Microparticle separation using a PMMA channel at an oblique angle to a SAW field

In systems using two opposing transducers to create standing waves in a microfluidic channel with flow, the acoustic force on microparticles in the channel is proportional to the volume of the particles, while the drag force is proportional to the radius of the microparticles. Consequently, larger particles migrate towards acoustic nodes faster than smaller particles. We have investigated particles flowing in channels at an oblique angle relative to the SAW field. By applying the drag force and the acoustic force to the particles at an angle, depending on the water velocity, larger particles migrate towards one side of the channel faster than smaller particles, enabling particle separation in a continuous flow system without dilution from sheath flow.