Determination of toxicological indexes of carbon nanotubes and Chrysotile according to invitro cytotoxicity on Human Lung epithelium cells

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).

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.

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.

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.