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 in vitro 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.