Self-assembly and metal ions-assisted one step fabrication of recoverable gelatin hydrogel with high mechanical strength

Gelatin hydrogel has been widely applied in bio-applications due to their good biocompatibility and high water content. However, poor mechanical properties of gelatin hydrogel greatly limit their application. Here we present a facile one-step soaking method to fabricate a recoverable gelatin hydrogel with high mechanical property, which is based on hydrogen bonds and metal ionic interaction. The mechanical properties of gelatin hydrogels can be tuned with different metal ions, temperatures and soaking times. Especially, gelatin-Fe3+ hydrogel can reach to 65 MPa compression stress with the compressive strain over 99% and possess good fatigue resistance under cyclic loadings. Besides, hydrogels crosslinked with metal ions show better antibacterial ability against Escherichia coli and Staphylococcus aureus. This work suggested an alternative for the design of tough gelatin-based hydrogels with desirable properties, which may hold promising for potential bio-applications under physiological conditions.