12:35pm UK, Wednesday May 21, 2008

A link between carbon nanotubes and the type of cancer caused by asbestos has been drawn by scientists.

A carbon nanotube-polymer composite (PIC: NASA)

However, the lead researcher told Sky News Online that the results were "not a scare story" and were "unwelcome but not surprising".

Carbon nanotubes, which are one fiftieth of the width of a human hair, are lightweight but extremely robust materials which are already being used in products such as bicycles and tennis rackets.

Future applications are likely to include building work and aerospace.

The researchers injected nanotubes into the abdomens of mice and induced lesions similar to those that appear on the outer lining of the lungs after the inhalation of asbestos.

Such a reaction can go on tocause the deadly cancer mesothelioma.

But Ken Donaldson of the University of Edinburgh explained that the result was nothing to do with the science of nanotechnology itself.

He said: "There's a paradigm in the toxicology world over what makes something harmful.

"It says that short fibres are harmless and long are harmful. Asbestos if it's short is harmless."

Long in this case means 20 microns, and it was found that fibres of that length caused harm to the mice in question.

Short nanotubes did not cause damage, while long ones which were "rolled up" like a piece of wool, rather than being one straight line, also caused no problems.

A further caveat is that the fibres were injected rather than inhaled, which is how asbestos-related problems arose.

Professor Donaldson said further research is needed to see whether inhaling material from carbon nanotubes causes health problems.

Nevertheless, the findings confirm that more work was needed to protect people working in the growing carbon nanotube industry,

Professor Donaldson said: "It's an important step towards ensuring a safe industry."

Dr Noemi Eiser, Medical Director at the British Lung Foundation, commented. "It is imperative that the questions raised by this research are answered before the commercial use of long carbon nanotubes becomes widespread."

The findings are not thought to have a bearing on people buying products containing carbon nanotubes.

Nanotechnology, the science of the tiny, works in dimensions of nanoparticles, and a nanometre is one billionth of a metre.