Development of Alginate/Graphene Oxide Bio-Ink for 3D-Printing of Electroconductive Patches: Aiming to Cardiac Regeneration

Cardiovascular diseases (CVDs) remain the leading cause of mortality worldwide, driving the rapid advancement of cardiac tissue engineering (CTE) as a strategy to develop effective therapeutic interventions. Among its notable achievements is the cardiac patch, a supportive scaffold designed to repair damaged tissue following myocardial infarction (MI). This study selected alginate (Alg) due to its superior biocompatibility and printability for the fabrication of cardiac patches through extrusion-based 3D bioprinting, a novel technology for scaffold construction. To further enhance scaffold performance, graphene oxide (GO) nanosheets were incorporated into the Alg matrix to improve electrical conductivity, mechanical strength, cell adhesion, and printability. Bioinks comprising 8% Alg and different concentrations of GO (0, 0.05, 0.1, and 0.2 mg mL⁻¹) were formulated and thoroughly assessed for their physicochemical characteristics and cytocompatibility. All formulations exhibited suitable rheological characteristics for 3D printing. Moreover, the addition of GO reduced strand thickness, increased pore size, and improved overall printability. Mechanical testing revealed an increase in tensile strength from 0.18 MPa to 0.79 MPa with the addition of 0.2 mg mL⁻¹ of GO, while electrical conductivity reached (0.3 ± 0.00) × 10⁻⁶ S/m, approaching the range required for CTE. MTT assays demonstrated a concentration-dependent cytotoxic effect, showing decreased viability at 0.1 and 0.2 mg mL⁻¹ GO, while scaffolds with 0 and 0.05 mg mL⁻¹ GO preserved high viability. Scanning electron microscopy (SEM) further confirmed enhanced cell adhesion and filopodia extension in Alg-GO-1 (0.05 mg mL⁻¹) compared to pure Alg scaffolds. The findings generally suggested that Alg/GO composites, particularly at optimized concentrations, hold significant promise as bioinks for CTE due to their favorable mechanical, electrical, and biological properties.