Encouraged by the hydrogel's rapid response to low-energy visible light, we next sought to examine whether hydrogels could be degraded through complex tissue. Skin-on pork belly was dissected and hydrogels placed at varying depths; a Rubiq-crosslinked hydrogel was deposited 2 cm below the skin surface, a Rubpy hydrogel at 1 cm, and oNB (modified with Cy5-azide to enhance visualization) at 0.5 cm. Gels were respectively subjected to red, green, and blue light (50 mW cm -2 at the skin) and in-tissue degradation was visually monitored (Fig. ). Hydrogel dissolution was observed for all three hydrogels following <2 hrs illumination at the depths reported. To the best of our knowledge, this is the first time that a photodegradable biomaterial has been directly controlled at these tissue depths, highlighting the potential of these materials for future in vivo applications. oNB-crosslinked gels under red and green light irradiation. d. Hydrogels were formed with equal ratios of all three photolabile crosslinkers and increasing amounts of nondegradable diazidotri(ethylene glycol) (TEG) crosslinker (0 -90%, white rectangle). e. Intermediate stiffnesses were accessible through partial degradation of hydrogel crosslinks. Hydrogels were exposed to red, green, then blue light (35 min each, 10 mW cm -2 ) to selectively cleave specific amounts of crosslinks within the material. f. Spatial control over hydrogel degradation demonstrated by the casting of individually crosslinked hydrogels in close proximity. Open microfluidic methadologies were used to cast interconnected multimaterial geometries; exposure to red light resulted in the center Rubiq degradation, with subsequent exposures to green and blye light respectively degrading the Rubpy and oNB portions. Scale bar = 5 mm. g. Rubpy and Rubiq hydrogels photodegraded with 530 nm light (10 mW cm -2 , 5 sec) following mask-based photolithography. Scale bar = 100 µm. h. Rubiq hydrogels were completely degraded through up to 2 cm of complex tissue (skin-on pork belly shown here), Rubpy hydrogels through 1 cm, and oNB (dyed with Cy5) through 0.5 cm.