Fig. 1.

Design of cyclic, enzyme-responsive progelator peptides for activatable gelation. a Cyclic progelator peptides, containing gelling sequence (green), matrix metalloproteinase (MMP)/elastase enzyme cleavage recognition sequence (red), and disulfide bridge (black), resist assembly due to conformational constraint. Rhodamine-labeled (pink ellipse) self-assembling peptides (SAPs) were employed for in vivo studies as a 5 mol% additive to provide a means for imaging the hydrogels in ex vivo microscopy analyses. b Enzymatic cleavage results in linearization into SAPs. c SAPs assemble into viscoelastic hydrogels composed of β-sheets fibrils