ZnO-Ag nanoparticles produced via two-step pulsed laser ablation in liquid (PLAL) as antibacterial agent against Staphylococcus aureus

Abstract

Recent years have witnessed the growing interest in Zinc oxide (ZnO) in nanoscale size on antimicrobial and nanomedicine applications. Two main antimicrobial mechanisms of ZnO, photo-catalysis, and Zn2+, ion release has left some possibilities for some improvement, including producing hybrid metal-ZnO nanoparticles and introducing dopant material into ZnO structure. Silver (Ag) is applied to the ZnO structure to improve the antimicrobial properties of ZnO by modifying the optical and structural properties of ZnO such that the photo-catalysis mechanism can work under normal ambient room light conditions. Ag+ ion release is expected to work in synergy with the photo-catalysis mechanism of ZnO. Pulsed laser ablation in liquid (PLAL) technique is a very promising technique to produce nanoparticles as an antibacterial agent which requires high purity and clean surface of the nanoparticle. In this work, PLAL has been performed in pure water as the solution to produce ZnO and ZnO-Ag nanoparticles, by varying Ag ablation time 1, 3, and 5 minutes expecting various concentrations of Ag in the sample. All samples were tested to inactivate Staphylococcus aureus (S. aureus) growth for 12 hours’ incubation time, which shows a very prominent result. The number of living bacteria was found to be 4.42 log CFU/mL after 12 hours in contact with pure ZnO nanoparticle and it reduced significantly down to 1.48, 1.00 and 2.83 log CFU/mL respectively after contact with ZnO-Ag nanoparticle sample by varying Ag ablation time of 1, 3 and 5 minutes.