Low-frequency, low-field dielectric spectroscopy of living cell suspensions

Prodan, Camelia; Mayo, Frank R.; Claycomb, J. R.; Miller, John H.; Benedik, Michael J.

doi:10.1063/1.1649455

Cited by 73 publications

(64 citation statements)

References 10 publications

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“…Capacitance measurement of cells has been shown to differentiate cells on the basis of their DNA content (65). Although in the original application cells were fixed and suspended in ethanol, it has been suggested that microchip sorters for live cells could be developed based on capacitance measurement principles (66).…”

Section: Microfluidic Flow Cell Sortersmentioning

confidence: 99%

Blood-on-a-Chip

Toner

Irimia²

2005

Annu. Rev. Biomed. Eng.

587

451

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Accurate, fast, and affordable analysis of the cellular component of blood is of prime interest for medicine and research. Yet, most often sample preparation procedures for blood analysis involve handling steps prone to introducing artifacts, whereas analysis methods commonly require skilled technicians and well-equipped, expensive laboratories. Developing more gentle protocols and affordable instruments for specific blood analysis tasks is becoming possible through the recent progress in the area of microfluidics and lab-on-a-chip-type devices. Precise control over the cell microenvironment during separation procedures and the ability to scale down the analysis to very small volumes of blood are among the most attractive capabilities of the new approaches. Here we review some of the emerging principles for manipulating blood cells at microscale and promising high-throughput approaches to blood cell separation using microdevices. Examples of specific single-purpose devices are described together with integration strategies for blood cell separation and analysis modules.

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Section: Microfluidic Flow Cell Sortersmentioning

confidence: 99%

Blood-on-a-Chip

Toner

Irimia²

2005

Annu. Rev. Biomed. Eng.

587

451

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“…One method [6] employs high-T c superconducting quantum interference devices (SQUIDs) to directly probe the tiny ac magnetic fields produced by the displacement currents. Another technique [7] uses conventional electronics, but uses a variable electrode spacing calibration technique to subtract the spurious low-frequency capacitance created by the dipole layers at the electrodes. Groundbreaking work on nonlinear response was spearheaded by Woodward and Kell [8,9], who correlated the generation of harmonics with changes in the conformational states of membrane proteins.…”

Section: Background On Dielectric Spectroscopymentioning

confidence: 99%

“…Dielectric spectroscopy is a powerful method for noninvasively characterizing the properties of biological systems [1][2][3][4][5][6][7][8][9][10][11][12]. It encompasses the frequency dependence of the complex linear dielectric response, which incorporates both the dielectric constant ε(ω) and the conductivity σ (ω) of the medium.…”

Section: Introduction: Background and Motivationmentioning

confidence: 99%

Dielectric Properties of Yeast Cells Expressed With the Motor Protein Prestin

et al. 2005

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Abstract. We report on the linear and nonlinear dielectric properties of budding yeast (S. cerevisiae) cells, one strain of which has been genetically modified to express prestin. This motor protein plays a crucial role in the large electromotility exhibited by the outer hair cells of mammalian inner ears. Live cell suspensions exhibit enormous dielectric responses, which can be used to probe metabolic activity, membrane potential, and other properties. The aims of this study are: (1) to compare the dielectric responses of organisms expressing prestin from those of control specimens, and (2) ultimately to further develop dielectric response as a tool to study live cells, proteins, and lipids.

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“…We have used successfully this method in the past to remove the polarization error in low conductivity fluids like pure water, toluene, glycol, and for cells suspended in low conductivity buffers [25]. This methodology is based on the observation that Z p is practically independent of the separation distance d between the capacitor's plates.…”

Section: Introductionmentioning

confidence: 99%

Correcting the polarization effect in very low frequency dielectric spectroscopy

Prodan¹,

Bot²

2009

J. Phys. D: Appl. Phys.

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Abstract. We demonstrate a simple and robust methodology for measuring and analyzing the polarization impedance appearing at interface between electrodes and ionic solutions, in the frequency range from 1 to 10 6 Hz. The method assumes no particular behavior of the electrode polarization impedance and it only makes use of the fact that the polarization effect dies out with frequency. The method allows a direct and un-biased measurement of the polarization impedance, whose behavior with the applied voltages and ionic concentration is methodically investigated. Furthermore, based on the previous findings, we propose a protocol for correcting the polarization effect in low frequency Dielectric Spectroscopy measurements of colloids. This could potentially lead to the quantitative resolution of the α-dispersion regime of live cells in suspension.

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Low-frequency, low-field dielectric spectroscopy of living cell suspensions

Cited by 73 publications

References 10 publications

Blood-on-a-Chip

Blood-on-a-Chip

Dielectric Properties of Yeast Cells Expressed With the Motor Protein Prestin

Correcting the polarization effect in very low frequency dielectric spectroscopy

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