Genotoxicity of titanium dioxide (TiO2) nanoparticles at two trophic levels Plant and human lymphocytes

The environmental fate and behaviour of titanium dioxide (TiO2) nanoparticles is a rapidly expanding area of research There is a paucity of information regarding toxic effect of TiO2 nanoparticles in plants and to certain extent in humans The present study focuses on the effect of exposure of TiO2 nanoparticles in two trophic levels plant and human lymphocytes The genotoxicity of TiO2 nanoparticles was evaluated using classical genotoxic endpoints comet assay and DNA laddering technique DNA damaging potential of TiO2 nanoparticles in Album cepa and Nicotiana tabacum as representative of plant system could be confirmed in the comet assay and DNA laddering experiments In Mum micronuclei and chromosomal aberrations correlated with the reduction in root growth We detected increased level of malondialdehyde (MDA) concentration at 4 mM (0 9 mu M) treatment dose of TiO2 nanoparticles in Album cepa This indicated that lipid peroxidation could be involved as one of the mechanism leading to DNA damage A comparative study of the cytotoxic and genotoxic potential of TiO2 nanoparticles and bulk TiO2 particles in human lymphocytes also reveal interesting results While TiO2 nanoparticles were found to be genotoxic at a low dose of 025 mM followed by a decrease in extent of DNA damage at higher concentrations bulk TiO2 particles reveal a more or less dose dependent effect genotoxic only at dose 1 25 mM and above The study thus confirms the genotoxic potential of TiO2 nanoparticles in both plant and human lymphocytes (C) 2010 Elsevier Ltd All rights reserved