Transglutaminase-catalyzed grafting collagen on chitosan and its characterization

• Collagen–chitosan was synthesized with microbial transglutaminase as bio-catalyst.
• Collagen–chitosan presents better moisture absorption and moisture retention abilities and antioxidant activity.
• Collagen–chitosan promotes cell proliferation effectively.

Collagen grafted chitosan was prepared with microbial transglutaminase (MTGase) as biocatalyst which showed high efficiency, selectivity, mild reaction condition and environmental friendliness. The reaction conditions that influenced the degree of substitution (DS) were optimized, which included the reaction time, the reaction temperature, the mass ratio of collagen to chitosan and the mass ratio of MTGase to chitosan. In this study, the water-solubility collagen–chitosan could serve not only to reduce the loss of moisture but also to absorb the moisture. And the moisture absorption and moisture retention abilities were closely related to the DS values. In addition, in vitro antioxidant activity was evaluated in terms of DS values and concentration. Furthermore, L929 mouse fibroblasts were cultured with collagen–chitosan, and methylthiazol tetrazolium (MTT) assay exhibited that collagen–chitosan with DS of 0.660 displayed pronounced cell viability at 2.5 mg/ml. Therefore, the water-soluble collagen–chitosan showed the potentiality to repair skin in cosmetic, biomedical and pharmaceutical fields.