Trapping cancer cells with carbon nanotubes

March 29, 2011 by Editor

MIT engineers have created a new device that can detect single cancer cells in a blood sample, potentially allowing doctors to quickly determine whether cancer has spread from its original site.

The microfluidic device is about the size of a dime, and could also detect viruses such as HIV. It could eventually be developed into low-cost tests for doctors to use in developing countries, where expensive diagnostic equipment is hard to come by, says Mehmet Toner, professor of biomedical engineering at Harvard Medical School and a member of the Harvard-MIT Division of Health Sciences and Technology.

Toner built an earlier version of the device four years ago. In that original version, blood taken from a patient flows past tens of thousands of tiny silicon posts coated with antibodies that stick to tumor cells. Any cancer cells that touch the posts become trapped. However, some cells might never encounter the posts at all.

Toner thought if the posts were porous instead of solid, cells could flow right through them, making it more likely they would stick. To achieve that, he enlisted the help of Brian Wardle, an MIT associate professor of aeronautics and astronautics, and an expert in designing nano-engineered advanced composite materials to make stronger aircraft parts.

Out of that collaboration came the new microfluidic device, studded with carbon nanotubes, that collects cancer cells eight times better than the original version.

Nanotube forest

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.

Rashid Bashir, director of the Micro and Nanotechnology Laboratory at the University of Illinois at Urbana-Champaign, says that the ability to filter specific particles, cells or viruses from a blood sample so they can be analyzed is a critical step towards creating handheld diagnostic devices.

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