Three-dimensionally-patterned submicrometer-scale hydrogel/air networks that offer a new platform for biomedical applications.

Phase mask interference lithography was employed to fabricate three-dimensional (3D) hydrogel structures with high surface area on neural prosthetic devices. A random terpolymer of poly(hydroxyethyl methacrylate- ran-methyl methacrylate- ran-methacrylic acid) was synthesized and used as a negative-tone photoresist to generate bicontinuous 3D hydrogel structures at the submicrometer scale. We demonstrated that the fully open 3D hydrogel/air networks can be used as a pH-responsive polymeric drug-release system for the delivery of neurotrophins to enhance the performance of neural prosthetic devices. Additionally an open hydrogel structure will provide direct access of neuronal growth to the device for improved electrical coupling.