Issue 1, 2023

Acoustic sorting of microfluidic droplets at kHz rates using optical absorbance

Abstract

Droplet microfluidics allows one to address the ever-increasing demand to screen large libraries of biological samples. Absorbance spectroscopy complements the golden standard of fluorescence detection by label free target identification and providing more quantifiable data. However, this is limited by speed and sensitivity. In this paper we increase the speed of sorting by including acoustofluidics, achieving sorting rates of target droplets of 1 kHz. We improved the device design for detection of absorbance using fibre-based interrogation of samples with integrated lenses in the microfluidic PDMS device for focusing and collimation of light. This optical improvement reduces the scattering and refraction artefacts, improving the signal quality and sensitivity. The novel design allows us to overcome limitations based on dielectrophoresis sorting, such as droplet size dependency, material and dielectric properties of samples. Our acoustic activated absorbance sorter removes the need for offset dyes or matching oils and sorts about a magnitude faster than current absorbance sorters.

Graphical abstract: Acoustic sorting of microfluidic droplets at kHz rates using optical absorbance

Supplementary files

Article information

Article type
Paper
Submitted
20 Sep 2022
Accepted
28 Nov 2022
First published
01 Dec 2022
This article is Open Access
Creative Commons BY license

Lab Chip, 2023,23, 195-202

Acoustic sorting of microfluidic droplets at kHz rates using optical absorbance

E. S. Richter, A. Link, J. S. McGrath, R. W. Sparrow, M. Gantz, E. J. Medcalf, F. Hollfelder and T. Franke, Lab Chip, 2023, 23, 195 DOI: 10.1039/D2LC00871H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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