V2CTx‑AuNanostructures for Rapid Surface-Enhanced Raman Scattering Detectionof Bacteria and Synergistic Photothermal/Photodynamic Therapy

The misuse of antibiotics has led to the emergence of multidrug-resistant bacteria. There is an urgent need to explore methods to effectively kill bacteria without relying on antibiotics. In this paper, a vanadium carbide-based (V₂CT_x-Au) nanostructures was successfully synthesized by electrostatic self-assembly for the direct detection and killing of bacteria. The nanostructures could be directly used for label-free surface-enhanced Raman spectroscopy detection of bacteria without tedious processing. Photothermal detection demonstrated that the temperature of the V₂CT_x-Au nanostructures can increase above 50 °C within just 200 s, and the photothermal conversion efficiency of the material is 37.82%. Reactive oxygen species detection experiments showed that the V₂CT_x-Au nanostructures can produce the O₂^·– and ¹O₂. Combined with SEM images of the bacteria, the results showed that V₂CT_x-Au nanostructures produced photothermal therapy antibacterial effects under 808 nm laser irradiation and exhibited photodynamic therapy synergistic antibacterial properties. The survival rates of Escherichia coli (E. coli) and extended-spectrum β-lactamase Escherichia coli (ESBL-E. coli) were 6.88 and 1.58%, respectively. In addition, cytotoxicity experiments and hemolytic tests showed that the prepared V₂CT_x-Au nanostructures exhibited good biocompatibility. This study provides a feasible route for the label-free and rapid detection of bacteria and rapid sterilization without antibiotics, which can help solve the problem of bacterial infection, especially drug-resistant bacteria.