Abstract
Nanoparticles are essential materials in modern technology due to their unique properties, compatibility with biological systems and wide application particularly in biomedical applications. Silver nanoparticles (Ag-NPs) have been used extensively due to their different characteristics such as surface plasmon resonance, chemical stability, and antimicrobial activity. Antimicrobial resistance (AMR) has increased due to the misuse of antibiotics particularly in developing and undeveloped countries where there are no proper dispensing criteria. Bacteria have acquired resistance genes, rendering most antibiotics ineffective especially in immunocompromised patients. Silver nanoparticles may present a favourable alternative in combating bacteria resistant to antibiotics. Biological synthesis has been identified as the most suitable approach for nanoparticle synthesis as it provides control over size, shape, distribution and is cost effective in contrast to chemical and physical approaches. The study aimed to optimise reaction parameters for synthesis of biological Ag-NPs using Enterobacter xiangfangensis Pb204 and determine their antimicrobial activity against eight common human pathogens known to contaminate water sources. A cell-free extract from an overnight culture of E. xiangfangensis Pb204 was added to 1 mM AgNO3 for Ag-NPs synthesis. Reaction pH (3, 5, 7 and 9), temperature (25 °C, 30 °C and 37 °C) and time (24 and 48 h) were evaluated during the synthesis of Ag-NPs which were characterised with the use of transmission electron microscopy (TEM) and energy dispersive x-ray (EDX) analysis...
M.Sc. (Biotechnology)