Determination of Clausius–Mossotti factors and surface capacitances for colloidal particles

Honegger, T.; Berton, K.; Picard, E.; Peyrade, D.

doi:10.1063/1.3583441

Cited by 80 publications

(82 citation statements)

References 20 publications

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“…Importantly, we show that the charging of the electrical double layer (EDL) is the interfacial polarization mechanism responsible for particle behaviour. This is in contrast with early publications where conducting particles in electrolytes have often been incorrectly characterized by a finite conductivity and permittivity, ignoring the double-layer polarization at the metal-electrolyte interface [15][16][17][18].…”

Section: Introductioncontrasting

confidence: 49%

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AC electrokinetics of conducting microparticles: A review

Ramos

García-Sánchez

Morgan

2016

Current Opinion in Colloid & Interface Science

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This paper reviews both theory and experimental observation of the AC electrokinetic properties of conducting microparticles suspended in an aqueous electrolyte. Applied AC electric fields interact with the induced charge in the electrical double layer at the metal particle-electrolyte interface. In general, particle motion is governed by both the electric field interacting with the induced dipole on the particle and also the induced-charge electro-osmotic (ICEO) flow around the particle. The importance of the RC time for charging the double layer is highlighted. Experimental measurements of the AC electrokinetic behaviour of conducting particles (dielectrophoresis, electro-rotation and electro-orientation) are compared with theory, providing a comprehensive review of the relative importance of particle motion due to forces on the induced dipole compared with motion arising from induced-charge electro-osmotic flow. In addition, the electric-field driven assembly of conducting particles is reviewed in relation to their AC electrokinetic properties and behaviour.

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Section: Introductioncontrasting

confidence: 49%

“…Other researchers have measured positive DEP of conducting micron and submicron particles at high frequencies [15]. The low frequency DEP behavior is difficult to observe experimentally because of the appearance of AC electroosmotic (ACEO) flow near the electrodes which tends to mask the observations [15,66].…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

AC electrokinetics of conducting microparticles: A review

Ramos

García-Sánchez

Morgan

2016

Current Opinion in Colloid & Interface Science

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“…1 is, in fact, an experimental signature produced by a 10 lm-diameter polystyrene sphere (PSS), a model dielectric particle that we use in our studies (e p ¼ 2:5e 0 , and r p < 10 À14 S=m, 45 ). PSS of this size will experience only nDEP 45 and will be deflected away from the electrodes (towards the region of a weaker electric field), resulting in a diminished amplitude (P 2 < P 1 ) on exit from the electrode region.…”

Section: A Experimental Setupmentioning

confidence: 99%

Differential electronic detector to monitor apoptosis using dielectrophoresis-induced translation of flowing cells (dielectrophoresis cytometry)

et al. 2013

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The instrument described here is an all-electronic dielectrophoresis (DEP) cytometer sensitive to changes in polarizability of single cells. The important novel feature of this work is the differential electrode array that allows independent detection and actuation of single cells within a short section ([Formula: see text]) of the microfluidic channel. DEP actuation modifies the altitude of the cells flowing between two altitude detection sites in proportion to cell polarizability; changes in altitude smaller than 0.25 μm can be detected electronically. Analysis of individual experimental signatures allows us to make a simple connection between the Clausius-Mossotti factor (CMF) and the amount of vertical cell deflection during actuation. This results in an all-electronic, label-free differential detector that monitors changes in physiological properties of the living cells and can be fully automated and miniaturized in order to be used in various online and offline probes and point-of-care medical applications. High sensitivity of the DEP cytometer facilitates observations of delicate changes in cell polarization that occur at the onset of apoptosis. We illustrate the application of this concept on a population of Chinese hamster ovary (CHO) cells that were followed in their rapid transition from a healthy viable to an early apoptotic state. DEP cytometer viability estimates closely match an Annexin V assay (an early apoptosis marker) on the same population of cells.

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“…Additionally, since this frequency is generally above 20 kHz, ACEO is not apparent. Conversely, studies on optimization of trapping percentage using a combination of ACEO and DEP have generally been performed in the absence of pressure driven background flow [19][20][21][22][23]. With the advent of pressure driven flow, maximum throughput may be increased but the convection of the particles from the edge of the electrodes -where the field gradient is at a maximum -to their center is expected to result in a drop in the trapping percentage as the hydrodynamic force can more easily dominate the weakened DEP [24].…”

Section: Introductionmentioning

confidence: 99%