Montmorillonite-Modified Reduced Graphene Oxide Stabilizes Copper Nanoparticles and Enhances Bacterial Adsorption and Antibacterial Activity

To increase antibacterial activity and reduce the cytotoxicity of copper nanoparticles (CuNPs), we used reduced graphene oxide with montmorillonite to support CuNPs and fixed CuNPs on reduced graphene oxide to synthesize the hybrid montmorillonite-reduced graphene oxide copper nanoparticles (MMT-rGO-CuNPs). The synthesized MMT-rGO-CuNPs complex showed a stronger antibacterial activity against Gram-positive bacteria S. aureus than Gram-negative E. coli. This may be due to the protective effect of the outer membrane of E. coli, as well as the fact that the MMT-rGO-CuNPs complex adsorbs S. aureus more strongly than E. coli. The hybrid molecule's antibacterial efficacy is the combined result of the synergistic effects of electrostatic adsorption and copper ion sterilization ability. At the same time, the MMT-rGO-CuNPs complex exhibits a lower cytotoxicity than PVP-CuNPs and provides a biocompatible composite material with a reduced cytotoxicity.