Fig. 5. Photopatterning and spatially controlled degradation of PhoCoil gels.

(A) PhoCoil gels can be patterned using photomasks to restrict 405 nm light to desired areas. (B) Photomask-based patterning of grids of varying sizes onto PhoCoil gels. Gels were exposed to 60 min of 10 mW cm⁻², 405 nm light through a grid photomask with light passing through 100, 50, or 25 μm-wide squares (top left). Images were obtained in the xy (top) and xz (bottom) planes via confocal microscopy. Scale bars are 100 μm. (C) Intensity in red and green channels was quantified via ImageJ to demonstrate changes in resolution of patterning. Intensity was quantified from the center of a red square to the center of a green line at 5 random locations. Data shown is mean ± SD. (D) 3D reconstruction of the 100 μm grid patten throughout the thickness of a gel. Scale bar is 250 μm. (E) Spatially controlled degradation of photomask patterned gels. Gels were exposed to 60 min of 10 mW cm⁻², 405 nm light through a photomask, then photographed (true color) or confocal imaged (initial). Gel degradation was allowed to occur in excess PBS, and gels were confocal imaged to visualize degradation (final). Scale bars are 1 mm. (F&G) Light-based degradation of PhoCoil gels through ex vivo tissue. The left half of each gel was covered with a photomask, and the entire gel was placed under 1 mm-thick deli turkey or chicken skin. Gels were exposed to 5 min of high-intensity 405 nm light through the tissue mimic, confocal imaged to visualize the pattern (initial), and left to degrade in excess PBS prior to final fluorescent imaging. Scale bars are 1 mm.