In a ground-breaking 2002 study, Weisman and colleagues at Rice, including the late Professor Richard Smalley, discovered that nanotubes fluoresce, or emit near infrared light. Because near-infrared light passes harmlessly into the body, biomedical researchers are keen to use carbon nanotubes for the noninvasive diagnosis and treatment of diseases such as cancer and atherosclerosis.
In the current study, Weisman, Curley and colleagues injected lab animals with water soluble single-walled carbon nanotubes. The nanotubes, whose biocompatible coating was displaced by proteins in the blood, continued to fluoresce in the animals.
"I still remember how excited we were when we confirmed that the tubes were fluorescing," said Paul Cherukuri, a doctoral degree candidate in Chemistry. The researchers used this fluorescence to track the nanotubes in the blood and image them in tissues under the microscope.
Cherukuri said Smalley initiated several follow-up projects shortly before his passing in 2005 from lymphoma. In one, researchers are working on methods that will allow nanotubes to circulate longer following injection, so that they can be more easily targeted to specific organs. In another, they are tracking the longer-term behavior and effects of nanotubes in research lab animals.
"This research grew out of Smalleys vision, and he followed our progress and offered daily guidance, even from his hospital bed at M.D. Anderson," Cherukuri said. Up to his very last day, he was simultaneously fighting his own battle with cancer and developing new ways to treat the disease that ultimately took his life. These new results are simply the first fruits of his final contributions in nanohealth research, and there are still more to come."