FIG. 1.

Hydrogel mechanical characterization. (A) Chemical structure of NorHA. (B) Schematic of reaction between NorHA (HA: blue, norbornene: red) and MMP-degradable dithiol peptide by UV light-mediated thiol-ene click chemistry. (C) Oscillatory shear rheology showed that increasing the concentration of MMP-degradable peptide crosslinker resulted in hydrogels of increasing stiffness. Low (1 kPa), medium (3 kPa), and high (10 kPa) elastic modulus hydrogels were developed to approximate a range of physiological muscle tissue stiffnesses. Data presented as mean ± SD, n = 3 hydrogels per experimental group. HA, hyaluronic acid; LAP, lithium acylphosphinate; MMP, matrix metalloproteinase; NorHA, norbornene-modified hyaluronic acid; SD, standard deviation; UV, ultraviolet. Color images are available online.