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Owing to its wide availability and biocompatibility, chitosan has been extensively investigated for role in wound healing, burn treatment, ophthalmology, drug delivery and as artificial skin [79]. It has the advantage of the flexibility of chemical modification at the –NH₂ group at C2 position, compared to cellulose (–OH at C2) [13]. Such modifications can often lead to improved biodegradability and hydrophilic nature.

Chitosan is an effective agent for wound healing and preparation of artificial skin. For the development of artificial skin, it is usually mixed with another agent. Reports like detailed chitosan–gelatin [80, 81], chitosan–gelatin–hyaluronic acid [82], or nanocomposites– chitosan [83] based chitosan composites as artificial skin due to their flexibility, antimicrobial properties, accelerated wound healing due to gas and liquid exchange through the matrix, and favourable mechanical properties. Wound infections result due to a disturbed host–bacteria equilibria in tissue, with the balance in favour of bacteria [84].

Due to its anti-microbial role and the hydrating ability of its hydrogels, chitosan composites were also tested as curative agents for wounds. This demonstrates a broad variety of antimicrobial and anti-fungal activities, while the efficacy and mode of action differs. However, fungi are more susceptible than bacteria in many cases [85]. In particular, chitosan–Zn complex has been found to be active against many microbes [86]. The lower molecular weight fractions were found to have greater activity [79]. Consequently, there are various commercial wound dressings based on chitin or chitosan as the chief biomolecule [87].

Chitosan–gelatin biocomposites with nanophase hydroxyapatite are investigated in tissue engineering applications for development of biological substitutes for implantation [79]. Tissue architecture includes functionalized scaffolds that have stable binding matrix for attachment and proliferation of cells and to maintain their functions; they are then implanted in the target organism. Additionally, porous scaffolds reported based on chitosan which were both flexible and broadly applicable [88, 89].