Cancer can spread through the body when cells break off from a tumor and try to metastasize to other organs. These circulating tumor cells are now considered an important biomarker in determining the progression of cancer, and even the success of therapy, says KFC at the Physics arXiv Blog. Unfortunately, however, they're really hard to find. "In a single milliliter of blood there are usually several billion red blood cells, several million white blood cells but fewer than ten circulating tumor cells," KFC says. "And there is the only one way to find them. The cells can be made to look different from normal blood cells. So you need a highly trained cell biologist with a microscope and plenty of time. The words needle and haystack don't do this task justice." So Markus Gusenbauer at St. Poelten University of Applied Sciences in Austria and his colleagues have come up with a new approach — they've created a computer model of the way blood flows through magnetic beads, KFC says. Magnetic beads can be set up to form a filter with a specific gap size, and researchers can determine what kind of cell is trying to pass through, depending on its ability to get through the magnetic filter. "The idea here is that the beads would also be covered in an antibody that latches onto the circulating tumor cells, keeping them trapped even when the magnetic field is switched off," KFC says. The beads could be stored on a microfluidic chip, and the filter set up to trap circulating tumor cells. There's still much more to be done to develop this device, KFC adds, like creating traps for the different kinds of circulating tumor cells, and figuring out a way to filter out white blood cells, which are roughly the same size as the tumor cells. But the simulation is a good first step to understanding how to engineer the capture of a few select cells from a sample.
They Can Circulate, but They Can't Hide
Oct 11, 2011