Composites Based on Chitosan and Inorganic Materials for Biomedical Applications

Chitosan, a linear and semicrystalline polysaccharide composed of randomly distributed β, 1–4 linkages of N-acetyl-d-glucosamine and d-glucosamine, obtained from partial deacetylation of chitin, is a natural polysaccharide present in shells of marine crustaceans and cell walls of fungi, as well as other invertebrate organisms. This biopolymer is a polyelectrolyte with reactive functional groups, high adsorption capacity, mucoadhesive, biodegradable, bioresorbable, innately biocompatible and non-toxic to living tissues as well as having antibacterial, antifungal, and antitumor activity. These features highlight the suitability and extensive applications of chitosan in the biomedical field, such as implant coatings, wound healing devices, tissue engineering, and drug delivery systems. However, its limited solubility in water and other organic solvents, poor colloidal stability, poor mechanical strength, and high swelling ratio limits its full exploitation for some biomedical purposes. To overcome these limitations, chitosan-inorganic composites have been formulated to enable the adjustment of the desired properties for intended applications. This chapter focused on the fundamentals of chitosan and its composites and how the chitosan-inorganic materials, called “green composites” or “bionanocomposites,” can be utilized in biomedical applications.