Analysis Study of Antibacterial Efficacy and Cytotoxicity of Prepared Metal-Based Nanoparticles against Streptococcus mutans: Focus on Gold Nanoparticles

New approaches have been developed to combat bacterial infections because of the growing threat of antibiotic-resistant bacteria. Gold colloidal nanoparticles and their applications as antibacterial agents have shown promising strategies due to these properties. The properties of nanoparticles, including size, shape, and surface charge, play an essential role in determining antibacterial activity. Pulsed laser ablation in a liquid medium was utilized to produce gold nanoparticles, an environmentally friendly method. Gold NPs were produced in ultrapure water. Experimental research was done to determine the impact of the number of laser pulses on the nanoparticles' size, shape, and concentration. Surface plasmon resonance (SPR) peaks for gold nanoparticles were detected by UV–visible spectroscopy at approximately 525 nm in the visible region. Transmission electron microscopy (TEM) showed the appearance of spherical nanoparticles with an average size of 20 to 80 nm. For gold nanoparticles, increasing laser pulses from 100 to 250 pulses while maintaining the fixed energy of the laser at 600 mJ reduced the average nanoparticle size. S. mutans were isolated to study and evaluate the antibacterial effects of AuNP substances using the suitable diffusion method. The antibacterial examination revealed valuable results for gold nanoparticles, which showed a more significant effect on bacteria at high concentrations. The best results were found for the sample prepared at the highest concentration at 250 pulses. Toxicity assessments of the materials revealed low toxicity levels of this material, confirming their safety for human use.