Active Posts in Deterministic Lateral Displacement Devices

Beech, Jason P.; Keim, Kevin; Ho, Bao Dang; Guiducci, Carlotta; Tegenfeldt, Jonas O.

doi:10.1002/admt.201900339

Cited by 26 publications

(25 citation statements)

References 15 publications

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“…Hanasoge et al also used DC field to drive the flow and explore the effect of different array orientations on particle separation in eDLD [ 76 ]. The development of eDLD has been driven primarily by the Tegenfeldt group at Lund University, Sweden, [ 77 , 78 , 79 ] and Morgan group at University of Southampton, UK, [ 39 , 80 , 81 ], who have made use of AC fields in various modes and geometries. Among the benefits of using AC fields are the fact that the flow (carrying the particle through the device) is decoupled from the forces near to the posts (causing separation) and that much greater control can be achieved through the balancing of these forces.…”

Section: Introductionmentioning

confidence: 99%

Charge-Based Separation of Micro- and Nanoparticles

Beech

Tegenfeldt

2020

Micromachines

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Deterministic Lateral Displacement (DLD) is a label-free particle sorting method that separates by size continuously and with high resolution. By combining DLD with electric fields (eDLD), we show separation of a variety of nano and micro-sized particles primarily by their zeta potential. Zeta potential is an indicator of electrokinetic charge—the charge corresponding to the electric field at the shear plane—an important property of micro- and nanoparticles in colloidal or separation science. We also demonstrate proof of principle of separation of nanoscale liposomes of different lipid compositions, with strong relevance for biomedicine. We perform careful characterization of relevant experimental conditions necessary to obtain adequate sorting of different particle types. By choosing a combination of frequency and amplitude, sorting can be made sensitive to the particle subgroup of interest. The enhanced displacement effect due to electrokinetics is found to be significant at low frequency and for particles with high zeta potential. The effect appears to scale with the square of the voltage, suggesting that it is associated with either non-linear electrokinetics or dielectrophoresis (DEP). However, since we observe large changes in separation behavior over the frequency range at which DEP forces are expected to remain constant, DEP can be ruled out.

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Section: Introductionmentioning

confidence: 99%

Charge-Based Separation of Micro- and Nanoparticles

Beech

Tegenfeldt

2020

Micromachines

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“…Beech et al 23 demonstrated that low-frequency AC electric fields applied along the DLD channel in the direction of flow leads to separation of particles smaller than the critical diameter. More recently, the same group reported the use of metal-coated DLD posts to improve this technique 24 , reducing the voltage requirements and the minimum particle size that could be separated at the expense of a more expensive and challenging device fabrication. In a recent publication 25 , we showed how AC electric fields applied orthogonal to the fluid flow can lead to significant and controlled deviation of particles smaller than the critical diameter through the action of a combination of different electrokinetic forces including Electrophoresis (EP) and Dielectrophoresis (DEP).…”

Section: Introductionmentioning

confidence: 99%

Combining DC and AC electric fields with deterministic lateral displacement for micro- and nano-particle separation

et al. 2019

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This paper describes the behaviour of particles in a Deterministic Lateral Displacement (DLD) separation device with DC and AC electric fields applied orthogonal to the fluid flow. As a proof of principle, we demonstrate tunable microand nano-particle separation and fractionation depending on both particle size and zeta potential. DLD is a microfluidic technique that performs size-based binary separation of particles in a continuous flow. Here, we explore how the application of both DC and AC electric fields (separate or together) can be used to improve separation in a DLD device. We show that particles significantly smaller than the critical diameter of the device can be efficiently separated by applying orthogonal electric fields. Following the application of a DC voltage, Faradaic processes at the electrodes cause local changes in medium conductivity. This conductivity change creates an electric field gradient across the channel that results in a non-uniform electrophoretic velocity orthogonal to the primary flow direction. This phenomenon causes particles to focus into tight bands as they flow along the channel countering the effect of particle diffusion. It is shown that the final lateral displacement of particles depends on both particle size and zeta potential. Experiments with six different types of negatively charged particles and five different sizes (from 100 nm to 3 µm) and different zeta potential demonstrate how a DC electric field combined with AC electric fields (that causes negative-dielectrophoresis particle deviation) could be used for fractionation of particles on the nano-scale in micro-scale devices.

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“…The device operates using either ac, dc, or a combination of both in order to exploit size, polarizability, and ζ -potential differences between particles. A device by Beech et al [103] uses similar principles but with metalcoated posts.…”

Section: Enrichmentmentioning

confidence: 99%

A review of dielectrophoretic separation and classification of non‐biological particles

Pesch

2020

Electrophoresis

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A review of dielectrophoretic separation and classification of non-biological particles Dielectrophoresis (DEP) is a selective electrokinetic particle manipulation technology that is applied for almost 100 years and currently finds most applications in biomedical research using microfluidic devices operating at moderate to low throughput. This paper reviews DEP separators capable of high-throughput operation and research addressing separation and analysis of non-biological particle systems. Apart from discussing particle polarization mechanisms, this review summarizes the early applications of DEP for dielectric sorting of minerals and lists contemporary applications in solid/liquid, liquid/liquid, and solid/air separation, for example, DEP filtration or airborne fiber length classification; the review also summarizes developments in DEP fouling suppression, gives a brief overview of electrocoalescence and addresses current problems in high-throughput DEP separation. We aim to provide inspiration for DEP application schemes outside of the biomedical sector, for example, for the recovery of precious metal from scrap or for extraction of metal from low-grade ore.

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Active Posts in Deterministic Lateral Displacement Devices

Cited by 26 publications

References 15 publications

Charge-Based Separation of Micro- and Nanoparticles

Charge-Based Separation of Micro- and Nanoparticles

Combining DC and AC electric fields with deterministic lateral displacement for micro- and nano-particle separation

A review of dielectrophoretic separation and classification of non‐biological particles

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