| This work concerns exposing CoMoCAT single-walled carbon nanotubes (SWCNTs) to cultured human epithelial-like HeLa cells and evaluating their uptake and any potential cytotoxicity. First, SWCNT dispersions were prepared in cell culture media supplemented with serum and characterized using AFM, ICP-MS, TGA, and UV-visible-NIR and Raman spectroscopies. Confocal micoRaman spectroscopy was utilized to determine that SWCNTs entered HeLa cells in a time- and temperature-dependent fashion. The population doubling times of HeLa cells exposed to SWCNTs were statistically similar to control cells over the course of 6 d. Finally, the potential production of superoxide by cells exposed to SWCNTs was evaluated using fluorescence-based flow cytometry and MitoSOX(TM) Red---a selective indicator of superoxide in mitochondria. The MitoSOX(TM) Red fluorescence detected from control cells was statistically similar to that observed for cells incubated in SWCNT dispersions for 60 h. The combined results indicate that under our conditions (i.e., SWCNT types, purities, concentrations, and exposure times) with HeLa cells, SWCNTs are not inherently cytotoxic. |
