Zarzar, Lauren D., Philseok Kim, Mathias Kolle, C. Jeffrey Brinker, Joanna Aizenberg, and Bryan Kaehr. 2011. “Direct Writing and Actuation of Three-Dimensionally Patterned Hydrogel Pads on Micropillar Supports.” Angew. Chem. Int. Ed. 50, no. 40: 9356–9360. doi:10.1002/anie.201102975.
Freely swelling, three-dimensionally patterned responsive hydrogels fabricated by multiphoton lithography on the tips of flexible pillars provide unique capabilities for the design of adaptive systems. The resulting materials have tunable actuation direction and angle, sensitive optical response, and precise spatial integration of gels with varying pH and temperature response (see picture; scale bar: 20 μm).