Scientists study nanotube effects on lungs

RALEIGH, N.C., Oct. 27 (UPI) -- A North Carolina State University-led study shows inhaling carbon nanotubes can affect the outer lining of the lung.

The collaborative study involving the university, the National Institute of Environmental Health Sciences and the Hamner Institutes for Health Sciences used mice to determine what happens when multi-walled carbon nanotubes are inhaled. Specifically, researchers wanted to determine whether the nanotubes would be able to reach the pleura -- the tissue that lines the outside of the lungs.

Associate Professor James Bonner, senior author of the study, said the inhaled nanotubes clearly reached the target tissue and caused a unique pathologic reaction on the surface of the pleura, and also produced fibrosis, or scarring.

Bonner said clusters of immune cells began collecting on the surface of the pleura within one day of nanotube inhalation. Localized fibrosis began two weeks after inhalation.

The study showed the immune response and fibrosis disappeared within three months of exposure.

"It remains unclear whether the pleura could recover from chronic, or repeated, exposures," Bonner said. "More work needs to be done in that area and it is completely unknown at this point whether inhaled carbon nanotubes will prove to be carcinogenic in the lungs or in the pleural lining."

The study is reported in the journal Nature Nanotechnology.