Chitin and chitosan: Properties and applications

Antimicrobial properties of chitosan and mode of action: A state of the art review

Chitosan, a versatile hydrophilic polysaccharide derived from chitin, has a broad antimicrobial spectrum to which gram-negative, gram-positive bacteria and fungi are highly susceptible. In the current review, three possible and accepted antimicrobial mechanisms for chitosan are presented and briefly discussed. The activity dependence on polymeric molecular weight (MW) and degree of acetylation (DA) are described. The chitosan minimum inhibitory concentrations (MIC) are summarized according to recent data found in the literature. The potential to improve inhibitory growth of bacteria by using water soluble chitosan derivatives is also discussed. The data indicate that the effectiveness of chitosan varies and is dependent on species of target microorganisms.

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A Review of the Antimicrobial Activity of Chitosan

Chitosan based edible films and coatings: A review

This review concerns the applications of some polysaccharides in the domain of biomaterials and bioactive polymers. Natural polysaccharides from different sources have been studied for a long time, and their main properties are summarized in this paper; some of their derivatives obtained by chemical modification are also described. The main polysaccharides currently used in the biomedical and pharmaceutical domains are chitin and its derivative chitosan, hyaluronan and alginates. Alginates are well known for their property of forming a physical gel in the presence of divalent counterions (Ca, Ba, Sr) whereas carrageenans form a thermoreversible gel; these seaweed polysaccharides are mainly used to encapsulate different materials (cells, bacteria, fungi). Other promising systems are the electrostatic complexes formed when an anionic polysaccharide is mixed with a cationic polysaccharide (e.g. alginate/chitosan or hyaluronan/chitosan). An important development of the applications of polysaccharides can be predicted for the next few years in relation to their intrinsic properties such as biocompatibility and biodegradability in the human body for some of them; they are also renewable and have interesting physical properties (film-forming, gelling and thickening properties). In addition, they are easily processed in different forms such as beads, films, capsules and fibres. Copyright © 2007 Society of Chemical Industry

Main properties and current applications of some polysaccharides as biomaterials

Chitin is the second most abundant carbohydrate polymer in nature next to cellulose. The main source of chitin is crustacean shells. Chitosan, derived from chitin by alkaline deacetylation, characteristically plays an important role in applications. Several parameters determine the chitosan specifications, namely, chitosan sources, incubation time, pretreatment conditions, temperature and acid and alkaline treatment. Chitosan extraction has been achieved by microwave heating and compared with that of conducting the deacetylation in an autoclave. High molecular weight chitosan (as determined by viscosity measurements of chitosan in dilute acetic acid solution), white color, high water binding capacity (WBC) and fat binding capacity (FBC) has been obtained by microwave treatment. In addition, microwave treatment saves a large amount of energy (due to the shorter time of heating) which is a very important factor for commercial productions. The data extracted from X-ray diffraction, nuclear magnetic resonance and Fourier transforms infrared spectroscopy have shown more crystalline and higher DDA of chitosan produced in microwave than the one in autoclave. Moreover, the antibacterial activity of chitosan prepared by microwaves was higher than that produced using the autoclave.

Enhancement and Characterization of Chitosan Extraction from the Wastes of Shrimp Packaging Plants

Sorption behavior of 60Co and 152+154Eu radionuclides onto chitosan derivatives

Corrosion inhibition efficiency of some hydrophobically modified chitosan surfactants in relation to their surface active properties

The swelling properties of poly(ether urethane)s and the preparation of interpenetrating polymer networks (IPNs) from a poly(ether urethane) thermoplastic elastomer and hydrogel forming polyacrylamide have been studied. The acrylamide monomer was polymerized with simultaneous crosslink formation, in the presence of the swollen thermoplastic elastomer. Upon removal of the swelling solvent, an IPN was obtained which absorbed water in the manner of a hydrogel but had mechanical properties superior to a hydrogel.

Maher Z. Elsabee

Papers

Enhancement and Characterization of Chitosan Extraction from the Wastes of Shrimp Packaging Plants

Sorption behavior of 60Co and 152+154Eu radionuclides onto chitosan derivatives

Corrosion inhibition efficiency of some hydrophobically modified chitosan surfactants in relation to their surface active properties

Gradient interpenetrating polymer networks. I. Poly(ether urethane) and polyacrylamide IPN

Metal uptake by chitosan derivatives and structure studies of the polymer metal complexes