How do you catch a mouse? By setting a trap for it. Engineers at Northwestern University have used the same principle to construct a device which catches cancer cells, stopping them from spreading.

A series of such channels, properly placed, would allow movement of normal cells but block the migration of cancer cells.

Most deaths from cancer are due to metastasis, the movement of cancer cells from one part of the body to another. The researchers have built a model of a device that alters the destination of migrating cancer cells. They propose that a similar device can be used to lead cancer cells into a permanent trap from which they can't escape and cause harm.

A key to this device is the creation of tiny molecular channels that are capable of separating normal cells from cancer cells. One type of channel contains obstacles; alternating spikes coming out from opposite sides of the channel. Migrating cancer cells are round and broad, and their movement is blocked by the spikes. Normal cells tend to be longer and thinner, with protrusions at their ends. These protrusions allow them to grab onto the spikes and pull themselves through the channels. A series of such channels, properly placed, would allow movement of normal cells but block the migration of cancer cells.

The device demonstrated by the researchers works outside of the body. Their goal is to build an implantable model, implant it next to a tumor and stop any migrating cancer cells from metastasizing to other parts of the body. Ideally, it could also be incorporated into the sutures used at the end of a surgical procedure, such as removal of a tumor.

Clearly it will take some time before such a device is ready to be used clinically. But the work suggests a completely different approach than current methods such as chemotherapy. Considering just how difficult it has been to find effective treatments for cancer, a new approach may be exactly what is needed.

The research was published online June 14, 2009 by the journal Nature Physics.