Green Synthesis and Characterization of Palladium Nanoparticles by Pulsed Laser Ablation and Their Antibacterial Activity

In this study, the technique of pulsed laser ablation in liquid PLAL media was successfully used to synthesize Palladium structures in nanoscale for antibacterial activity. The synthesized palladium nanoparticles (Pd NPs) were confirmed using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), and UV-Visible spectroscopy analysis. The crystalline nature of Pd NPs with face-centered cubic structure is revealed by XRD analysis. The TEM images clearly demonstrated the spherical shape, with average particle sizes ranging from a few nanometers to several tens of nanometers. UV-vis absorption spectroscopy revealed that the absorbance intensity of the prepared Pd NPs increased as the laser fluences increased. Palladium nanoparticles were tested for antibacterial activity against two bacterial strains: Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus). The agar well diffusion method results revealed that Pd NPs prepared at 10.2 J/m(2) had a higher antibacterial activity for both bacterial strains due to the higher concentration. Furthermore, the effect of Pd NPs was stronger against Gram-negative bacteria than Gram-positive.