Numerical and Experimental Investigation of High-Resolution Manipulation of Microparticles Using a Developed Two-Stage Acoustofluidic Platform

Acoustophoresis as an emerging label-free, biocompatible, and contactless technique in particle separation has attracted recent interest in the separation of cells and particles from heterogeneous samples. Improving sepa-ration resolution in many biological applications in which particles of close sizes must be separated is of great importance. To study the separation of microparticles with similar sizes, a two-stage acoustofluidic platform is developed in this study. The device uses acoustic and hydrodynamic focusing mechanisms to boost alignment efficiency in its first stage. The device's second module separates microparticles using standing acoustic waves. In both numerical and experimental studies, multiple parameters such as geometrical features, pressure distribu-tion, and sheath-flow variation were investigated to optimize separation performance. The experimental results show that particles of sizes 8-10 & mu;m can be separated with a purity of more than 80% and a throughput of 10 & mu;l/ min. As a potential application, the separation resolution demonstrated in the study can be applied to the sep-aration of white blood cells, e.g., neutrophils from leukocytes.