Biosynthesis of Triangular-Shape ZnO Nanoparticles Using Tecoma Stans and Its Antimicrobial Activity

The present work reports the first green synthesis of zinc oxide nanoparticles (ZnO-NPs) using Tecoma stans leaf extract. The ZnO-NPs have been investigated by X-Ray Diffraction (XRD), Ultra Violet-Visible (UV-Vis), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) analysis. XRD investigation confirms the crystalline structure of ZnO. The TEM images show triangular shape ZnO-NPs with sizes running from 15-20 nm. The XPS spectrum revealed the presence of Zn and O in the sample. Photoluminescence studies of ZnO-NPs displayed a sharp emission of blue band at 447 nm which is attributed to the defect structures in ZnO crystal. The presence of alcoholic, phenolic amide groups in the plant extracts is responsible for the formation of ZnO-NPs. The synthesized ZnO-NPs showed a very high antibacterial property against five bacterial strains such as Bacillus cereus,

Acinetobacter johnsonii, Achromobacter xylosoxidans, Achromobacter spanius and Chromobacterium pseudoviolaceum, with the highest zone of inhibition (ZOI) of 24 mm being shown against Achromobacter spanius strain. Further, the synthesized nanoparticles displayed excellent activities against four fungal strains, where a highest ZOI of 30 mm was observed against Penicillium citirinum, hence proving its high efficacy as antimicrobial agents.