Fabrication of conductive polyaniline hydrogel using porogen leaching and projection microstereolithography

Conducting hydrogels represent a new generation of "smart" biomaterials which combine the favorable biocompatibility properties of hydrogels and electrical properties of organic conductors, and would potentially lead to the development of new biointerfaces with controllable properties. Currently, conductive hydrogels are synthesized by either adding conducting particles to, or polymerizing conducting polymer monomers within, hydrogel matrix, however challenges in processing limit their applications in functional devices. In this work, a poly(ethylene glycol) diacrylate-polyaniline (PEGda-PANI) conductive hydrogel is developed using interfacial polymerization process. In this process, aniline monomers polymerize at the organic/water interface between hexane media and hydrophilic PEGda hydrogel networks. PANI chains become hydrophilic with acid doping and migrate into aqueous phase confined within PEGda networks. The synthesized PEGda-PANI hydrogel has acceptable mechanical, electrical and biocompatible properties. Traditional fabrication methods including process-driven salt-leaching and design-driven projection stereolithography were used to develop 3D scaffolds using PEGda-PANI hydrogels. This methodology can be potentially extended to a wide variety of fabrication techniques to develop hydrogels with complex geometries and next-generation functional biointerfaces.