Modification of chitosan grafted with collagen peptide by enzyme crosslinking.

Free radicals are closely related to the occurrence and development of aging, cancer and inflammation. In this paper, the microbial transglutaminase (MTGase) was used as a catalyst to graft the collagen peptide (COP) molecules on the amino group of carboxymethyl chitosan sulfate (CMCS) to improve the antioxidant effects. FT-IR and NMR spectroscopy were used to confirm the successful grafting of COP to CMCS. Degree of substitution (DS) of CMCS-COP could be controlled by adjusting the reaction conditions. With the increase of concentration, the ability of each sample on scavenging capacity and reducibility tends to increase obviously. The results of anticoagulant experiments showed that the ability of CMCS and CMCS-COP with three different degrees of substitution on activated partial thrombin time (APTT) and prothrombin time (PT) values were all increased to compare with the control group. No relevant cytotoxicity against NIH-3T3 mouse fibroblasts was found for the copolymers. These results suggested that CMCS-COP would appear to be a promising candidate for wound dressing application.