The chitosan hydrogels: from structure to function

Knowledge of the structure of hydrogels and the mechanism of gelation of intelligent hydrogels is essential to designing bioinspired hydrogels. As one of the raw materials in hydrogels, chitosan has been highly pursued due to the polymer's biocompatibility, biodegradability and low toxicity. The biomimetic principles for preparing intelligent chitosan hydrogels have drawn great research interest in materials science and engineering. In this paper, we present the recent progress in fabricating intelligent chitosan hydrogels. The features of hydrogels, the advantages of chitosan, and the development of the chitosan intelligent hydrogels are discussed. Diverse physical interactions and chemical covalent bonds have been used to construct the hydrogel network; this review focuses on the interactions that form the hydrogels that are based on chitosan. The stimuli-responsive characteristics, bio-inspired functions and high mechanical strength properties of the chitosan hydrogels are detailed herein. The emphasis of this paper is on the relationship between the structural characteristics and the corresponding functions of the intelligent hydrogels. A perspective on the challenges facing the field and prospects for future development are given.