Single-walled carbon nanotube interactions with HeLa cells

This work concerns exposing cultured human epithelial-like HeLa cells to single-walled carbon nanotubes (SWNTs) dispersed in cell culture media supplemented with serum. First, the as-received CoMoCAT SWNT-containing powder was characterized using scanning electron microscopy and thermal gravimetric analyses. Characterizations of the purified dispersions, termed DM-SWNTs, involved atomic force microscopy, inductively coupled plasma – mass spectrometry, and absorption and Raman spectroscopies. Confocal microRaman spectroscopy was used to demonstrate that DM-SWNTs were taken up by HeLa cells in a time- and temperature-dependent fashion. Transmission electron microscopy revealed SWNT-like material in intracellular vacuoles. The morphologies and growth rates of HeLa cells exposed to DM-SWNTs were statistically similar to control cells over the course of 4 d. Finally, flow cytometry was used to show that the fluorescence from MitoSOX™ Red, a selective indicator of superoxide in mitochondria, was statistically similar in both control cells and cells incubated in DM-SWNTs. The combined results indicate that under our sample preparation protocols and assay conditions, CoMoCAT DM-SWNT dispersions are not inherently cytotoxic to HeLa cells. We conclude with recommendations for improving the accuracy and comparability of carbon nanotube (CNT) cytotoxicity reports

Flow cytometry analysis of intracellular MitoSOX™ Red fluorescence from live HeLa cells incubated at 37°C for 60 h in: DMEM/FBS, CoMoCAT DM-SWNTs, DMEM/FBS + MitoSOX™ Red, DM-SWNTs + MitoSOX™ Red, and DMEM/FBS + MitoSOX™ Red + HO

<p><b>Copyright information:</b></p><p>Taken from "Single-walled carbon nanotube interactions with HeLa cells"</p><p>http://www.jnanobiotechnology.com/content/5/1/8</p><p>Journal of Nanobiotechnology 2007;5():8-8.</p><p>Published online 23 Oct 2007</p><p>PMCID:PMC2131758.</p><p></p> The -axis denotes the MitoSOX™ Red fluorescence detected in the 564–606 nm spectral region and the -axis denotes the number of events recorded for each analysis

Growth curves for living HeLa cells incubated at 37°C for 4 d in DMEM/FBS or DM-SWNTs

<p><b>Copyright information:</b></p><p>Taken from "Single-walled carbon nanotube interactions with HeLa cells"</p><p>http://www.jnanobiotechnology.com/content/5/1/8</p><p>Journal of Nanobiotechnology 2007;5():8-8.</p><p>Published online 23 Oct 2007</p><p>PMCID:PMC2131758.</p><p></p> The final concentration of SWNTs in DMEM/FBS was estimated to be ~50 μg/mL (Additional File ) and SWNT lengths were estimated to be 100–400 nm (Additional File )

Representative differential image contrast (DIC) images of live HeLa cells incubated for 60 h at 37°C in DMEM/FBS or CoMoCAT DM-SWNTs

<p><b>Copyright information:</b></p><p>Taken from "Single-walled carbon nanotube interactions with HeLa cells"</p><p>http://www.jnanobiotechnology.com/content/5/1/8</p><p>Journal of Nanobiotechnology 2007;5():8-8.</p><p>Published online 23 Oct 2007</p><p>PMCID:PMC2131758.</p><p></p