Carbon nanotubes and antibodies that are labelled with complementary strands of a synthetic DNA-like molecule could be used to deliver cancer drugs to tumours, reports a study published online this week in Nature Nanotechnology. This method is successful in overcoming some of the toxicity issues associated with current cancer treatments in mice.

Carbon nanotubes are well suited to drug-delivery applications because they can carry a large amount of therapeutic drug and, like a small molecule, be rapidly eliminated from circulation by renal filtration.

David Scheinberg and colleagues show that single-walled carbon nanotubes can target tumours in a two-step approach. First, cancer cells are pre-targeted with antibodies that have been modified with short strands of a DNA analogue known as morpholino oligonucleotides. Next, nanotubes modified with short strands complementary to those on the antibodies are administered and bind to the antibodies on the cancer cells, delivering the appropriate therapeutic or imaging agent to the target. The researchers show that the nanotubes selectively bind to cancer cells in vitro and in tumour-bearing mice. In particular, they find that nanotubes labelled with the radioactive isotope 225Ac can be used to treat lymphoma in mouse models and could be cleared rapidly, therefore reducing radioisotope toxicity.