A Facile and Straightforward Strategy to Decorate ZnO Nanoparticles on Graphene Surface: Antimicrobial Property

We successfully fabricated zinc oxide/reduced graphene oxide (ZnO/rGO) nanocomposite via a simple and environmentally-friendly route using supercritical carbon dioxide (scCO₂), where reduction of graphene oxide and growth of ZnO nanoparticles occurred in one-step. Transmission electron microscopic analysis revealed that the ZnO nanoparticles of size 10–20 nm were decorated onto the rGO surface. The ZnO nanoparticles on the rGO surface were spherical and well dispersed. Antibacterial activity of the composite was tested against Escherichia coli, Bacillus cereus, and Staphylococcus aureus as model strains. Minimum inhibitory concentrations (MICs) ranging 0.08–1.3 μg/mL were observed for all the pathogens. The MIC of the composite against the test strains showed that it has a less significant effect on the growth of S. aureus than B. cereus and E. coli. The efficient antibacterial activity was attributed to the synergistic effect of rGO and ZnO nanoparticles.