Tracking nanotubes in mice.

While studies have demonstrated that carbon nanotubes with certain molecular attachments can target specific cells in culture, researchers haven't known whether the tubes would show the same capability in live animals. Now, a team from Stanford University reports that these nanopartides can target tumors in mice.

Xiaoyuan Chen, Hongjie Dai, and their colleagues used several imaging techniques, including positron emission tomography, to track the distribution of nanotubes injected into the tail veins of mice. The researchers wrapped the tubes with polymer chains and attached radioactive copper, for tracking purposes, and a sequence of three amino acids that targets certain tumor cells.

In the January Nature Nanotechnology, the group writes that tumor tissues were 15 times as likely to take up the nanotubes as nearby normal tissues were.

The researchers found no adverse symptoms in the mice 3 months after injection. But the imaging data also revealed that the tubes weren't excreted quickly from the body, and remained in particular in the liver and spleen. Longer toxicity studies will be necessary to evaluate how this affects the animals' health, says Chen.