Optimization of Processing Parameters for Hydrothermal Silver Nanoparticles Synthesis Using Aloe vera Leaf Extract and Estimation of their Physico-Chemical and Antifungal Properties.

Aloe vera leaf extract has been obtained and utilized for silver nanoparticles (AgNPs) synthesis by autoclave at 121 °C and 1.5 bar (pressure) for 15 min. The results of GC-MS analysis of A. vera life extract indicated that there were several natural reducing agents such as acetic acid, hexanol and ethyl amine in the A. vera peel. Central composition design and response surface methodology have been used to design the experiment and to evaluate the effect of independent variables on dependent variables, respectively. After extraction of A. vera leaf extract with different concentrations (0.5–5.5% w/v), 0.1 mL of the prepared extract has been added into different amounts of 1 mM AgNO₃ solution (9.5–20.5 mL) and placed into the autoclave. The obtained results indicated that the minimum particle size (53.9 nm) and maximum concentration (46.25 ppm) and color (0.851 IU) values for synthesized AgNPs were obtained using 4.69% w/v of A. vera leaf extract and 11.1 mL of AgNO₃ solution (1 mM). The zeta potential value of the synthesized AgNPs at obtained optimum conditions was +15.5 mV which indicated the high stability of the synthesized AgNPs. The high antifungal activity of the synthesized AgNPs was evaluated against to Aspergillus flavus and Aspergillus terreus strains. [ABSTRACT FROM AUTHOR]