July 25, 2003

t takes more than a bit of creativity and imagination to envision the link between breast cancer research and electrical engineering and chemistry. Yet, that’s exactly what Naomi Halas of Rice University in Houston, Texas, is doing with metal nanoshells and $3 million from the U.S. Department of Defense.

The tiny metal shells could in theory be placed inside a person and used as “biomarkers” to detect and destroy cancerous tumors. The idea is that the nanoshells could attach to a tumor and, when hit by a certain type of light, heat up and kill cancer cells.

Computer simulation depicts growth of gold nanoshell with silica core and over layer of gold. Courtesy N. Halas

The nanoshells are a little like Hershey’s Milk Duds. But the “candy” center is made of silica, and the outside is a gold shell instead of chocolate.

The researchers designed the shells to absorb specific wavelengths of light, such as those in the near-infrared-light range. And they have coated the shells with antibodies that bind to cancerous cells in culture.

The nanoshells are small enough to travel through the human bloodstream and could theoretically be injected into a patient. Each shell is roughly 100 nanometers in diameter; a nanometer is one-billionth of a meter.

Doctors could then shine near-infrared light on the patients, which is harmless, to light up the shells, revealing the tumor. By increasing the intensity of the light, the bound shells would heat up and kill the cancerous cells.

When the scientists created the first metal nanoshells, they had no idea how and where they might be used. But Halas and her Rice colleague Jennifer West brainstormed ways the novel devices could be used in human medicine.

“The cool thing is combining the imaging side with the therapy side,” says Halas. She recently received the Innovator Award from DOD’s Breast Cancer Research Program to pursue the technology to fight breast cancer.

With the grant, creative individuals outside the cancer research world are given the opportunity to pursue innovative approaches to eradicating the disease. The Breast Cancer Research Program was established in 1992; its 2002 funding from Congress was $150 million.

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