The research exposed mice to different types of asbestos, carbon nanoparticles and multi-walled carbon nanotubes (MWNT). MWNT consist of many nanotubes stacked inside each other. The mice were exposed to the substances in the lining of their abdominal cavity which is similar to the lining of the human chest cavity which is affected by asbestos and where mesothelioma normally arises. Indicators of the harmful effects usually caused by asbestos were monitored, such as inflammation and the production of scar-like structures or lesions.
The results revealed that only long multi-walled carbon nanotubes show asbestos-like behaviour. However, the authors point out that their test was specific for fibres and that nanocarbon in the form of particles could be harmful in ways that are not addressed in this study. This flags up the importance of choosing the correct method of evaluating toxicity.
The authors also point out some limitations in their study. Although the results do suggest a link between long CNT and the cancer caused by asbestos, it remains unknown whether there will be sufficient exposure in the environment or workplace to actually cause it. This indicates that there needs to be more in-depth research into exposure levels of long CNT before their use becomes more widespread.