Incorporation of Visible Light-Responsive Push-Pull Azobenzene into Polymer Networks toward the Construction of Photodynamic Hydrogel Scaffolds.

Forces play vital roles in regulating cellular behavior, and integrins are prime examples that cells use to sense forces. Designer scaffolds have been developed to trigger integrin-mediated mechanotransduction to control cellular functions. However, current scaffolds lack spatiotemporal control of integrin mechanostimulation in a three-dimensional matrix. In this study, a photoresponsive hydrogel scaffold in which a cell-adhesive push-pull azobenzene was covalently loaded onto the hydrogel was synthesized. The cis-trans photoisomerization of azobenzene is expected to mechanostimulate the interaction of integrins with the cell-adhesive peptides (RGD peptide; arginine-glycine-aspartic acid) bound to azobenzene. The photoresponsive behavior of the synthesized azobenzene exhibited a photoresponse immediately after the on-off switching of blue light. The efficient cross-linking of azobenzene-bearing PEG through a click reaction allowed successful cell encapsulation in the azobenzene-bearing hydrogel. Taken together, the photoresponsive hydrogel scaffold is expected to find applications in controlling cellular behaviors in four dimensions via integrin-mediated mechanotransduction.