Unlike other molecules that are used to encapsulate drugs, fullerenes resist breakdown by the body. This stability is especially important for holding compounds that would cause harm if released in healthy cells, for example, radioactive metal atoms.
L. Wilson have modified 60-carbon fullerenes, called buckyballs, to home in on bone when injected into the body. Gonzalez and Wilson designed their compound to stick to hydroxyapatite. They also got a surprise when characterizing the compound: The molecule has one unpaired electron, making it magnetic. This property makes the compound a potential contrast agent for magnetic resonance imaging (MRI). A contrast agent injected into a patient can sharpen an MRI picture, revealing otherwise invisible features.
S. R. Wilson is working on fitting radioactive metals inside the buckyball, which as they travel through the bloodstream, will emit radiation. But since they are excreted intact, they will completely remove the radiation from the body after the procedure. He is also working on fullerenes that will deliver bone-building drugs for osteoporosis. Currently, most of those drugs are not well absorbed and are toxic. Buckyballs might offer a non-toxic molecular ship to deliver the materials safely to fragile bones. And on a more distant horizon, buckyballs may someday carry light-activated and/or cancer-killing drugs to tumour cells. Smalley would love to see this last application happen soon. The discoverer of buckyballs has recently suffered a recurrence of lymphatic cancer.
Bianco et.al at the CNRS Institute in Strasbourg, have shown that carbon nanotubes are adept at entering the nuclei of cells and may one day be used to deliver drugs and vaccines. They have modified nanotubes to transport small peptide into the nuclei of fibroblast calls. This gives hope that the nanotubes may be useful for forming the basis of anti-cancer treatments, gene therapies and vaccines.