“Labyrinth” device sorts cancer cells from healthy blood

Microfluidics — the phenomenon that underlies ‘lab-on-a-chip’ technologies — has long been of interest to medicine. Its ability to pass samples of fluids through channels containing compounds that bind to specific chemical groups or regions on chemicals in the sample make it potentially useful both in diagnosing diseases from body fluid samples taken from patients and in testing the activity of potential drug molecules. A team from the University of Michigan at Ann Arbor has now devised a microfluidic chip with another use — separating circulating cancer cells in blood samples.

Circulating cancer cells break off from malignant tumours and roam through the body. They may latch on to other tissues and grow into new tumours, but they also might be important to treating the original cancer: if they could be isolated and studied, doctors could design a targeted drug therapy for the individual patient; monitor the cancer for genetic changes, and gain an early warning that the disease is about to spread. But the cells are elusive; they only account for a tiny proportion of blood cells, and they can transform into a type of drug-resistant stem cell while travelling through the bloodstream, making the usual method for targeting and grabbing cells — using enzymes that bind onto proteins on the cell surface — unreliable.