Ingesting Nanotubes

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Science  24 Dec 2004:
Vol. 306, Issue 5705, pp. 2164
DOI: 10.1126/science.306.5705.2164c

One concern in nanotechnology is that the uptake and fate of nanomaterials in cells may differ from those of larger micrometer-scale particles. Two groups have imaged the uptake of carbon nano-tubes into mammalian cells. Cherukuri et al. incubated single-walled carbon nanotubes (SWNTs, about 1 nm in diameter and 1 μm in length) solubilized in Pluronic surfactant with cultured mouse peritoneal macrophage-like cells. Using near-infrared fluorescence imaging, they found that the macrophages ingested the SWNTs and apparently localized them in phagocytic compartments, without signs of acute toxicity. Monteiro-Riviere et al. looked at the uptake of multiwalled carbon nanotubes (MWNTs) by cultured human epidermal keratinocytes. Although most of the MWNTs, which were not modified after growth on silicon wafers, did not interact with the cells, enough did that 84% of the cells took up MWNTs after 48 hours of exposure at 0.4 mg/ml. After 24 hours at this concentration, the percentage of viable cells decreased by 30%, and transmission electron microscopy revealed MWNTs (some almost 4 mm in length) within cytoplasmic vacuoles in 60% of the cells. Although these cultured keratinocytes lack the protective stratum corneum of human skin, these results indicate that further studies of carbon nanotube exposure risks are in order. — PDS

J. Am. Chem. Soc. 126, 15638 (2004); Toxicol. Lett.10.1016/ j. toxlet.2004.11.004

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