Toxicity of Single-Wall Carbon Nanotubes in the Lungs of Mice Exposed by Intratracheal Instillation

Abstract

Single-wall carbon nanotubes (NTs) are light and could become airborne; fine NT particles could potentially reach the lung. The pulmonary toxicity of three NT products was investigated in mice by intratracheal instillation. Mice (4 to 5 per group) were each instilled once with a fine-particle suspension containing 0, 0.1 or 0.5 mg of NTs or a reference dust (carbon black or quartz), and killed 7 or 90 days later for lung histopathological study. Carbon black elicited minimal effects and high-dose quartz produced mild to moderate inflammation in the lungs. All the three NT products studied produced granulomas (microscopic nodules) and other lung lesions. These results show that, for the test conditions described here and on an equal-weight basis, if NTs reach the lung, they can be more toxic than quartz. If airborne NT dusts are present in the working environment, respiratory protection should be used to minimize inhalation exposures.