New method separates cancer cells from normal cells

The vast majority of cancer deaths are due to metastasis, the spread of cancer cells from its primary site to other parts of the body. These metastatic cells tend to move more than their non-metastatic variants but this movement is poorly understood. Scientists are studying cancer cells intently with the hope they can learn to control the movements of the dangerous cells.

Northwestern University researchers now have demonstrated a novel and simple method that can direct and separate cancer cells from normal cells. Based on this method, they have proposed that cancer cells possibly could be sequestered permanently in a sort of "cancer trap" made of implantable and biodegradable materials.

The demonstrated device, which takes advantage of a physical principle called ratcheting, is a very tiny system of channels for cell locomotion. Each channel is less than a tenth of a millimeter wide. The asymmetric obstacles inside these channels direct cell movement along a preferred direction.

Details are published online by the journal Nature Physics.

"We have demonstrated a principle that offers an unconventional way to fight metastasis, a very different approach from other methods, such as chemotherapy," said Bartosz Grzybowski, the paper's senior author. "These are fundamental studies so the method needs to be optimized, but the idea has promise for a new approach to cancer therapy."

Grzybowski is associate professor of chemical and biological engineering in the McCormick School of Engineering and Applied Science and associate professor of chemistry in the Weinberg College of Arts and Sciences.

The researchers first discovered they could design channels of different geometries -- some a series of connected triangles -- through which cells can move in a single direction. (Live mammalian melanoma, breast cancer and normal cells were studied.)