Synthesis and characterization of polysaccharide-based antimicrobial materials

Abstract

Novel broad-spectrum antimicrobial materials were developed based on the natural polysaccharide chitosan. Firstly, a group of antimicrobial materials were synthesized by quaternization and alkylation of chitosan. An argon plasma-ultraviolet (UV) induced coating method for hydrogel surface immobilization was developed, which can be applied on diverse soft biomedical surfaces. A novel mechanism of these hydrogels based on “anion sponge” concept was proposed and proven. The optimized coating formulation and conditions show excellent antimicrobial potency. The in vitro and in vivo studies suggest this antimicrobial coating is biocompatible with mammalian cells. Secondly, a peptidopolysaccharide that mimics the bacterial peptidoglycan structure, which is a feature unique to bacterial membrane but absent in mammalian cells, was designed, synthesized and tested. By the ring-opening polymerization of N-carboxyanhydrides (NCA), a polysaccharide backbone was copolymerized with cationic polylysine, and the resulting optimized peptidopolysacchride shows high selectivity to bacteria over mammalian cell. Thirdly, a polysaccharide-nanomaterial hybrid was designed by combining quaternized chitosan and nanomaterial. The huge specific surface area of the nanomaterial enables high surface density of the cationic polymers, and the nanomaterial act as the delivery vehicle for the targeted anionic bacterial membrane, thus enhancing the antimicrobial properties. These novel polysaccharide-based antimicrobial materials have a promising prospect in further applications.