Biohybrid oxidized alginate/myocardial extracellular matrix injectable hydrogels with improved electromechanical properties for cardiac tissue engineering.

Injectable hydrogels which mimic the physicochemical and electromechanical properties of cardiac tissue is advantageous for cardiac tissue engineering. Here, a newly-developed in situ forming double-network hydrogel derived from biological macromolecules (oxidized alginate (OA) and myocardial extracellular matrix (ECM)) with improved mechanical properties and electrical conductivity was optimized. 3-(2-aminoethyl amino) propyltrimethoxysilane (APTMS)-functionalized reduced graphene oxide (Amine-rGO) was added to this system with varied concentrations to promote electromechanical properties of the hydrogel. Alginate was partially oxidized with an oxidation degree of 5% and the resulting OA was cross-linked via calcium ions which was reacted with amine groups of ECM and Amine-rGO through Schiff-base reaction. In situ forming hydrogels composed of 4% w/v OA and 0.8% w/v ECM showed appropriate gelation time and tensile Young's modulus. The electroactive hydrogels showed electrical conductivity in the range of semi-conductors and a suitable biodegradation profile for cardiac tissue engineering. Cytocompatibility analysis was performed by MTT assay against human umbilical vein endothelial cells (HUVECs), and the optimal hydrogel with 25 μg/ml concentration of Amine-rGO showed higher cell viability than that for other samples. The results of this study present the potential of OA/myocardial ECM-based hydrogel incorporated with Amine-rGO to provide a desirable platform for cardiac tissue engineering.