Publication Date
2019
Document Type
Thesis
Committee Members
Ioana E. Pavel, Ph.D. (Advisor); David A. Dolson, Ph.D. (Committee Member); Steven R. Higgins, Ph.D. (Committee Member); Marjorie M. Markopoulos, Ph.D. (Committee Member)
Degree Name
Master of Science (MS)
Abstract
A fourth of the world’s population lack access to safe water, thus the need for a more effective water treatment is imperative. Interest in silver nanoparticles (AgNPs) has grown in the last decade. Unlike chlorine, AgNPs do not form disinfection by products (DBPs), making them a prime candidate for drinking water treatment. The main aim of this study was to compare the antibacterial activity of electrochemical silver nanoparticles (eAgNPs-f) of ~5 nm in diameter against well-established pathogens: Escherichia coli (E. coli), Klebsiella variicola (K. variicola), and Pseudomonas aeruginosa (P. aeruginosa) to chlorine and Ag+ for drinking water. This was achieved by determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of eAgNPs, which were synthesized electrochemically and then concentrated (eAgNPs-f). The MIC values for E. coli, K. variicola, and P. aeruginosa were 4 ± 3, 3 ± 2, and 3 ± 2 mg/L, respectively. The MBC values for the same bacteria were 4 ± 3, 5 ± 2, and 5 ± 4 mg/L, respectively. When tested against chlorine, the MIC and MBC values increased over 1000-fold. CytoViva Hyperspectral Microscopy demonstrated the eAgNPs-f’s affinity for the cellular membrane of E. coli after 30 minutes and physical cellular damage after 1 hour. Membrane disruption was confirmed through monitoring K+ leakage on ICP-OES. It was found that eAgNPs-f have a rapid and time consistent effect on K+ leakage, when compared to untreated control cells and Ag+. These results suggest that eAgNPs-f containing Ag+ ions are a more effective antibacterial agent than Ag+ alone, or chlorine.
Page Count
52
Department or Program
Department of Chemistry
Year Degree Awarded
2019
Copyright
Copyright 2019, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.
