Determination of cytotoxicity attributed to multiwall carbon nanotubes (MWCNT) in normal human embryonic lung cell (WI-38) line.

Carbon nanotubes (CNT) possess beneficial physicochemical and mechanical properties; however, despite these advantages there are concerns regarding the adverse effects of CNT on lung and development of diseases, such as lung cancer and mesothelioma. According to fiber characteristics of length and diameter (aspect ratio), fibers with high aspect ratio (10-15 nm diameter and containing two different length distributions of 545 ± 230 and 10451 ± 8422 nm length) are more toxic to lung than low-aspect-ratio fibers (10-15 nm diameter and length of 192 nm). It was thus of interest to investigate the effects of multiwall carbon nanotubes (MWCNT) on the viability of normal human embryonic lung cells (WI-38) using trypan blue dye exclusion, the tetrazolium salt WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate) assay, and lactate dehydrogenase (LDH) activity assay. MWCNT produced cell growth inhibition and death at 12.5-200 μg/ml after 24-72 h of incubation. In addition, high-aspect-ratio MWCNT were found to produce higher incidence of cytotoxicity than low-aspect-ratio fibers at 50-200 μg/ml concentration. In the presence of less than 10% trace element content such as iron in MWCNT, the trace element exerted no marked effect on cellular viability. Data indicate that MWCNT inhibited cell proliferation and triggered cell death, and it would appear that the MWCNT fiber characteristics rather than impurities play a predominant role in the observed the cytotoxicity attributed to MWCNT.