Comparison of in vitro, pharyngeal aspiration, and inhalation results for single-walled carbon nanotubes.
Toxicologist 2008 Mar; 102(1):485
Once contaminating iron is removed from single-walled carbon nanotubes, they do not generate reactive oxygen species in vitro and their cytotoxicity is relatively low. In addition, these purified SWCNT fail to activate cytokine production or phagocytosis in cultured macrophages. These in vitro results correlate with the low level of uptake of SWCNT by macrophages following pharyngeal aspiration and the lack of persistent inflammation. In contrast, in vitro assays of oxidant stress or macrophage activation fail to predict the progressive interstitial fibrotic response to pharyngeal aspiration of SWCNT. However, SWCNT significantly enhance proliferation and collagen synthesis by fibroblasts in culture. Therefore, care must be taken in recommending a single in vitro screening assay (oxidant stress) as predictive of biological activity for all nanoparticles. Inhalation exposure to SWCNT results in pulmonary responses (transient inflammation but rapid and progressive interstitial fibrosis) very similar to those following pharyngeal aspiration. This indicates that pharyngeal aspiration is a reasonable alternative to more costly and time consuming inhalation studies as long as care is taken to use relevant exposure concentrations and to avoid exposure to non-respirable size agglomerates of SWCNT.
Biological-effects; Oxidative-metabolism; Cell-function; Cell-transformation; Dust-inhalation; Inhalation-studies; Pulmonary-system-disorders; Fibrous-bodies; Fibrous-dusts; Nanotechnology
The Toxicologist. Society of Toxicology 47th Annual Meeting and ToxExpo, March 16-20, 2008, Seattle, Washington