Microfluidic device can diagnose cancer from blood samples

MIT Technology Review : The standard method for cancer detection is a biopsy, which can be invasive and expensive. Now, Mehmet Toner of Harvard Medical School and his colleagues have developed a device that can identify the presence of almost any sort of cancer cell in the blood stream. The microfluidic device builds on a similar earlier device that Toner’s team developed, which had to be specifically prepared to detect certain cancers and took four to five hours to complete a diagnosis. The new device is faster and works by removing all the noncancerous cells from a blood sample in a single process. White blood cells are tagged with magnetic beads covered in antibodies that recognize the white blood cells. The red blood cells, plasma, and unused magnetic beads are filtered out by microfluidic chambers, and then the white blood cells are removed by a magnetic field. What’s left is easy to examine for the presence of cancer cells. The device will be very useful for identifying the presence of circulating cancer cells, but it is unknown if it will be useful for early identification of cancer, because early-stage cancers aren’t known to produce a large number of circulating cells.