Investigating antibacterial activity of biosynthesized silver oxide nanoparticles using Phragmanthera Macrosolen L. leaf extract

Abstract

The crude leaf extract of Phragmanthera macrosolen L. has been utilized for the first time as an effective reducing, capping and stabilizing agent to synthesize silver oxide nanoparticles (Ag₂O NPs) through a green approach. The prepared Ag₂O NPs were analyzed by scanning electron-microscopy (SEM), High Resolution Transmission electron microscope (HR-TEM), X-ray diffractions (XRD), Fourier transforms infrared (FTIR) spectroscopy, energy dispersive spectroscopy (EDS), and Ultra-violet visible spectrometry (UV-Vis). The biosynthesized Ag₂O NPs applied on gram-positive (S. aureus) and gram-negative (E. coli) bacterial types. FTIR spectral peaks indicate that the phytochemicals in the extract are responsible for the formation of Ag₂O nanoparticles. The XRD result shown, poly-crystalline nanoparticles and the average crystalline size calculated was 45.8 nm. UV-Vis analysis shows absorbance existed at 590.5 nm, and the energy band gap calculated through the Tauc relation was 2.1 eV. The SEM images gave a globular and some rod like morphology with diameter of particle obtained between 20.11 and 46.50 nm with some hollow cubic microstructure of Ag₂O NPs which makes it suitable for antimicrobial application. The EDS confirms the elemental composition and existence of Ag and O₂. The HR-TEM images, specific area electron diffraction (SAED), and XRD patterns confirmed the morphology of Ag₂O NPs mean 45.84 nm and polycrystalline nature of the nanoparticles. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were 15 and 30 µl respectively for the samples tested. In this study, it was observed that Ag₂O NPs highly sensitive to E. coli than s. aureus. The present study revealed that the possible use of green synthesized Ag₂O NPs as potential antibacterial agent.