Preparation, characterization and antioxidant activity of silk peptides grafted carboxymethyl chitosan

Free radicals are closely related to the occurrence and development of aging, cancer and inflammation, the ability to scavenge free radicals is an important indicator of the antioxidant activity. In this study, we prepared a water soluble, free radical scavenging and biocompatible copolymer for regenerative therapy. Carboxymethyl chitosan (CMC) was modified with silk peptide (SP) by microbial transglutaminase (MTGase), FT-IR and NMR spectroscopy were used to confirm the successful grafting of SP to CMC. The degree of substitution was determined by ultraviolet spectrophotometry. In vitro antioxidant activity assays demonstrated that, within the scope of study the highest scavenging activity of DPPH was 24.86%, 91% of hydroxyl radical and 36.8% of H₂O₂. Finally, no relevant cytotoxicity against NIH-3T3 mouse fibroblasts was found for the copolymers. Briefly, our results suggested the potential application of CMC-SP as an antioxidant for regenerative therapy.