobin and possible cell lysis. All neutralized solutions of chitosan nanoparticles presented positive haemagglutination, without any change in reaction color. Chitosan nanoparticles presented hemolytic activity ranging from 186.20 to 223.12%, while neutralized solutions ranged from 2.56 to 72.54%, comparing to distilled water. Results highlight the need for development of new routes of synthesis of chitosan nanoparticles within human physiologic pH. PMID:25759815

  15. Synthesis and evaluation of chitosan-Vitamin C complex

    Directory of Open Access Journals (Sweden)

    Tian X

    2009-01-01

    Full Text Available Chitosan is a biocompatible, biodegradable and non-toxic polysaccharide polymer. It dissolves in water only if the pH is lower than 6.5. To extend its range of application, many water-soluble derivatives have therefore been prepared. In this research, chitosan-vitamin C complex was synthesized and characterized with Fourier transformed infrared spectroscopy, differential scanning calorimetry and 1 H-NMR. The solubility of chitosan-vitamin C complex in distilled water was greatly improved. The ·O2 - scavenging activity of chitosan-vitamin C complex was compared with chitosan and vitamin C by measuring the auto-oxidation rate of pyrogallic acid. Results showed that the scavenging activity on ·O2 - by chitosan-vitamin C complex was stronger than that by CS. At low concentrations (< 0.05 mg/ml, the scavenging activity of chitosan-vitamin C complex was stronger than that of vitamin C, but after certain concentrations (>0.1mg/ml, its scavenging activity was lower than that of vitamin C.

  16. Remediation of coal mining wastewaters using chitosan microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Geremias, R.; Pedrosa, R.C.; Benassi, J.C.; Favere, V.T.; Stolberg, J.; Menezes, C.T.B.; Laranjeira, M.C.M. [Federal University of Santa Catarina, Florianopolis (Brazil)

    2003-12-01

    This study aimed to evaluate the potential use of chitosan and chitosan/poly(vinylalcohol) microspheres incorporating tetrasulphonated copper (II) phthalocyanine (CTS / PVA / TCP) in the remediation of coal mining wastewaters. The process was monitored by toxicity tests both before and after adsorption treatments with chitosan and microspheres. Physicochemical parameters, including pH and trace-metal concentration, as well as bioindicators of water pollution were used to that end. Wastewater samples collected from drainage of underground coal mines, decantation pools, and contaminated rivers were scrutinized. Acute toxicity tests were performed using the Brine Shrimp Test (BST) in order to evaluate the remediation efficiency of different treatments. The results showed that the pH of treated wastewater samples were improved to values close to neutrality. Chitosan treatments were also effective in removing trace-metals. Pre-treatment with chitosan followed by microsphere treatment (CTS / PVA / TCP) was more effective in decreasing toxicity than the treatment using only chitosan. This was probably due to the elimination of pollutants other than trace-metals. Thus, the use of chitosan and microspheres is an adequate alternative towards remediation of water pollution from coal mining.

  17. In vitro Binding Capacity of Cholesterol and Bile Salts by Partially Depolymerized Chitosans

    OpenAIRE

    Xia Wenshui; Mamadouba Bangoura; Zhang Jiali

    2009-01-01

    Orthogonal design was used to optimize the binding capacity of Sodium Cholate (SC) and Sodium Deoxycholate (SD) by nine partially depolymerized chitosans obtained from a native chitosan using sodium nitrite (NaNO2). The effects of sodium treatment on depolymerization of chitosan were investigated by measuring the molecular weight, viscosity and reducing sugar of chitosan. Depolymerization for 3 h reduced the molecular weight of the chitosan by 91% (26 kDa) compared to the native chitosan (458...

  18. Penggunaan Chitosan Dari Cangkang Udang ( Litopenaeus Vannamei ) Sebagai Pengawet Alami Untuk Buah Stroberi ( Fragaria X Ananassa Duch )

    OpenAIRE

    Christy, Johanna

    2015-01-01

    Chitosan is the modification of chitin, which found on the outer skin of Crustaceae species such as shrimps. The typical quality of chitosan as antibacterial with the ability to immobilize bacteria, it might chitosan is used to be food preservation. The aims of this research were knowing how long this fruit preservative used chitosan would be defence in strawberry, knowing the optimal concentration of chitosan for strawberry preservation and knowing the effect of chitosan in strawberry phy...

  19. Chitosan-nanosilica hybrid materials: Preparation and properties

    International Nuclear Information System (INIS)

    Highlights: • Hybrid chitosan-nanosilica materials were synthesized using an adsorption modification method. • The chitosan adsorption capacity is higher on the silica/titania and silica/alumina than on the fumed silica. • Nanosilicas undergo structural and textural alterations due to modification by chitosan. • The more severe chitosan thermodestruction occurs on the silica/titania and silica/alumina surfaces than on the plain silica surface. - Abstract: The research focuses on the synthesis of novel organic–inorganic hybrid materials based on polysaccharide chitosan and nanosilicas (SiO2, TiO2/SiO2 and Al2O3/SiO2). The chitosan modified nanooxides were obtained by the equilibrium adsorption method. The chitosan adsorption capacities of silica/titania and silica/alumina are higher than of the plain silica due to the additional active sites present on the surfaces of the mixed oxides. The hybrid materials were characterized by low-temperature nitrogen adsorption/desorption, photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), thermogravimetry (TG/DTG) and temperature-programmed desorption with mass spectrometry control (TPD MS) methods. The chitosan treatment only modestly influences the surface area SBET of the nanooxides but the rearrangement of the secondary and tertiary structures (aggregates and agglomerates) results in an enhancement of the mesoporosity and affects the size of the aggregates. The more severe thermodestruction of the polysaccharide desorbing from the modified mixed silicas indicates a stronger interaction between the chitosan and the mixed oxides compared to the silanol groups of the plain silica surface

  20. Chitosan-nanosilica hybrid materials: Preparation and properties

    Energy Technology Data Exchange (ETDEWEB)

    Podust, T.V., E-mail: tania_list@yahoo.com [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164 (Ukraine); Kulik, T.V., E-mail: tanyakulyk@i.ua [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164 (Ukraine); Palyanytsya, B.B.; Gun’ko, V.M. [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164 (Ukraine); Tóth, A. [Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Mikhalovska, L. [School of Pharmacy and Biomolecular Sciences, University of Brighton, Lewes Road, Brighton BN2 4GJ (United Kingdom); Menyhárd, A. [Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Institute of Materials Science and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences (Hungary); László, K. [Department of Physical Chemistry and Material Science, Budapest University of Technology and Economics, H-1521 Budapest (Hungary)

    2014-11-30

    Highlights: • Hybrid chitosan-nanosilica materials were synthesized using an adsorption modification method. • The chitosan adsorption capacity is higher on the silica/titania and silica/alumina than on the fumed silica. • Nanosilicas undergo structural and textural alterations due to modification by chitosan. • The more severe chitosan thermodestruction occurs on the silica/titania and silica/alumina surfaces than on the plain silica surface. - Abstract: The research focuses on the synthesis of novel organic–inorganic hybrid materials based on polysaccharide chitosan and nanosilicas (SiO{sub 2}, TiO{sub 2}/SiO{sub 2} and Al{sub 2}O{sub 3}/SiO{sub 2}). The chitosan modified nanooxides were obtained by the equilibrium adsorption method. The chitosan adsorption capacities of silica/titania and silica/alumina are higher than of the plain silica due to the additional active sites present on the surfaces of the mixed oxides. The hybrid materials were characterized by low-temperature nitrogen adsorption/desorption, photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), thermogravimetry (TG/DTG) and temperature-programmed desorption with mass spectrometry control (TPD MS) methods. The chitosan treatment only modestly influences the surface area S{sub BET} of the nanooxides but the rearrangement of the secondary and tertiary structures (aggregates and agglomerates) results in an enhancement of the mesoporosity and affects the size of the aggregates. The more severe thermodestruction of the polysaccharide desorbing from the modified mixed silicas indicates a stronger interaction between the chitosan and the mixed oxides compared to the silanol groups of the plain silica surface.

  1. Magnetic chitosan for removal of uranium (VI)

    International Nuclear Information System (INIS)

    The chitosan, an aminopolysaccharide formed for repeated units of D-glucosamine, is a deacetylation product of chitin. It presents favorable ionic properties acting as chelant, being considered a removing ionic of contaminants from water effluents. It has ample bioactivity, that is, is biocompatible, biodegradable, bioadhesive and biosorbent. The chitosan interacts for crosslinked by means of its active groups with other substances, can still coat superparamagnetic materials as magnetite nanoparticles producing one conjugated polymer-magnetite. Superparamagnetic materials are susceptible for the magnetic field, thus these particles can be attracted and grouped by a magnetic field and as they do not hold back the magnetization, they can be disagrouped and reused in processes for removal of contaminants from industrial effluents and waste water. The present work consisted of preparing coated magnetic magnetite particles with chitosan (PMQ). The PMQ powder has showed a magnetic response of intense attraction in the presence of a magnetic field without however becoming magnetic, a typical behavior of superparamagnetic material. It was characterized by Fourier transform infrared spectrometry and measurements of magnetization. Its performance of Uranium (VI) adsorption as uranyl species, U022+, was evaluated with regard to the influence of adsorbent dose, speed of agitation, pH, the contact time and had studied the isotherms of adsorption as well as the behavior of desorption using ions of carbonate and oxalate. The optimal pH to the best removal occurred in pH 5 and that the increase of the dose increases the removal, becoming constant above of 20 g.L-1. In the kinetic study the equilibrium was achieved after 20 minutes. The results of equilibrium isotherm agreed well with the Langmuir model, being the maximum adsorption capacity equal 41.7 mg.g-1. In the desorption studies were verified 94% of U022+ recovered with carbonate ion and 49.9% with oxalate ion. (author)

  2. Stabilization of Papain by Modification with Chitosan

    OpenAIRE

    KILINÇ, Ali; TELEFONCU, Seçil ÖNAL and Azmi

    2002-01-01

    Papain (EC 3.4.22.2) was immobilized on chitosan by adsorption and subsequent cross-linking with glutaraldehyde. The immobilized papain displayed a lower specific activity than did the native enzyme. The thermal stability of the immobilized papain, relative to that of the free enzyme, was markedly increased. The storage stability of the conjugated enzyme was enhanced such that more than 85% of the initial activity remained after a month storage at 45°C. The optimum pH of immobilize...

  3. Structure of chitosan gels mineralized by sorption

    Science.gov (United States)

    Modrzejewska, Z.; Skwarczyńska, A.; Douglas, T. E. L.; Biniaś, D.; Maniukiewicz, W.; Sielski, J.

    2015-10-01

    The paper presents the structural studies of mineralized chitosan hydrogels. Hydrogels produced by using sodium beta-glycerophosphate (Na-β-GP) as a neutralizing agent. Mineralization was performed method "post loading", which consisted in sorption to the gels structure Ca ions. In order to obtain - in the structure of gels - compounds similar to the hydroxyapatites present naturally in bone tissue, gels after sorption were modified in: pH 7 buffer and sodium hydrogen phosphate. In order to determine the structural properties of the gels, the following methods were used: infrared spectroscopy with Fourier transformation, FTIR, X-ray diffractometry, XRD, scanning electron microscopy, SEM.

  4. Detection of the antibacterial activity of chitosan

    OpenAIRE

    Mayer, Gerd; Claußen, Tatjana; Heisig, Peter

    2007-01-01

    Using three bacterial strains the antibacterial activity of Chitoskin®, a chitosan-containing wound-dressing, was investigated by determining the viable bacterial cell count in liquid cultures in the absence and presence of Chitoskin®. Results were compared to those obtained for cellulose and silver-laminated cellulose.While the pure cellulose wound-dressing had no impact on the bacterial growth, Chitoskin® and, to an even greater extend, silver-laminated cellulose reduced the viable cell cou...

  5. Kappe neurons, a novel population of olfactory sensory neurons

    OpenAIRE

    Ahuja, Gaurav; Nia, Shahrzad Bozorg; Zapilko, Veronika; Shiriagin, Vladimir; Kowatschew, Daniel; Oka, Yuichiro; Korsching, Sigrun I.

    2014-01-01

    Perception of olfactory stimuli is mediated by distinct populations of olfactory sensory neurons, each with a characteristic set of morphological as well as functional parameters. Beyond two large populations of ciliated and microvillous neurons, a third population, crypt neurons, has been identified in teleost and cartilaginous fishes. We report here a novel, fourth olfactory sensory neuron population in zebrafish, which we named kappe neurons for their characteristic shape. Kappe neurons ar...

  6. Strong adhesion and cohesion of chitosan in aqueous solutions

    OpenAIRE

    Lee, DW; Lim, C. (Cheryl); Israelachvili, JN; Hwang, DS

    2013-01-01

    Chitosan, a load-bearing biomacromolecule found in the exoskeletons of crustaceans and insects, is a promising biopolymer for the replacement of synthetic plastic compounds. Here, surface interactions mediated by chitosan in aqueous solutions, including the effects of pH and contact time, were investigated using a surface forces apparatus (SFA). Chitosan films showed an adhesion to mica for all tested pH ranges (3.0-8.5), achieving a maximum value at pH 3.0 after a contact time of 1 h (Wad ∼ ...

  7. Effects of Dietary Chitosan on Hormone Level in Dairy Calves

    OpenAIRE

    Dong Li; Xiuming Mu; Jian Ge; Chunwang Yue; Maohong Sun; Qiang Hao

    2012-01-01

    The objective of the present study was to evaluate the effects of chitosan on serum GH, T3 and T4 in and to determine the appropriate supplemental dosage level of chitosan in dairy calves diet. A 30 days trial of dietary chitosan supplementation was reported. Twenty dairy calves were allotted at random to four groups at 10 days of age. Calves in the control group were fed the basal diet alone and calves in treatment groups I-III were fed the basal diet supplemented with 200, 400, 600 mg/day/h...

  8. Strong adhesion and cohesion of chitosan in aqueous solutions

    OpenAIRE

    Lee, Dong Woog; Lim, Chanoong; Israelachvili, Jacob N.; Hwang, Dong Soo

    2013-01-01

    Chitosan, a load-bearing biomacromolecule found in the exoskeletons of crustaceans and insects, is a promising biopolymer for the replacement of synthetic plastic compounds. Here, surface interactions mediated by chitosan in aqueous solutions, including the effects of pH and contact time, were investigated using a surface forces apparatus (SFA). Chitosan films showed an adhesion to mica for all tested pH ranges (3.0–8.5), achieving a maximum value at pH 3.0 after a contact time of 1 hr (Wad ~...

  9. Quaternary Salts of Chitosan: History, Antimicrobial Features, and Prospects

    Directory of Open Access Journals (Sweden)

    Douglas de Britto

    2011-01-01

    Full Text Available Recently, increasing attention has been paid to water-soluble derivatives of chitosan at its applications. The chemical characteristics and the antimicrobial properties of these salts can play significant role in pharmacological and food areas mainly as carriers for drug delivery systems and as antimicrobial packaging materials. In the current paper, a historical sequence of the main preparative methods, physical chemistry aspects, and antimicrobial activity of chitosan quaternized derivatives are presented and briefly discussed. In general, the results indicated that the quaternary derivatives had better inhibitory effects than the unmodified chitosan.

  10. Chitosan-based nanoparticles for mucosal delivery of RNAi therapeutics.

    Science.gov (United States)

    Martirosyan, Alina; Olesen, Morten Jarlstad; Howard, Kenneth A

    2014-01-01

    RNA interference (RNAi) gene silencing by small interfering RNAs (siRNAs) offers a potent and highly specific therapeutic strategy; however, enabling technologies that overcome extracellular and intracellular barriers are required. Polycation-based nanoparticles (termed polyplexes) composed of the polysaccharide chitosan have been used to facilitate delivery of siRNA across mucosal surfaces following local administration. This chapter describes the mucosal barriers that need to be addressed in order to design an effective mucosal delivery strategy and the utilization of the mucoadhesive properties of chitosan. Focus is given to preparation methods and the preclinical application of chitosan nanoparticles for respiratory and oral delivery of siRNA. PMID:25409611

  11. Development of polycaprolactone/chitosan blend porous scaffolds.

    Science.gov (United States)

    Wan, Ying; Xiao, Bo; Dalai, Siqin; Cao, Xiaoying; Wu, Quan

    2009-03-01

    Polycaprolactone (PCL) and chitosan were blended to fabricate porous scaffolds for tissue-engineering applications by employing a concentrated acetic acid solution as solvent and salt particles as porogen. These scaffolds showed well-controlled and interconnected porous structures. The pore size and porosity of the scaffolds could be effectively modulated by selecting appropriate amounts and sizes of porogen. The results obtained from compressive mechanical measurements indicated that PCL/chitosan could basically retain their strength in their dry state compared to individual components. In a hydrated state, their compressive stress and modulus could be still well maintained even though the weight ratio of chitosan reached around 50 wt%. PMID:18987952

  12. Neuronal Response Clamp

    Directory of Open Access Journals (Sweden)

    Avner Wallach

    2011-04-01

    Full Text Available Responses of individual neurons to ongoing input are highly variable, reflecting complex threshold dynamics. Experimental access to this threshold dynamics is required in order to fully characterize neuronal input-output relationships. The challenge is practically intractable using present day experimental paradigms due to the cumulative, nonlinear interactions involved. Here we introduce the Neuronal Response Clamp, a closed-loop technique enabling control over the instantaneous response probability of the neuron. The potential of the technique is demonstrated by showing direct access to threshold dynamics of cortical neuron in-vitro using extracellular recording and stimulation, over timescales ranging from seconds to many hours. Moreover, the method allowed us to expose the sensitivity of threshold dynamics to spontaneous input from the network in which the neuron is embedded. The Response Clamp technique follows the rationale of the voltage-clamp and dynamic-clamp approaches, extending it to the neuron's spiking behavior. The general framework offered here is applicable in the study of other neural systems, beyond the single neuron level.

  13. Preparation of a Cyclomaltoheptaose (β-cyclodextrin) Cross-linked Chitosan Derivative via Glyoxal or Glutaraldehyde

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A cyclomaltoheptaose-β-cyclodextrin (β-CD) crosslinked chitosan derivative via glyoxal or glutaraldehyde was prepared. The structures of β-CD crosslined chitosan with glyoxal or glutaraldehyde were characterized by IR spectra. The surface morphology of the β-CD crosslinked chitosan particles was examined using a scanning electron microscope. The immobilization capacity of β-CD on chitosan was affected on the weight ratio of β-CD/chitosan, the utilization amount of crosslinking agent, the acidity of the reaction system and the temperature. The adsorption for nicotine indicated that the chitosan-β-CD was a good adsorbent.

  14. PREPARATION AND CHARACTERIZATION OF SOLUBLE EGGSHELL MEMBRANE PROTEIN/CHITOSAN BLEND FILMS

    Institute of Scientific and Technical Information of China (English)

    Qing-lei Qi; Qiang Li; Jian-wei Lu; Zhao-xia Guo; Jian Yu

    2009-01-01

    Biopolymer chitosan was used to modify the mechanical properties of soluble eggshell membrane protein (SEP) films. The SEP/chitosan blend films were prepared by solution casting from 10% aqueous acetic acid. Tensile strength and elongation at break of the blend films increased with increasing amount of chitosan. Microphase separation was observed by field emission scanning electron microscopy, although interaction between the two components was revealed by FTIR. The biocompatibility of SEP/chitosan blend flints containing 10%-50% of chitosan, as demonstrated by cell culture of NIH3T3, was much better than that of pure chitosan.

  15. Evaluation of chitosan based vaginal bioadhesive gel formulations for antifungal drugs

    OpenAIRE

    ŞENYIĞIT, ZEYNEP AY; Karavana, Sinem Yaprak; ERAÇ, BAYRI; GÜRSEL, ÖZGE; LIMONCU, MINE HOŞGÖR; Baloğlu, Esra

    2014-01-01

    The aim of the present study was to evaluate chitosan as a vaginal mucoadhesive gel base for econazole nitrate and miconazole nitrate. For this aim, different types of chitosan with different molecular massess and viscosity properties [low molecular mass chitosan (viscosity: 20.000 mPa s), medium molecular mass chitosan (viscosity: 200.000 mPa s), high molecular mass chitosan (viscosity: 800.000 mPa s)] have been used. Firstl, rheological studies were conducted on chitosan gels. Mechanical, s...

  16. PRODUCTION OF LOW MOLECULAR WEIGHT CHITOSAN BY HOT DILUTE SULFURIC ACID

    OpenAIRE

    Akram Zamani; Mohammad Taherzadeh

    2010-01-01

    new method was developed for production of low molecular weight chitosan, in which high molecular weight chitosan was treated with dilute sulfuric acid at 120°C. Chitosan was dissolved in the acid solution in a few minutes, and as depolymerized to low molecular weight chitosan by longer times. Low molecular weight chitosan was recovered from the acid by cooling down the solution and increasing the pH to 8-10. A low molecular weight chitosan with Mv (viscosity average molecular weight) of 174×...

  17. Recent progress on synthesis, property and application of modified chitosan: An overview.

    Science.gov (United States)

    Wang, Junhua; Wang, Li; Yu, Haojie; Zain-Ul-Abdin; Chen, Yongsheng; Chen, Qing; Zhou, Weidong; Zhang, Hongtao; Chen, Xiao

    2016-07-01

    Because of the unique chemical structure, chitosan and its derivatives have been paid close extensive attention as the potential bio-functional material. This review presents recent synthesis of modified chitosan via N-substitution, O-substitution, free radical graft copolymerization and other modification methods and properties of the modified chitosan. The applications of the modified chitosan in metal ions adsorption, dye removal and pharmaceutical fields are illustrated as well. The rapid development in the modification of chitosan describes broad perspectives of the modified chitosan. PMID:27044349

  18. NEURON and Python

    Directory of Open Access Journals (Sweden)

    Michael Hines

    2009-01-01

    Full Text Available The NEURON simulation program now allows Python to be used, alone or in combination with NEURON's traditional Hoc interpreter. Adding Python to NEURON has the immediate benefit of making available a very extensive suite of analysis tools written for engineering and science. It also catalyzes NEURON software development by offering users a modern programming tool that is recognized for its flexibility and power to create and maintain complex programs. At the same time, nothing is lost because all existing models written in Hoc, including GUI tools, continue to work without change and are also available within the Python context. An example of the benefits of Python availability is the use of the XML module in implementing NEURON's Import3D and CellBuild tools to read MorphML and NeuroML model specifications.

  19. Experimental Study and Stabilization Mechanisms of Silica Nanoparticles Based Brine Mud with High Temperature Resistance for Horizontal Shale Gas Wells

    Directory of Open Access Journals (Sweden)

    Xian-yu Yang

    2015-01-01

    Full Text Available Previous studies showed that silica nanoparticles based fresh water drilling muds had good thermal stability up to 160°C; however its performance at high salt concentration was rather poor. Therefore, high performance silica nanoparticles based brine mud (NPBMs with high temperature resistance for horizontal shale gas wells was proposed. Thermal stability tests from ambient temperature to 180°C, along with pressure transmission tests and rheology analysis, were performed to evaluate comprehensive properties of the NPBMs. Results show that the NPBMs embody excellent salt tolerance and thermal resistance for their rheological parameters did not suffer significant fluctuation. Fluid loss of the NPBM-1 (4% NaCl plus 3% KCl at 180°C was only 7.6 mL while the NPBM-2 (10% NaCl plus 3% KCl had a fluid loss of 6.6 mL at 150°C. Low water activity and good lubricity of the NPBMs were beneficial to improve wellbore stability and reduce friction resistance. Pressure transmission tests on the NPBM-1 show that it can mitigate or even prevent the transmission of drilling mud pressure into shale thus improving wellbore stability. Additionally, optimal rheological models for the NPBM-1 and the NPBM-2 were Herschel-Bulkley model and Power Law model separately.

  20. Effect of degree of deacetylation of chitosan on thermal stability and compatibility of chitosan-polyamide blend

    OpenAIRE

    Zainoha Zakaria; Zatil Izzah; Mohammad Jawaid; Azman Hassan

    2012-01-01

    The effect of the degree of deacetylation of chitosan on the chemical structure, thermal properties, and compatibility of chitosan/polyamide66 (CS/PA66) blends were investigated. Blends of CS with PA66 were prepared via the solution casting technique by using 85% formic acid. Structural interaction between PA66, CS, and CS/PA66 blends were analyzed by infrared spectroscopy. FT-IR spectra showed displacement of the carbonyl band of the amide group of chitosan toward smaller wave numbers, indic...

  1. 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)

  2. Radiation degradation of alginate and chitosan

    International Nuclear Information System (INIS)

    Alginate and chitosan were irradiated in solid or aqueous solution condition with Co60 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 105 for 0 kGy to 6 x 103 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)

  3. Comprehensive characterization of chitosan/PEO/levan ternary blend films.

    Science.gov (United States)

    Bostan, Muge Sennaroglu; Mutlu, Esra Cansever; Kazak, Hande; Sinan Keskin, S; Oner, Ebru Toksoy; Eroglu, Mehmet S

    2014-02-15

    Ternary blend films of chitosan, PEO (300,000) and levan were prepared by solution casting method and their phase behavior, miscibility, thermal and mechanical properties as well as their surface energy and morphology were characterized by different techniques. FT-IR analyses of blend films indicated intermolecular hydrogen bonding between blend components. Thermal and XRD analysis showed that chitosan and levan suppressed the crystallinity of PEO up to nearly 25% of PEO content in the blend, which resulted in more amorphous film structures at higher PEO/(chitosan+levan) ratios. At more than 30% of PEO concentration, contact angle (CA) measurements showed a surface enrichment of PEO whereas at lower PEO concentrations, chitosan and levan were enriched on the surfaces leading to more amorphous and homogenous surfaces. This result was further confirmed by atomic force microscopy (AFM) images. Cell proliferation and viability assay established the high biocompatibility of the blend films. PMID:24507374

  4. Chitosan-based formulations of drugs, imaging agents and biotherapeutics

    NARCIS (Netherlands)

    Amidi, M.; Hennink, W.E.

    2010-01-01

    This preface is part of the Advanced Drug Delivery Reviews theme issue on “Chitosan-Based Formulations of Drugs, Imaging Agents and Biotherapeutics”. This special Advanced Drug Delivery Reviews issue summarizes recent progress and different applications of chitosanbased formulations.

  5. Drug delivery glucantime in PVP/chitosan membranes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Maria J.A.; Lugao, Ademar B.; Parra, Duclerc F., E-mail: mariajhho@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Amato, Valdir S. [Universidade de Sao Paulo (DMIP/FM/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Departamento de Molestias Infecciosas e Parasitarias

    2015-07-01

    The current study of polymer science considers the area of biomedical application very important to establish developments in new polymeric materials. Examples of that are hydrogels for controlled release of drugs. In this work, hydrogels of poly (N-2-vinil-pyrrolidone) (PVP) containing chitosan and clay nanoparticles were obtained and characterized to investigate chitosan influence on Glucantime drug delivery. The matrixes were crosslinked by gamma irradiation process with doses of 25 kGy. Hydrogels morphologies were observed by X Ray diffraction (DRX). Atomic Force Microscopy (AFM) and swelling kinetic at 22 °C to study the capacity of water retention and, finally, drug delivery tests were performed 'in vitro'. The system showed higher gel fraction for the matrix with 1.0% of clay and 0.5% of chitosan. In this case, besides the interactions of clay ions with PVP, there are interactions of chitosan amine group with PVP amide group. (author)

  6. A NOVEL APPROACH TO SYNTHESIZE CHITOSAN BEADS CROSSLINKED BY EPICHLOROHYDRIN

    Institute of Scientific and Technical Information of China (English)

    WANG Yongjian; BAI Shu; SUN Yan

    2001-01-01

    The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin. Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization. Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads. The effects of reaction conditions, such as crosslinking time, the amount of crosslinking agent and the NaOtt concentration,on the physical properties of the chitosan beads were investigated. The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde. The capacity for copper ions is as high as 40mg/g. The beads have good mechanical strength and can be reused.

  7. A NOVEL APPROACH TO SYNTHESIZE CHITOSAN BEADS CROSSLINKED BY EPICHLOROHYDRIN

    Institute of Scientific and Technical Information of China (English)

    WANGYongjina; BAIShu; 等

    2001-01-01

    The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin.Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization.Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads.The effects of reaction conditions,such as crosslinking time,the amount of crosslinking agent and the NaOH concentration,on the physical properties of the chitosan beads were investigated.The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde.The capacity for copper ions in as high as 40mg/g,The beads have good mechanical strength and can be reused.

  8. PERFORMANCE EVALUATION OF SAND AND CHITOSAN AS DUAL FILTER MEDIA

    Directory of Open Access Journals (Sweden)

    MADHUKAR M

    2012-01-01

    Full Text Available Nuisance due to suspended and colloidal particles causing turbidity has become widespread, severe problem due to urban population and industrial activities. The consequences of turbidity are presence of microorganisms,reduction of dissolved oxygen, etc. Consumption of such water is known to cause water borne diseases.Available water treatment methods for the removal of turbidity and pathogens are coagulation, filtration and disinfection. The common filter media used are sand, activated carbon etc. Chitosan has been used as acoagulant aid and adsorbent. Chitosan when used as a filter media causes the colloidal particles to bind together and is subsequently removed during the process. The column studies using Chitosan in combination with conventional sand filter was carried out in a borosilicate glass column. Chitosan was placed on top of sand layerand constant down flow pattern of 100mL/min was followed. Dual filter media was effective in the reducing turbidity by 93%.

  9. Adsorption of nuclease p1 on chitosan nano-particles

    Directory of Open Access Journals (Sweden)

    Lu-E Shi

    2009-06-01

    Full Text Available The sorption of nuclease P1 onto chitosan nano-particles is studied in this paper. The effect of some adsorption kinetics factors such as nuclease P1 concentration, chitosan nano-particles solution concentration, adsorption temperature, chitosan nano-particles size, solution pH, etc. is investigated. Adsorption of nuclease P1 onto chitosan nano-particles is fitted into Lagergren first-order equation at initial nuclease P1 concentration of 3.0 mg/mL. The first-order constant for nuclease P1 is 22.98 h-1. When nuclease P1 concentration is controlled into certain region, the adsorption fits into Freundlich isothermal linear equation. A mechanism of adsorption for nuclease P1 is proposed by analyzing IR spectra. The IR spectra shows that the hydrogen bond might be the main force between the hydroxyl group, the NH2 group and the nuclease P1.

  10. Synthesis, characterization and antibacterial activity of new fluorescent chitosan derivatives

    Czech Academy of Sciences Publication Activity Database

    Přichystalová, H.; Almonasy, N.; Abdel-Mohsen, A. M.; Abdel-Rahman, R. M.; Fouda, M. M. G.; Vojtova, L.; Kobera, Libor; Spotz, Z.; Burgert, L.; Jancar, J.

    2014-01-01

    Roč. 65, April (2014), s. 234-240. ISSN 0141-8130 Institutional support: RVO:61389013 Keywords : chitosan derivatives * fluorescence * antibacterial activity Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.858, year: 2014

  11. Femtosecond Laser Patterning of the Biopolymer Chitosan for Biofilm Formation

    Science.gov (United States)

    Estevam-Alves, Regina; Ferreira, Paulo Henrique Dias; Coatrini, Andrey C.; Oliveira, Osvaldo N.; Fontana, Carla Raquel; Mendonca, Cleber Renato

    2016-01-01

    Controlling microbial growth is crucial for many biomedical, pharmaceutical and food industry applications. In this paper, we used a femtosecond laser to microstructure the surface of chitosan, a biocompatible polymer that has been explored for applications ranging from antimicrobial action to drug delivery. The influence of energy density on the features produced on chitosan was investigated by optical and atomic force microscopies. An increase in the hydrophilic character of the chitosan surface was attained upon laser micromachining. Patterned chitosan films were used to observe Staphylococcus aureus (ATCC 25923) biofilm formation, revealing an increase in the biofilm formation in the structured regions. Our results indicate that fs-laser micromachining is an attractive option to pattern biocompatible surfaces, and to investigate basic aspects of the relationship between surface topography and bacterial adhesion. PMID:27548153

  12. PLA/chitosan/keratin composites for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Tanase, Constantin Edi, E-mail: etanase@live.com [Faculty of Medical Bioengineering, ‘Grigore T. Popa’ University of Medicine and Pharmacy, 9-13 Kogalniceanu Street, 700454 Iasi (Romania); Spiridon, Iuliana [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania)

    2014-07-01

    Novel composites based on PLA, chitosan and keratin was obtained via blend preparation. The goal of this contribution was to evaluate mechanical and in vitro behavior of the composites. The results point out composites with improved Young modulus and decreased tensile strength, significant increase in hardness (compared to PLA) and a good uptake of the surface properties. Biological assessments using human osteosarcoma cell line on these composites indicate a good viability/proliferation outcome. Hence preliminary results regarding mechanical behavior and in vitro osteoblast response suggest that these composites might have prospective application in medical field. - Highlights: • PLA, chitosan and keratin composites are prepared by blend preparation. • PLA, chitosan and keratin composites present improved mechanical properties and water uptake compare to PLA. • PLA, chitosan and keratin composites present good in vitro behavior.

  13. Study on preparation the egg yolk puff with chitosan

    Directory of Open Access Journals (Sweden)

    LI Hui

    2014-12-01

    Full Text Available This paper was studied chitosans with different degrees of deacetylation (70%,80%,90%,95% and different usages of chitosan that were added to research the effect of functional indexs in the egg yolk puff,such as calcium content and cholesterol content.Preliminarily chitosan was explored in the application of the Egg yolk puff.Text results showed that when the deacetylation degree of chitosan and its usage were 90% and 1% separately,the functional indexs and sensory quality of the Egg yolk puff can reach the equilibrium.Its calcium content was 76.2 mg/100 g,increased by 44.3 percent.Its cholesterol content was 290 mg/100 g,decreased by 35.1%.

  14. Emerging chitin and chitosan nanofibrous materials for biomedical applications

    Science.gov (United States)

    Ding, Fuyuan; Deng, Hongbing; Du, Yumin; Shi, Xiaowen; Wang, Qun

    2014-07-01

    Over the past several decades, we have witnessed significant progress in chitosan and chitin based nanostructured materials. The nanofibers from chitin and chitosan with appealing physical and biological features have attracted intense attention due to their excellent biological properties related to biodegradability, biocompatibility, antibacterial activity, low immunogenicity and wound healing capacity. Various methods, such as electrospinning, self-assembly, phase separation, mechanical treatment, printing, ultrasonication and chemical treatment were employed to prepare chitin and chitosan nanofibers. These nanofibrous materials have tremendous potential to be used as drug delivery systems, tissue engineering scaffolds, wound dressing materials, antimicrobial agents, and biosensors. This review article discusses the most recent progress in the preparation and application of chitin and chitosan based nanofibrous materials in biomedical fields.

  15. Radiation sterilization of chitosan sealant for vascular prostheses

    International Nuclear Information System (INIS)

    Chitosan was used as a sealant of knitted polyester vascular grafts. Three sterilization methods for chitosan-coated protheses were tested: sterilization with ethylene oxide, formaldehyde and irradiation with gamma rays. Radiation sterilization was found to be the most promising of tested methods. The radiation-induced changes in chitosan irradiated in solid state were investigated. Main chain scission was found as the predominant effect of irradiation. Changes in IR and UV spectra were analyzed. Existence of some post-effects was detected. It seems that the observed increase in biocompatibility of chitosan surface caused by irradiation with sterilizing dose (25 kGy) is due to some structural factor connected with a decrease in molecular weight. (author) 12 refs.; 3 figs.; 4 tabs

  16. Femtosecond Laser Patterning of the Biopolymer Chitosan for Biofilm Formation.

    Science.gov (United States)

    Estevam-Alves, Regina; Ferreira, Paulo Henrique Dias; Coatrini, Andrey C; Oliveira, Osvaldo N; Fontana, Carla Raquel; Mendonca, Cleber Renato

    2016-01-01

    Controlling microbial growth is crucial for many biomedical, pharmaceutical and food industry applications. In this paper, we used a femtosecond laser to microstructure the surface of chitosan, a biocompatible polymer that has been explored for applications ranging from antimicrobial action to drug delivery. The influence of energy density on the features produced on chitosan was investigated by optical and atomic force microscopies. An increase in the hydrophilic character of the chitosan surface was attained upon laser micromachining. Patterned chitosan films were used to observe Staphylococcus aureus (ATCC 25923) biofilm formation, revealing an increase in the biofilm formation in the structured regions. Our results indicate that fs-laser micromachining is an attractive option to pattern biocompatible surfaces, and to investigate basic aspects of the relationship between surface topography and bacterial adhesion. PMID:27548153

  17. Synthesis and properties of chitosan/polypeptide bioconjugate composite

    International Nuclear Information System (INIS)

    Adhesive polypeptide containing the key component of mussel adhesive protein was synthesized by ring-opening polymerization, and a hybrid material of the adhesive polypeptide and chitosan was prepared through the solution method. Some strong hydrogen bond interaction existed, but without the chemical bond between chitosan and polypeptide molecular in the composites, which was demonstrated by IR and XRD. Tensile strength and elongation-at-break of the composite increased with the increase of the polypeptide content. However, the mechanical properties decreased when the content of polypeptide was more than 2% in the composite; all in all, the mechanical properties of the composite were better than the pure chitosan. Furthermore, the introduction of polypeptide was beneficial in improving the hydrophilicity and cell affinity of the composite. The results indicated that the novel chitosan/polypeptide composite has excellent biocompatibility, which could be a scaffold material for cell culture in tissue engineering

  18. Postharvest Chitosan Treatment Induces Resistance in Potato Against Fusarium sulphureum

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-juan; BI Yang; LI Yong-cai; HAN Rui-feng; GE Yong-hong

    2008-01-01

    The effects of chitosan treatment and inoculation on dry rot in tubers and slices of potato were studied. The results showed that chitosan treatment significantly reduced the lesion diameter of potato inoculated with Fusarium sulphureum.The treatment at 0.25% showed the best effect. Chitosan at 0.25% increased the activities of peroxidase and polyphenoloxidase, and the contents of flavonoid compounds and lignin in tissues. Increased activities of β-1,3-glucanase,and phenylalanine ammonialyase were observed, but there were no significant differences between the treated and the control. These findings suggested that the effects of chitosan could be associated with the induced resistance against Fusarium dry rot in potato.

  19. A new route for chitosan immobilization onto polyethylene surface

    Czech Academy of Sciences Publication Activity Database

    Popelka, A.; Novák, I.; Lehocký, M.; Junkar, I.; Mozetič, M.; Kleinová, A.; Janigová, I.; Šlouf, Miroslav; Bílek, F.; Chodák, I.

    2012-01-01

    Roč. 90, č. 4 (2012), s. 1501-1508. ISSN 0144-8617 Institutional support: RVO:61389013 Keywords : immobilization * plasma treatment * chitosan Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.479, year: 2012

  20. PLA/chitosan/keratin composites for biomedical applications

    International Nuclear Information System (INIS)

    Novel composites based on PLA, chitosan and keratin was obtained via blend preparation. The goal of this contribution was to evaluate mechanical and in vitro behavior of the composites. The results point out composites with improved Young modulus and decreased tensile strength, significant increase in hardness (compared to PLA) and a good uptake of the surface properties. Biological assessments using human osteosarcoma cell line on these composites indicate a good viability/proliferation outcome. Hence preliminary results regarding mechanical behavior and in vitro osteoblast response suggest that these composites might have prospective application in medical field. - Highlights: • PLA, chitosan and keratin composites are prepared by blend preparation. • PLA, chitosan and keratin composites present improved mechanical properties and water uptake compare to PLA. • PLA, chitosan and keratin composites present good in vitro behavior

  1. A review on chitosan-based adsorptive membranes.

    Science.gov (United States)

    Salehi, Ehsan; Daraei, Parisa; Arabi Shamsabadi, Ahmad

    2016-11-01

    Membrane adsorbents have emerged as powerful and attractive tools for the removal of hazardous materials such as dyes and heavy metal ions, mainly in trace amounts, from water resources. Among membrane adsorbents, those prepared from or modified with chitosan biopolymer and its derivatives are cases of interest because of chitosan advantages including biocompatibility, biodegradability, nontoxicity, reactivity, film and fiber forming capacity and favorable hydrophilicity. This review is oriented to provide a framework for better insight into fabrication methods and applications of chitosan-based adsorptive membranes. Critical aspects including thermokinetic analyses of adsorption and regeneration capacity of the membrane adsorbents have been also overviewed. Future of chitosan-based adsorptive membranes might include efforts for the improvement of mechanical stability and reusability and also most targeted application of appropriate copolymers as well as nanostructures in preparing high performance adsorptive membranes. PMID:27516289

  2. Development of chitosan-based antimicrobial leather coatings.

    Science.gov (United States)

    Fernandes, Isabel P; Amaral, Joana S; Pinto, Vera; Ferreira, Maria José; Barreiro, Maria Filomena

    2013-10-15

    The development of antimicrobial coatings for footwear components is of great interest both from industry and consumer's point of view. In this work, antimicrobial leather materials were developed taking advantage of chitosan intrinsic antimicrobial activity and film forming capacity. Considering the specificities of the leather tanning industry, different coating technologies, namely drum, calender and spray, were tested, being the best results achieved with the drum. This last approach was further investigated to assess the effect of chitosan content, type of solubilizing acid, and impregnation time on the achieved antimicrobial capacity. Considering chitosan price (economic reasons) and the obtained results (antimicrobial activity and coating effectiveness, as inspected by SEM), the impregnation in the drum using a chitosan content of 1% (w/v) in a formic acid solution during 2h, is proposed as the best option for obtaining leather with antimicrobial capacity. PMID:23987468

  3. Effectiveness of Gamma Irradiated Chitosan for Fresh Meat Preservation

    International Nuclear Information System (INIS)

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

  4. Effect of water-soluble P-chitosan and S-chitosan on human primary osteoblasts and giant cell tumor of bone stromal cells

    International Nuclear Information System (INIS)

    Water-soluble phosphorylated chitosan (P-chitosan) and disodium (1 → 4)-2-deoxy-2-sulfoamino-β-D-glucopyranuronan (S-chitosan) are two chemically modified chitosans. In this study, we found that P-chitosan significantly promotes cell proliferation of both human primary osteoblasts (OBs) and the OB like stromal cell component of the giant cell tumor of bone (GCTB) cells at the concentration from 125 to 1000 μg ml-1 at all time points of 1, 3, 5 and 7 days after treatment. Further investigation of the osteogenic effect of the P-chitosan suggested that it regulates the levels of osteoclastogenic factors, receptor activator of nuclear factor kappa B ligand and osteoprotegerin expression. An interesting finding is that S-chitosan at lower concentration (100 μg ml-1) stimulates cell proliferation while a higher dose (1000 μg ml-1) of S-chitosan inhibits it. The inhibitory effect of S-chitosan on human primary GCT stromal cells was greater than that of OBs (p < 0.05). Taken together, our findings elucidated the osteogenic effect of P-chitosan and the varying effects of S-chitosan on the proliferation of human primary OBs and GCT stromal cells and provided us the rationale for the construction of novel bone repair biomaterials with the dual properties of bone induction and bone tumor inhibition.

  5. Biodegradation Study of Microcrystalline Chitosan and Microcrystalline Chitosan/β-TCP Complex Composites

    OpenAIRE

    Kinga Brzoza-Malczewska; Magdalena Kucharska; Bogdan Gruchała; Maria Wísniewska-Wrona; Luciano Pighinelli

    2012-01-01

    Bone repair or regeneration is a common and complicated clinical problem in orthopedic surgery. The importance of natural polymers, such as microcrystalline chitosan, and minerals such as HAp and β-TCP, has grown significantly over the last two decades due to their renewable and biodegradable source, increasing the knowledge and functionality of composites in technological and biomedical applications. This study compares the biodegradation process, bioactivity, structure, morphology, and mech...

  6. Evaluation of antibacterial efficiency of chitosan and chitosan nanoparticles on cariogenic streptococci: an in vitro study

    OpenAIRE

    Aliasghari, Azam; Rabbani Khorasgani, Mohammad; Vaezifar, Sedigheh; Rahimi, Fateh; Younesi, Habibollah; Khoroushi, Maryam

    2016-01-01

    Background and Objectives: The most prevalent and worldwide oral disease is dental caries that affects a significant proportion of the world population. There are some classical approaches for control, prevention and treatment of this pathologic condition; however, the results are still not completely successful. Therefore new methods are needed for better management of this important challenge. Chitosan is a natural and non-toxic polysaccharide with many biological applications, particularly...

  7. Preparatin and characterization of chitooligosacharides and low-molecular weight chitosans by enzymatic spliting of chitosans

    Czech Academy of Sciences Publication Activity Database

    Koppová, Ingrid; Šimůnek, Jiří; Tishchenko, Galina

    Clermont - Ferrand: INRA, 2008. s. 1-1. [6th INRA-RRI SYMPOSIUM: Gut microbiome . 18.06.-20.06.2008, Clermont-Ferrand] R&D Projects: GA ČR(CZ) GA525/08/0803 Institutional research plan: CEZ:AV0Z50450515; CEZ:AV0Z40500505 Keywords : chitosans * chitooligosacharides * low-molecular weight Subject RIV: EE - Microbiology, Virology

  8. Recovery of uranium from sea water by chelation on chitosan

    International Nuclear Information System (INIS)

    The results presented for the best chitosans (scarcely acetylated polymers of glucosamine) available implement and confirm the authors' early results obtained twelve years ago. In view of its selectivity (indifference to alkali and alkali-earth elements) and its hydrophilicity, chitosan is quite suitable for the recovery of uranium from water and NaCl brine, thus it will certainly be applicable for the recovery of naturally occurring uranium from sea water

  9. Properties of emulsions stabilised by sodium caseinate–chitosan complexes

    NARCIS (Netherlands)

    Zinoviadou, K.; Scholten, E.; Moschakis, T.; Biliaderis, C.G.

    2012-01-01

    Oil-in-water emulsions (10%, w/w, oil) were prepared at pH 5.7 by using electrostatically formed complexes of 0.5% (w/w) sodium caseinate (Na-CAS) and 0–0.6% (w/w) chitosan. Emulsions stabilized by complexes with increased levels of chitosan (>0.2% w/w) had a smaller average droplet size and exhi

  10. APPLICATION OF CHITOSAN-BASED BIOMATERIALS IN BIOARTIFICIAL LIVE

    Institute of Scientific and Technical Information of China (English)

    BAO Zhiming; PAN Jilun; LI Li; YU Yaoting

    2006-01-01

    Bioartificial liver support system (BALS) has the potential to provide temporary support for patients with fulminant hepatic failure and consist of viable hepatocytes and scaffolding materials for hepatocytes attachment. Various scaffolding materials are used in BALS, including chitosan,which is easily obtained by deacetylation of chitin and widely applied in biomedical applications. In this paper, we introduce and discuses chitosan-based biomaterials for BALS application.

  11. Optimization and Characterization of Chitosan Enzymolysis by Pepsin

    OpenAIRE

    Bi Foua Claude Alain Gohi; Hong-Yan Zeng; A Dan Pan

    2016-01-01

    Pepsin was used to effectively degrade chitosan in order to make it more useful in biotechnological applications. The optimal conditions of enzymolysis were investigated on the basis of the response surface methodology (RSM). The structure of the degraded product was characterized by degree of depolymerization (DD), viscosity, molecular weight, FTIR, UV-VIS, SEM and polydispersity index analyses. The mechanism of chitosan degradation was correlated with cleavage of the glycosidic bond, whereb...

  12. Characterisation of chitosan solubilised in aqueous formic and acetic acids

    Directory of Open Access Journals (Sweden)

    Esam A. El-hefian

    2009-11-01

    Full Text Available The intrinsic viscosity of chitosan (MW 7.9 x 105 g mol-1 having a high degree of deacetylation and solubilised in aqueous formic and acetic acids was determined at room temperature. Contact angle and conductivity of the chitosan solutions were also studied. The values of critical coagulation concentration (CCC were then obtained from the plots of contact angle or conductivity versus concentration.

  13. Production and characterization of Chitosan from shrimp shells waste

    OpenAIRE

    Anshar Patria

    2013-01-01

    This research aims to study the production of chitosan from shrimp shell waste origin andcharacterize the chitosan quality of shrimp shell waste that includes parameters yield, solubility,intrinsic viscosity, molecular weight and deacetylation degree. Results showed that the treatment ofheating temperature and heating time in the process of deacetylation caused significant (P≤0.01)influence on yield, solubility, intrinsic viscosity, molecular weight and deacetylation degree of producedchitosa...

  14. RHEOLOGICAL ASPECTS OF N-CARBOXYMETHYL-CHITOSAN IN DILUTED SOLUTIONS

    OpenAIRE

    MARIA ENOI DOS SANTOS MIRANDA; CLOVIS ANTôNIO RODRIGUES; TANIA MARI BELLE BRESOLIN; RILTON ALVES DE FREITAS; EVANILDA TEIXEIRA

    2009-01-01

    The N-carboxymethylchitosan (N-CMCh) is a polyelectrolite with negative charge formed by the carboxymethylation of Chitosan. The derivatization is due to soluble gel with imino groups reduced with sodium borohidrate. Then a range of N-CMChs is generated containing acethyl, carboxymethyl and free amino groups controlled according to the proportions of chitosan and glioxylic acid. To use this polymer in industrial applications, the macromolecular behaviour in solution n...

  15. The Importance of Chitosan Films in Food Industry

    OpenAIRE

    Filiz Uçan; Hatice Aysun Mercimek

    2013-01-01

    Requirement simple technology, low production costs, lack of polluting effects and reliability in terms of health of it is the most important advantages of edible films. Chitosan that extend the shelf life of food and increase the economic efficiency of packaging materials is one of the new materials used for edible films. Chitosan was obtained by deacetylation of chitin which is the most commonly occurred polymer after cellulose in nature, in shells of arthropods such as crab, shrimp, lobste...

  16. Chitosan application as a biocoagulant in wastewater contaminated with hydrocarbons

    OpenAIRE

    Juan M. Álava

    2015-01-01

    The environment contamination in Ecuador, done by the production, transport and commercialization of hydrocarbons, requires further research regarding new treatment alternatives that use biodegradable substances. In this study, abdominal shrimp shell waste, Litopenaeus vannamei was used to obtain chitosan and then apply it as a biocoagulant to a wastewater sample contaminated with hydrocarbon products. The produced chitosan was characterised by potentiometric titration, resulting in a deacety...

  17. ELECTROLESS NICKEL PLATING ON CHITOSAN-MODIFIED WOOD VENEER

    OpenAIRE

    Lijuan Wang; Haibing Liu

    2011-01-01

    An activation process involving chitosan was conducted to prepare electroless nickel plated wood veneers for electromagnetic interference (EMI) shielding. In this process Pd(Ⅱ) ions were chemically adsorbed on wood surface modified with chitosan. Then they were reduced and dipped into a plating bath in which Ni-P co-deposition was successfully initiated. The coatings were characterized by SEM-EDS and XRD. The metal deposition, surface resistivity, and electromagnetic shielding effectiveness w...

  18. Chitosan as a Tool for the Purification of Waters

    OpenAIRE

    Jeuniaux, Charles

    1986-01-01

    It is well known that surface waters are polluted not only by inorganic chemicals such as heavy metals, but also by organic compounds. Owing to the high sorption capacities of chitosan this polymer can be utilized as a tool for the epuration of wastewaters on polluted stream waters. Some typical examples of the application of chitosan to this kind of environmental problems are given here. They include the prevention of water pollution by highly toxic chlorinated aromatic compounds, metal ions...

  19. Hydroxyapatite reinforced chitosan and polyester blends for biomedical applications

    OpenAIRE

    Correlo, V.M.; Boesel, L. F.; Bhattacharya, Mrinal; Mano, J. F.; Neves, N. M.; Reis, R. L.

    2005-01-01

    Hydroxyapatite, chitosan, and aliphatic polyester were compounded using a twin-screw extruder. The polyesters include poly(e-caprolactone) (PCL), poly(lactic acid) , poly(butylene succinate) (PBS), and poly(butylene terephthalate adipate). The mass fraction of chitosan ranged from 17.5 to 45%, while that of HA ranged from 10 to 30%. These blends were injection molded and evaluated for thermal, morphological, and mechanical properties. The addition of hydroxyapatite dec...

  20. Chitosan as flocculant agent for clarification of stevia extract

    OpenAIRE

    Silvia P. D. de Oliveira; Mahl, Cynthia R.A.; Márcia R. Simões; Classius F. da Silva

    2012-01-01

    Stevia is used as a sweetener due to its low calorific value and its taste, which is very similar to that of sucrose. After extraction from dried leaves, stevia extract is dark in colour, and therefore needs to be whitened to increase acceptance by consumers. In this study we tested chitosan, a cationic polyelectrolyte, as flocculant agent for the whitening of the Stevia extract. Positive charges of chitosan can interact electrostatically with a counter-ion, sodium tripolyphosphate (TPP), and...

  1. Chitosan-mediated synthesis of carbon nanotube-gold nanohybrids

    Institute of Scientific and Technical Information of China (English)

    GRAVEL; Edmond; FOILLARD; Stéphanie; DORIS; Eric

    2010-01-01

    Metal-nanotube nanohybrids were produced by in situ synthesis and stabilization of gold nanoparticles on chitosan-functionalized carbon nanotubes.The formation of gold nanoparticles from tetrachloroauric acid was observed after only a few minutes of contact with the functionalized nanotubes,at room temperature.These results suggest that adsorption of chitosan at the surface of carbon nanotubes permits smooth reduction of the metallic salt and efficient anchoring of gold nanoparticles to the nanotubes.

  2. How microglia kill neurons.

    Science.gov (United States)

    Brown, Guy C; Vilalta, Anna

    2015-12-01

    Microglia are resident brain macrophages that become inflammatory activated in most brain pathologies. Microglia normally protect neurons, but may accidentally kill neurons when attempting to limit infections or damage, and this may be more common with degenerative disease as there was no significant selection pressure on the aged brain in the past. A number of mechanisms by which activated microglia kill neurons have been identified, including: (i) stimulation of the phagocyte NADPH oxidase (PHOX) to produce superoxide and derivative oxidants, (ii) expression of inducible nitric oxide synthase (iNOS) producing NO and derivative oxidants, (iii) release of glutamate and glutaminase, (iv) release of TNFα, (v) release of cathepsin B, (vi) phagocytosis of stressed neurons, and (vii) decreased release of nutritive BDNF and IGF-1. PHOX stimulation contributes to microglial activation, but is not directly neurotoxic unless NO is present. NO is normally neuroprotective, but can react with superoxide to produce neurotoxic peroxynitrite, or in the presence of hypoxia inhibit mitochondrial respiration. Glutamate can be released by glia or neurons, but is neurotoxic only if the neurons are depolarised, for example as a result of mitochondrial inhibition. TNFα is normally neuroprotective, but can become toxic if caspase-8 or NF-κB activation are inhibited. If the above mechanisms do not kill neurons, they may still stress the neurons sufficiently to make them susceptible to phagocytosis by activated microglia. We review here whether microglial killing of neurons is an artefact, makes evolutionary sense or contributes in common neuropathologies and by what mechanisms. This article is part of a Special Issue entitled SI: Neuroprotection. PMID:26341532

  3. Single neuron computation

    CERN Document Server

    McKenna, Thomas M; Zornetzer, Steven F

    1992-01-01

    This book contains twenty-two original contributions that provide a comprehensive overview of computational approaches to understanding a single neuron structure. The focus on cellular-level processes is twofold. From a computational neuroscience perspective, a thorough understanding of the information processing performed by single neurons leads to an understanding of circuit- and systems-level activity. From the standpoint of artificial neural networks (ANNs), a single real neuron is as complex an operational unit as an entire ANN, and formalizing the complex computations performed by real n

  4. Straintronic spin-neuron

    OpenAIRE

    Biswas, Ayan K.; Atulasimha, Jayasimha; Bandyopadhyay, Supriyo

    2015-01-01

    In artificial neural networks, neurons are usually implemented with highly dissipative CMOS-based operational amplifiers. A more energy-efficient implementation is a 'spin-neuron' realized with a magneto-tunneling junction (MTJ) that is switched with a spin-polarized current (representing weighted sum of input currents) that either delivers a spin transfer torque or induces domain wall motion in the soft layer of the MTJ. Here, we propose and analyze a different type of spin-neuron in which t...

  5. Solid-Phase Preparation and Characterization of Chitosan

    Institute of Scientific and Technical Information of China (English)

    GaoLe-ping; DuYu-min; ZhangDao-bin; ShiXiao-wen; ZhanHuai-yu; SongWen-hua

    2003-01-01

    Chitosan was prepared with stressing method by blending chitin and solid alkali in a single-screw extruder at given temperature and characterized by potentiometric titration, gel permeation chromatography (GPC), infrared spectrum (IR) and carborr13 magnetic resonance sperctroscopy (13C NMR). Chitosan with a deacetylation degree (DD) of 76. 1% was obtained at a mass ratio 0.2 : 1 : 1 for H20/chitin/NaOH at 160℃ for 12 mirL Compared to conventional solution method(usually 1 : 10 for chitin/NaOH), the alkali assumption greatly decreased. Molecular weight of chitosan obtained by solid-phase method(S3,M. 1.54 X 10s ) was lower than that obtained by suspension method(Y2,Mw3. 34×105). During deacetylation, molecular weight decreased with high reaction temperature and long reaction time but remained same at different initial ratios of NaOH/chitirL It might be concluded that degradation of chitosan was caused by breakout of the main chain of the oxidized chitosan catalyzed by alkali during the deactylation. IR and 13C NMR showed that structures of chitosans prepared by solid-phase method were not changed.

  6. Polyphenol-chitosan conjugates: Synthesis, characterization, and applications.

    Science.gov (United States)

    Hu, Qiaobin; Luo, Yangchao

    2016-10-20

    Chitosan, the only positively charged polysaccharide in the world, is very attractive for food, medicinal and pharmaceutical applications because of its promising properties, including non-toxicity, superb biodegradability, high biocompatibility, abundant availability and low cost. In order to overcome the poor water solubility and widen the applications of chitosan, various polyphenol-chitosan conjugates have been synthesized in recent years. The present review focuses on the chitosan-based conjugates formed using different polyphenols, including gallic acid, caffeic acid, ferulic acid, salicylic acid, catechin, and EGGE, etc. Three major synthesis techniques, namely, activated ester-mediated modification, enzyme-mediated strategy, and free radical induced grafting approach are introduced in detail. In addition, the new physicochemical and biological properties of polyphenol-chitosan conjugates are introduced, including water solubility, thermo stability, in vitro and in vivo antioxidant activity, antimicrobial and anticancer activity. Furthermore, the novel applications of each conjugate are discussed in detail. Lastly, the challenges and prospective areas of study related to polyphenol-chitosan are summarized. PMID:27474608

  7. Development of an injectable chitosan/marine collagen composite gel

    International Nuclear Information System (INIS)

    A chitosan/marine-originated collagen composite has been developed. This composite gel was characterized and its biocompatibility, as well as an inflammatory reaction, was observed. The chitosan gel including N-3-carboxypropanoil-6-O-(carboxymethyl) chitosan of 3 mol%, 6-O-(carboxymethyl) chitosan of 62 mol% and 6-O-(carboxymethyl) chitin of 35 mol% was prepared and compounded with the salmon atelocollagen (SA) gel at different mixture ratios. The composite gels were injected subcutaneously in to the back of rats. The specimens were harvested for a histological survey as well as a tumor necrosis factor-alpha (TNF-α) assay by ELISA. The inflammatory cell infiltration and release of TNF-α were successively controlled low with the ratio of SA to chitosan at 10:90 or 20:80. The SA gel first, within 2 weeks, and then chitosan in the composite gel were slowly absorbed after implantation, followed by soft tissue formation. It is expected that this composite gel will be available as a carrier for tissue filler and drug delivery systems.

  8. Development of an injectable chitosan/marine collagen composite gel

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wei [Department of Inorganic Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062 (Japan); Itoh, Soichiro [Affiliated Facility for Clinical and Fieldwork Practices, International University of Health and Welfare, 6-1-14 Kounodai, Ichikawa-shi, Chiba 272-0827 (Japan); Aizawa, Tomoyasu; Demura, Makoto [Division of Molecular Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810 (Japan); Okawa, Atsushi [Department of Orthopaedic and Spinal Surgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519 (Japan); Sakai, Katsuyoshi; Ohkuma, Tsuneo, E-mail: itoso.gene@kaken-hp.or.j [Research and Development Division, Hokkaido Soda Co., Ltd, 2-12 Chitose, Noboribetsu-shi 059-0003 (Japan)

    2010-12-15

    A chitosan/marine-originated collagen composite has been developed. This composite gel was characterized and its biocompatibility, as well as an inflammatory reaction, was observed. The chitosan gel including N-3-carboxypropanoil-6-O-(carboxymethyl) chitosan of 3 mol%, 6-O-(carboxymethyl) chitosan of 62 mol% and 6-O-(carboxymethyl) chitin of 35 mol% was prepared and compounded with the salmon atelocollagen (SA) gel at different mixture ratios. The composite gels were injected subcutaneously in to the back of rats. The specimens were harvested for a histological survey as well as a tumor necrosis factor-alpha (TNF-{alpha}) assay by ELISA. The inflammatory cell infiltration and release of TNF-{alpha} were successively controlled low with the ratio of SA to chitosan at 10:90 or 20:80. The SA gel first, within 2 weeks, and then chitosan in the composite gel were slowly absorbed after implantation, followed by soft tissue formation. It is expected that this composite gel will be available as a carrier for tissue filler and drug delivery systems.

  9. Optimizing Conditions to Cholesterol Adsorbed with Carboxymethyl Chitosan

    Directory of Open Access Journals (Sweden)

    Mardiyah Kurniasih

    2016-05-01

    Full Text Available A research on optimizing conditions to cholesterol adsorbed have been performed. Optimization was performed by varying: contact time, adsorbent weight and temperature of the system's. A full factorial experimental design was used in this study. Characterization performed on the synthesized chitosan and carboxymethyl chitosan including FTIR, water content, ash content, solubility, porosity, and swelling effect. The results showed that carboxymethyl chitosan able to adsorb cholesterol under conditions optimal adsorbent with cholesterol ratio (1:200 with a contact time of 90 minutes at temperature of 40 °C. Meanwhile, at a temperature of 55 °C carboxymethyl chitosan capable of adsorb cholesterol under conditions optimal adsorbent with cholesterol ratio (1:300 with a contact time of 30 minutes. Chitosan and carboxymethyl chitosan synthesized has a water content of 7.4 and 10.2%, ash content of 0.14 and 2.29%, solubility in distilled water at 1.10-5and 1.98.10-3%, solubility in acetic acid 0.02 and 0.04%, porosity at 88.3% and 88.8%, and swelling at 163.13 and 182.98%.

  10. Preparation and Evaluation of Inhalable Itraconazole Chitosan Based Polymeric Micelles

    Directory of Open Access Journals (Sweden)

    Esmaeil Moazeni

    2012-12-01

    Full Text Available Background: This study evaluated the potential of chitosan based polymeric micelles as a nanocarrier system for pulmonary delivery of itraconazole (ITRA.Methods: Hydrophobically modified chitosan were synthesized by conjugation of stearic acid to the hydrophilic depolymerized chitosan. FTIR and 1HNMR were used to prove the chemical structure and physical properties of the depolymerized and the stearic acid grafted chitosan. ITRA was entrapped into the micelles and physicochemical properties of the micelles were investigated. Fluorescence spectroscopy, dynamic laser light scattering andtransmission electron microscopy were used to characterize the physicochemical properties of the prepared micelles. The in vitro pulmonary profile of polymeric micelles was studied by an air-jet nebulizer connected to a twin stage impinger.Results: The polymeric micelles prepared in this study could entrap up to 43.2±2.27 μg of ITRA per milliliter. All micelles showed mean diameter between 120–200 nm. The critical micelle concentration of the stearic acid grafted chitosan was found to be 1.58×10-2 mg/ml. The nebulization efficiency was up to 89% and the fine particle fraction (FPF varied from 38% to 47%. The micelles had enough stability to remain encapsulation of the drug during nebulization process.Conclusions: In vitro data showed that stearic acid grafted chitosan based polymeric micelles has a potential to be used as nanocarriers for delivery of itraconazole through inhalation.

  11. Electrical Characteristics of Pulsed Corona Discharge Plasmas in Chitosan Solution

    International Nuclear Information System (INIS)

    Pulsed discharge plasma has exhibited active potential to prepare low molecular weight chitosan. In the present study, the viscosity of chitosan solution was decreased noticeably after treated with pulsed corona discharge plasma. An experimental investigation on electrical characteristics of pulsed corona discharge plasma in chitosan solution was conducted with a view toward getting insight into discharge process. Factors affecting I–V curve, single pulse injection energy and pulse width were studied. Experimental results showed positive effect of pulsed peak voltage on discharge plasma in chitosan solution. Pulse-forming capacitor greatly influenced the discharge form, and 4 nF was observed as a suitable value for efficiently generating stable discharge plasmas. As the electrode distance was larger than 10 mm, it had slight impact on discharge plasma due to the excellent conductive-property of chitosan solution. The injection energy significantly increased with air flow rate, while the pulse width hardly changed as the air flow rate increased from 0.5 m3/h to 1.0 m3/h. This study is expected to provide reference for promoting the application of pulsed corona discharge plasma to chitosan solution treatment. (plasma technology)

  12. Chitosan Composites for Bone Tissue Engineering—An Overview

    Directory of Open Access Journals (Sweden)

    Jayachandran Venkatesan

    2010-08-01

    Full Text Available Bone contains considerable amounts of minerals and proteins. Hydroxyapatite [Ca10(PO46(OH2] is one of the most stable forms of calcium phosphate and it occurs in bones as major component (60 to 65%, along with other materials including collagen, chondroitin sulfate, keratin sulfate and lipids. In recent years, significant progress has been made in organ transplantation, surgical reconstruction and the use of artificial protheses to treat the loss or failure of an organ or bone tissue. Chitosan has played a major role in bone tissue engineering over the last two decades, being a natural polymer obtained from chitin, which forms a major component of crustacean exoskeleton. In recent years, considerable attention has been given to chitosan composite materials and their applications in the field of bone tissue engineering due to its minimal foreign body reactions, an intrinsic antibacterial nature, biocompatibility, biodegradability, and the ability to be molded into various geometries and forms such as porous structures, suitable for cell ingrowth and osteoconduction. The composite of chitosan including hydroxyapatite is very popular because of the biodegradability and biocompatibility in nature. Recently, grafted chitosan natural polymer with carbon nanotubes has been incorporated to increase the mechanical strength of these composites. Chitosan composites are thus emerging as potential materials for artificial bone and bone regeneration in tissue engineering. Herein, the preparation, mechanical properties, chemical interactions and in vitro activity of chitosan composites for bone tissue engineering will be discussed.

  13. Porous PCL/Chitosan and nHA/PCL/Chitosan Scaffolds for Tissue Engineering Applications: Fabrication and Evaluation

    Directory of Open Access Journals (Sweden)

    Rashid Mad Jin

    2015-01-01

    Full Text Available Two semicrystalline polymers were blended to fabricate porous scaffolds for tissue engineering applications. Scaffolds containing polycaprolactone (PCL/chitosan and nanohydroxyapatite (nHA incorporated nHA/PCL/chitosan were produced using the freeze-drying technique. A model drug, tetracycline hydrochloride (tetracycline HCL, was incorporated into the scaffolds. The scaffolds were characterized using a scanning electron microscope (SEM, EDX, and water contact angle. The antibacterial properties of the nHA/PCL/chitosan/tetracycline HCL scaffold were tested and the scaffolds showed positive results on gram-positive and gram-negative bacteria. The cell biocompatibility using human skin fibroblast cells (HSF 1184 was examined. The scaffold materials were found to be nontoxic to human skin fibroblast cells (HSF 1184 and showed positive proliferation activities. The nHA/PCL/chitosan/tetracycline HCL scaffold has potential for controlling implant-associated bacterial infections during operative procedures and can potentially be used as a scaffold for tissue engineering applications.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-01-01

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

  15. 166Ho-chitosan as a radiation synovectomy agent - biocompatibility study of 166Ho-chitosan in rabbits

    International Nuclear Information System (INIS)

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

  16. Chitosan nanopolymers effect in activating of mouse bone marrow derived dendritic cells

    Directory of Open Access Journals (Sweden)

    Saeed Daneshmandi

    2014-08-01

    Conclusion: Results showed that chitosan nanopolymers significantly increased dendertic cell maturation phenotype, proinflamatory cytokine production, and induction of T cell proliferation. Therefore, chitosan nanocomplexes and scaffolds can induce and accelerate immune responses.

  17. Chitosan blended bacterial cellulose as a smart material for biomedical application

    Science.gov (United States)

    Cai, Zhijiang; Jin, Hyoung-Joon; Kim, Jaehwan

    2009-03-01

    Bacterial cellulose and chitosan blends have been successfully prepared by immersing wet bacterial cellulose pellicle in chitosan solution followed by freeze-drying. By changing chitosan concentration and immersion time, the chitosan content in the blends is ranged from 12% to 45%. The products look like a foam structure. SEM images show that chitosan molecules can penetrate into bacterial cellulose forming multilayer structure. The foam has very well interconnected porous network structure and large aspect surface. By incorporation of chitosan in bacterial cellulose, XRD patterns indicate that crystalline structure does not change but crystallinity decreases from 82% to 61% with chitosan content increasing from 12% to 45%. According to TGA results, the thermal stability has been improved. At the same time, the mechanical properties of bacterial cellulose and chitosan blends are good enough for potential biomedical application such as tissue engineering scaffold and would dressing material.

  18. Chitosan filled recycled low density polyethylene composite: Melt flow behaviour and thermal degradation properties

    Science.gov (United States)

    Lim, B. Y.; Voon, C. H.; Salmah, H.; Nordin, H.

    2016-07-01

    An environmentally friendly composite was fabricated from chitosan and recycled low density polyethylene (rLDPE) with the means of melt mixing at 180 °C. The composites were prepared in different loading (10, 20, 30 and 40 php) of chitosan. Due to the incompatibility between filler and matrix, a coupling agent, Ultraplus TP01, was added into the composites. The melt flow index (MFI) values of rLDPE/chitosan composites decreased with chitosan loading but increased with rise of temperature. With the presence of Ultraplus TP01, MFI values of composites were decreased. The thermal stability of rLDPE/chitosan was reduced with increase of chitosan loading but increased with addition of Ultraplus TP01. It was believed that Ultraplus TP01 had provided better interfacial bonding between chitosan and rLDPE, thus enhanced the thermal stability of rLDPE/chitosan composites.

  19. Antibacterial Characteristics and Activity of Water-Soluble Chitosan Derivatives Prepared by the Maillard Reaction

    Directory of Open Access Journals (Sweden)

    Ying-Chien Chung

    2011-10-01

    Full Text Available The antibacterial activity of water-soluble chitosan derivatives prepared by Maillard reactions against Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Escherichia coli, Shigella dysenteriae, and Salmonella typhimurium was examined. Relatively high antibacterial activity against various microorganisms was noted for the chitosan-glucosamine derivative as compared to the acid-soluble chitosan. In addition, it was found that the susceptibility of the test organisms to the water-soluble chitosan derivative was higher in deionized water than in saline solution. Metal ions were also found to reduce the antibacterial activity of the water-soluble chitosan derivative on S. aureus. The marked increase in glucose level, protein content and lactate dehydrogenase (LDH activity was observed in the cell supernatant of S. aureus exposed to the water-soluble chitosan derivative in deionized water. The results suggest that the water-soluble chitosan produced by Maillard reaction may be a promising commercial substitute for acid-soluble chitosan.

  20. Investigating Effects of Gelatin-Chitosan Film on Culture of Bone Marrow Stromal Cells in Rat

    Directory of Open Access Journals (Sweden)

    A Karami joyani

    2015-02-01

    Conclusion: Results of proliferation,differentiation and apoptosis cultured BMSCs on a gelatin-chitosan film showed that gelatin-chitosan film can be used as a good model of a biodegradable scaffold in tissue engineering and cell therapy.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  3. Porous PCL/Chitosan and nHA/PCL/Chitosan Scaffolds for Tissue Engineering Applications: Fabrication and Evaluation

    OpenAIRE

    Rashid Mad Jin; Naznin Sultana; Sayang Baba; Salehhuddin Hamdan; Ahmad Fauzi Ismail

    2015-01-01

    Two semicrystalline polymers were blended to fabricate porous scaffolds for tissue engineering applications. Scaffolds containing polycaprolactone (PCL)/chitosan and nanohydroxyapatite (nHA) incorporated nHA/PCL/chitosan were produced using the freeze-drying technique. A model drug, tetracycline hydrochloride (tetracycline HCL), was incorporated into the scaffolds. The scaffolds were characterized using a scanning electron microscope (SEM), EDX, and water contact angle. The antibacterial prop...

  4. Selective Modification of Chitosan to Enable the Formation of Chitosan-DNA Condensates by Electron Donator Stabilization

    OpenAIRE

    Kador, Karl E.; Anuradha Subramanian

    2011-01-01

    Chitosan, a polyaminosaccharide, has been investigated for its use in the field of drug-delivery and biomaterial applications because of its natural biocompatibility and polycationic properties. Chemical modifications of chitosan have been attempted in an effort to increase the transfection efficiency with respect to gene delivery applications; however, it is unknown how these modifications affect the formation of the condensates. This study attempts to determine the effects of modification o...

  5. The effect of chitosan on the in vitro biological performance of chitosan-poly(butylene succinate) blends

    OpenAIRE

    Coutinho, Daniela F.; Pashkuleva, I.; Alves, Catarina M.; Marques, A.P.; Neves, N. M.; Reis, R. L.

    2008-01-01

    Chitosan blends with synthetic biodegradable polymers have been proposed for various biomedical applications due to their versatile mechanical properties and easier processing. However, details regarding the main surface characteristics that may benefit from the blending of these two types of materials are still missing. Hence, this work aims at investigating the surface properties of chitosan-based blends, illustrating the way these properties determine the material-proteins inte...

  6. Recent Developments in NEURON

    OpenAIRE

    Hines, Michael L.; Carnevale, Nicholas T.

    2005-01-01

    We describe four recent additions to NEURON's suite of graphical tools that make it easier for users to create and manage models: an enhancement to the Channel Builder that facilitates the specification and efficient simulation of stochastic channel models

  7. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    GiacomoIndiveri

    2011-05-01

    Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

  8. Synthesis and Characterization of Chitosan-g-poly(D, L-lactic acid) Copolymer

    Institute of Scientific and Technical Information of China (English)

    Hua YANG; Shao Bing ZHOU; Xian Mo DENG

    2005-01-01

    Biodegradable chitosan-g-poly (D, L-lactic acid) copolymers were prepared via two methods. (1) The lactide was grafted onto hydroxyl groups of chitosan by using macromolecular initiator sodium of trimethylsilyl-chitosan, (2) poly (D,L-lactic acid)(PLA) with low molecular weight can be linked to the amino group by coupling activated PLA to trimethylsilyl-chitosan. Two graft copolymers had hydrophilic-hydrophobic character and can be applied as carriers for drug delivery.

  9. Sorption properties of chitosan and the prospects for its use in purification of liquid media

    International Nuclear Information System (INIS)

    Basic sorption characteristics of chitosan samples prepared from crab chitin towards cesium-137, strontium-90 and yttrium-90 radionuclides have been ascertained. Dependence of chitosan sorption properties on its molecular mass has been proved. It is shown that sorption ability of chitosan towards the above-mentioned radionuclides is at the level of a similar characteristic of industrial cationite KU-2-8. Chitosan application on a porous base permits using the composition sorbent prepared for deep purification of water media from radionuclides

  10. Chitosan cooperates with mesenchyme-derived factors inregulating salivary gland epithelial morphogenesis

    OpenAIRE

    Yang, Tsung-Lin; Young, Tai-Horng

    2008-01-01

    Chitosan is a widely used biocompatible biomaterial in the tissue regeneration, but its utility and application in the tissue morphogenesis of salivary gland remains unclear. The study aimed to explore the effects of chitosan on the epithelial morphogenesis of submandibular gland (SMG). With chitosan, the branching morphogenesis of the whole SMG explant was facilitated, and the morphogenetic-promoting effects of mesenchymal tissue on SMG were further enhanced. Furthermore, chitosan was compet...

  11. Synthesis of Conjugated Chitosan and its Effect on Drug Permeation from Transdermal Patches

    OpenAIRE

    B K Satheeshababu; K L Shivakumar

    2013-01-01

    The aim of this study was to synthesis the conjugated chitosan by covalent attachment of thiol moieties to the cationic polymer, mediated by a carbodiimide to improve permeation properties of chitosan. Thioglycolic acid was covalently attached to chitosan by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid groups of thioglycolic acid. Hence, these polymers are called as thiomers or thiolated polymers. Conjugation of chitosan was confirmed by...

  12. Physiochemical, Optical and Biological Activity of Chitosan-Chromone Derivative for Biomedical Applications

    OpenAIRE

    Joonseok Koh; Santosh Kumar

    2012-01-01

    This paper describes the physiochemical, optical and biological activity of chitosan-chromone derivative. The chitosan-chromone derivative gels were prepared by reacting chitosan with chromone-3-carbaldehyde, followed by solvent exchange, filtration and drying by evaporation. The identity of Schiff base was confirmed by UV-Vis absorption spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. The chitosan-chromone derivative was evaluated by X-ray diffraction (XRD), thermogravimetric...

  13. Preparation and Characterization of Chitosan/Agar Blended Films: Part 1. Chemical Structure and Morphology

    OpenAIRE

    Esam A. El-Hefian; Mohamed Mahmoud NASEF; Yahaya, Abdul Hamid

    2012-01-01

    Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar (considering chitosan as the main component) in solution forms. The chemical structure and the morphology of the obtained blended films were investigated using Fourier transform infrared (FTIR) and field emission scanning electron microscope (FESEM). It was revealed that chitosan and agar form a highly compatible blend and their films displayed homogenous and smooth surface properties compared to ...

  14. Antimicrobial Activity of Chitosan Derivatives Containing N-Quaternized Moieties in Its Backbone: A Review

    OpenAIRE

    Alessandro F. Martins; Suelen P. Facchi; Follmann, Heveline D. M.; Antonio G. B. Pereira; Adley F. Rubira; Muniz, Edvani C.

    2014-01-01

    Chitosan, which is derived from a deacetylation reaction of chitin, has attractive antimicrobial activity. However, chitosan applications as a biocide are only effective in acidic medium due to its low solubility in neutral and basic conditions. Also, the positive charges carried by the protonated amine groups of chitosan (in acidic conditions) that are the driving force for its solubilization are also associated with its antimicrobial activity. Therefore, chemical modifications of chitosan ...

  15. Processing and characterization of 3D dense chitosan pieces, for orthopedic applications, by adding plasticizers

    OpenAIRE

    Figueiredo, Lígia; Moura, Carla; Pinto, Luís F. V.; Ferreira, Frederico Castelo; Rodrigues, Alexandra

    2015-01-01

    In this work, plasticizer agents were incorporated in a chitosan based formulation, as a strategy to improve the fragile structure of chitosan based-materials. Three different plasticizers: ethylene glycol, glycerol and sorbitol, were blended with chitosan to prepare 3D dense chitosan specimens. The properties of the obtained structures were assessed for mechanical, microstructural, physical and biocompatibility behavior. The results obtained revealed that from the different specimens prepare...

  16. Haemostatic chitosan coated gauze: in vitro interaction with human blood and in-vivo effectiveness

    OpenAIRE

    Pogorielov, M.; Kalinkevich, O.; Deineka, V.; Garbuzova, V.; Solodovnik, A.; Kalinkevich, A.; Kalinichenko, T.; Gapchenko, A.; Sklyar, A.; Danilchenko, S.

    2015-01-01

    Background Chitosan and its derivates are widely used for biomedical application due to antioxidative, anti-inflammatory, antimicrobial and tissue repair induced properties. Chitosan-based materials also used as a haemostatic agent but influence of different molecular weight and concentration of chitosan on biological response of blood cells is still not clear. The aim of this research was to evaluate interaction between human blood cells and various forms of chitosan-based materials with dif...

  17. Carbon and nitrogen limitation increase chitosan antifungal activity in Neurospora crassa and fungal human pathogens

    OpenAIRE

    Lopez-Moya, Federico; Colom-Valiente, Maria F.; Martínez Peinado, Pascual; Martinez-Lopez, Jesus E.; Puelles, Eduardo; Sempere Ortells, José Miguel; López Llorca, Luis Vicente

    2015-01-01

    Chitosan permeabilizes plasma membrane and kills sensitive filamentous fungi and yeast. Membrane fluidity and cell energy determine chitosan sensitivity in fungi. A five-fold reduction of both glucose (main carbon (C) source) and nitrogen (N) increased 2-fold Neurospora crassa sensitivity to chitosan. We linked this increase with production of intracellular reactive oxygen species (ROS) and plasma membrane permeabilization. Releasing N. crassa from nutrient limitation reduced chitosan antifun...

  18. Fabrication, characterization and in vitro drug release behavior of electrospun PLGA/chitosan nanofibrous scaffold

    International Nuclear Information System (INIS)

    Graphical abstract: The fenbufen loaded PLGA/chitosan nanofibrous scaffolds were fabricated by electrospinning. The hydrophilicity of nanofibrous scaffold was enhanced with the increase of chitosan content. The drug release also is accelerated with chitosan increasing because the higher hydrophilicity makes drug diffusing from scaffold more easily. Research highlights: → The average diameter increased with the increase of chitosan content and then decreased. → The release rate of fenbufen increased with the increase of chitosan. → The aligned nanofibrous scaffold exhibits lower drug release rate. → The drug release could be controlled by crosslinking in glutaraldehyde vapor. - Abstract: In this study both aligned and randomly oriented poly(D,L-lactide-co-glycolide) (PLGA)/chitosan nanofibrous scaffold have been prepared by electrospinning. The ratio of PLGA to chitosan was adjusted to get smooth nanofiber surface. Morphological characterization using scanning electron microscopy showed that the aligned nanofiber diameter distribution obtained by electrospinning of polymer blend increased with the increase of chitosan content which was similar to that of randomly oriented nanofibers. The release characteristic of model drug fenbufen (FBF) from the FBF-loaded aligned and randomly oriented PLGA and PLGA/chitosan nanofibrous scaffolds was investigated. The drug release rate increased with the increase of chitosan content because the addition of chitosan enhanced the hydrophilicity of the PLGA/chitosan composite scaffold. Moreover, for the aligned PLGA/chitosan nanofibrous scaffold the release rate was lower than that of randomly oriented PLGA/chitosan nanofibrous scaffold, which indicated that the nanofiber arrangement would influence the release behavior. In addition, crosslinking in glutaraldehyde vapor would decrease the burst release of FBF from FBF-loaded PLGA/chitosan nanofibrous scaffold with a PLGA/chitosan ratio less than 9/1, which would be beneficial

  19. Biopolymer chitosan: Properties, interactions and its use in the treatment of textiles

    OpenAIRE

    Jocić Dragan; Topalović Tatjana

    2004-01-01

    The biopolymer chitosan is obtained by the deacetylation of chitin, the second most abundant polysaccharide in nature, after cellulose. It is becoming an increasingly important biopolymer because it offers unique physico-chemical and biological properties. Due to its solubility, chitosan allows processing from aqueous solutions. This review provides information on important chitosan properties, as well as on some interactions that are of special interest for chitosan application. It summarize...

  20. Novel highly-soluble peptide-chitosan polymers: Chemical synthesis and spectral characterization

    OpenAIRE

    Batista, MKS; Pinto, LF; Gomes, CAR; Gomes, P.

    2006-01-01

    Novel water-soluble polymers, N-(gamma-propanoyl-valin)-chitosan and N-(gamma-propanoyi-aspartic acid)-chitosan, were synthesized by reaction of low molecular weight chitosan with N-alpha-(3-bromopropanoyl)-valine and N-alpha-(3-bromopropanoyl)-aspartic acid, respectively, under mild conditions. Prior to reaction with chitosan, the peptide substituents have been prepared by standard peptide chemistry methods from 3-bromopropanoic acid and the relevant a-amino acid tert-butyl esters. The chemi...