Chitosan-Based Polyelectrolyte Complex Hydrogels for Biomedical Applications

Abstract

Chitosan is produced by deacetylation of chitin, a structural element in the exoskeleton of crustaceans and insects, which is the second most abundant natural biopolymer after cellulose. Chitosan has found applications in many primary industries such as: agriculture, paper, textiles, pharmacology, cosmetology, and wastewater treatment. There is a major interest in using chitosan for biomedical applications due to its generous properties including biocompatibility, low toxicity, hemostatic potential, good film-forming character, anti-infectional activity, and susceptibility to enzymatic degradation. The property of chitosan which will be in detail discussed in this chapter refers to its ability to form polyelectrolyte complexes due to the presence of amine groups in its repetitive unit. Therefore, chitosan in aqueous acid solution reacted with anionic polysaccharides such as: carboxymethylcellulose, xanthan, alginate, carrageenan, gellan, oxychitin and oxypullulan, chondroitin and hyaluronan, poly(galacturonic acid), poly(L-glutamic acid) as well as synthetic polyanions such as poly(acrylic acid) to give polyelectrolyte complexes. One major advantage of polyelectrolyte complexes for biomedical use is their superior biocompatibility in respect with other formulations which are using synthetic crosslinkers to obtain stable hydrogels. The aim of this chapter is to describe the process of chitosan complexation with other natural and synthetic polyanions, the factors that influence the formation and stability of these polyelectrolyte complexes and the potential applications in biomedical field.