Conductive GelMA/alginate/polypyrrole/graphene hydrogel as a potential scaffold for cardiac tissue engineering; Physiochemical, mechanical, and biological evaluations

Cardiac failure can be a life-threatening condition that, if left untreated, can have significant consequences. Functional hydrogel has emerged as a promising platform for cardiac tissue engineering. In the proposed study, gelatin methacrylate (GelMA) and alginate, as a primary matrix to maintain cell viability and proliferation, and polypyrrole and carboxyl-graphene, to improve mechanical and electrical properties, are thoroughly evaluated. Initially, a polymer blend of GelMA/Alginate (1:1) was prepared, and then the addition of 2-5 wt% of polypyrrole was evaluated. Next, the effect of incorporating graphene-carboxyl nanosheets (1, 2, and 3 wt%) within the optimized scaffold with 2 wt% polypyrrole was thoroughly studied. The electrical conductivity of the hydrogels was significantly enhanced from 0.0615 ± 0.007 S/cm in GelMA/alginate to 0.124 ± 0.04 S/cm with the addition of 5 wt% polypyrrole. Also, 3 wt% carboxyl graphene improved the electrical conductivity to 0.27 ± 0.09 S/cm. The compressive strength of carboxyl-graphene-containing hydrogel was in the range of 175 to 520 kPa, and tensile strength was 61 and 133 kPa. The simplicity and low-cost fabrication, tunable mechanical properties, optimal electrical conductivity, blood compatibility, and non-cytotoxicity of GelMA/alginate/polypyrrole/graphene biocomposite hydrogel is a promising construct for cardiac tissue engineering.