Washington, May 21 : A new study has suggested that some forms of carbon nanotubes, which look and behave like asbestos, could be as harmful as the fire-resistant material if inhaled in sufficient quantities, leading to a harmful disease.
The study used established methods to see if specific types of nanotubes have the potential to cause mesothelioma - a cancer of the lung lining that can take 30-40 years to appear following exposure, a disease which is usually related to asbestos.
The results show that these specific long, thin multi-walled carbon nanotubes, look and behave like asbestos fibers.
Discovered nearly 20 years ago, carbon nanotubes have been described as the wonder material of the 21st Century. Light as plastic and stronger that steel, they are being developed for use in new drugs, energy-efficient batteries and futuristic electronics.
But since their discovery, questions have been raised about whether some of these nanoscale materials may cause harm and undermine a nascent market for all types of carbon nanotubes, including multi- and single-walled carbon nanotubes.
"This study is exactly the kind of strategic, highly focused research needed to ensure the safe and responsible development of nanotechnology," said Andrew Maynard, Chief Science Advisor to the Project on Emerging Nanotechnologies and a co-author on the paper.
"It looks at a specific nanoscale material expected to have widespread commercial applications and asks specific questions about a specific health hazard," he added.
Researchers, led by Professor Kenneth Donaldson at the University of Edinburgh in the United Kingdom, examined the potential for long and short carbon nanotubes, long and short asbestos fibers, and carbon black to cause pathological responses known to be precursors of mesothelioma.
For this purpose, material was injected into the abdominal cavity of mice - a sensitive predictor of long fiber response in the lung lining.
"The results were clear," said Donaldson. "Long, thin carbon nanotubes showed the same effects as long, thin asbestos fibers," he added.
Asbestos fibers are harmful because they are thin enough to penetrate deep into the lungs, but sufficiently long to confound the lungs' built-in clearance mechanisms for getting rid of particles.
According to Donaldson, "We still don't know whether carbon nanotubes will become airborne and be inhaled, or whether, if they do reach the lungs, they can work their way to the sensitive outer lining."
"But if they do get there in sufficient quantity, there is a chance that some people will develop cancer-perhaps decades after breathing the stuff," he added.