Abara, Uzoma Chidozie2025-04-162025-04-162021-05Abara, U. C. (2021). Green synthesis of zinc oxide nanoparticles using different plant extracts and its antibacterial activity. (Unpublished Master's Thesis). Federal University of Technology, Owerri, Owerrihttps://repository.futo.edu.ng/handle/20.500.14562/1776A Master's thesis in Environmental microbiology.Nanotechnology is the understanding and control of matter in the 1-100 nm range. Nanomaterials have unique physiochemical properties, such as ultra-small size, large surface area to mass ratio and high reactivity which are different from bulk materials of the same composition. The synthesis of metal oxide nanoparticles with the use of plant extracts is a promising alternative to conventional chemical methods. Zincoxide nanoparticles have received considerable attention due to their unique antibacterial, antifungal and UV filtering properties, high catalytic and photochemical activity. Green synthesis of zincoxide nanoparticles using aqueous plant leaf extracts of Neem (Azadirachtaindica L), Bitter leaf (Vernonia amygdalina L), Scent leaf (Ocimumgratissimum L), Moringa leaf (Moringaoliefera L), Ginger lilly (Costusafer L) and the antimicrobial activity of green synthesized zincoxide nanoparticles were carried out in this study. Standard top-down method of green synthesis was carried out using the fresh leaves which were pulverised to powdered form ,boiled and finally filtered to get the aqueous extract which was eventually mixed with 1M of zinc nitrate hexahydrate in a 1:1 ratio. The resultant solution was mixed thoroughly with a magnetic stirrer and was further centrifuged, washed and calcinised at 420oC. Characterization was done usingUV-Visible spectroscopy, Fourier Transform infrared spectroscopy (FTIR), X-ray Diffractometer, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX) to ascertain the physico-chemical and morphological properties of the zinc oxide nanoparticles. The antimicrobial activity of the ZnO nanoparticle were tested using clinical isolates of Staphylococcus aureus, Staphylococous epidermidis, Escherichia coli, Klebisiella species, Proteus species and Pseudomonas aerugenosa. The UV-Visible spectrum of colloidal solutions had absorbance peaks at 356-369 nm. The Fourier Transform infrared spectroscopy (FTIR) gave band peaks which were characteristic to specific functional groups. The Energy Dispersive X-ray spectroscopy (EDX) showed that the zinc oxide nanoparticles of the five samples contain higher amount of Zn both in atomic concentration, weight concentration and few other elements which showed high rate of purity of the samples, while the SEM and XRD revealed clustered flake-like crystal arrangement of nanorod-like structures. The antibacterial activity revealed zone of clearance on some and little or none zone of clearance on others. Escherichia coli, Klebisiella species and Pseudomonas aerugenosa recorded higher zones of inhibition. This study reveals another application of the use ofnanoparticles in the control of bacterial diseases and could be very suitable for those in animal husbandry and livestock management to reduce drastically the ever growing rate of antibiotic resistance.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalgreen synthesisZnO nanoparticlecharacterizationantibacteriananoparticlesDepartment of MicrobiologyMaster’s Thesis