Evaluation of the impact of industrial single-walled and multi-walled carbon nanotubes on human respiratory tract epithelial cells

Abstract

Introduction. In the present study, a comparative assessment of the toxic effects of industrial single-walled and multi-walled carbon nanotubes (SWCNT and MWCNT) at doses corresponding to industrial exposures on BEAS-2B and A549 cells was carried out. Materials and methods. The size distribution of SWCNT and MWCNT agglomerates in dispersions was estimated by dynamic light scattering and transmission electron microscopy. Cytotoxicity was assessed using a MTS test and LDH assay. The interaction of CNTs with cells was visualized using dark-field and transmission electron microscopy. Results. Cytotoxic effects of pristine SWCNT and MWCNT in concentrations of 50-200 μg/ml and purified SWCNT in the range of 25-200 μg/ml were found in BEAS-2B cells. SWCNT and MWCNT were found to penetrate into the cytoplasm of both BEAS-2B and A549 cells, while MWCNT are more often revealed in the intracellular content as vacuolized clusters, and single SWCNT and agglomerates are visualized in the cytoplasm without a tendency to vacuolization. Limitations. CNT were introduced into cells in the form of dispersions, where both single nanotubes and their agglomerates were found. The calculation of CNT concentrations for introduction into cells was based on computer simulation. Conclusion. Further study of the mechanisms of cytotoxic and genotoxic effects of different types of carbon nanotubes (CNT) may contribute to the identification of MWCNT and SWCNT specific effects on the cells of the respiratory system to develop methodological approaches to the safe use of CNT.