Photoelectric nature of nanocomposite ZnO/CuO antibacterial activity

We present the study of the antibacterial properties of ZnO/CuO films, activated by LED lamp light with an emission spectrum close to that of natural sunlight, on an example of antibiotic-resistant S. aureus bacterial culture. The antibacterial properties of films with photoinduced electroporation lead to the emergence of a potential difference between semiconductor $n$-type ZnO and $p$-type CuO nanoparticles with a local increase in field intensity to a value $ \sim 1 \times {{10}^{4}}$ V/cm, sufficient for irreversible electroporation to occur. Exposure leads to a decrease in bacterial contamination from the value $8 \times {{10}^{8}}$ CFU/mL to $0$. Raman spectra before and after exposure were analyzed by calculating spectral peak parameters corresponding to molecular vibrations in nucleic acids, cell membranes, and proteins. The disappearance or degradation of peaks illustrating vibrations of $A$, $G$ in nucleic acids, disruption of the secondary structure of proteins and the appearance of disordered forms of amide I were detected, as well as the emerging disorder of lipid chains in the membrane and the destruction of $N$-acetylmuramic acid and $N$-acetylglucosamine, which are part of the gram-positive microorganisms' cell membrane, therefore indicating the destruction of the cell wall and irreversible destruction of the internal structure of the cells.