EVANSTON, Ill.-Researchers at Northwestern University have shown that nanodiamonds are very effective at delivering chemotherapy drugs to cells without the negative effects associated with current drug delivery agents. Their study, published online by the journal Nano Letters, is the first to demonstrate the use of nanodiamonds, a new class of nanomaterials, in biomedicine. In addition to delivering cancer drugs, the model could be used for other applications, such as fighting tuberculosis or viral infections, say the researchers.

 Nanodiamonds promise to play a significant role in improving cancer treatment by limiting uncontrolled exposure of toxic drugs to the body. The research team reports that aggregated clusters of nanodiamonds were shown to be ideal for carrying a chemotherapy drug and shielding it from normal cells so as not to kill them, releasing the drug slowly only after it reached its cellular target.

 Another advantage of the material, confirmed by a series of genetic studies also reported in the paper, is that nanodiamonds do not cause cell inflammation once the drug has been released and only bare diamonds are left. Materials currently used for drug delivery can cause inflammation, a serious complication that can predispose a patient to cancer, block the activity of cancer drugs and even promote tumor growth.

 "There are a lot of materials that can deliver drugs well, but we need to look at what happens after drug delivery," says Dean Ho, assistant professor of biomedical engineering and mechanical engineering at Northwestern's McCormick School of Engineering and Applied Science, who led the research. "How do cells react to an artificial material left in the body? Nanodiamonds are highly ordered structures, which cells like. If they didn't, cells would become inflamed. From a patient's perspective, this is very important. And that's why clinicians are interested in our work."

 To make the material effective, Ho and his colleagues manipulated single nanodiamonds, each only 2 nm in diameter, to form aggregated clusters, ranging from 50 nm to 100 nm in diameter. The drug, loaded onto the surface of the individual diamonds, is not active when the nanodiamonds are aggregated; it only becomes active when the cluster reaches its target, breaks apart and slowly releases the drug.