Natural protein-based hydrogels with high strength and rapid self-recovery

Natural protein hydrogels are considered as the promising candidates for biomaterials. However, natural protein hydrogels often exhibit poor mechanical properties. Herein, using bovine serum albumin (BSA) as natural protein model, a new kind of D/C-hybrid DN gels, consisting of tetrakis(hydroxymethyl)phosphonium chloride (THPC) cross-linked BSA (THPC-BSA) as dynamic covalent bond cross-linked first network and covalently cross-linked polyacrylamide (PAAm) as second network, were successfully synthesized by a facile method. Different from fully chemical DN gels without recovery, the optimized THPC-BSA/PAAm D/C-hybrid DN gel not only demonstrated excellent tensile properties, but also displayed extremely fast self-recovery property and fatigue resistance. More importantly, various natural proteins could be also used to prepare natural protein-based D/C-hybrid DN gels, and all of them showed improved mechanical properties and fast self-recovery properties. The results indicate our new strategy to fabricate recoverable natural protein-based D/C-hybrid DN gels is general. We hope our new strategy as well as our natural protein-based D/C-hybrid DN gels will provide a new avenue to prepare and study high performance natural protein hydrogels.