Warheit, David B. and Webb, Thomas R. and Reed, Kenneth L. and Frerichs, Scott and Sayes, Christie M. (2007) Pulmonary toxicity study in rats with three forms of ultrafine-TiO2 particles: Differential responses related to surface properties. TOXICOLOGY, 230 (1). pp. 90-104.
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Surface properties are critical to assess effects of ultrafine-TiO2 particles. The aim of this study was to assess lung toxicity in rats of newly developed, well characterized, ultrafine-TiO2 particles and compare them to Ti02 samples in two different size ranges and surface modifications. Groups of rats were intratracheally instilled with doses of 1 or 5 mglkg of either two ultrafine rutile Ti02 particles (uf-1 or uf-2); rutile R-100 fine-TiO2 (F-1); 80/20 anatase/rutile P25 ultrafine-TiO2 (uf-3); or alpha-quartz particles. Phosphate-buffered saline (PBS) solution instilled rats served as vehicle controls. Following exposures, the lungs of PBS and particle-exposed rats were evaluated for bronchoalveolar lavage (BAL) fluid inflammatory markers, cell proliferation, and by histopathology at post-instillation time points of 24 h, 1 week, 1 and 3 months. The ranking of lung inflammation/cytotoxicity/cell proliferation and histopathological responses was quartz > uf-3 > F-1 = uf-1 = uf-2. Exposures to quartz and to a lesser degree, uf-3 anatase/rutile TiO2 particles produced pulmonary inflammation, cytotoxicity and adverse lung tissue effects. In contrast, exposures to F- 1 fine-TiO2 particles or to uf- 1/uf-2 ultrafine-TiO2 particle--types produced transient inflammation. We conclude that differences in responses to anatase/rutile uf-3 TiO2 particles versus the rutile uf-1 and uf-2 TiO2 particles could be related to crystal structure, inherent pH of the particles, or surface chemical reactivity. Thus, based on these results, inhaled rutile ultrafine-TiO2 particles are expected to have a low risk potential for producing adverse pulmonary health effects. Finally, the results demonstrate that exposures to ultrafine-TiO2 particle-types can produce differential pulmonary effects, based upon their composition, and crystal structure. Thus, the lung toxicity of anatase/rutile uf-3 should not be viewed as representative for all ultrafine-TiO2 particle-types. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
|Uncontrolled Keywords:||titanium dioxide particles; ultrafine particles; titanium dioxide nanocrystals; pulmonary toxicity; rutile crystal structure; particle surface treatments; nanomaterials|
|Subjects:||Risk > Environment, health and safety aspects of nanotechnology|
|Deposited By:||Farnush Anwar|
|Deposited On:||15 Dec 2008 10:48|
|Last Modified:||13 Jan 2009 14:16|
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