ELECTRODE POLARIZATION IMPEDANCE AND MEASUREMENTS IN BIOLOGICAL MATERIALS<sup>*</sup>

Schwan, Herman P.

doi:10.1111/j.1749-6632.1968.tb20349.x

Cited by 350 publications

(200 citation statements)

References 11 publications

(1 reference statement)

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“…There is, however, a serious difficulty that has likely prevented the method from being more extensively used: this is the phenomenon of electrode polarization (EP). Recall that it is related to the existence of the metal/electrolyte solution interface, which manifests itself as a potential barrier at the latter and can be modelled as a complex impedance Z * EP in series with the true sample impedance, Z * s (14)(15)(16). The important point here is that the presence of Z * EP can lead to apparent low-frequency dielectric constants much higher (even orders of magnitude higher) than the actual value of the suspension.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Dielectric Permittivity of Suspensions by Means of the Logarithmic Derivative of Its Real Part

Jiménez

Arroyo

Turnhout

et al. 2002

Journal of Colloid and Interface Science

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Section: Introductionmentioning

confidence: 99%

Analysis of the Dielectric Permittivity of Suspensions by Means of the Logarithmic Derivative of Its Real Part

Jiménez

Arroyo

Turnhout

et al. 2002

Journal of Colloid and Interface Science

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“…The charge in the diffuse double layer can be represented as a constant term and a time dependent excess charge, ⌬ q (t) which varies with the electric field. For AC voltages, double layer polarization effects mean that the magnitude of E t (t) and ⌬ q (t) will depend on frequency (9). In the linear approximation and neglecting the compact layer, the excess charge can be estimated to be ⌬ q ϭ ⑀V d where V d is the induced potential across the double layer (10).…”

mentioning

confidence: 99%

AC Electric-Field-Induced Fluid Flow in Microelectrodes

Ramos

Morgan

Green

et al. 1999

Journal of Colloid and Interface Science

460

441

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During the AC electrokinetic manipulation of particles in suspension on microelectrode structures, strong frequency-dependent fluid flow is observed. The fluid movement is predominant at frequencies below the reciprocal charge relaxation time, with a reproducible pattern occurring close to and across the electrode surface. This paper reports measurements of the fluid velocity as a function of frequency and position across the electrode. Evidence is presented indicating that the flow occurs due to electroosmotic stress arising from the interaction of the electric field and the electrical double layer on the electrodes. The electrode polarization plays a significant role in controlling the frequency dependence of the flow. © 1999 Academic Press Key Words: electroosmosis; microelectrode; ac electrokinetics; electrohydrodynamics; electrode polarization.Recent work in the field of AC electrokinetics has shown that submicrometer particles can be characterized and manipulated in microelectrode arrays using dielectrophoresis (1-4). Advanced fabrication methods have been used to manufacture complicated electrode structures that can generate precise electric fields up to 10 7 V m Ϫ1 over a wide range of frequencies (2-4). However, the high electric fields give rise to fluid movement, particularly close to the electrode surface. The observation of the dielectrophoretic behavior of submicrometer particles in electrolytes has revealed a reproducible pattern of fluid flow at frequencies below the charge relaxation frequency of the liquid. Measurements show that the velocity of the fluid is frequency dependent, tending to zero at upper and lower frequency limits, and with magnitudes up to 500 m s Ϫ1 . This field-induced fluid flow is likely to be the cause of previously unexplained phenomena in the dielectrophoretic manipulation of particles on microelectrodes (3).We postulate that the driving force for this flow arises from the interaction of the nonuniform electric field with the charge in the diffuse double layer. Other authors have also observed particle motion in microelectrode structures and have related these effects to electrical stresses on the double layer (5, 6). In these references the motion of the particles was attributed to gradients in the conduction current arising due to the collective interaction of the particles or inhomogeneities in the surface conductivity of the microstructures. In this paper we present measurements of fluid motion in AC fields generated in microelectrodes and show the frequency dependent nature of the fluid velocity. A novel mechanism is postulated for the underlying physical origin of the flow, which takes into account the polarization of the electrodes. This could be the origin of previously observed phenomena resulting from the action of AC fields on fluids, in particular, the cessation of fluid motion above 1 MHz (5). We term this mechanism AC electroosmosis.Experimental observations were made on microelectrodes, consisting of two parallel coplanar plates fabricated on planar glass ...

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“…84,85 Early work on cell electrical measurements dates back to the 1910s, [86][87][88] the foundation for interpreting the electrical properties of cells, where the cell is modeled as a spherical cytoplasm surrounded by a thin dielectric membrane. 89,90 Generally, the electrical properties of a plasma membrane are affected by the membrane morphology, lipid bilayer composition and thickness, and embedded proteins. [91][92][93] Electrical properties of the cytoplasm are influenced by the intracellular structures and physiological conditions (e.g., nucleus-to-cytoplasm ratio and ion concentrations inside the cell).…”

Section: Electrical Characterization Techniquesmentioning

confidence: 99%

Recent advances in microfluidic techniques for single-cell biophysical characterization

et al. 2013

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ELECTRODE POLARIZATION IMPEDANCE AND MEASUREMENTS IN BIOLOGICAL MATERIALS^*

Cited by 350 publications

References 11 publications

Analysis of the Dielectric Permittivity of Suspensions by Means of the Logarithmic Derivative of Its Real Part

Analysis of the Dielectric Permittivity of Suspensions by Means of the Logarithmic Derivative of Its Real Part

AC Electric-Field-Induced Fluid Flow in Microelectrodes

Recent advances in microfluidic techniques for single-cell biophysical characterization

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ELECTRODE POLARIZATION IMPEDANCE AND MEASUREMENTS IN BIOLOGICAL MATERIALS*

Cited by 350 publications

References 11 publications

Analysis of the Dielectric Permittivity of Suspensions by Means of the Logarithmic Derivative of Its Real Part

Analysis of the Dielectric Permittivity of Suspensions by Means of the Logarithmic Derivative of Its Real Part

AC Electric-Field-Induced Fluid Flow in Microelectrodes

Recent advances in microfluidic techniques for single-cell biophysical characterization

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ELECTRODE POLARIZATION IMPEDANCE AND MEASUREMENTS IN BIOLOGICAL MATERIALS^*