Conductive gelatin methacrylate-poly(aniline) hydrogel for cell encapsulation

New conductive hydrogels with superior biocompatibility continue to be developed in order to serve as bioactive scaffolds capable of modulating cellular functionality for tissue engineering applications. We developed an electrically conductive gelatin methacrylate-poly(aniline) (GelMA-PANi) hydrogel that is permissive of matrix mineralization by encapsulated osteoblast-like cells. Incorporation of PANi clusters within the GelMA matrix increases the electro-conductivity of the composite gel, while maintaining the osteoid-like soft mechanical properties that allows three-dimensional encapsulation of living cells. Viability of human osteogenic cells encapsulated within GelMA-PANi hydrogels was similar to that of GelMA. Cells within GelMA-PANi also demonstrated the capability of depositing mineral within the hydrogel matrix after being chemically induced for two weeks, although the total mineral content was lower as compared to GelMA. Additionally, we demonstrated that the GelMA-PANi-composite hydrogel could be printed in complex, user-defined geometries using digital projection stereolithography.