Synthesis of Antibacterial Copper Oxide Nanoparticles by Pulsed Laser Ablation in Liquids: Potential Application against Foodborne Pathogens

Abstract

Spherical copper oxide nanoparticles (CuO/Cu2O NPs) were synthesized by pulsed laser ablation in liquids (PLAL). The copper target was totally submerged in deionized (DI) water and irradiated by an infrared laser beam at 1064 nm for 30 min. The NPs were then characterized by dynamic light scattering (DLS) and atomic emission spectroscopy (AES) to determine their size distribution and concentration, respectively. The phases of copper oxide were identified by Raman spectroscopy. Then, the antibacterial activity of CuO/Cu2O NPs against foodborne pathogens, such as Salmonella enterica subsp. enterica serotype Typhimurium DT7, Escherichia coli O157:H7, Shigella sonnei ATCC 9290, Yersinia enterocolitica ATCC 27729, Vibrio parahaemolyticus ATCC 49398, Bacillus cereus ATCC 11778, and Listeria monocytogenes EGD, was tested. At a 3 ppm concentration, the CuO/Cu2O NPs exhibited an outstanding antimicrobial effect by killing most bacteria after 5 h incubation at 25 °C. Field emission scanning electron microscope (FESEM) confirmed that the CuO/Cu2O NPs destructed the bacterial cell wall.