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)
Master of Science (MS)
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.
Department or Program
Department of Chemistry
Year Degree Awarded
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