There are a million ways to sort cells, each technique having its benefits and limitations. Ideally, sorting should be fast, accurate, and result in undamaged cells that are ready for identification. Most techniques use some kind of tagging and the separation can involve forces that injure the cells, but scientists from MIT, Penn State, and Carnegie Melon have put a twist on an existing sound-based sorting method to make it a lot more practical and efficient.
A standing audio wave created from two transducers that are facing opposite of each other can push a cell moving through its pressure node. The distance a cell travels off center is dependent on its weight and other characteristics. This has been used in the past to sort cells, but the cells only moved a small distance from the standing wave, severely limiting the usefulness of the technique. The research team adapted this concept, but aligned the transducers at an angle to the channel through which cells travel so that the cells move through successive pressure nodes. This multiplies the effect and pushes each cell type further away from the others. The technique has particularly high value for catching rare circulating tumor cells (CTCs) that are used to diagnose and monitor the spread of cancer.
Here’s video of the new cell sorter under the microscope doing its thing:
Study in Proceedings of the National Academy of Sciences: Cell separation using tilted-angle standing surface acoustic waves…
Press release: Sorting cells with sound waves…
