Carbon nanotubes can trap cancer and other cells as they flow through this microfluidic device. Each post is 30 microns in diameter: image credit: Brian WardleThe collaboration of a Harvard bioengineer and an MIT aeronautical engineer has led to the development of a device that can detect as little as a single nanogram-size cancer cell in a blood sample. This microfluidic device is essential for the earliest identification of a spreading cancer.
Circulating breakaway cancer cells are extremely difficult to find, largely because there are so few of them in a sample of blood; among billions of normal cells, there may be one to a just a few straying cancer cells.
Mehmet Toner, the Harvard Medical School developer, had tried using thousands of tiny silicon posts coated with antibodies for the task of detecting cancer cells, but later decided to create porous posts so that the cells could flow through them, not just around them. He contacted Brian Wardle, an MIT professor of aeronautics and astronautics and a designer of nano-engineered advanced composite materials for use in making stronger aircraft parts.
The result of their collaboration is a new microfluidic device that is 8 times more effective than Toner's first model. The new model, made from geometrically intricate carbon tubes arranged in 'forests' of 10 billion to 100 billion carbon nanotubes per square centimeter turns out to be only 1 percent carbon and 99 percent air, so there is plenty of space for the cancer cells to get caught.
"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
The device is very versatile. It can be customized with different antibodies attached to the surfaces of the nanotubes to attract different kinds of diseased cells. The spaces in the nanotubes can also be adjusted to catch larger cells up to a micron in diameter, or smaller cells, like viruses, down to 40 nanometers.
The researchers are now modifying their microfluid device for HIV diagnosis.
source: MIT via RDMag