Detecting cancer cells in blood with a new microfluidic device

Researchers at the University of Illinois at Chicago and Queensland University of Technology of Australia, have developed a device that can isolate individual cancer cells from patient blood samples.

The microfluidic device works by separating the various cell types found in blood by their size. The device may one day enable rapid, cheap liquid biopsies to help detect cancer and develop targeted treatment plans. The findings are reported in the journal Microsystems & Nanoengineering.

“This new microfluidics chip lets us separate cancer cells from whole blood or minimally-diluted blood,” said Ian Papautsky, the Richard and Loan Hill Professor of Bioengineering in the UIC College of Engineering and corresponding author on the paper. “While devices for detecting cancer cells circulating in the blood are becoming available, most are relatively expensive and are out of reach of many research labs or hospitals. Our device is cheap, and doesn’t require much specimen preparation or dilution, making it fast and easy to use.”

The ability to successfully isolate cancer cells is a crucial step in enabling liquid biopsy where cancer could be detected through a simple blood draw. This would eliminate the discomfort and cost of tissue biopsies which use needles or surgical procedures as part of cancer diagnosis. Liquid biopsy could also be useful in tracking the efficacy of chemotherapy over the course of time, and for detecting cancer in organs difficult to access through traditional biopsy techniques, including the brain and lungs.

However, isolating circulating tumor cells from the blood is no easy task, since they are present in extremely small quantities. For many cancers, circulating cells are present at levels close to one per 1 billion blood cells. “A 7.5-milliliter tube of blood, which is a typical volume for a blood draw, might have ten cancer cells and 35-40 billion blood cells,” said Papautsky. “So we are really looking for a needle in a haystack.”

Microfluidic technologies present an alternative to traditional methods of cell detection in fluids. These devices either use markers to capture targeted cells as they float by, or they take advantage of the physical properties of targeted cells — mainly size — to separate them from other cells present in fluids.

Papautsky and his colleagues developed a device that uses size to separate tumor cells from blood. “Using size differences to separate cell types within a fluid is much easier than affinity separation which uses ‘sticky’ tags that capture the right cell type as it goes by,” said Papautsky. “Affinity separation also requires a lot of advanced purification work which size separation techniques don’t need.”

Learn more: New microfluidics device can detect cancer cells in blood