Photo and Reduction Dual-Responsive Hydrogel for Regulating Cell Adhesion and Cell Sheet Harvest

Regulating cell-surface interactions plays a key role for biomaterials and their applications in cell-based therapies. In this paper, we demonstrated a dual-responsive hydrogel platform to achieve phototriggered protein immobilization and reduction-induced protein release. By o-nitrobenzyl photochemistry, including sequential aldehyde generation upon light irradiation and imine ligation with amine compounds, adhesive proteins can be effectively immobilized on the hydrogel with spatial and quantitative control, thus mediating cell adhesion in designed areas. By reduction chemistry of the disulfide bond, the patterned proteins can be released from the hydrogel, thus detaching cells in a noninvasive manner. Finally, the dynamic adsorption-dissociation of proteins enables the hydrogel to be tactfully used for cell sheet harvesting in an enzyme-free mode with light-defined shapes. This work not only provides an efficient strategy for recovery of cells and cell sheets but also provides insights into cell-material interactions mediated by proteins.