Assessment of the Toxicity of Single-Wall Carbon Nanotubes Using Different Types of Cell Cultures: Review of the Current State of Knowledge

Abstract

With the growing global market of nanocarbon materials, including single-wall nanotubes (SWCNTs), the number of people that may be exposed to carbon nanotubes (CNTs) in the form of aerosols is growing as well. In vitro methods are a promising means for obtaining an accelerated evaluation of SWCNT toxicity. Toxic effects due to SWCNTs have been investigated in the last decade using various types of cell cultures, but conclusions about their toxicity are not unequivocal. In a number of studies, dose-dependent effects such as cytotoxicity, reduction in cell viability, inhibition of cell proliferation, apoptosis, nitric oxide release, oxidative stress, and a reduction in the level of antioxidants have been reported. Other studies find little to no cytotoxic effects of SWCNTs on different cell cultures. To date, there is no ambiguity in the findings on the comparative toxicity of SWCNTs and multiwall CNTs (MWCNTs). While some authors report that SWCNTs exhibit considerable cytotoxicity, others find no considerable toxicity associated with the two types of CNTs. Finding an optimal route for preparing stable SWCNT dispersions for in vitro studies is an important methodological problem in researching SWCNT toxicity.