Magnetically separable MXene@Fe3O4/Au/PDA nanosheets with photothermal-magnetolytic coupling antibacterial performance

Harmful bacteria are common substances in water that endanger human health, so it is urgent to establish a simple system that can tackle these hazardous substances simultaneously. In this work, a novel magnetic MXene@Fe3O4/Au/polydopamine (PDA) nanosheet with excellent photothermal-magnetolytic coupling anti-bacterial performance is developed. MXene, Au and polydopamine all have good photothermal properties, so the photothermal conversion efficiency of the MXene@Fe3O4/Au/PDA nanosheet reaches as high as 48.7%. After 6 min of 808 nm laser irradiation, the MXene@Fe3O4/Au/PDA nanosheets (120 mu g.mL(-1)) can achieve nearly 100% antibacterial effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In comparison to the sole photothermal treatment, the nanosheet at lower concentration (80 mu g.mL(-1)) also exhibit stronger antibacterial properties against both Gram-negative and Gram-positive bacteria during the photothermal-magnetic coupling treatment. The result is mainly because the heat generated by the photothermal effect of the nanosheet is directly transferred to the cell membrane, and the edge of the nanosheet cuts the cytomembrane similar to a magnetic hot nanoblade , resulting in subsequent shrinkage, deformation and even rupture.

Automated summary

A novel magnetic MXene@Fe3O4/Au/polydopamine (PDA) nanosheet with excellent photothermal-magnetolytic coupling anti-bacterial performance is developed. The nanosheet exhibits high photothermal conversion efficiency and can achieve nearly 100% antibacterial effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The photothermal-magnetic coupling treatment enhances the antibacterial properties of the nanosheet.