"Of all deaths from cancer, 90 percent are not the result of cancer at the primary site. They're from tumors that spread from the original site," Wardle says.
When designing advanced materials, Wardle often uses carbon nanotubes tiny, hollow cylinders whose walls are lattices of carbon atoms. Assemblies of the tubes are highly porous: A forest of carbon nanotubes, which contains 10 billion to 100 billion carbon nanotubes per square centimeter, is less than 1 percent carbon and 99 percent air. This leaves plenty of space for fluid to flow through.
The MIT/Harvard team placed various geometries of carbon nanotube forest into the microfluidic device. As in the original device, the surface of each tube can be decorated with antibodies specific to cancer cells. However, because the fluid can go through the forest geometries as well as around them, there is much greater opportunity for the target cells or particles to get caught.
The researchers can customize the device by attaching different antibodies to the nanotubes' surfaces. Changing the spacing between the nanotube geometric features also allows them to capture different sized objects from tumor cells, about a micron in diameter, down to viruses, which are only 40 nm.
The researchers are now beginning to work on tailoring the device for HIV diagnosis. Toner's original cancer-cell-detecting device is now being tested in several hospitals and may be commercially available within the next few years.
|Contact: Caroline McCall|
Massachusetts Institute of Technology