GREEN SYNTHESIS, CHARACTERIZATION, AND ANTIBACTERIAL ACTIVITY OF ZINC OXIDE NANOPARTICLE

Abstract

Objectives: Zinc oxide (ZnO) nanoparticles have received considerable attention due to their antimicrobial, UV blocking, and high catalytic and photochemical activities. Hence, an investigation has been carried out to synthesize the ZnO nanoparticle using aqueous Phyllanthus niruri (Keezhanelli) leaf extract. Aims and objectives of the present study are to synthesize using Keezhanelli (P. niruri) leaf extract, to study its characterization, and to determine its antibacterial activity. Methods: Green synthesized ZnO nanoparticle was characterized by Fourier transform infrared (FTIR), scanning electron microscope (SEM), and transmission electron microscope (TEM) analysis. Antimicrobial activity of ZnO nanoparticle was carried out using agar well diffusion method. Results: The result of the synthesized ZnO nanoparticle using Keezhanelli (P. niruri) leaf extract showed the change of color from pale white to brown color. The result of FTIR analysis of green synthesized ZnO nanoparticle revealed the presence of biomolecules such as polyphenols, flavonoids, alkaloids, polysaccharide, amino acid, and proteins. The result of the SEM studies showed that the green synthesized ZnO nanoparticle was spherical and cylindrical in shape. The size of the ZnO nanoparticle was recorded to be 5 μm. The result of TEM studies of ZnO nanoparticle showed that majority of the particles were spherical in shape with the size of 2 μm. The result of antibacterial activity against four bacterial species showed that green synthesized ZnO nanoparticle was found to be efficient in inhibiting the growth of the bacterial isolates. Maximum zone formation was exhibited against Staphylococcus saprophyticus. Conclusion: Thus, from the results of the present study, it can be concluded that synthesis of ZnO nanoparticle using leaf extract of Keezhanelli (P. niruri) has several advantages such as simple, cost-effective, time consuming, safe, and eco-friendly compared to other methods of nanoparticle synthesis as evidenced in the present study.