Biosynthesis of Ag and Fe nanoparticles using Erodium cicutarium; study, optimization, and modeling of the antibacterial properties using response surface methodology

The present study deals with the preparation of silver (Ag) and iron (Fe) nanoparticles, extracted from AgNO3 and FeSO4 · 7H2O solutions, respectively. For this, the aqueous extract of Erodium cicutarium was used. The Ag and Fe nanoparticles were characterized by several techniques such as X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray (EDX) spectrometer, UV– visible, and Fourier transform infrared (FTIR) spectroscopy. FE-SEM images showed that the Ag and Fe particles had nearly spherical morphology with diameters less than 100 nm. Low amounts of impurity and different chemicals in the prepared nanoparticles were confirmed by EDX spectrometers. Furthermore, different functional groups in the nanoparticles were indicated using FTIR spectrum. Antibacterial activity of the Ag and Fe nanoparticles was evaluated by minimum inhibitory concentration (MIC) for E. coli and S. aureus bacteria. Two parameters such as the concentration of Ag and Fe nanoparticles (X1) and pH (X2) were modeled by the use of the response surface methodology (RSM). These experiments were carried out as a central composite design (CCD) consisting of 13 experiments. The results showed that the concentration of Ag and Fe nanoparticles had a better effect on antibacterial activity. Under optimal conditions— with concentrations of Ag and Fe nanoparticles at 399. 53 and 397. 38 (μ g/mL) and pH values of 8. 20 and 8. 39, respectively— the bacterial growth inhibition halo was found to have the highest diameter.