Tough biopolymer IPN hydrogel fibers by bienzymatic crosslinking approach

In this report, bienzymatic crosslinking approach was applied to prepare biopolymer hydrogel fibers composed of gelatin and chitosan with an interpenetrating polymer network (IPN) structure. The IPN biopolymer hydrogel fibers were prepared by wet spinning while microbial transglutaminase (mTG) catalyzed the formation of one network of gelatin and horseradish peroxidase (HRP) in the presence of H2O2 induced another network of chitosan grafted with phloretic acid (chitosan-PA) intertwining with the former. The mechanical performances of the hydrogel fibers were measured by an electronic single fiber strength tester. It was found that the mechanical properties of the gelatin/chitosan IPN hydrogel fibers had a significant improvement with the increase of the concentration of gelatin and chitosan, and the IPN fiber has the highest tension of 38.6 cN and elongation of 387.2%. Accelerated degradation in the presence of papin indicated that the gelatin/chitosan-PA IPN hydrogel fibers own controllable degradability. In addition, biological evaluation indicated the IPN hydrogel fibers can support cell adhesion and proliferation. Moreover, hand weaving trail showed the knittablity of the IPN hydrogel fibers. Therefore, the gelatin/chitosan IPN hydrogel fibers prepared by bienzymatic crosslinking approach possess excellent biocompatibility and mechanical strength, which may be desirable candidates for engineering tissue scaffolds.