Danger in the tubes

NANOTUBES, one of the wonder materials of the new age of nanotechnology, may carry a health risk similar to that of asbestos, a wonder material of an earlier age that turned into a scourge after decades of use when its fibres were found to cause lung disease.

This time, the warning comes long before anyone has fallen ill, and experts say the findings call for caution, not alarm, in handling nanotubes, which are tiny, superstrong carbon fibres. Although nanotubes are already found in some products, like tennis rackets, researchers say the fibres appear to pose little risk to consumers.

Nanotubes, discovered in 1991, are essentially rolled-up sheets of carbon that can be used to produce materials that are far lighter and stronger than steel, for example. But scientists have also long wondered whether the needle-shaped nanotubes might cause the same types of disease as needle-shaped asbestos fibres.

The researchers, though, portrayed their results as good news by providing people who work with nanotubes with knowledge of how to minimise the dangers. “In a sense, we’re forewarned and forearmed with respect to nanotubes,” said Anthony Seaton, a professor of environmental and occupational medicine at the University of Aberdeen in Scotland.

Vicki Colvin, a professor of chemistry at Rice University in Houston, who was not involved with the research, said that she saw no need to restrict the use of nanotubes in products. “I’m not alarmed,” Colvin said, “but it seems we should have better information about where it is and how it’s being used.”

When foreign particles like smoke or dust land in the lungs, cells known as macrophages engulf the particles and clear them away. Some asbestos fibres are too long for the macrophages to handle, resulting in lesions. The researchers hypothesised that nanotubes would cause similar problems if they were long, but not if they were short or tangled into a ball.

In their study, the researchers injected four groups of mice: one with short...