Preparation of photo-crosslinking carboxymethyl chitosan hydrogel for sustained drug release

Carboxymethyl chitosan is an important chitosan derivative with good biocompatibility and degradability, and has a wide range of biomedical applications. In this study, water-soluble carboxymethyl chitosan derivative that can be photo-crosslinked by UV irradiation was synthesized. Methacrylated carboxymethyl chitosan (M-CMCS) was synthesized by N-methacrylation of carboxymethyl chitosan (CMCS). The chemical structures of M-CMCS were characterized by H-1 NMR and FT-IR. The M-CMCS hydrogels with different degrees of crosslinking was prepared by UV-triggered photo-crosslinking. The microscopic morphology, mechanical properties, swelling properties, enzymatic degradation properties and in vitro drug release behaviors of M-CMCS hydrogels were investigated by SEM, rheometer, and UV-Vis spectroscopy, respectively. The results show that the degree of methacrylation is gradually increased as the molar ratio of glycidyl methacrylate to carboxymethyl chitosan increases. M-CMCS hydrogels have the structure of high porosity and interconnected pores with the pore size of 1-20 mu m. The swelling ratio of M-CMCS hydrogels is decreased as the degree of crosslinking increases. M-CMCS hydrogel can be slowly degraded by lysozyme, and the degradation rate is decreased by increasing the degree of crosslinking. M-CMCS hydrogels show sustained release behavior for anticancer drug gemcitabine, and the drug release can be extended to 4 days. Photo-crosslinked M-CMCS hydrogels show great promise for drug release and tissue engineering.