Antibacterial Silver Nanoparticles Supported on Graphene Oxide with Reduced Cytotoxicity

The effect of graphene oxide (GO) on both the antibacterial and cytotoxicity behavior of silver nanoparticles (Ag NPs) has been studied. Ag NPs supported on GO were synthesized by two methods, ex situ and in situ. These nanocomposites were characterized by transmission electron microscopy, ultraviolet-visible spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The antibacterial activity of the nanomaterials was evaluated against Escherichia coli and Staphylococcus aureus by the disk-diffusion method and dynamic contact assays. While GO flakes showed antibacterial behavior only in the dynamic contact test, both GO-Ag NPs nanohybrids eradicated bacteria independent of the condition. Noteworthily, the high cytotoxicity of Ag NPs to human-derived cells was dramatically decreased by the GO layers in the nanocomposite. The in situ hybrid particles showed the lowest cytotoxicity without losing the strong antibacterial effect. These results demonstrate that growth of Ag NPs on GO layers could enable the development of a new family of antibacterial materials with low cytotoxicity to human cells.