Could a hi-tech material prove as hazardous as asbestos?
ONCE, asbestos was hailed as a key product whose ability to cope with heat was vital to the shipbuilding, automotive and construction industries. But it left a tragic legacy – the US estimates 14 in every thousand Second World War shipyard workers died from asbestosis or mesothelioma – a type of cancer – and Scotland has the highest incidence of the condition, with 175 cases diagnosed a year.
Now scientists are warning a form of carbon used in modern state-of-the art products may pose a similar cancer risk.
It has come after tests showed carbon nanotubes, used to create modern lightweight materials, could have a similarly harmful effect on the lungs.
Carbon nanotubes have a long, hollow structure and are used in the manufacture of strong but lightweight materials. The fibres are used in bicycle frames, boat hulls, aircraft, sports cars and computers.
But scientists from the University of Edinburgh and the Medical Research Council (MRC) – which funded the research – have warned of the ‘possible dangers’ of being exposed to the molecules.
Carbon nanotubes have a diameter 10,000 times smaller than that of a human hair but can be up to several centimetres long.
Some are similar in size and shape to asbestos fibres, leading researchers to investigate whether they might have the same harmful effect on the lungs.
Initially thought of as a ‘wonder product’, asbestos is a strong natural fibre with many useful properties, including heat resistance.
Scotland, and Glasgow in particular, had many asbestos factories. Asbestos lagging insulated the pipework of Clyde-built ships. Scotland was home to one of the world’s first and most prosperous asbestos industries, with workers first coming into contact with it on a large scale during the 1970s.
But long-term inhalation of asbestos fibres can cause fatal illnesses, including lung cancer, mesothelioma and asbestosis. Asbestos was banned in 1999.
In the study, researchers placed either long carbon nanotubes or asbestos fibres directly into the pleural space – which separates the lungs and chest wall – of mice. This is the part of the body where mesothelioma usually develops in humans exposed to asbestos.
It was done to mimic occupational exposure where free fibres might be inhaled during the manufacturing process. There is no evidence of risk from finished products with carbon nanotubes.
The researchers studied changes in the cells lining the pleural space over a number of months. Mesothelioma in the mice after asbestos or carbon nanotube exposure was similar to samples from humans exposed to asbestos.
They found that, like asbestos fibres, long nanotubes caused long-term inflammation in the pleural space. Over time, this inflammation damaged the genes that stop the formation of tumours which, in people with mesothelioma, are also found to be altered.
Carbon nanotubes are 100 times stronger than steel but one-sixth its weight. They also conduct heat and electricity better than copper. They have been used in wind turbines, batteries, skis, hockey sticks and surfboards.
Dr Craig Poland, senior research fellow at the University of Edinburgh’s Centre for Inflammation Research, said: ‘New advanced materials such as carbon nanotubes offer an exciting frontier for innovation – but safety is imperative.
‘Prior to understanding the risks posed by exposure to asbestos, it was considered a wonder material with numerous applications; yet a tragic legacy arose from its widespread use.
‘Knowledge of the sequence of events from exposure to asbestos to the formation of mesothelioma is vital for identifying any risks posed by new fibres.
‘We have demonstrated the potential risks posed by long carbon nanotubes. These findings open up the possibility of more effective and efficient screening of advanced fibres to better identify risks and ensure safety.’
MRC head of molecular and cellular medicine Dr Nathan Richardson said: ‘This is an important study in mice and we now need to better understand real-world exposures to carbon nanotubes in humans and whether we see any similar molecular changes that might lead to disease.
‘These studies will also help inform human studies on asbestos exposure and disease and perhaps develop earlier diagnostics and effective treatments.’