The University of Southampton
University of Southampton Institutional Repository

Electrokinetic biased deterministic lateral displacement: scaling analysis and simulations

Electrokinetic biased deterministic lateral displacement: scaling analysis and simulations
Electrokinetic biased deterministic lateral displacement: scaling analysis and simulations
Deterministic Lateral Displacement (DLD) is a microfluidic technique where arrays of micropillars within a microchannel deflect particles leading to size-based segregation. We recently demonstrated that applying AC electric fields orthogonal to the fluid flow increases the separation capabilities of these devices with a deflection angle that depends on the electric field magnitude and frequency. Particle deviation occurs in two distinct regimes depending on frequency. At high frequencies particles deviate due to negative dielectrophoresis (DEP). At low frequencies (below 1 kHz) particles oscillate perpendicular to the flow direction due to electrophoresis and are also deflected within the device. Significantly, the threshold electric field magnitude for the low frequency deviation is much lower than for deflection at high frequencies by DEP. In order to characterize the enhanced separation at low frequencies, the induced deviation was compared between the two frequency ranges. For high frequencies, we develop both theoretically and experimentally scaling laws for the dependence of particle deviation on several parameters, namely the amplitude of the applied voltage, particle size and liquid velocity where DEP forces compete with viscous drag. A novel theoretical framework is presented that enables simulation of particle trajectories subjected to DEP forces in DLD devices. Deviation angles predicted by simulations are in very good agreement with experimental data. At low frequencies (below 1 kHz), particles follow the same scaling law, but with much lower voltages. This indicates that electrokinetic phenomena other than DEP play an important role in driving particle behaviour. Experiments show that at low frequencies, particle motion is affected by quadrupolar electrohydrodynamic flows around the insulating pillars of the DLD array. We quantify the difference between the two frequency regimes and show that an electrokinetic model based only on DEP forces is limited to frequencies of 1 kHz and above.
0021-9673
Calero, Victor
b2e82567-e1f1-466d-a283-3517a4a9e71b
Morgan, Hywel
de00d59f-a5a2-48c4-a99a-1d5dd7854174
Garcia-Sanchez, Pablo
b4e76544-6ef3-4b9f-8c33-0f3225c827fc
Ramos, Antonio
b22a8818-ae06-4bc5-a10d-a503f5ad626a
Calero, Victor
b2e82567-e1f1-466d-a283-3517a4a9e71b
Morgan, Hywel
de00d59f-a5a2-48c4-a99a-1d5dd7854174
Garcia-Sanchez, Pablo
b4e76544-6ef3-4b9f-8c33-0f3225c827fc
Ramos, Antonio
b22a8818-ae06-4bc5-a10d-a503f5ad626a

Calero, Victor, Morgan, Hywel, Garcia-Sanchez, Pablo and Ramos, Antonio (2020) Electrokinetic biased deterministic lateral displacement: scaling analysis and simulations. Journal of Chromatography A, 1623. (doi:10.1016/j.chroma.2020.461151).

Record type: Article

Abstract

Deterministic Lateral Displacement (DLD) is a microfluidic technique where arrays of micropillars within a microchannel deflect particles leading to size-based segregation. We recently demonstrated that applying AC electric fields orthogonal to the fluid flow increases the separation capabilities of these devices with a deflection angle that depends on the electric field magnitude and frequency. Particle deviation occurs in two distinct regimes depending on frequency. At high frequencies particles deviate due to negative dielectrophoresis (DEP). At low frequencies (below 1 kHz) particles oscillate perpendicular to the flow direction due to electrophoresis and are also deflected within the device. Significantly, the threshold electric field magnitude for the low frequency deviation is much lower than for deflection at high frequencies by DEP. In order to characterize the enhanced separation at low frequencies, the induced deviation was compared between the two frequency ranges. For high frequencies, we develop both theoretically and experimentally scaling laws for the dependence of particle deviation on several parameters, namely the amplitude of the applied voltage, particle size and liquid velocity where DEP forces compete with viscous drag. A novel theoretical framework is presented that enables simulation of particle trajectories subjected to DEP forces in DLD devices. Deviation angles predicted by simulations are in very good agreement with experimental data. At low frequencies (below 1 kHz), particles follow the same scaling law, but with much lower voltages. This indicates that electrokinetic phenomena other than DEP play an important role in driving particle behaviour. Experiments show that at low frequencies, particle motion is affected by quadrupolar electrohydrodynamic flows around the insulating pillars of the DLD array. We quantify the difference between the two frequency regimes and show that an electrokinetic model based only on DEP forces is limited to frequencies of 1 kHz and above.

Text
Electrokinetic biased deterministic lateral displacement scaling analysis and simulations - Accepted Manuscript
Restricted to Repository staff only until 12 May 2022.
Request a copy

More information

Accepted/In Press date: 20 April 2020
e-pub ahead of print date: 12 May 2020

Identifiers

Local EPrints ID: 442035
URI: http://eprints.soton.ac.uk/id/eprint/442035
ISSN: 0021-9673
PURE UUID: a36b6e1f-d343-4767-87aa-f87dedc1de52
ORCID for Hywel Morgan: ORCID iD orcid.org/0000-0003-4850-5676

Catalogue record

Date deposited: 06 Jul 2020 16:30
Last modified: 07 Oct 2020 01:49

Export record

Altmetrics

Contributors

Author: Victor Calero
Author: Hywel Morgan ORCID iD
Author: Pablo Garcia-Sanchez
Author: Antonio Ramos

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×