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COMPARATIVE IN VITRO PULMONARY TOXICITY OF ENGINEERED, MANUFACTURED, AND ENVIRONMENTAL NANOPARTICLES
Citation:
DREHER, K. L., S. RHODES, Z. TYCZ, AND R. J. SNYDER. COMPARATIVE IN VITRO PULMONARY TOXICITY OF ENGINEERED, MANUFACTURED, AND ENVIRONMENTAL NANOPARTICLES. Presented at Society of Toxicology Annual Meeting, Charlotte, NC, March 25 - 29, 2007.
Description:
Engineered nanomaterials display many unique physicochemical properties for a variety of applications and due to their novel propertiesapplications may have unique routes of exposure and toxicity. This study examines the: 1) ability of the MTT assay to generate false positives or negatives when examining the cellular toxicity of single wall carbon nanotubes (SWCNTs); 2) comparative cellular toxicity using BEAS 2B human airway cell line of three different commercially manufactured SWCNTs (#1-3), nanographite fiber (nGF), ultrafine carbon black particles (ufCB), diesel exhaust particles (DEPs), and residual oil fly ash particles (ROFA); and 3) relationship between nanoparticle surface reactivity and in vitro pulmonary toxicity. The MTT assay did not produce either false positive or negative results since SWCNTs alone were negative in this assay and did not bind the reduced formazan dye. BEAS 2B cells were exposed to various doses of each nanoparticle and their viability assessed using the MTT assay at 24 hr post-exposure. These studies identified a hierarchy of BEAS 2B cellular toxicity with SWCNT#1 (ED50= 12.5 ug/ml) = SWCNT#2 > SWCNT#3 (ED50=50 ug/ml) >> ROFA (ED50=75 ug/ml) > DEP (ED50=100 ug/ml) > nGF (ED50>200 ug/ml) = ufCB. Nanoparticles were tested for their ability to generate thiobarbituric acid reactive substances in an acellular assay and demonstrated the following hierarchy of reactivity: ROFA >> DEP > ufCB = SWCNTs #1- #3. These results demonstrate that engineered nanoparticles display a significantly greater in vitro pulmonary toxicity when compared to manufactured and environmental particles. In addition, SWCNTs in vitro pulmonary toxicity did not correlate with their ¿reactivity¿. (Funding: USEPA-NCSU Cooperative Training Agreement CT 829470. This abstract does not necessary reflect EPA Policy)