Rarely has a class of new materials offered so many opportunities for unique products as carbon nanotubes (CNTs) and other carbon nanostructures.

Carbon nanotubes are already incorporated into high performance sports equipment to improve specific strength and stiffness. Their ability, when used in quantum tunneling composites, to perform as sensors and electrical switches on the application of pressure has been effectively demonstrated by David Lussey of Peratech. Future sales of these materials are now estimated to be worth more than $10 billion over the next five years.

The widespread use of nanoscale materials has led to speculation on the possible health risks. There was concern that certain forms of CNTs might produce similar responses to those caused by asbestos if ingested in sufficient quantities. This was reviewed in a study by the Royal Society and Royal Academy of Engineering, whose report, published in 2004, concluded that there was insufficient data to make firm conclusions. It recommended that the UK Government sponsor specific research programmes, and while the Government welcomed the review, it has failed to support any new initiatives.

Recently-published UK research has started to contribute firm data. The detection and visualization of the tiny carbon structures represented by CNTs in tissue is a challenge as they are difficult to distinguish from carbon-rich organelles. Nevertheless, Dr Alexandra Porter (now at Imperial College London), using state-of-the-art low-loss-energy filtered transmission electron microscopy, showed that CNTs can, and do, penetrate the nucleus of cells.

Researchers at the University of Edinburgh, under the leadership of Professor Kenneth Donaldson, have demonstrated that long CNTs can produce similar short-term effects on the lung tissue of laboratory animals as long, thin asbestos fibres. The long-term effects of ingesting CNTs are unknown, but these findings illustrate the need for all those who handle and work with nanotubes, from research to processing into end products, and the recycling and disposal of those products, to follow the Seven Principles of the Responsible NanoCode, a voluntary code of conduct for businesses engaged in nanotechnology. The results reinforce that ‘size matters’ when determining the strategy for safe handling and use of any material, even those which are quite inert in large dimensions.

It should be emphasized that many potentially-hazardous materials are in everyday use in the manufacture of products that we take for granted, but the way they are used is carefully controlled by health and safety legislation to protect the user. The same principles should apply to these new carbon-based materials which have such enormous potential. Nothing illustrates this better than their capability for cell penetration, which may eventually be employed as a means to deliver drugs to specific cells, for example, in treating cancer.

Further information

Nanotechnology health threat in the news – the Guardian

Royal Society and Royal Academy of Engineering 2004 nanotechnology report

Government’s response to the Royal Society and Royal Academy of Engineering report

Responsible NanoCode