Green synthesis, characterization and antibacterial evaluation of ZnO and Ag-doped ZnO nanoparticles using <i>Ruta chalepensis</i> leaf extract

In this study, a facile, green, and eco-friendly approach was followed for the synthesis of zinc oxide (ZnO), Ag-doped ZnO nanoparticles (NPs) using Ruta chalepensis leaf extract. The biosynthesized nanoparticles were characterized by X-ray diffraction (X-RD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), and ultraviolet–visible spectroscopy (UV-Vis). The UV-Vis absorbance peaks for ZnO, 5%, and 7% Ag-doped ZnO NPs were 357, 360, and 364 nm, with band gaps of 3.00, 2.73, and 2.83 eV, respectively. The XRD data showed average crystalline sizes of ZnO, 5% Ag-doped ZnO, and 7% Ag-doped ZnO NPs were 13.82, 27.50, and 25.92 nm, respectively. The presence of a functional group was confirmed by FTIR spectrum. The improved antibacterial activity of Ag-doped ZnO NPs was due to Reactive Oxygen Species (ROS) formation. The higher zone of inhibition was observed in S. aureus and B. cereus (11 ± 1.0 and 12.33 ± 0.57 mm, respectively), by 7% Ag-doped ZnO NPs. Our finding showed that synthesized Ag-doped ZnO NPs possessed good antibacterial activity as compared to pure ZnO NPs. Hence, the designed plant leaf mediated Ag-doped ZnO NPs synthesis has provided avenues for the enhancement of the high efficiency of its antibacterial activity, this makes the study unique.