Continuously Phase-Modulated Standing Surface Acoustic Waves for Separation of Particles and Cells in Microfluidic Channels Containing Multiple Pressure Nodes

TL;DR

This paper introduces a novel phase modulation technique for standing surface acoustic waves in microfluidics, enabling efficient separation of particles and cells across multiple pressure nodes with high throughput.

Contribution

It presents a continuously phase-modulated SSAW method for particle separation in microfluidic channels with multiple pressure nodes, improving throughput and selectivity.

Findings

Target particles are translated along moving pressure nodes.

Smaller particles exhibit oscillatory movements.

Human keratinocyte cells can be effectively separated.

Abstract

This paper describes continuously phase-modulated standing surface acoustic waves (CPM-SSAW) and its application for particle separation in multiple pressure nodes. A linear change of phase in CPM-SSAW applies a force to particles whose magnitude depends on their size and contrast factors. During continuous phase modulation, we demonstrate that particles with the target dimension are translated in the direction of moving pressure nodes, whereas smaller particles show oscillatory movements. The rate of phase modulation is optimized for separation of target particles from the relationship between mean particle velocity and period of oscillation. The developed technique is applied to separate particles of the target dimension from the particle mixture. Furthermore, we also demonstrate human keratinocyte cells can be separated in the cell and bead mixture. The separation technique is incorporated with a microfluidic channel spanning multiple pressure nodes, which is advantageous over separation in a single pressure node in terms of high throughput.