Cell detachment and label-free cell sorting using modulated surface acoustic waves (SAW) in droplet-based microfluidics

TL;DR

This paper introduces a label-free, droplet-based surface acoustic wave system that efficiently detaches and sorts biological cells based on adhesion differences, achieving high purity and efficiency in minutes.

Contribution

The study demonstrates a novel modulated SAW approach for cell detachment and sorting without molecular labels, reducing power and exposure time.

Findings

Sorting purity of 97% achieved

Sorting efficiency of 95% achieved

System operates in minutes

Abstract

We present a droplet-based surface acoustic wave (SAW) system designed to viably detach biological cells from a surface and sort cell types based on differences in adhesion strength (adhesion contrast), without the need to label cells with molecular markers. The system uses modulated SAW to generate pulsatile flows in the droplets and efficiently detach the cells, thereby minimizing SAW excitation power and exposure time. As a proof-of-principle, the system is shown to efficiently sort HEK 293 from A7r5 cells based on adhesion contrast. Results are obtained in minutes with sorting purity and efficiency reaching 97 % and 95 %, respectively.