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.