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Single-walled carbon nanotube interactions with HeLa cells.

Yehia HN, Draper RK, Mikoryak C, Walker EK, Bajaj P, Musselman IH, Daigrepont MC, Dieckmann GR, Pantano P - J Nanobiotechnology (2007)

Bottom Line: Transmission electron microscopy revealed SWNT-like material in intracellular vacuoles.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, The University of Texas at Dallas, Richardson, TX 75080, USA. pantano@utdallas.edu.

ABSTRACT
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 MitoSOXtrade mark 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.

No MeSH data available.


Background-corrected absorption spectrum of a CoMoCAT DM-SWNT dispersion prepared using a 10-min probe sonication and two 2-min centrifugations. The two main semi-conducting SWNT structures are denoted by their rollup vector integers (n, m), and the two absorptions at ~460 and ~515 nm represent metallic (6, 6) and (7, 7) nanotubes, respectively. The sharp feature at 861 nm is due to a grating and detector change associated with the spectrometer.
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Figure 3: Background-corrected absorption spectrum of a CoMoCAT DM-SWNT dispersion prepared using a 10-min probe sonication and two 2-min centrifugations. The two main semi-conducting SWNT structures are denoted by their rollup vector integers (n, m), and the two absorptions at ~460 and ~515 nm represent metallic (6, 6) and (7, 7) nanotubes, respectively. The sharp feature at 861 nm is due to a grating and detector change associated with the spectrometer.

Mentions: SWNT dispersions were prepared using a sonication and centrifugation protocol and DMEM supplemented with 5% FBS (DMEM/FBS). The resulting DM-SWNTs were homogeneous in appearance and could be stored for 30 d at 4°C before any SWNTs were observed to precipitate. The final concentration of SWNTs in DMEM/FBS was estimated to be ~50 μg/mL (Additional File 1) and SWNT lengths were estimated to be 100–400 nm (Additional File 2). Figure 3 shows the absorption spectrum of a representative DM-SWNT dispersion. The observed spectral profiles of DM-SWNTs were similar to the spectra of CoMoCAT SWNTs dispersed in sodium dodecyl sulfate (SDS) as prepared by Resasco and co-workers [103] and Stupp and co-workers [41], where the two predominant semi-conducting SWNT types present were (6,5) and (7,5) tubes with an average diameter of 0.8 nm. Specifically, the DM-SWNT peak observed at ~569 nm corresponds to the S22 optical transition of (6,5) tubes, the shoulder observed at ~587 nm corresponds to the S22 optical transition of (8,4) tubes, the peak observed at ~652 nm corresponds to the S22 optical transitions of (7,5) tubes at 644 nm and (7,6) tubes at 647 nm, the broad peak at ~1011 nm corresponds to S11 optical transitions of (6,5) tubes at 975 nm and (7,5) tubes at 1025, and the peak at ~1120 nm corresponds to the S11 optical transitions of (8,4) tubes at 1113 nm and (7,6) tubes at 1122 nm, which are all in accordance with spectroscopic assignments by Bachilo et al. [102]. In summary, the data indicate that CoMoCAT SWNTs dispersed in media supplemented with serum retain their optical transitions between van Hove singularities in the electronic density of states.


Single-walled carbon nanotube interactions with HeLa cells.

Yehia HN, Draper RK, Mikoryak C, Walker EK, Bajaj P, Musselman IH, Daigrepont MC, Dieckmann GR, Pantano P - J Nanobiotechnology (2007)

Background-corrected absorption spectrum of a CoMoCAT DM-SWNT dispersion prepared using a 10-min probe sonication and two 2-min centrifugations. The two main semi-conducting SWNT structures are denoted by their rollup vector integers (n, m), and the two absorptions at ~460 and ~515 nm represent metallic (6, 6) and (7, 7) nanotubes, respectively. The sharp feature at 861 nm is due to a grating and detector change associated with the spectrometer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2131758&req=5

Figure 3: Background-corrected absorption spectrum of a CoMoCAT DM-SWNT dispersion prepared using a 10-min probe sonication and two 2-min centrifugations. The two main semi-conducting SWNT structures are denoted by their rollup vector integers (n, m), and the two absorptions at ~460 and ~515 nm represent metallic (6, 6) and (7, 7) nanotubes, respectively. The sharp feature at 861 nm is due to a grating and detector change associated with the spectrometer.
Mentions: SWNT dispersions were prepared using a sonication and centrifugation protocol and DMEM supplemented with 5% FBS (DMEM/FBS). The resulting DM-SWNTs were homogeneous in appearance and could be stored for 30 d at 4°C before any SWNTs were observed to precipitate. The final concentration of SWNTs in DMEM/FBS was estimated to be ~50 μg/mL (Additional File 1) and SWNT lengths were estimated to be 100–400 nm (Additional File 2). Figure 3 shows the absorption spectrum of a representative DM-SWNT dispersion. The observed spectral profiles of DM-SWNTs were similar to the spectra of CoMoCAT SWNTs dispersed in sodium dodecyl sulfate (SDS) as prepared by Resasco and co-workers [103] and Stupp and co-workers [41], where the two predominant semi-conducting SWNT types present were (6,5) and (7,5) tubes with an average diameter of 0.8 nm. Specifically, the DM-SWNT peak observed at ~569 nm corresponds to the S22 optical transition of (6,5) tubes, the shoulder observed at ~587 nm corresponds to the S22 optical transition of (8,4) tubes, the peak observed at ~652 nm corresponds to the S22 optical transitions of (7,5) tubes at 644 nm and (7,6) tubes at 647 nm, the broad peak at ~1011 nm corresponds to S11 optical transitions of (6,5) tubes at 975 nm and (7,5) tubes at 1025, and the peak at ~1120 nm corresponds to the S11 optical transitions of (8,4) tubes at 1113 nm and (7,6) tubes at 1122 nm, which are all in accordance with spectroscopic assignments by Bachilo et al. [102]. In summary, the data indicate that CoMoCAT SWNTs dispersed in media supplemented with serum retain their optical transitions between van Hove singularities in the electronic density of states.

Bottom Line: Transmission electron microscopy revealed SWNT-like material in intracellular vacuoles.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, The University of Texas at Dallas, Richardson, TX 75080, USA. pantano@utdallas.edu.

ABSTRACT
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 MitoSOXtrade mark 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.

No MeSH data available.