Antimicrobial Activity of Zinc Oxide Nanoparticles Compared to Silver Nanoparticles Administered towards Methicillin-Resistant Staphylococcus aureus Biofilms

Author

Kevin Núño, University of South Florida

Graduation Year

2022

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Medical Sciences

Major Professor

Alya Limayem, Ph.D.

Committee Member

Mark Kindy, Ph.D.

Committee Member

Feng Cheng, Ph.D.

Keywords

TEM, confocal microscopy, antimicrobial susceptibity, biofilm quantification, MRSA, multi-drug resistance, nanomedicine

Abstract

Zinc oxide nanoparticles (ZnO NPs), silver nanoparticles (AgNPs), and chitosan nanoparticles have strong antibacterial activity as a broad-spectrum antibiotic against multi-drug resistant (MDR) bacteria. MDR bacteria have a mechanism that increases antibiotic resistance through biofilm formations. MDR methicillin-resistant Staphylococcus aureus BAA-1720 was chosen for an in vitro assessment to calculate the biofilm reduction rate and the median effective dose (ED50) by performing biofilm quantification. Dynamic light scattering was chosen to determine the physiochemical characteristics of ZnO NPs, silver nanoparticles (AgNPs), and chitosan NPs. Transmission electron microscopy was conducted to verify each treatment’s physiochemical characteristics. Antimicrobial susceptibility testing of broad-spectrum and Gram-positive antibiotics was coordinated for MRSA and revealed a total of 17 resistant antibiotics, with 2 additional ones assumed from performed tests. Biofilm quantification revealed the average biofilm reduction rate for 26.7 µg/mL AgNPs at 177.0% after 24 hours (ED50 = 7.54 µg/mL), when compared to 150 µg/mL ZnO NPs (75.97%, ED50 = 98.72 µg/mL) and 150 µg/mL chitosan NPs (6.53%, ED50 = 1149 µg/mL). Based on previous experiments, it is unlikely that chitosan would have such a low biofilm reduction potential and such a high ED 50; however, this value could be due to an experimental error. Confocal microscopy reflected the antibacterial activity of AgNPs. Despite AgNPs exhibiting a higher biofilm reduction rate and lower ED50 than ZnO NPs, both metallic NPs show promise in treating MDR bacterial biofilms.

Scholar Commons Citation

Núño, Kevin, "Antimicrobial Activity of Zinc Oxide Nanoparticles Compared to Silver Nanoparticles Administered towards Methicillin-Resistant Staphylococcus aureus Biofilms" (2022). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/10338