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Titanium dioxide nanoparticles cause genotoxicity in human lung epithelial cells
Prasad, R. Y., K. WALLACE, A. H. TENNANT, K. T. KITCHIN, A. D. KLIGERMAN, J. G. MUNIZ ORTIZ, AND C. F. BLACKMAN. Titanium dioxide nanoparticles cause genotoxicity in human lung epithelial cells. Presented at Society of Toxicology 49th Annual Meeting, Salt Lake City, UT, March 07 - 11, 2010.
Investigate acellular and cellular effects of selected nano-materials
The use of engineered nanoparticles in consumer products is steadily increasing. However, the health effects of exposure to these nanoparticles are not thoroughly understood. This study investigated the genotoxicity of six titanium dioxide and two cerium oxide nanoparticles of various sizes and manufacturers. Immuno spin trapping (1ST), an acellular assay, was used to determine DNA radical production. Based on an initial screening with 1ST, two titanium dioxide particles and one cerium oxide particle were tested in human bronchial epithelial cells (BEAS-2B) cultured in KGM defined medium. Trypan blue dye exclusion was used to establish a dose-response curve of cell toxicity. Only Degussa P25 AEROXIDE@ Ti02 was cytotoxic at the highest dose tested, 150 IJg/ml after 24 hours of exposure. The alkali comet assay was used to assess DNA single-strand breaks in culture after 24 hr treatment with different concentrations of nanoparticles (10,50,100, 150 IJg/ml). Degussa P25 AEROXIDE@ Ti02 (27.5 nm) and Alfa Aesar Ti02 (32 nm) caused significant single strand breaks in DNA perhaps due to oxidative modification at concentrations of 100 and 150 IJg/ml. Tail DNA was significantly elevated compared to control for Degussa P25 AEROXIDE@ Ti02 and Alfa Aesar Ti02 (32 nm) at all concentrations after 24 hr treatment. The range of average particle size in suspension was significantly larger than the manufacturer's listed size due to substantial agglomeration in the liquid phase. The results suggest that titanium dioxide particles, Degussa P25 AEROXIDE@ Ti02 and Alfa Aesar Ti02 (32 nm) (anatase and rutile mixtures) caused oxidative damage to DNA. Additionally, the results indicate that Degussa P25 AEROXIDE@ Ti02 and Alfa Aesar Ti02 (32 nm) may be genotoxic, potentially due to free radical formation and oxidative stress mechanisms. [Abstract does not necessarily reflect the policies of the U.S. EPA.