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In this work, room temperature laser ablation with an iron target in water was used to create iron oxide nanoparticles (IONPs) with a different number of pulses (100, 200, 300, 400 and 500) at a constant energy of 200 mJ. The colloidal solutions of the IONPs were studied and the effects of the number of pulses on the properties were investigated by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), ultraviolet-visible spectroscopy (UV-VIS) and photoluminescence (PL). The FTIR spectra showed that the synthesised IONPs were formed, and the peaks appeared between (500-600) cm-1. FESEM images showed that the IONPs have hemispherical structures and become spherical with increasing laser pulses. They also exhibited a small aggregation due to electrostatic forces. The UV-VIS results showed that the IONPs had an absorption shoulder at 300-400 nm, which increased with the laser pulses. The PL spectra of the IONPs showed strong, sharp peaks in the UV region at 370 nm, the intensity of which increased with increasing pulse duration, while the density of the nanoparticles in the solution increased. In addition, the antibacterial activities were evaluated using an agar well diffusion assay against Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans) and Acinetobacter baumannii (A. baumannii). The result showed that the IONPs have good antibacterial activity, which increased with the laser pulses due to the increased concentration of IONPs. A hemolysis and in vitro toxicity test also evaluated the compatibility with human blood on red blood cells. |
