Carbon Nanotube–Based Microfluidic Device Traps Cancer Cells

As the previous Medtech Pulse post comments, the field of microfluidic devices is one of the hottest research disciplines in the the area of medical device design and development. Adding to the heat, scientists at Harvard University (Cambridge, MA) and MIT (Cambridge, MA) have developed a microfluidic device that can single out individual cancer cells in a blood sample--a breakthrough that could eventually enable medical professionals to quickly determine whether cancer has spread from its original site.

Described in the journal Small, the current device is based on a version built four years ago by Mehmet Toner, professor of biomedical engineering at Harvard Medical School and a member of the Harvard-MIT Division of Health Sciences and Technology. This device consisted of thousands of nanoscale silicon posts coated with antibodies that adhere to tumor cells. When blood is drawn from a patient, it flows past the posts. Cancer cells that make contact with the posts become trapped. However, some cells might not touch the posts.

Approximately the size of a dime, the new iteration features posts that are porous rather than solid in order to better trap cancer cells. To create these posts, Toner turned to Brian Wardle, an MIT associate professor of aeronautics and astronautics and an expert in nanoengineered composite materials used for making strong aircraft parts. As a result of their collaboration, the researchers developed a microfluidic device consisting of carbon nanotubes that can collect cancer cells eight times better than the original version.

"Of all deaths from cancer, 90% are not the result of cancer at the primary site," Wardle remarks. "They're from tumors that spread from the original site." Motivated to find such breakaway cancer cells, the MIT/Harvard scientists engineered carbon nanotubes of various geometries into a microfluidic device. As in the original device, the surface of each tube can be coated with antibodies specific to cancer cells. However, because the fluid can pass through as well as around the nanotubes, the chances for trapping them is much greater than with the earlier device. The researchers can also customize the device by attaching different antibodies to the nanotubes' surfaces. In addition, changing the spacing between the posts allows them to capture objects of different sizes, including tumor cells measuring approximately 1 µm and viruses measuring only 40 nm.

For more information on this technology, visit MIT News.