Structural, Optical and Antibacterial Properties of Green Synthesized Silver Nanoparticles (AgNPs) Using Justicia adhatoda L. Leaf Extract

Abstract

Recently, AgNPs were used as a potential candidate for the applications of the human contacting areas such as cosmetics, food and medicine. Based on the above facts, in the present investigation, synthesis of silver nanoparticle was done using Justicia adhatoda leaf extract. The AgNPs were synthesized by bioreduction method of silver nitrate at different concentrations of J. adhatoda leaf extract (10, 20, 30, 40 ml). It was characterized by a powder X-ray diffraction technique, SEM (Scanning Electron Microscope) with EDAX and FTIR (Fourier Transform Infrared Spectroscopy). It exhibited face centered cubic structure and the particle size was found to be 30 nm and the lattice strain (W–H plot) was 0.0079. The functional groups present in the compound were confirmed by the FTIR spectrum (424 cm⁻¹ and 402 cm⁻¹). In this work spherical morphology of the particles at different concentrations was identified by TEM (particles size 16–21 nm) and SEM images. The optical energy band gap was found to be 2.9 eV from the UV–Vis spectrum. Zeta potential of AgNPs was determined as − 17.2 nm. The antibacterial activity of the synthesized AgNPs was tested using both gram positive bacteria (Staphylococcus aureus) and gram negative bacteria (Escherichia coli) and concluded that it may be a harmful nanomedicine for respiratory track ailments.