A label-free cell separation using surface acoustic waves

We present two-stage microfluidic platform for a continuous label-free cell separation using surface acoustic waves. In the proposed platform, cells are first lined up at the center of the channel by using standing surface acoustic waves without introducing any external sheath flow. After focused at the center of the channel, the cells are then entered to the actual cell separation stage where the larger cell are exposed to more lateral displacement in the channel towards the pressure node due to the acoustic force differences. Consequently, different size cells are separated into multiple collection outlets. The focusing and separation of the cells can be accomplished simultaneously in the present two-stage microfluidic device. The device doesn't require the use of the sheath flow for positioning or aligning of cells. In this study, we demonstrated the separation of two different size particle streams (3μm and 10μm) with this microfluidic platform without introducing any external sheath flow.