Electrorotation of semiconducting microspheres

Rodríguez-Sánchez, Laida; Ramos, António; García-Sánchez, Pablo

doi:10.1103/physreve.100.042616

Cited by 12 publications

(13 citation statements)

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“…In fact, DEP and ICEP always tend to counterbalance one another, and gold spheres should keep stationary in DC limits from a theoretical perspective [42]. Nevertheless, dipolophoresis takes place in static fields in practical experiments; in that the present theory of ICEP would routinely overestimate the ICEO flow velocity by about one to two orders of magnitude, resulting in the dominating role of DEP over ICEP [43,44].…”

Section: Introductionmentioning

confidence: 87%

Buoyancy-Free Janus Microcylinders as Mobile Microelectrode Arrays for Continuous Microfluidic Biomolecule Collection within a Wide Frequency Range: A Numerical Simulation Study

et al. 2020

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We numerically study herein the AC electrokinetic motion of Janus mobile microelectrode (ME) arrays in electrolyte solution in a wide field frequency, which holds great potential for biomedical applications. A fully coupled physical model, which incorporates the fluid-structure interaction under the synergy of induced-charge electroosmotic (ICEO) slipping and interfacial Maxwell stress, is developed for this purpose. A freely suspended Janus cylinder free from buoyancy, whose main body is made of polystyrene, while half of the particle surface is coated with a thin conducting film of negligible thickness, will react actively on application of an AC signal. In the low-frequency limit, induced-charge electrophoretic (ICEP) translation occurs due to symmetric breaking in ICEO slipping, which renders the insulating end to move ahead. At higher field frequencies, a brand-new electrokinetic transport phenomenon called “ego-dielectrophoresis (e-DEP)” arises due to the action of the localized uneven field on the inhomogeneous particle dipole moment. In stark contrast with the low-frequency ICEP translation, the high-frequency e-DEP force tends to drive the asymmetric dipole moment to move in the direction of the conducting end. The bidirectional transport feature of Janus microspheres in a wide AC frequency range can be vividly interpreted as an array of ME for continuous loading of secondary bioparticles from the surrounding liquid medium along its direction-controllable path by long-range electroconvection. These results pave the way for achieving flexible and high-throughput on-chip extraction of nanoscale biological contents for subsequent on-site bioassay based upon AC electrokinetics of Janus ME arrays.

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Section: Introductionmentioning

confidence: 87%

Buoyancy-Free Janus Microcylinders as Mobile Microelectrode Arrays for Continuous Microfluidic Biomolecule Collection within a Wide Frequency Range: A Numerical Simulation Study

et al. 2020

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“…Considering semi-conducting particles, the same lowfrequency behavior can be observed. Then, particles show two dispersions [51,52]: A low-frequency dispersion from the EDL charging (according to Eq. (4)) and a high-frequency dispersion from the Maxwell-Wagner polarization (since σ P of semi-conducting particles is only around 0.1 S/m instead of 5 × 10 7 S/m as in the case of fully conductive particles).…”

Section: Polarization Of Metal and Semiconducting Particlesmentioning

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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“…In particular, manipulation of metal and semiconducting particles dispersed in aqueous electrolytes has received much attention in the last decade. Examples of particle manipulation by AC fields include the transport of metal spheres and nanowires [3,4], orientation of metal [5][6][7][8] and semiconducting nanowires [9][10][11], continuous rotation of metal spheres and nanowires [12][13][14][15][16][17], and self-assembly of metal nanowires [18,19]. Additionally, the electrical manipulation of metallo-dielectric Janus spheres has been recently investigated and electrokinetic phenomena such as transport [20,21], orientation [22], rotation [23], and assembly [24] of Janus spheres have been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Dipolophoresis and Travelling-Wave Dipolophoresis of Metal Microparticles

2020

Self Cite

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We study theoretically and numerically the electrokinetic behavior of metal microparticles immersed in aqueous electrolytes. We consider small particles subjected to non-homogeneous ac electric fields and we describe their motion as arising from the combination of electrical forces (dielectrophoresis) and the electroosmotic flows on the particle surface (induced-charge electrophoresis). The net particle motion is known as dipolophoresis. We also study the particle motion induced by travelling electric fields. We find analytical expressions for the dielectrophoresis and induced-charge electrophoresis of metal spheres and we compare them with numerical solutions. This validates our numerical method, which we also use to study the dipolophoresis of metal cylinders.

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Electrorotation of semiconducting microspheres

Cited by 12 publications

References 50 publications

Buoyancy-Free Janus Microcylinders as Mobile Microelectrode Arrays for Continuous Microfluidic Biomolecule Collection within a Wide Frequency Range: A Numerical Simulation Study

Buoyancy-Free Janus Microcylinders as Mobile Microelectrode Arrays for Continuous Microfluidic Biomolecule Collection within a Wide Frequency Range: A Numerical Simulation Study

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

Dipolophoresis and Travelling-Wave Dipolophoresis of Metal Microparticles

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