Chemistry resolves toxic concerns about carbon nanotubes

Safety fears about carbon nanotubes, due to their structural similarity to asbestos, have been alleviated following research showing that reducing their length removes their toxic properties. In a new study, published today in the journal Angewandte Chemie, evidence is provided that the asbestos-like reactivity and pathogenicity reported for long, pristine nanotubes can be completely alleviated if their surface is modified and their effective length is reduced as a result of chemical treatment. First atomically described in the 1990s, carbon nanotubes are sheets of carbon atoms rolled up into hollow tubes just a few nanometres in diameter. Engineered carbon nanotubes can be chemically modified, with the addition of chemotherapeutic drugs, fluorescent tags or nucleic acids - opening up applications in cancer and gene therapy. Furthermore, these chemically modified carbon nanotubes can pierce the cell membrane, acting as a kind of 'nano-needle', allowing the possibility of efficient transport of therapeutic and diagnostic agents directly into the cytoplasm of cells. The apparent structural similarity between carbon nanotubes and asbestos fibres has generated serious concerns about their safety profile and has resulted in many unreasonable proposals of a halt in the use of these materials even in well-controlled and strictly regulated applications, such as biomedical ones. Kostas Kostarelos Among their downsides however, have been concerns about their safety profile.