Nanotoxicology: Does Inhalation of Carbon Nanotubes Cause Pulmonary Fibrosis?

Are carbon nanotubes toxic? Mice that inhaled multilayer carbon nanotubes in a single dose have traces of these nanotubes in their lungs and after a few weeks developed lung fibrosis, one of the causes of lung cancer.

Inhalation of Carbon Nanotubes is the Cause of Lung Tumors

James Bonner of the University of North Carolina, Raleigh, USA, and his colleagues exposed mice to aerosols of nanoparticles (multilayer carbon nanotubes) for 6 hours at both high doses of 30 milligrams per cubic meter and low doses of 1 milligram per cubic meter.

At high doses, macrophages, a type of white blood cell that phagocytes foreign elements, engulfed the nanotubes and passed them through the bronchi and bronchioles. A few weeks after exposure, these mice developed subpleural-type pulmonary fibrosis (small scars in the airways). At low doses, these effects are not as well observed as at high doses of carbon nanoparticles.

Pulmonary fibrosis is associated with the development of some lung cancers. Although the study does not prove it directly, it may be that inhalation of carbon nanotubes is the cause of lung tumors.

Employees in nanotechnology companies who deal with nanotubes on a daily basis should be very aware of these studies: they should try to avoid inhaling an environment contaminated with nanotubes if possible.