Protein co-assembled silk fibroin-whey protein isolate hydrogels mediated by metal-polyphenol coordination: Formation mechanism and antimicrobial activity

The advancement of functional materials through the utilization of food proteins has increasing attention within the realm of food science and technology. In this research, it was reported that two food-grade namely silk fibroin (SF) and whey protein isolate (WPI), are capable of coagulating under physical action. They were conjugated with oxidized guar gum (OGG), epigallocatechin gallate (EGCG), and silver ion (Ag + ) to construct a hydrogel system. The dynamic Schiff base linkage between the amino group of SF-WPI complex and the aldehyde group of OGG, along with the metal-polyphenol coordination between Ag + and EGCG, facilitated the formation of the hydrogel. The findings regarding the antibacterial activity of the hydrogel demonstrated that it exerted antibacterial effects against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus . Moreover, the hydrogel in this research also exhibited remarkable antioxidant capacity within the cell model, along with excellent adhesive and injectable properties. The integration of protein co-assembly, dynamic covalent cross-linking, and metal coordination provides a novel approach for the fabrication of multifunctional food-protein-based hydrogels. The results of this study indicate that this hydrogel holds potential applications in food-contact antibacterial materials or biomedical domain.