Antimicrobial Effects of Silver and Gold Nanoparticles Alone, and Functionalized with Ampicillin
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Authors
Helmstetter, Nicholas J.
Issue Date
2010
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
There is a need for the development of effective and novel antimicrobials as
alternatives for the control of antibiotic resistant pathogens. Certain nanomaterials like
metallic nanoparticles (NPs) show antimicrobial activity and may be an inexpensive and
effective solution. The goals of this study were to first demonstrate the antimicrobial
effects of NPs then to explore the synergistic antimicrobial effect of ampicillin bound to
NPs (NPs-amp).
Gold and silver NPs (Au-NPs, Ag-NPs) 5 nm in diameter were added to Luria-
Bertani (LB) agar at a concentration of 1.2 x 1016 NPs/mL. To demonstrate antibacterial
activity, Escherichia coli (E. coli) was plated onto Petri dishes containing NPs, grown
overnight and then counted. The count for E. coli grown in the absence of NPs was 9
log10 Colony Forming Units/mL (CFU/mL). Growth on plates containing Au-NPs was
8.98 log10 CFU/mL, while the count for E. coli grown in the presence of Ag-NPs was
4.49 log10 CFU/mL. Bacteria grown in the presence of Ag-NPs showed a significantly
lower rate of survival compared to control plates while E. coli grown on plates containing
Au-NPs did not.
For the second component of the study, ampicillin was functionalized, or bound to
the surface of the NPs. E. coli grown in absence of NPs-amp had a CFU/mL of 8.81
log10. Interestingly, there were no CFUs of E. coli in the presence of Ag-NPs-amp or Au-
NPs-amp. These results suggest that Ag-NPs bound to bactericidal agents may be useful
as effective and novel agents for use in the control of bacterial pathogens.
Description
iv, 24 p.
Citation
Publisher
Kalamazoo College
License
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