Antibacterial Activity of Gold Nanoparticles Produced by One-Step Pulsed Laser Ablation in Liquid

In the current study, pulsed laser ablation in a liquid process was used to create gold nanoparticles (Au NPs) in the deionized distilled water. The pulsed laser ablation in liquid (PLAL) technique was used to create the NPs in two different processes. In first method, the Au nanoparticles were prepared with different laser fluences (2.2, 4.4, 6.64, 8.85, and 11.1) J.cm −2 , and the number of pulses was fixed at 300 pulses for each fluence. The second method uses different number of laser pulses (100, 200, 300, 400, and 500) while maintaining a consistent laser fluence (4.4 J.cm −2 ). The characterization of nanoparticles was investigated using different techniques like UV-VIS, FTIR, XRD analysis, FE-SEM, and PL spectra. The UV-visible absorbed spectrum of Au nanoparticles revealed an absorption peak at about 530 nm and another peak at about 433 nm. The FTIR measurements have successfully shown that the entire (Au NPs), which are being generated. The X-ray diffraction pattern of the nanoparticles indicated the presence of Au nanomaterials and 111, 200, and 311 planes that correspond to Au NPs. The images of FE-SEM show that the Au NPs exhibited a spherical shape framework, agglomeration, and aggregation. With increasing laser fluence, the highest level of fluorescence emission was seen at 380 and 370 nm for Au NPs. The antibacterial activities of Au NPs were investigated using well diffusion method. Two gram-positive and two gram-negative bacteria of four different species have each been exposed to antibiotic activity. Au NPs have revealed a higher activity against tested bacteria. The results revealed that the 1250 µg/mL has high activity against Pseudomonas aeruginosa and Staphylococcus aureus , while Streptococcus mutans has been affected by all concentrations of Au NPs, and Acinetobacter baumannii has been highly affected by 1000 µg/mL and 1250 µg/mL.