Bioinspired Reversibly Cross-linked Hydrogels Comprising Polypeptide Micelles Exhibit Enhanced Mechanical Properties

and biosensing. [ 5 ] Hydrogels based on engineered peptides and proteins, termed biohydrogels, herein, are being studied extensively because of their biocompatibility and the ease with which biofunctionality—typically incorporated as one or more copies of a fused bioactive protein or peptide—can be encoded into these systems at the genetic level. [ 1a , 6 ] The majority of efforts to engineer biohydrogels have focused on creating covalently cross-linked networks because of their mechanical stability. [ 7 ] Covalently cross-linked biohydrogels, however, are not always ideal because of i) their often complex synthesis, which in some cases results in the formation of toxic by-products from the cross-linking reaction, and ii) their inherently static and nonreversible crosslinks. [ 8 ] This irreversibility can impede the remodeling of these hydrogels in a biological environment, and in vivo can potentially lead to cell death, induction of infl ammatory responses, and ultimately failure of implanted devices. [ 7,9 ]