EFFECTIVENESS OF METAL NANOPARTICLES AS ANTIMICROBIALS

picture of Alexandra Peterson presenting his/her poster: EFFECTIVENESS OF METAL NANOPARTICLES AS ANTIMICROBIALS

Alexandra Peterson , A

EFFECTIVENESS OF METAL NANOPARTICLES AS ANTIMICROBIALS

With the emergence of bacterial resistance, there is need for alternative antibacterial substances. Metals have been recognized as having antibacterial properties for millennia. The purpose of this study was to assess the effectiveness of copper and silver nanoparticles (composed of collections of metal ions several nanometers in size) against pathogenic (disease-causing) bacteria. Numerous nanoparticle formulations were evaluated against Pseudomonas aeruginosa in solution. Samples were taken at various time exposures to determine the decrease in bacterial concentrations. Overall, copper nanoparticles were more effective than silver nanoparticles. The most effective copper formulation was tested in additional tests against P. aeruginosa, Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, and Streptococcus mutans. These pathogenic species include bacteria with different cell wall characteristics to ensure that the nanoparticles have broad-spectrum antibacterial efficacy. Copper nanoparticles were more effective against Gram-negative (P. aeruginosa, E. coli, S. Typhimurium) than Gram-positive (S. aureus, S. mutans) bacteria, although >99.99% reductions were observed in all tests within two hours. These copper nanoparticles were then placed into a polymer matrix and applied to stainless steel surfaces to create antibacterial coatings used in experiments to mimic real-world contamination. P. aeruginosa was inoculated onto coated surfaces and the viable bacteria were recovered after various exposure times. Copper nanoparticle coated surfaces were shown to reduce P. aeruginosa >99.999% within 30 minutes. These results are quite promising; therefore, these nanoparticles may one day be used in hospitals, daycare centers, food service establishments, and other settings in which the control of bacterial contamination is critical.

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