Reduced Graphene Oxide Functionalized with Gold Nanostar Nanocomposites for Synergistically Killing Bacteria through Intrinsic Antimicrobial Activity and Photothermal Ablation

The exploration of multifunctional photothermal agents is important for antibacterial photothermal lysis, which has emerged as an effective approach to address the problem of pathogenic bacteria infection irrespective of the drug-resistant effect. In the present work, a 2D reduced graphene oxide supported Au nanostar nanocomposite (rGO/AuNS) was prepared by the seed-mediated growth method for synergistically killing multidrug-resistant bacteria. Owing to the prickly and sharp-edge nanostructure, the rGO/AuNS displayed superior antibacterial activity probably due to the damage of the cell walls or membranes. The cell viability of Methicillin-resistant Staphylococcus aureus (MRSA) was as low as 32% when the MRSAs were incubated with the rGO/AuNS for 180 min in the absence of light. The 2D structure of the rGO/AuNS facilitated the strong binding affinity toward bacteria. Upon the 808 nm NIR laser irradiation, significant enhancement in bactericidal efficiency (complete death) was obtained due to the localized hyperthermal effect of rGO/AuNS. Moreover, the RGO/AuNS displayed promising biocompatibility. It indicates that the rGO/AuNS can be an alternative and effective dual functional photothermal agent for synergistically killing the multidrug-resistant bacteria.