LAUSR

Black Phosphorus (BP) as a layered two-dimensional (2D) semiconductor material with a tunable band-gap has attracted growing attention for promising applications in diverse fields including biotechnology owing to its excellent physical and chemical properties. In this study, BP crystals were synthesized by using a chemical vapor transport method and exfoliated into BP nanosheets in deoxygenated water or hexane. Next, monodisperse Au nanoparticles that were synthesized by using a surfactant assistant chemical reduction method were assembled on exfoliated BP in hexane to yield BP/Au nanocomposites. The photothermal antibacterial and antibiofilm activity of BP nanosheets and BP/Au nanocomposites were investigated against Enterococcus faecalis as a pathogen biofilm-forming bacteria by studying the photothermal effect, bacterial growth curve, colony counting and live/dead fluorescence staining methods under near infrared (NIR) light irradiation. Thanks to the higher photothermal conversion efficiency of BP/Au nanocomposites than that of bare BP nanosheets under NIR light irradiation, they destructed the bacterial cell membrane more efficiently than bare BP with the biofilm inhibition rate of 58%. It should be noted that this is the first study on the antibacterial and antibiofilm activity of BP/Au nanocomposites via a photothermal process under NIR light irradiation. This work shows the potential of BP/Au nanocomposites in fighting against pathogen bacteria and paves the way for the exploration of biocompatible 2D semiconductor BP-based antibacterial platforms.