title: Oxidative stress studies of six TiO₂ and two CeO₂ nanomaterials: immuno-spin trapping results with DNA.
abstract: Six TiO₂ and two CeO₂ nanomaterials with dry sizes ranging from 6-410 nm were tested for their ability to cause DNA centered free radicals in vitro in the concentration range of 10-3,000 ug/ml. All eight of the nanomaterials significantly increased the adduction of the spin trap agent 5,5-dimethyl-1-pyroline N-oxide (DMPO) to DNA as measured by the experimental technique of immuno-spin trapping. The eight nanomaterials differed considerably in their potency, slope, and active concentration. The largest increase in DNA nitrone adducts was caused by a TiO₂ nanomaterial (25 nm, anatase) from Alfa Aesar. Some nanomaterials that increased the amount of DNA nitrone adducts at the lowest exposure concentrations (100 ug/ml) were Degussa TiO₂ (31 nm), Alfa Aesar TiO₂ (25 nm, anatase) and Nanoamor CeO₂ (8 nm, cerianite). At exposure concentrations of 10 or 30 ug/ml, no nanomaterials showed significant in vitro formation of DNA nitrone adducts.
authors.affiliation: Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, North Carolina 27711, USA. kitchin.kirk@epa.gov
authors.forename: Kirk T
authors.initials: KT
authors.lastname: Kitchin
authors.forename: Raju Y
authors.initials: RY
authors.lastname: Prasad
authors.forename: Kathleen
authors.initials: K
authors.lastname: Wallace
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D002563:Cerium / Q000633:toxicity*; D003497:Cyclic N-Oxides; D004247:DNA / Q000187:drug effects*; D018736:DNA Adducts / Q000032:analysis*; D004305:Dose-Response Relationship, Drug; D049329:Nanostructures / Q000633:toxicity*; D009589:Nitrogen Oxides; D018384:Oxidative Stress / Q000187:drug effects*; D010316:Particle Size; D019097:Spin Trapping; D014025:Titanium / Q000633:toxicity*
chemical_list: D003497:Cyclic N-Oxides; D018736:DNA Adducts; D009589:Nitrogen Oxides; C015388:nitrones; C009495:titanium dioxide; D002563:Cerium; C030583:ceric oxide; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D004247:DNA; C427203:calf thymus DNA; D014025:Titanium