Spatial Patterning of Hydrogels via 3D Covalent Transfer Stamping from a Fugitive Ink.

In this study, a novel hydrogel patterning approach using 3D covalent transfer stamping from a fugitive ink is introduced. A model transfer molecule (7-diethylamino-3-(4'maleimidylphenyl)-4-methylcoumarin (CPM)) is absorbed into a 3D fugitive ink stamp made from poly(caprolactone), and then encapsulated in a poly(ethylene glycol) hydrogel. As the CPM diffuses from the fugitive ink to the curing hydrogel it is selectively covalently bound at the boundary of the ink and the hydrogel. Removal of the fugitive ink by solvent exchange leads to a negative copy of interconnected channels patterned with the localized transfer of the molecules at the hydrogel interface. The results suggest that small molecules can be patterned in porous hydrogels in a spatially controllable manner and that the transferred amount can be tuned.