Fig. 6. Selective degradation of 1 and 3 in solution and hydrogel. (A) Irradiation at 592 nm photolyzed 3 in solution while leaving 1 intact, until irradiation at 410 nm. (B) Striped hydrogel incorporating alternating sections of 1 and 3 was selectively degraded at 592 nm, leaving the orange gel regions intact. The remaining sections crosslinked by 1 were degraded by 410 nm light.