▎ 摘　　要

Two-dimensional monolayer structures of graphene-based materials and their hybrids offer interesting physico-chemical properties and have been extensively explored in a wide variety of applications in recent years. We have developed a simple, rapid, eco-friendly and cost-effective route for the synthesis of cobalt oxide (Co3O4) nanoparticle-decorated reduced graphene oxide (GO) by using date syrup as the reducing agent. The GO reduction process occurs simultaneously with Co3O4 nanoparticle formation at 95 A degrees C under stirring. The structure and composition of the Co3O4 nanoparticle-decorated reduced graphene oxide (rGO) sheets were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. Our XRD and SEM results suggested that the Co3O4 nanoparticles decorated the surface of the rGO. The biocompatibility of the Co3O4 nanoparticle-decorated rGO (Co3O4-rGO) was assessed using human mesenchymal stem cells (hMSCs) as in vitro model by MTT cell viability assay and AO/EB staining. The cell viability assay indicated that Co3O4-rGO exhibited biocompatibility with hMSCs. Compared with a control, no changes were observed in the fluorescent microscopy images of cells exposed to Co3O4-rGO. Our present findings suggest a green and easy route for the synthesis of biocompatible Co3O4-rGO with hMSCs, which is promising for biomedical applications.