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Odaudu, Ruth Opiotu and Covenant University, Theses (2022) ANTIMICROBIAL AND TOXICITY EVALUATION OF SILVER-COBALT NANOPARTICLES USING Annona muricata LEAF EXTRACT. Masters thesis, Covenant University Ota.

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Globally, the health sector needs to take advantage of nanotechnology as nanotoxicology is gaining interest. More so, there is a need to check the drug resistance of the disease-causing microbes and find alternative cancer drug treatments in humans. However, the safety of human health and the environment is a major concern as some nanoparticles were reported to be toxic due to their fabrication methods. Thus, these challenges lead to the quest for a safer choice of synthetic routes. While the search for contextualization of the harmful effects of nanoparticles is ongoing, a green approach method that makes use of biodiversity plants instead of toxic chemicals is considered primarily for biomedical applications. This research evaluated the antimicrobial, toxicity, and cytotoxicity of the green synthesized silver-cobalt nanoparticles (Ag-Co NPs). Aqueous extract of Annona muricata leaf prepared via hot maceration was utilised as a reducing agent. Progress of the reaction was monitored by a UV-Visible spectrophotometer. The biomolecules responsible for reducing and capping the particles were analysed qualitatively. SEM and TEM were used to investigate the morphological characteristics of the particles and further characterization by X-Ray Diffraction (XRD) and zeta sizer. Furthermore, antimicrobial activity of the Ag-Co NPs was carried out using 6 test organisms, two gram-positive: Staphylococcus aureus, Streptococcus pneumoniae and three gram-negative, Escherichia coli, Klebsiella sp, and Salmonella sp and one fungus, Candida albicans. The cytotoxic effect of the Ag-Co NPs was tested on a cancer cell line. In vivo toxicity assessment was done using Drosophila melanogaster as the assessment model. The characteristic absorption wavelength of the as-prepared nanoparticles was observed with a broad peak around 400-450 nm, indicating that the nanocluster formed was silver enriched. The FTIR showed the functional groups present in the plant extract and the Ag-Co NPs. In the plant extract, the following absorption bands occurred at 3322, 1585, and 1277 cm-1, stretches assigned to O-H, N-H, and C-N, respectively, while peaks occurred at 1649 cm-1 and (N-H) 1163 cm-1 in the corresponding Ag-Co NPs. Both the extract and Ag-Co NPs possessed antimicrobial activities against the test organisms moderately, compared to the control (antibiotics). Moreover, there were no significant toxicity observations on the two developmental stages and locomotive assessment of Drosophila melanogaster. The finding in this study indicates that the Annona muricata-based Ag-Co NPs synthetic route is an excellent alternative technique to the conventional method. Also, the nanoparticles demonstrated little or no toxicity that indicated them as potential candidates for drug development as they exhibited promising antimicrobial activity with no significant toxic effect, as shown in the Drosophilla melanogasta in vivo model.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Ag-Co nanoparticle, toxicity, cytotoxicity, green chemistry, Sustainability Developmental Goals (SDG), antimicrobial
Subjects: Q Science > QD Chemistry
Divisions: Faculty of Engineering, Science and Mathematics > School of Chemistry
Depositing User: nwokealisi
Date Deposited: 09 Nov 2022 15:30
Last Modified: 09 Nov 2022 15:30

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