Dai points out that the carbon nanotubes also can be delivered to diseased cells by direct injection. "In breast cancer, for example, there might come a time when we inject nanotubes into the tumor and expose the breast to near-infrared light," he says. This benign therapy could potentially eliminate months of debilitating chemotherapy and radiation treatment, he adds.
"The laser we used is a 3-centimeter beam that's held like a flashlight," he notes. "We can take the beam and put anywhere we want. We can shine it on a local area of the skin or inside an internal organ using a fiber-optic device."
Dai has applied for a patent on the procedure through Stanford's Office of Technology Licensing (OTL). He also has patented another technique that uses pulses of near-infrared light to shake the DNA molecule loose from the carbon nanotube after they've entered the cell. The idea is to use the nanotube to deliver therapeutic molecules of DNA, RNA or protein directly into the cell nucleus to fight various infections and diseases.
"Nanotechnology has long been known for its applications in electronics," Dai concludes. "But this experiment is a wonderful example of nanobiotechnology--using the unique properties of nanomaterials to advance biology and medicine."
Dai's graduate student, Nadine Wong Shi Kam, is lead author of the PNAS study. Other co-authors are Michael O'Connell, a former postdoctoral fellow in the Department of Chemistry, and graduate student Jeffrey A. Wisdom in the Department of Applied Physics.
The study was partly supported by the National Science Foundation Center on Polymer Interfaces and Macromolecular Assemblies, a research partnership among Stanford, IBM Almaden Research Center