Synthesis and characterization of gold/silica hybrid nanoparticles incorporated gelatin methacrylate conductive hydrogels for H9C2 cardiac cell compatibility study

Herein, gold/silica (Au/SiO₂) hybrid nanoparticles (NPs) were incorporated into the gelatin methacrylate (GelMA) matrix to construct mechanically strong and electrically conductive GelMA hydrogel for biomedical applications. As-prepared GelMA-Au/SiO₂ hydrogels were characterized by field emission scanning microscopy (FESEM), compressive strength test, and conductivity/resistivity measurement. Accordingly, to evaluate the cell compatibility of as-prepared conductive hydrogel, the in-vitro biocompatibility assay was performed in rat cardiomyoblast H9C2 cells. The results showed composite hydrogel possessed enhanced compressive strength and conductive property without compromising the beneficial properties such as porous morphology and biocompatible nature of GelMA hydrogel. After incorporation of hybrid NPs, the compressive strength and Young's modulus of composite hydrogels were increased by two-folds. Similarly, the cyclic compression test showed that the pure GelMA hydrogel loses its mechanical stability from the initial cycles, while GelMA-Au/SiO₂ hydrogels were sustained up to 50 cycles. In case of cell viability study, the CCK-8 assay result showed enhanced cardiomyoblast cell adhesion and proliferation on the conductive hydrogels. Moreover, the GelMA-Au/SiO₂ conductive hydrogels exhibited an increased cell viability by 15% of pure GelMA hydrogels. Similarly, the confocal laser scanning microscopy (CLSM) results showed uniformly aligned cell growth throughout the conductive hydrogels. Overall, this study presents a novel strategy for inducing electrical conductivity and improving mechanical integrity to the gelatin-based GelMA hydrogel by incorporating bifunctional hybrid NPs for regenerative medicine and tissue engineering applications.