Figure 1: Schematic illustration of the acoustic separation mechanism showing cells beginning to translate from the sidewall to the center of the channel due to axial acoustic forces applied to the cells when they enter the working region of the standing surface acoustic waves. The differing acoustic forces cause differing displacements, repositioning larger cells closer to the channel center and smaller cells farther from the center.
We developed a method of continuous cell/particle separation through standing surface acoustic wave (SSAW) in a microfluidic channel. Using this SSAW-based method, cells in a continuous laminar flow can be separated based on their volume, density and compressibility. The device was fabricated using standard soft-lithography and micro-electro-mechanical system (MEMS) procedures, which facilitate device integration and miniaturization. Our acoustic cell separation method is simple and versatile, capable of separating virtually all kinds of cells/particles (regardless of charge/polarization or optical properties) with high separation efficiency and low power consumption.
Jinjie Shi, Hua Huang, Zak Stratton, Yiping Huang and Tony Jun Huang, Continuous Particle Separation in a Microfluidic Channel via Standing Surface Acoustic Waves (SSAW), Lab on a Chip, Vol. 9, pp. 3354-3359, 2009. [PDF]