Antibacterial effect assessment of ZnO: Mn nanoparticles

Introduction: Greater effectiveness on resistant strains of microbial pathogens, less toxicity and heat resistance are the characteristic of metal oxide nanoparticles, which make them the selective candidates for eradicating bacteria. Nano ZnO can disrupt the bacterial cell membrane integrity, Reduce cell surface hydrophobicity and down-regulate the transcription of oxidative stress-resistance genes in bacteria, then degradation and finally cell death. It should be noted that the Mn2+ ions are particularly suitable as sensitive atomic probes in Zn based compounds, as they have similar charge state and very close ionic radius with the host Zn2+ cations.Material and methods: Wet chemical method was used to synthesis the ZnO:Mn nanoparticles. First, four solutions of zinc chloride, manganese chloride, mercapto ethanol and caustic soda were prepared by a powerful mixer in distilled water. Next, zinc chloride solution was poured in a three-neck flask; then, zinc chloride solution and later mercapto ethanol was added to the flask. Finally, NaOH was added to the flask using the same method. ZnO:Mn solution was obtained with the above-mentioned process. To extract any impurity density, the final solution was washed several times using distilled water and then it was centrifuged. Then, the sample was left in oven for 24 hours at 40 0C to be dried completely. All processes were performed at room temperature. X-ray diffraction and UV-Vis spectrophotometer were used for optical and structural assessing properties of ZnO quantum dots and for achieving the exact size, surface structure and distribution of nanoparticles, transmission electron microscopy, was utilized. Results: The size of inhibition zone was different according to the type of bacteria and concentrations of ZnO: Mn QDs. The maximum diameter was happen for Staphylococcus aureus Conclusion: By increasing the concentration of nanoparticles in the wells and plates, limits of bacterial growth and growth inhibition zone diameters were also increased

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Antibacterial effect ، ZnO: Mn Quantum dots