Journal of School of Public Health and

Background and aim: In this study the cytotoxicity to human epithelial lung cells of single-walled carbon nanotubes, multi-walled carbon nanotubes and chrysotile was compared based on the following cytotoxicity indices: no observable adverse effect concentration (NOAEC), inhibitory concentration 50 (IC50), and Total Lethal Concentration (TLC).

Materials and Methods: Human epithelial lung cells were exposed to different concentrations (1 to 1500 µg/ml) of carbon nanotubes and chrysotile for 6 and 24 hours. Cytotoxicity was assessed using the MTT assay. NOAEC, IC50, and TLC idices were determined by probit analysis.

Results: The results showed statistically significant correlations (p<0.001) between cytoxicity and exposure concentration in the case of all the three compounds. The NOAEC and IC50 indices were lowest for the multi-walled carbon nanotubes, while the single-walled carbon nanotubes showed the lowest TLC index.

Conclusion: Cytotoxicity of multi-walled carbon nanotubes at low concentrations was higher than that of single-walled carbon nanotubes and chrysotile. This would mean that exposure to this compound occurs at low concentrations. Thus, cytotoxicity of multi-walled carbon nanotubes is a cause for concern. It can be concluded, then, that, like chrysotile fibers, crabon nanotubes are also considerably toxic to human epithelial lung cells.