Comparative analysis of antibacterial efficacy of copper oxide nanoparticles synthesized via pulsed laser ablation in liquid against Escherichia coli

Pulsed Laser Ablation in Liquid (PLAL) is a promising technique for synthesizing nanoparticles (NPs) due to its simplicity, environmental friendliness, and versatility. This study investigates the synthesis of copper oxide NPs using PLAL by irradiating a copper target with an Nd:YAG laser in pure water, followed by an assessment of their antibacterial activity against Escherichia coli (E. coli). Initially, uniform spherical Cu2O NPs were formed through PLAL; however, these transformed into larger, straw-like CuO NPs after undergoing high-temperature aging. While Cu2O NPs effectively inhibited the growth of E. coli, CuO NPs exhibited minimal antibacterial activity. When compared to commercially available Cu2O nanopowders, the Cu2O NPs synthesized through PLAL displayed similar composition, morphology, and colloidal stability, but their smaller particle size contributed to superior antibacterial performance. Additionally, Cu2O NPs with high zeta potential were successfully applied by directly introducing the PLAL-synthesized NPs into an E. coli suspension without drying, further enhancing their antibacterial efficacy. This study highlights the potential of the PLAL process to produce NPs with enhanced antibacterial properties by allowing for precise control over particle size and surface characteristics.