Title: Zinc oxide nanoparticles-induced DNA damage in human lymphocytes

Authors: Javed Musarrat, Quaiser Saquib, Ameer Azam, S. Alim Husain Naqvi

Addresses: Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh 202002, India. ' Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh 202002, India. ' Department of Applied Physics, Aligarh Muslim University, Aligarh 202002, India. ' Department of Applied Physics, Aligarh Muslim University, Aligarh 202002, India

Abstract: Zinc oxide (ZnO) nanoparticles (<20 nm) were synthesised by sol-gel method and characterised by X-ray diffraction (XRD). Extensive use of ZnO in sunscreens and cosmetics, and their reported photoclastogenicity has prompted us to investigate its genotoxic potential. We have assessed the ZnO-induced DNA damage, intracellular ROS generation and change in mitochondrial membrane potential (ΔΨm), employing alkaline single cell gel electrophoresis (comet assay), flow cytometry and spectrofluorometric analysis. Significant increase in the Olive tail moment (OTM-62.72) in treated lymphocytes vis-a-vis untreated control (OTM-0.78), clearly indicated the formation of ZnO nanoparticles-induced single strand breaks. Exposure of human lymphocytes to ZnO nanoparticles also resulted in significant reduction in membrane potential (ΔΨm). Enhancement in fluorescence intensity of intracellular probe 2′,7′-dichlorofluorescein (DCF), in treated cells suggested the ZnO-induced oxidative stress. Overall, the data revealed the genotoxic potential of ZnO nanoparticles and their ability to perturb the mitochondrial membrane potential, possibly through oxidative mechanism.

Keywords: nanoparticles; zinc oxide; ZnO; X-ray diffraction; XRD; comet assay; DNA damage; genotoxicity; DNA strand breaks; human lymphocytes; sol-gel; nanotechnology; mitochondrial membrane.

DOI: 10.1504/IJNP.2009.028775

International Journal of Nanoparticles, 2009 Vol.2 No.1/2/3/4/5/6, pp.402-415

Published online: 30 Sep 2009 *

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