Document Detail

ZnO particulate matter requires cell contact for toxicity in human colon cancer cells.
MedLine Citation:
PMID:  20155942     Owner:  NLM     Status:  MEDLINE    
There is ongoing concern regarding the toxicity of nanoparticles with sizes less than 100 nm as compared to larger particles of the same nominal substance. Two commercial ZnO types, one sold as a 8-10 nm powder and the other described as -325 mesh (<44 mum) powder, were evaluated in human colon-derived RKO cells. The powders had a volume-to-surface area ratio equivalent to 40 and 330 nm spheres, respectively. Both materials formed micrometer-sized agglomerates in cell culture media. The nanosized ZnO was more cytotoxic than the micrometer-sized ZnO with LC(50) values of 15 +/- 1 and 29 +/- 4 mug/cm(2), respectively. Transfer of Zn from the solid phase to the cell culture media in the presence of RKO cells was time- and concentration-dependent. However, direct particle-cell contact was required for RKO cell cytotoxicity, and the toxicity of particles was independent of the amount of soluble Zn in the cell culture media. The mechanism of cell death includes the disruption of mitochondrial function. Robust markers of apoptosis, Annexin V staining, loss of mitochondrial potential, and increased generation of superoxide were observed when cells were treated with ZnO particulate matter but not when treated with comparable concentration of a soluble Zn salt. Both ZnO samples induced similar mechanisms of toxicity, but there was a statistically significant increase in potency per unit mass with the smaller particles.
Philip J Moos; Kevin Chung; David Woessner; Matthew Honeggar; N Shane Cutler; John M Veranth
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Chemical research in toxicology     Volume:  23     ISSN:  1520-5010     ISO Abbreviation:  Chem. Res. Toxicol.     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-04-19     Completed Date:  2010-07-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8807448     Medline TA:  Chem Res Toxicol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  733-9     Citation Subset:  IM    
Department of Pharmacology and Toxicology, University of Utah, L. S. Skaggs Pharmacy, Room 201, 30 S 2000 East, Salt Lake City, Utah 84112, USA.
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MeSH Terms
Annexin A5 / metabolism
Colonic Neoplasms / drug therapy,  pathology*
Metal Nanoparticles / chemistry,  toxicity*,  ultrastructure
Mitochondria / drug effects
Particle Size
Particulate Matter / chemistry,  toxicity*
Superoxides / metabolism
Tumor Cells, Cultured
Zinc Oxide / chemistry,  toxicity*
Grant Support
Reg. No./Substance:
0/Annexin A5; 0/Particulate Matter; 11062-77-4/Superoxides; 1314-13-2/Zinc Oxide

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