Isolating cancer cells with acoustic waves

Ars Technica : Cancerous tumors can shed cells that travel through the bloodstream and act as seeds to spread the cancer to other parts of the body. To isolate and study such circulating tumor cells (CTCs), various methods have been tried. However, most have proven unsatisfactory because they either require invasive biopsies or destroy the CTCs. Now researchers have found a way to separate CTCs from healthy blood cells by using sound waves. A blood sample is sent flowing through an acoustic wave field, in which transducers create pairs of pressure nodes and antinodes that are tilted relative to the direction of fluid flow. The so-called “tilted-angle standing surface acoustic waves” apply different forces to different types of cells, which affects their trajectories. Using the method, the researchers say they were able to separate a variety of cancerous cells from healthy white blood cells “with a recovery rate better than 83%.” More study is needed, however, before the device is ready for clinical use.