Fig. 3. Light-induced patterning and imaging of a photoresponsive polyacrylamide hydrogel film functionalized with (1) and the o-nitrobenzylphosphate ester photocleavable hairpin (3).

a Photolithographic patterning of the hydrogel through a circular hole-containing mask (λ = 365 nm), and the fluorescence imaging of the resulting pattern by the hybridization of TAMRA labeled (3’) to the activated (3) tethers associated with the irradiated domains. b Panel I—Fluorescence confocal microscope imaging of the patterned hydrogel. Panel II—Three-dimensional confocal microscope imaging of the hydrogel film across the x-y, x-z, and y-z planes. Panel III– Fluorescence confocal microscope imaging of the reconstructed three-dimensional patterned hydrogel. Scale bar lengths 50 μm. c Fluorescence confocal microscope imaging of twelve layered circular domains generated by two-photon laser scanning confocal microscope photopatterning process (λ = 740 nm) using different spatial and positional focusing depths. Panel I—Confocal microscope imaging of the two-photon laser patterned hydrogel fluorescence images recorded along the x-y plane (a), the x-z plane (b) and the y-z plane (c). Panel III– Confocal microscope imaging of reconstructed three-dimensional patterned hydrogel that includes twelve patterned discs in rectangular configurations along the x-y-z axes. Scale bars correspond to 20 μm. N = 4 independent experiments were performed.