光动力水凝胶生物材料在触发式治疗释放、有序器官发育和体外四维控制先进细胞命运方面展示了巨大潜力。目前的光敏材料因依赖于高能紫外光（<400 nm），导致组织穿透性差并限制了其使用可见光谱的范围而存在限制。在本文中，我们报道了一类快速响应和具有独特三色波长选择性的光可降解材料交联剂，其对低能可见光（400-617 nm）具有响应。我们展示了当与多功能聚乙二醇大分子前体混合时，基于钌多吡啶和邻硝基苯（oNB）的交联剂可形成细胞相容性生物材料，可通过复杂组织中的深部进行时空图案化均一软化和多重降解。我们证明了这些光敏凝胶中的封装生物活细胞具有较高的存活率，并且可以在光降解后成功地从水凝胶中恢复。展望未来，我们预期这些先进材料平台将推动3D机械生物学、控制性药物递送和新一代组织工程应用的研究。© 2023. Springer Nature Limited.

Photodynamic hydrogel biomaterials have demonstrated great potential for user-triggered therapeutic release, patterned organoid development, and four-dimensional control over advanced cell fates in vitro. Current photosensitive materials are constrained by their reliance on high-energy ultraviolet light (<400 nm) that offers poor tissue penetrance and limits access to the broader visible spectrum. Here, we report a family of three photolabile material crosslinkers that respond rapidly and with unique tricolor wavelength-selectivity to low-energy visible light (400-617 nm). We show that when mixed with multifunctional poly(ethylene glycol) macromolecular precursors, ruthenium polypyridyl- and ortho-nitrobenzyl (oNB)-based crosslinkers yield cytocompatible biomaterials that can undergo spatiotemporally patterned, uniform bulk softening, and multiplexed degradation several centimeters deep through complex tissue. We demonstrate that encapsulated living cells within these photoresponsive gels show high viability and can be successfully recovered from the hydrogels following photodegradation. Moving forward, we anticipate that these advanced material platforms will enable new studies in 3D mechanobiology, controlled drug delivery, and next-generation tissue engineering applications.© 2023. Springer Nature Limited.