An electrically conductive gellan gum/polyvinyl alcohol interpenetrating network hydrogel: a dual crosslinked 3D printing ink for cardiac tissue

Biofabrication of cardiac tissue constructs with inherent electrical conductivity and contractility presents a significant challenge. In this study, an interpenetrating network (IPN) hydrogel composed of methacrylate-modified polyvinyl alcohol (M-PVA) and gellan gum (GG) reinforced with reduced graphene oxide (rGO) has been developed. The M-PVA/GG/rGO hydrogel leverages the thermoresponsive property of polysaccharide gellan gum for controlled gelation during the 3D printing process, followed by post-printing photocrosslinking of M-PVA to enhance structural stability. The IPN hydrogel exhibited porous morphology with interconnected pores, high porosity, swellability, and significant electrical conductivity (0.62 ± 0.05 mS cm^-1) imparted by the inclusion of rGO. Rheological analysis demonstrated the shear-thinning property and predominant elastic modulus of the developed hydrogel, thereby being suitable for pneumatic extrusion-based 3D printing. The printed constructs cultured with H9c2 cardiomyoblasts and EA.hy926 endothelial cells demonstrated favorable <i>in vitro</i> cell viability, proliferation, and cardiac specific gene expression, influenced by the matrix composition. The dual-crosslinked, electroconductive M-PVA/GG/rGO hydrogel shows significant promise for promoting vascularization in cardiac tissue engineering, facilitating tissue regeneration, development of organotypic models and potentially enabling the development of electroconductive biomedical devices.