Researchers from Edinburgh tested varying lengths of nanofibres, to see the effects inhalation had on mice, and found that the longer fibres caused similar effects to asbestos fibres, which cause lung cancers such as mesothelioma. Those larger than five micrometres, or five-thousandths of a millimetre, tended to become lodged in the lungs and cause inflammation. The smaller ones were cleared from the lungs.
The researchers hope the study will help to design safer nanofibres.
Ken Donaldson, Professor of Respiratory Toxicology at the University of Edinburgh, said:
“Concern has been expressed that new kinds of nanofibres being made by nanotechnology industries might pose a risk because they have a similar shape to asbestos.
“We knew that long fibres, compared with shorter fibres, could cause tumours, but until now we did not know the cut-off length at which this happened.
“Knowing the length beyond which the tiny fibres can cause disease is important in ensuring that safe fibres are made in the future as well as helping to understand the current risk from asbestos and other fibres.”
Prof Stephen Spiro, from the British Lung Foundation, said:
“This research is particularly interesting as it gives us an indication of the size of fibre that might lead to mesothelioma if inhaled.
“If confirmed by subsequent studies, this minimum fibre length can be cited in industry guidelines to help ensure people are not exposed to the sorts of fibres that may lead to such deadly diseases.”
Cases of mesothelioma have nearly quadrupled in the past 30 years because of asbestos and more than 3,000 lives are lost to mesothelioma in the UK each year. The peak of mesothelioma deaths from asbestos is predicted to occur around 2016.