Nanotech News

April 2007

Nanotube High-Energy Electron Source Boosts Cancer Cell Studies

High-energy electrons have proved to be a powerful weapon in the war on cancer, having become an important component of modern cancer therapy, particularly for prostate cancer, certain types of lymphoma, and breast cancer. But irradiating a tumor with even the most focused electron beam is a bit like hitting an archery target with a howitzer shell, making it nearly impossible for researchers to determine how individual tumor cells respond to lethal or near-lethal doses of radiation.

Now, however, researchers at the Carolina Center of Cancer Nanotechnology Excellence have developed a method for making a single-cell electron beam source using carbon nanotubes. This team, led by Otto Zhou, Ph.D., of the University of North Carolina at Chapel Hill, published the first results of their work in the journal Radiation Protection Dosimetry.

Unlike conventional electrodes, where electrons are "boiled off" the entire surface and then accelerated toward their target, electrodes made of carbon nanotubes emit their high-energy electrons only from their tips. As a result, the electrons emitted from a carbon nanotube electrode travel to their target in a much tighter beam. Tests with the carbon nanotube system showed that each carbon nanotube produces a beam of about 10 microns in diameter.

The Carolina team also demonstrated that they can combine as many as 10,000 of these microbeam electrodes to produce an electron source capable of irradiating single cells or large numbers of individually selected cells. Each nanotube in the cluster is controlled individually, allowing the investigators to vary the energy of the electron beam and the total dose of electrons delivered to each cell being irradiated.

This work, which was funded in part by the National Cancer Institute's Alliance for Nanotechnology in Cancer, is detailed in the paper "Development of a nanotechnology based low-LET multi-microbeam array single cell irradiation system." An abstract of this paper is available through PubMed.
View abstract.