Chitosan-Based Nanogels for Biomedical Applications

Abstract

Regarding biomedical applications, chitosan has emerged as an interesting biopolymer in tissue engineering because it can be tuned to suit the biocompatibility, functional and mechanical stability, as well as the increasing requirements that this area demands. Thermoresponsive chitosan-based nanogels were also prepared by complexation and crosslinking of carboxymethyl chitosan with poly-vinyl alcohol (PVA) in order to obtain antibacterial nanogels in the absence of any surfactant. For this, thermosensitive PVA chains could collapse forming by precipitation stable nanospheres above their lower critical solution temperature in aqueous media. Nanogels were formed by posterior interaction of PVA nanospheres with chitosan and covalent crosslinking with N,N-methylenebis(acrylamide), leading to doubly responsive nanogels. Nanoparticles of chitosan have been synthesized by diverse methods and employing different crosslinkers. All methods are based on the restriction of the particle size during crosslinking, which is basically controlled by carrying out it, or in an heterogeneous reaction, such as suspension, emulsion/nanoemulsion/microemulsion, dispersion or precipitation, or based on self-assembly process.