Phyto-Mediated Synthesis of Pure and Silver-Doped Zinc Oxide Nanoparticles Using Stachytarpheta Jamaicensis Leaf Extract: Optical, Morphological and Antibacterial Properties

Pure and silver-doped zinc oxide (ZnO) nanoparticles were synthesized via phyto-mediation using Stachytarpheta jamaicensis leaf extract to develop an eco-friendly method for synthesizing nanoparticles with enhanced properties. Zinc nitrate and silver nitrate were employed as precursors for ZnO and Ag-doped ZnO nanoparticles, respectively. The synthesized nanoparticles were characterized using Ultraviolet-Visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy (SEM-EDS) to investigate their optical and morphological properties. Results revealed that the absorption peaks of the synthesized nanoparticles confirmed the formation of nanoparticles, with Ag doping causing a red shift in the absorption spectrum. SEM images indicated a spherical morphology, with slight agglomeration in the doped samples. Doping with silver enhanced the optical properties, which could have potential applications in catalysis, sensing, and biomedical fields. Furthermore, the nanoparticle extracts were subjected to antimicrobial test against two bacterial strains (Escherichia coli and Staphylococcus aureus) using a modified disk diffusion method and compared with the antibacterial effect with the standard antibacterial drug, Ampicillin. Ampicillin only showed antibacterial activity against S. aureus and had no antibacterial effect on E. Coli. Result of this study showed that the 5% and 10% Ag-doped ZnO NPs showed strong antibacterial activity against both gram-positive (S. aureus) and gram-negative (E. coli) bacterial strains.