The theory of the frequency response of ellipsoidal biological cells in rotating electrical fields

Paul, R.; Otwinowski, M.

doi:10.1016/s0022-5193(05)80233-4

Cited by 19 publications

(15 citation statements)

References 8 publications

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“…The reason for this discrepancy is that the curvature at the equatorial zone of the cell is more critical for polarization than the actual axis ratio. In the previous model, internal conductivity, the long half-axis, membrane capacitance, and internal permittivity were fixed at 0.535 S/m, 3.3 ,um, 0.82 X 10-2 F/M2, and 50, respectively (Gimsa et al, 1994; for a spheroidal model see Paul and Otwinowski, 1991;Muller et al, 1993). These parameters were obtained from combined measurements of the first critical frequency of DP and the first characteristic frequency of ER in the low external conductivity range up to 40 mS/m.…”

Section: The Dielectric Cell Modelmentioning

confidence: 99%

“…(2) DP and ER allow the determination of dielectric properties of single colloidal particles or cells. Biological applications mainly use the so-called (3-dispersion frequency range to determine specific membrane capacitance, membrane con-ductance, and cytoplasmic properties (Arnold and Zimmermann, 1982;Pastushenko et al, 1985;Georgiewa et al, 1989;Marszalek et al, 1991;Paul and Otwinowski, 1991;Huang et al, 1992;Kaler et al, 1992;Sokirko, 1992; Gascoyne Muller et al, 1993;Sukhorukov et al, 1993;Gimsa et al, 1994). Because in ER the torque as well as the counteracting frictional force increase proportionally to the volume, investigations of objects of varying sizes like cells and even macroscopic objects require similar field strengths (Lertes, 1921;.…”

Section: Introductionmentioning

confidence: 99%

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Dielectric spectroscopy of single human erythrocytes at physiological ionic strength: dispersion of the cytoplasm

Gimsa

Müller

Schnelle

et al. 1996

Biophysical Journal

192

178

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Usually dielectrophoretic and electrorotation measurements are carried out at low ionic strength to reduce electrolysis and heat production. Such problems are minimized in microelectrode chambers. In a planar ultramicroelectrode chamber fabricated by semiconductor technology, we were able to measure the dielectric properties of human red blood cells in the frequency range from 2 kHz to 200 MHz up to physiological ion concentrations. At low ionic strength, red cells exhibit a typical electrorotation spectrum with an antifield rotation peak at low frequencies and a cofield rotation peak at higher ones. With increasing medium conductivity, both electrorotational peaks shift toward higher frequencies. The cofield peak becomes antifield for conductivities higher than 0.5 S/m. Because the polarizability of the external medium at these ionic strengths becomes similar to that of the cytoplasm, properties can be measured more sensitively. The critical dielectrophoretic frequencies were also determined. From our measurements, in the wide conductivity range from 2 mS/m to 1.5 S/m we propose a single-shell erythrocyte model. This pictures the cell as an oblate spheroid with a long semiaxis of 3.3 microns and an axial ratio of 1:2. Its membrane exhibits a capacitance of 0.997 x 10(-2) F/m2 and a specific conductance of 480 S/m2. The cytoplasmic parameters, a conductivity of 0.4 S/m at a dielectric constant of 212, disperse around 15 MHz to become 0.535 S/m and 50, respectively. We attribute this cytoplasmic dispersion to hemoglobin and cytoplasmic ion properties. In electrorotation measurements at about 60 MHz, an unexpectedly low rotation speed was observed. Around 180 MHz, the speed increased dramatically. By analysis of the electric chamber circuit properties, we were able to show that these effects are not due to cell polarization but are instead caused by a dramatic increase in the chamber field strength around 180 MHz. Although the chamber exhibits a resonance around 180 MHz, the harmonic content of the square-topped driving signals generates distortions of electrorotational spectra at far lower frequencies. Possible technological applications of chamber resonances are mentioned.

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Section: The Dielectric Cell Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dielectric spectroscopy of single human erythrocytes at physiological ionic strength: dispersion of the cytoplasm

Gimsa

Müller

Schnelle

et al. 1996

Biophysical Journal

192

178

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“…et al, 1966;Pastushenko et al, 1988). Paul and Otwinowski ( 1991 ) obtained the frequency response of ellipsoidal biological cells in rotating electrical fields; the results are mathematically complicated. A simple model can be used to describe the mean orientation ofa spheroid ofrevolution in a constant electric field (Saito et al, 1966).…”

Section: Nonspherical Particlesmentioning

confidence: 99%

Electrorotation and levitation of cells and colloidal particles

Foster¹,

Sauer²,

Schwan³

1992

Biophysical Journal

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We review dielectrophoretic forces on cells and colloidal particles, emphasizing their use for manipulating and characterizing the electrical properties of suspended particles. Compared with dielectric spectroscopy, these methods offer a measure of independence from electrode artifacts and mixture theory. On the assumption that the particles can be modeled as uniform dielectric objects with effective dielectric properties, a simple theory can be developed for the frequency variation in the field-induced forces. For particles exhibiting counterion polarization, dielectrophoretic forces differ considerably from predictions of this theory at low frequencies, apparently because of double layer phenomena.

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“…1988Gimsa et at. , 1996Paul and Otwinowski 1991;Donath et al 1993;Gascoyne etal. 1995;Jones 1995;Sukhorukov and Zimmermann 1996).…”

Section: Theoretical Considerationsmentioning

confidence: 99%

Electrorotational spectra of protoplasts generated from the giant marine algaValonia utricularis

et al. 1997

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Smnmary. Protoplasts of Valonia utricularis lacking the large central vacuole can be generated by cutting multi-nucleated, giant "'mother" cells into small pieces after short exposure to air. When the protoplasmic content was squeezed out into sea water, irregularly shaped, green coloured aggregates were formed which changed into spherical protoplasts (radius of 20-60 gm) after about 2 h. In these protoplasts the dense internal material (consisting mainly of organelles) was separated from the plasmalemma by a thin transparent layer containing a large number of small lipid vesicles. Cell wall regeneration occurred rapidly after protoplast formation. A central vacuole developed alter about 10 h. The regenerated cells continued to grow and were viable for several months. Electrorotation studies on 2-3 h old protoplasts at pH 7 in low-and fairly high-conductivity solutions showed one or two anti-field rotation peaks (depending on medium conductivity) between 10 kHz to 1 MHz as well as one cofield rotation peak between 10 MHz to 100 MHz. The rotation spectra could not be fitted on the basis of the single-(or multi-) shell model (i.e., by modelling the cells as a homogeneous sphere surrounded by one or more layers). However, fairly good agreement between the experimental data and theory could be obtained by assmning that the rotational behaviour of the protoplasts depends not only on passive eleclrical properties of the plasmalemma but is influenced by "'mobile charges" of carrier transport systems and/or the dielectric behaviour of the aggregated chloroplasts and vesicles.

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The theory of the frequency response of ellipsoidal biological cells in rotating electrical fields

Cited by 19 publications

References 8 publications

Dielectric spectroscopy of single human erythrocytes at physiological ionic strength: dispersion of the cytoplasm

Dielectric spectroscopy of single human erythrocytes at physiological ionic strength: dispersion of the cytoplasm

Electrorotation and levitation of cells and colloidal particles

Electrorotational spectra of protoplasts generated from the giant marine algaValonia utricularis

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