Figure 4.

Spatially patterned degradation of thiol–maleimide hydrogels by photoinitiated radicals. a) Hydrogels were prepared for FRAP measurement with and without LAP (1 wt.%) and with and without 405 nm light patterning (10 min before fluorophore bleaching). Monitoring fluorescence recovery for 90 s and fitting the resulting intensity measurements yielded diffusion coefficients for each condition. Normalizing to fluorophore diffusion inside hydrogels before photodegradation, samples treated with LAP and 405 nm light had comparable diffusion to free fluorophore (a ≈25% increase in relative diffusion rate), suggesting total or near‐complete gel degradation. Samples treated with 405 nm light only (no LAP) exhibited no changes in diffusion. b) Resolution testing of photodegradation in a thiol–maleimide hydrogel showed high pattern fidelity for both positive (yellow boxes) and negative (pink boxes) features. Scale bar = 100 µm. c) Arbitrary subtractive photopatterning in thiol–maleimide hydrogels of the i) University of Oregon Duck and ii) University of Colorado Buffalo, as well as iii) an aperiodic monotile metamaterial, showing complex pattern retention following photodegradation. Scale bars = 50 µm.