Chitosan is obtained by alkaline deacetylation of chitin from the shell of shrimp, crab and insects etc, is an alkaline polymer, one of the abundant and reproducible natural polymers in the world. Due to the biocompatibility, biodegradable, no toxicity and environmental friendship, chitosan and its ramifications are potentially be widely applied especially in biomedical applications such as in drug delivery system and artificial soft tissues and so on. Chitosan contains hydroxyl and ammoniac in its unit str...