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Chitosan Films (chitosan + film)

Distribution by Scientific Domains

Polymers and Materials Science	60%
Chemistry	30%

Selected Abstracts

EFFECT OF POLYGODIAL ON MECHANICAL, OPTICAL AND BARRIER PROPERTIES OF CHITOSAN FILMS

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2010
L. MORENO-OSORIO
ABSTRACT The mechanical, optical and barrier properties of chitosan films containing polygodial (0.0, 2.7, 13.9, 25.0 mg/g of chitosan) were studied. Water vapor permeability (WVP), tensile strength, percentage elongation at break, CIELab color parameters, hue angle and chroma of films were determined. Fourier transform infrared (FTIR) was also performed to determine functional group interaction between the matrix and polygodial added. The use of polygodial resulted in stronger films without losing their extensibility and with low WVP. Films became darker with yellow-green coloration with increasing polygodial concentration. Polygodial added to chitosan films did not have any interaction with the amino groups of chitosan as measured by FTIR. Polygodial as a natural dialdehyde can effectively be applied to enhance some physical properties of edible films prepared with chitosan. PRACTICAL APPLICATIONS There has been an increased interest in the study of edible,biodegradable packaging films during the last decade, offering an alternative and partial solution to the problem of accumulation of solid waste composed of synthetic inert polymers, and chitosan films has been studied with this purpose. Furthermore, replacing synthetic additives by natural compounds such us polygodial can be a suitable manner to improve some physical properties of those chitosan films. [source]

Biomimetic Approach to Confer Redox Activity to Thin Chitosan Films

ADVANCED FUNCTIONAL MATERIALS, Issue 16 2010
Eunkyoung Kim
Abstract Electron transfer in biology occurs with individual or pairs of electrons, and is often mediated by catechol/o -quinone redox couples. Here, a biomimetic polysaccharide-catecholic film is fabricated in two steps. First, the stimuli-responsive polysaccharide chitosan is electrodeposited as a permeable film. Next, the chitosan-coated electrode is immersed in a solution containing catechol and the electrode is biased to anodically-oxidize the catechol. The oxidation products covalently graft to the chitosan films as evidenced by electrochemical quartz crystal microbalance (EQCM) studies. Cyclic voltammetry (CV) measurements demonstrate that the catechol-modified chitosan films are redox-active although they are non-conducting and cannot directly transfer electrons to the underlying electrode. The catechol-modified chitosan films serve as a localized source or sink of electrons that can be transferred to soluble mediators (e.g., ferrocene dimethanol and Ru(NH3) 6Cl3). This electron source/sink is finite, can be depleted, but can be repeatedly regenerated by brief (30 s) electrochemical treatments. Further, the catechol-modified chitosan films can i) amplify currents associated with the soluble mediators, ii) partially-rectify these currents in either oxidative or reductive directions (depending on the mediator), and iii) switch between regenerated-ON and depleted-OFF states. Physical models are proposed to explain these novel redox properties and possible precedents from nature are discussed. [source]

Chitosan/Gold Nanocomposites: Chitosan Films Doped with Gold Nanorods as Laser-Activatable Hybrid Bioadhesives (Adv. Mater.

ADVANCED MATERIALS, Issue 38 2010
38/2010)
The cover image represents an inside view of a laser-activated gold nanorod/chitosan film. Gold nanorods dispersed throughout the polymeric chitosan matrix absorb incident near-infrared laser light. The photothermal conversion from the gold nanorods activates the surrounding chitosan strands to mediate functional adhesion with biological tissue, as discussed in work reported on p. 4313 by Paolo Matteini and co-workers. [source]

Chitosan Films Doped with Gold Nanorods as Laser-Activatable Hybrid Bioadhesives

ADVANCED MATERIALS, Issue 38 2010
Paolo Matteini
Biocompatible chitosan/gold nanorods films are fabricated and tested as laser-activatable adhesives. When exposed to near-infrared laser light the nanoparticles carry out efficient photothermal conversion, which activates the polar groups of chitosan strands and mediates functional adhesion with a biological tissue. This technology may enable a number of key applications in medicine including tissue repair, wound dressing and drug delivery. [source]

Water Vapor Transmission Rates and Sorption Behavior of Chitosan Films

JOURNAL OF FOOD SCIENCE, Issue 7 2000
J.L. Wiles
ABSTRACT: This study measured the water vapor transmission rates (WVTR) and moisture sorption of chitosan films over a range of water vapor pressures at 25 °C. Films of a constant thickness were made using chitosan with 3 levels of deacetylation. Films were tested at test relative humidity (RH) difference between RH values of 84%, 75%, 69%, 53%, 43%, 33%, 23%, 11%, and 0 at 25 °C using ASTM F1249-90 or ASTM E 96-80. The equilibrium moisture content in the films ranged from 3.7% to 31.8% (dry basis) corresponding to 11% to 84% RH. WVTRs of films increased with increase in water vapor pressure. The mean WVTR ranged from 6.7 to 1146 (g/m2/d) over the range of water vapor pressure from 2.68 (11% RH) to 19.9 mmHg (84% RH). The percentage of deacetylation of chitosan films and the viscosity of the cast solution did not have an effect on the WVTR properties of chitosan films. [source]

Preparation and Characterization of Microwave-treated Carboxymethyl Chitin and Carboxymethyl Chitosan Films for Potential Use in Wound Care Application

MACROMOLECULAR BIOSCIENCE, Issue 10 2005
Panya Wongpanit
Abstract Summary: CM-chitin and CM-chitosan films were successfully crosslinked by microwave treatment. Crosslinking of the microwave-treated CM-chitin films involved mainly the carboxylate and the secondary alcohol groups, while crosslinking of microwave-treated CM-chitosan films involved the carboxylate and the amino groups. In addition, the crystallinity of CM-chitin increased with increasing microwave treatment time, whereas an increase in the crystallinity of the microwave-treated CM-chitosan films was not observed. At a similar percentage of weight loss, the crosslinking of either CM-chitin or CM-chitosan films by microwave treatment required much less stringent condition when compared with the crosslinking by autoclave treatment. Based on both direct and indirect cytotoxicity assays, the cytotoxicity of the microwave-treated CM-chitin films was negative, while that of the microwave-treated CM-chitosan films was positive. Human fibroblasts adhered on the surface of microwave-treated CM-chitosan films much better than on the surface of microwave-treated CM-chitin films. Total amount of protein synthesis of living NHGF cells that were cultured on chitin, microwave-treated CM-chitin, chitosan, microwave-treated CM-chitosan films. [source]

Reagentless Glucose Biosensor Based on the Direct Electrochemistry of Glucose Oxidase on Carbon Nanotube-Modified Electrodes

ELECTROANALYSIS, Issue 11 2006
Xiliang Luo
Abstract The direct electrochemistry of glucose oxidase (GOD) was revealed at a carbon nanotube (CNT)-modified glassy carbon electrode, where the enzyme was immobilized with a chitosan film containing gold nanoparticles. The immobilized GOD displays a pair of redox peaks in pH,7.4 phosphate buffer solutions (PBS) with the formal potential of about ,455,mV (vs. Ag/AgCl) and shows a surface-controlled electrode process. Bioactivity remains good, along with effective catalysis of the reduction of oxygen. In the presence of dissolved oxygen, the reduction peak current decreased gradually with the addition of glucose, which could be used for reagentless detection of glucose with a linear range from 0.04 to 1.0,mM. The proposed glucose biosensor exhibited high sensitivity, good stability and reproducibility, and was also insensitive to common interferences such as ascorbic and uric acid. The excellent performance of the reagentless biosensor is attributed to the effective enhancement of electron transfer between enzyme and electrode surface by CNTs, and the biocompatible environment that the chitosan film containing gold nanoparticles provides for immobilized GOD. [source]

Reagentless Protein Assembly Triggered by Localized Electrical Signals

ADVANCED MATERIALS, Issue 9 2009
Xiao-Wen Shi
Electrode-imposed signals are used to assemble proteins without the need for reactive reagents. The two-step assembly approach uses i) cathodic signals to electrodeposit the amino-polysaccharide chitosan and ii) anodic signals to activate the chitosan film for protein assembly. Proteins are shown to assemble at individual electrode addresses, with spatial selectivity and quantitative control. [source]

Evaluation of a Non-Woven Fabric Coated with a Chitosan Bi-Layer Composite for Wound Dressing

MACROMOLECULAR BIOSCIENCE, Issue 5 2008
Bai-Shuan Liu
Abstract This study presents a novel design of an easily stripped bi-layer composite that consists of an upper layer of a soybean protein non-woven fabric coated with a lower layer, a genipin-crosslinked chitosan film, as a wound dressing material. This study examines the in vitro properties of the genipin-crosslinked chitosan film and the bi-layer composite. Furthermore, in vivo experiments are conducted to study wounds treated with the composite in a rat model. Experimental results show that the degree of crosslinking and the in vitro degradation rate of the genipin-crosslinked chitosan films can be controlled by varying the genipin contents. In addition, the genipin contents should exceed 0.025 wt.-% of the chitosan-based material if complete crosslinking reactions between genipin and chitosan molecules are required. Water contact angle analysis shows that the genipin-crosslinked chitosan film is not highly hydrophilic; therefore, the genipin-crosslinked chitosan layer is not entangled with the soybean protein non-woven fabric, which forms an easily stripped interface layer between them. Furthermore, this new wound dressing material provides adequate moisture, thereby minimizing the risk of wound dehydration, and exhibits good mechanical properties. The in vivo histological assessment results reveal that epithelialization and reconstruction of the wound are achieved by covering the wound with the composite, and the composite is easily stripped from the wound surface without damaging newly regenerated tissue. [source]

Preparation and characterization of chitosan/KSF biocomposite film

POLYMER COMPOSITES, Issue 8 2009
Aylin Alt
Chitosan,clay biocomposites have been prepared in which KSF-montmorillonite (KSF) is used as filler and diluted acetic acid is used as solvent for dissolving and dispersing chitosan and montmorillonite, respectively. The effect of KSF loadings in biocomposites has been investigated. The characterization with different methods (FTIR, DSC, TGA, SEM, and XRD) on chitosan/KSF biocomposites systems was examined. Morphology and properties of chitosan biocomposites have been studied compared with those of pure chitosan. The FTIR and SEM results indicated the formation of an intercalated-and-exfoliated structure at low KSF content and an intercalated-and-flocculated structure at high KSF content. The thermal stability and the mechanical properties of the composites were also examined by DSC, TGA/DTG, and tensile strength measurements, respectively. The dispersed clay improves the thermal stability of the matrix systematically with the increase of clay loading. Tensile strength of a chitosan film was enhanced until the clay ratio up to 2 wt% and elongation-at break decreased with addition of clay into the chitosan matrix. The XRD results confirmed the intercalation of the biopolymer in the clay interlayer by the decrease of 2, values while the chitosan,clayratio increases. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source]

Biomimetic modification of chitosan with covalently grafted lactose and blended heparin for improvement of in vitro cellular interaction

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2008
Huaping Tan
Abstract Lactose- and heparin-modified chitosan films were prepared and their physical and biological properties were compared with chitosan, chitosan-g-heparin, and chitosan-g-lactose films. Atomic force microscopy (AFM) measurement showed that all these films in the dry state were rather flat with a roughness smaller than 20,nm. While the chitosan-g-lactose/heparin and chitosan-g-lactose films have the highest swelling and weight loss ratios, the chitosan and chitosan-g-heparin films have the lowest. The chitosan-g-lactose/heparin film showed stronger ability to induce chondrocyte attachment, proliferation, viability, and glycosaminoglycan (GAG) secretion than that of the chitosan, chitosan-g-heparin, and chitosan-g-lactose films. Chondrocyte aggregates and nodules were observed on the chitosan-g-lactose/heparin and chitosan-g-lactose films, which still preserved viable metabolic ability. These results show that the lactose-modified and heparin-incorporated chitosan film can enhance the cell,biomaterial interaction synchronously. The resulting chitosan-g-lactose/heparin material is more bioactive that might be applicable as promising scaffold for chondrogenesis. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Biomimetic Approach to Confer Redox Activity to Thin Chitosan Films

EFFECT OF POLYGODIAL ON MECHANICAL, OPTICAL AND BARRIER PROPERTIES OF CHITOSAN FILMS

Functional Properties of Antimicrobial Lysozyme-Chitosan Composite Films

JOURNAL OF FOOD SCIENCE, Issue 8 2004
S.-I. Park
ABSTRACT: Lysozyme-chitosan composite films were developed for enhancing the antimicrobial properties of chitosan films. A 10% lysozyme solution was incorporated into 2% chitosan film-forming solution (FFS) at a ratio of 0%, 20%, 60%, and 100% (w lysozyme/w chitosan). Films were prepared by solvent evaporation. Lysozyme release from the film matrix, the antimicrobial activity of films against Escherichia coli and Streptococcus faecalis, and basic film properties were investigated. The lysozyme release proportionally increased with increasing initial concentration of lysozyme in the film matrix, and the amount of released lysozyme was in natural log relationship with time. The films with 60% lysozyme incorporation enhanced the inhibition efficacy of chitosan films against both S. faecalis and E. coli, where 3.8 log cycles reduction in S. faecalis and 2.7 log cycles reduction in E. coli were achieved. Water vapor permeability of the chitosan films was not affected by lysozyme incorporation, whereas the tensile strength and percent elongation values decreased with increased lysozyme concentration. Scanning electron microscopy images revealed that lysozyme was homogeneously distributed throughout the film matrix. This study demonstrated that enhanced antimicrobial activity of lysozyme-chitosan composite films can be achieved by incorporating lysozyme into chitosan, thus broadening their applications in ensuring food quality and safety. [source]

Water Vapor Transmission Rates and Sorption Behavior of Chitosan Films

Evaluation of a Non-Woven Fabric Coated with a Chitosan Bi-Layer Composite for Wound Dressing

Chitosan tailor-made films: the effects of additives on barrier and mechanical properties

PACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2009
Cristiana M. P. Yoshida
Abstract With the aim of achieving ,tailor-made' chitosan films, the effects of several variables on the properties of chitosan films were studied. These variables were chitosan concentration and molecular weight of thermally depolymerized chitosan, addition of lipids (palmitic acid, beeswax or carnauba wax) and plasticizer (glycerol). The water vapour transmission rate (WVTR) and mechanical properties of these films were measured. The innovative feature of this study is that it provides specific information to support the design of tailor-made films. These can only be formulated when the effects of the important variables are well understood. It was found that WVTR was reduced by 57% in film made from chitosan that had been thermally treated for 7,h at 100°C (molecular mass 13.7,kDa), while in the emulsion films, the WVTR was increased by incorporation of palmitic acid, beeswax or carnauba wax incorporation. The mechanical properties (tensile strength and elongation at break) were improved when glycerol was used as plasticizer, resulting in more elastic films (increasing the elongation at break by 62%). Copyright © 2008 John Wiley & Sons, Ltd. [source]