Green Synthesis of Silver Nanoparticles for Studying their Physical and Antibacterial Properties

In this study, Aloe vera leaf extract was used to synthesize silver nanoparticles from silver nitrate. Three different concentrations (10%, 15%, and 25%) of the silver nanoparticles were prepared by dissolving them in deionized water. The optimal concentration for biological applications was then determined. Various techniques were employed to analyze the silver nanoparticles, including ultraviolet-visible spectroscopy, zeta potential measurements, field-emission scanning electron microscopy, and X-ray diffraction (XRD). Confirmation of the synthesized silver nanoparticles was provided by the color change of the particles, which changed from colorless to yellow and ultimately to brown. UV–Vis spectroscopy revealed a blue shift in the surface plasmon absorption peak. The XRD data revealed the crystalline characteristics of the silver nanoparticles, which exhibited a face-centered cubic structure. Field-emission scanning electron microscopy results showed the formation of spherical nanoparticles with diameters less than 100 nm. Particle concentration measurements (15%) yielded a high-quality, well-distinguishable signal relative to the zeta potential. The optimal concentration was selected based on the above test to evaluate the antibacterial activity of the synthesized silver nanoparticles against Staphylococcus epidermidis and Escherichia coli. The results indicated that the inhibitory effect on bacterial growth was concentration-dependent, with higher silver concentrations exhibiting greater antibacterial activity.