Fig. 4:

Spatiotemporal control of hydrogel properties with light. a. Spatial patterning of hydrogels can be achieved by directing light through a pre-designed photomask into a hydrogel where spatial regions exposed to light undergo changes in mechanics or signaling ligand composition. Precise patterning of hydrogels with sub-micron resolution in the x,y,z planes can be achieved with a laser scanning microscope. This technique allows (b) local photo-degradation to create channels or other microscale features, or (c) peri-cellular alteration in mechanics through photo-stiffening or photo-softening to control and perturb cellular processes.