Particle separation using bulk acoustic waves in a tilted angle microfluidic channel

In prior research, separation of particles or biological cells in liquids has been accomplished using a balance of ultrasonic forces and viscous drag forces, which depend on particle size and acoustic contrast. Recent work by two groups has exploited surface acoustic waves launched into tilted microfluidic channels for particle or cell separation. Here we demonstrate a similar tilted-channel approach using machined channels in PMMA (poly (methyl methacrylate)) and PZT (lead zirconate titanate) wafer excitation. Experimental observations confirm the separation of particles. Simulations have been used to understand the observed particle motion and to identify operating parameters for particle separation.