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.

中文翻译：

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用于调节细胞粘附和细胞片收获的光和还原双响应水凝胶

调节细胞-表面相互作用对于生物材料及其在细胞疗法中的应用起着关键作用。在本文中，我们展示了一种双响应水凝胶平台，以实现光触发的蛋白质固定和还原诱导的蛋白质释放。由o-硝基苄基光化学，包括光照射后连续生成醛和与胺化合物连接的亚胺，可以通过空间和定量控制将粘附蛋白有效地固定在水凝胶上，从而在设计区域介导细胞粘附。通过二硫键的还原化学，图案化的蛋白质可以从水凝胶中释放出来，从而以非侵入性的方式分离细胞。最后，蛋白质的动态吸附-解离使水凝胶能够以无酶模式巧妙地用于细胞片收获，具有光定义的形状。这项工作不仅为恢复细胞和细胞片层提供了一种有效的策略，而且还提供了对蛋白质介导的细胞-材料相互作用的见解。