Disruption of Bacterial Biofilms by a Green Synthesized Artemisinin Nano-copper Nanomaterial

Abstract Bacterial biofilms are associated with antibiotic resistance and account for approximately 80% of all bacterial infections. In this study, we explored novel nanomaterials for combating bacteria and their biofilms. Artemisinin nano-copper (ANC) was synthesised using a green synthesis strategy, and its shape, size, structure, elemental composition, chemical valence, zeta potential, and conductivity were characterised using transmission electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, zeta potential, and dynamic light scattering (DLS). The results showed that ANC was successfully synthesised utilizing a liquid-phase chemical reduction method using chitosan as a modified protectant and l-ascorbic acid as a green reducing agent. The stability of ANC was evaluated using DLS. The results showed that the particle size of the ANC at different concentrations was comparable to that of the original solution after 7 days of storage, and there was no significant change in PDI (P > 0.05). The antibacterial effects of ANC on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were determined by Disk diffusion and broth dilution methods. The results demonstrated that ANC inhibited and killed E. coli and S. aureus. The effect of ANC on bacterial biofilms was investigated using Crystal Violet staining, scanning electron microscopy, laser confocal microscope, and quantitative PCR. The results showed that ANC treatment was able to destroy bacterial biofilms and downregulate biofilm- and virulence-related genes in E. coli (HlyA, gyrA, and F17) and S. aureus (cna, PVL, ClfA, and femB). Green-synthesised ANC possesses excellent anti-biofilm properties and is expected to exhibit antibacterial and anti-biofilm properties.