Carbon nanotubes which are used in everything from sports equipment to medical applications can affect the lining of the lungs, say researchers.
The long term effects, however, remain unclear.
The study was a collaboration between North Carolina State University (NCSU), The Hamner Institutes for Health Sciences, and the National Institute of Environmental Health Sciences.
Using mice in an animal model study, researchers set out 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, which is the tissue that lines the outside of the lungs and is affected by exposure to certain types of asbestos fibres which cause cancer.
Researchers found that inhaled nanotubes do reach the pleura and cause health effects. Short-term studies described in the paper do not allow conclusions about long-term responses such as cancer.
The "unique reaction" began within one day of inhalation of the nanotubes, when clusters of immune cells (lymphocytes and monocytes) began collecting on the surface of the pleura.
Localised fibrosis, or scarring on parts of the pleural surface that is also found with asbestos exposure, began two weeks after inhalation.
The study showed the immune response and fibrosis disappeared within three months of exposure. However, this study used only a single exposure to the nanotubes, says an NCSU release.
It remains unclear whether the pleura could recover from chronic, or repeated, exposures.
"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," an NCSU release said.
These findings were published in Nature Nanotechnology.
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