AOPs Including This Stressor
Events Including This Stressor
Carbon nanotubes (CNTs) are allotropes of carbon, are made of rolled up sheet of graphene (single-walled carbon nanotubes) and are tubular in shape. A multi-walled carbon nanotube (MWCNT) is multi-layered concentric cylinders of graphene sheets stacked one inside the other (N. Saifuddin et al., 2013). CNTs exhibit a combination of unique mechanical, thermal and electronic properties and are highly desired commercially. They are light weight but their tensile strength is 50 times higher than that of steel, and they are stable chemically as well as in the environment. Consequently, they are produced in massive amounts and are increasingly incorporated in several industrial products.
CNTs are high aspect ratio materials and are shown to cause lung fibrosis in experimental animals (Muller J et al., 2005; Porter DW et al., 2010). In an intelligence bulletin published by NIOSH on ‘Occupational exposure to carbon nanotubes and nanofibers’, NIOSH reviewed 54 individual animal studies investigating the pulmonary toxicity induced by CNTs and reported that half of those studies consistently showed lung fibrosis (NIOSH bulletin, 2013). However, the evidence is inconsistent and the occurrence of fibrotic pathology is influenced by the specific physical-chemical properties of CNTs (length, rigidity), their dispersion in exposure vehicle, and the mode of exposure.
Characterization of Exposure
- N. Saifuddin, A. Z. Raziah, and A. R. Junizah. Carbon Nanotubes: A Review on Structure and Their Interaction with Proteins. Journal of Chemistry, vol. 2013, Article ID 676815, 18 pages, 2013.
Julie Muller, Franc¸ois Huaux, Nicolas Moreau, Pierre Misson, Jean-Francois Heilier, Monique Delos, Mohammed Arras, Antonio Fonseca, Janos B. Nagy, Dominique Lison Respiratory toxicity of multi-wall carbon nanotubes. Toxicology and Applied Pharmacology 207 (2005) 221–231.
- Dale W. Porter, Ann F. Hubbs, Robert R. Mercer, Nianqiang Wu, Michael G. Wolfarth, Krishnan Sriram, Stephen Leonard, Lori Battelli, Diane Schwegler-Berry, Sherry Friend, Michael Andrew, Bean T. Chen, Shuji Tsuruoka, Morinobu Endo, Vincent Castranova, Mouse pulmonary dose- and time course-responses induced by exposure to multi-walled carbon nanotubes. Toxicology, Volume 269, Issues 2–3, 2010, Pages 136-147.
- NIOSH: Occupational exposure to carbon nanotubes and nanofibers: current intelligence bulletin 65. 2013.