Chitin and chitosan are biopolymers with excellent bioactive properties, such as biodegradability, non-toxicity, biocompatibility, haemostatic activity and antimicrobial activity. A wide variety of biomedical applications for chitin and chitin derivatives have been reported, including wound-healing applications. They are reported to promote rapid dermal regeneration and accelerate wound healing. A number of dressing materials based on chitin and chitosan have been developed for the treatment of wounds. Chitin and chitosan with beneficial intrinsic properties and high potential for wound healing are attractive biopolymers for wound management. This review presents an overview of properties, biomedical applications and the role of these biopolymers in wound care.

Chitin membranes containing nanosilver were evaluated for use as antimicrobial wound dressings. Chitin at a concentration of 0.25% dissolved in 5% lithium chloride-dimethylacetamide and nanosilver synthesized by gamma irradiation were used for fabrication of chitin-nanosilver membranes. UV-vis spectroscopy and energy dispersive x-ray (EDX) analysis with scanning electron microscopy (SEM) were used to confirm the presence of silver nanoparticles. Fluid absorption capacity, moisture vapour transmission rate, antimicrobial activity, effect on cell viability, in vitro wound healing property and the silver elution profile were determined, to assess the wound dressing properties of the chitin-nanosilver membranes. The antimicrobial efficacy of chitin membranes containing silver nanoparticles was observed against a broad range of microbes such as Acinetobacter baumanii, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris and Candida albicans. The chitin-nanosilver membranes prepared with 100 ppm silver resulted in 6-log to 8-log reduction in viable counts after 24 h and had a positive impact on fibroblast proliferation. The fluid handling capacity, cell viability test and silver elution profile indicate that the chitin-nanosilver dressing can contribute to effective management of infected wounds. In vitro studies have demonstrated the antimicrobial activity and wound-healing properties of chitin membranes containing nanosilver.

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Biological approaches for the removal of heavy metals and radionuclides from contaminated water are reported. The present study was carried out with the objective of identifying bacterial strains for the uptake of cesium that could be used for bioremediation. Polymer carriers prepared by radiation polymerization were used for the immobilization of bacteria and the efficiency of free cells and immobilized cells for the removal of cesium was evaluated. Thirty-five bacterial isolates were screened for resistance to cesium and five bacterial isolates based on resistance to cesium (BR-3, BR-6, BR-21, BR-39, BR-40) were selected for immobilization. Polymer carriers were prepared using 10, 20, 30, 40 and 50% acrylamide at different doses of 1 to 5 kGy gamma radiation. The polymer carriers prepared using 30% and 40% acrylamide at 5 kGy were found to be suitable based on gel fraction and absorption capacity for the immobilization of bacterial cells. Bioremoval of cesium by free and immobilized bacterial cells was evaluated. Significant reductions of 76–81% cesium were observed with bacterial cells immobilized by radiation polymerization.