Systematically engineered graphene sheets with electrostatic Au-reinforcement to strengthen 2D nanofibrous scaffolds for improved bone regeneration

Here, we report the polycaprolactone (PCL) based 2D nanofibrous scaffold with minimal loading (0.0005-0.002 wt%) of Au-reinforced graphene (RG) sheets for improved bone tissue regeneration. The microsized graphene oxide (GO) sheets (829 nm) were tailored strategically to 282 nm-sized monodispersed nanosheets for uniform electrostatic attachment of gold nanoparticles (GNPs). The GNPs-GO sheets were reduced to GNPs-RG sheets using a visible-light-induced chemical-free green method where the oxygen functional groups of GO have not been removed completely to enhance the functionality of GNPs-RG for bone tissue regeneration. The monodispersibility of GNPs-RG sheets helped to prepare PCL-based nanofibrous scaffolds with uniformly distributed GNPs-RG (0.002 wt%) with higher electrical conductivity (>3.5 times) and greater mechanical strength (>4.5 times). The electrostatic field simulation studies with COMSOL suggested that there was a uniform distribution of the electric field. The GNPs-RG addition creates an apt adhesion site due to their multifunctional and conductive properties for PCL@GNPs-RG nanofibrous scaffold which resulted in enhanced cell adhesion and proliferation of MC3T3-E1 cells. The PCL@GNPs-RG nanofibrous scaffold showed higher alkaline phosphatase activity and improved calcium mineralization after 21 d of incubation. The results indicated that the PCL@GNPs-RG scaffold has a promising capacity and potential for bone tissue regeneration.