Antibacterial Activity of ZnO Nanoparticles and Filters Coated with ZnO Nanoparticles on Eliminating Escherichia coli and Enterococcus faecalis

Document Type : Research Paper


1 MSc, Dept. of Microbiology, Falavarjan Branch, Islamic Azad University, Isfahan, Iran

2 . Instructor of Microbiology, Dept. of Microbiology, Falavarjan Branch, Islamic Azad University, Isfahan, Iran

3 Assoc. Prof. of Physics, Malek-e-Ashtar University of Tech., Shahinshahr, Isfahan, Iran


Clean water is vital to both human life and preservation of ecosystems. The goal of this study was to investigate the antibacterial effects of ZnO nanoparticles and filters coated with different sizes of ZnO nanoparticles on Escherichia coli (ATCC: 25922) and Enterococcus faecalis (ATCC: 11700) as the predominant bacteria in contaminated water. The antibacterial effects of ZnO nanoparticles (5 and 100 nm in size) at concentrations of 12.5, 25.0, 50.0, and 100.0 mg/ml were determined using the well diffusion method in vitro. Minimum inhibitory concentrations and minimal bactericidal concentrations of ZnO nanoparticles were determined by the broth micro-dilution method. In another part of the study, ZnO nanoparticles were coated on polypropylene filters using the precipitation method to investigate their removal efficiency. Filtration of contaminated water was performed using a standard number of the bacteria being tested. ZnO nanoparticles (5 nm) at a concentration of 100.0 mg/ml showed maximum sensitivity against E.coli and Enterococcus faecalis by inhibition zones of 14.00±1.73 and 11.67±1.52 mm, respectively. Maximum inhibitory concentration of ZnO nanoparticles was determined as 25mg/ml. A significant relationship was found between antibacterial activity and ZnO nanoparticles concentration (P. value <0.001). It may be claimed that treatment with polypropylene filters coated with ZnO nanoparticles (5nm) is an effective process for controlling bacterial growth and eliminating E.coli.


Main Subjects

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