Novel Microbial Palladium Nanoparticles with a High Photothermal Effect for Antibacterial Applications

Abstract

Novel biocompatible palladium nanoparticles (Pd-NPs) have been prepared by microorganisms via <i>Bacillus megaterium</i> Y-4. It was demonstrated that ultrasonication treatment of biologically reduced Pd-NPs impart a much higher absorption in NIR regions and a better photothermal conversion efficiency to the material. The as-prepared material showed excellent biocompatibility and antibacterial activity under NIR irradiation. In less than 10 min, the disinfection efficiency for a low dosage of Pd-NPs (20 mg/L) was 99.99% toward both <i>Staphylococcus aureus</i> and <i>Escherichia coli</i>. The exclusive and even dispersed microbial Pd-NPs display a high efficiency of photothermal conversion under the irradiation of NIR, which endows them with excellent antibacterial activity in a low dosage.