A bridge technique for measuring the permittivity of a biological solution between 1 and 100 MHz

Essex, C G; South, G. P.; Sheppard, R J; Grant, E H

doi:10.1088/0022-3735/8/5/015

Cited by 33 publications

(11 citation statements)

References 14 publications

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“…Dielectric spectroscopy up to 100 MHz is usually performed with a capacitance chamber [13][14][15][16][17]. There, a sample solution is applied between the electrodes of a parallel plate capacitor and a frequency dependent impedance is measured.…”

Section: A Capacitance Chamber and The Electrode Polarizationmentioning

confidence: 99%

“…The contributions (of polarization currents) due to the system of interest (e.g., polyelectrolyte, colloid) may be extracted only in the frequency range where they are of comparable or larger magnitude than EP effects. This practically limits dielectric spectroscopy below 100 MHz to studies of samples in electrolytes with I s not above 10 mM [13,14,16,17].…”

Section: A Capacitance Chamber and The Electrode Polarizationmentioning

confidence: 99%

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Structure and dynamics of hyaluronic acid semidilute solutions: A dielectric spectroscopy study

et al. 2010

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Dielectric spectroscopy is used to investigate fundamental length scales describing the structure of hyaluronic acid sodium salt (Na-HA) semidilute aqueous solutions. In salt-free regime, the length scale of the relaxation mode detected in MHz range scales with HA concentration as c(HA)(-0.5) and corresponds to the de Gennes-Pfeuty-Dobrynin correlation length of polyelectrolytes in semidilute solution. The same scaling was observed for the case of long, genomic DNA. Conversely, the length scale of the mode detected in kilohertz range also varies with HA concentration as c(HA)(-0.5) which differs from the case of DNA (c(DNA)(-0.25)). The observed behavior suggests that the relaxation in the kilohertz range reveals the de Gennes-Dobrynin renormalized Debye screening length, and not the average size of the chain, as the pertinent length scale. Similarly, with increasing added salt the electrostatic contribution to the HA persistence length is observed to scale as the Debye length, contrary to scaling pertinent to the Odijk-Skolnick-Fixman electrostatic persistence length observed in the case of DNA. We argue that the observed features of the kilohertz range relaxation are due to much weaker electrostatic interactions that lead to the absence of Manning condensation as well as a rather high flexibility of HA as compared to DNA.

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Section: A Capacitance Chamber and The Electrode Polarizationmentioning

confidence: 99%

Section: A Capacitance Chamber and The Electrode Polarizationmentioning

confidence: 99%

Structure and dynamics of hyaluronic acid semidilute solutions: A dielectric spectroscopy study

et al. 2010

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“…Dipole moments were obtained by measuring the dielectric constants of protein solutions via a capacitance cell connected to a HP4194A impedance analyzer through an Agilent 16047 D test fixture (Agilent Technologies, Palo Alto, CA) 14, 16. The cell's design is similar to that of Hollingsworth and Saville16 and Essex et al 20. (Fig.…”

Section: Methodsmentioning

confidence: 99%

Determination of the dipole moments of RNAse SA wild type and a basic mutant

et al. 2011

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In this study, we report the effects of acidic to basic residue point mutations (5K) on the dipole moment of RNAse SA at different pHs. Dipole moments were determined by measuring solution capacitance of the wild type (WT) and the 5K mutant with an impedance analyzer. The dipole moments were then (1) compared with theoretically calculated dipole moments, (2) analyzed to determine the effect of the point mutations, and (3) analyzed for their contribution to overall protein-protein interactions (PPI) in solution as quantitated by experimentally derived second virial coefficients. We determined that experimental and calculated dipoles were in reasonable agreement. Differences are likely due to local motions of residue side chains, which are not accounted for by the calculated dipole. We observed that the proteins' dipole moments increase as the pH is shifted further from their isoelectric points and that the wild-type dipole moments were greater than those of the 5K. This is likely due to an increase in the proportion of one charge (either negative or positive) relative to the other. A greater charge disparity corresponded to a larger dipole moment. Finally, the larger dipole moments of the WT resulted in greater attractive overall PPI for that protein as compared to the 5K.

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“…Low-frequency frequency domain techniques to measure the complex permittivity of materials are often based on refinements [302][303][304] of sensitive methods for impedance compensation as originally designed as, for instance, Wheatstone [305,306], Wien [307], Schering [308], and Scheiber [309] bridge circuits. The principle of operation at the basis of all bridge methods is illustrated by Figure 54.…”

Section: Lcr Bridges Impedance Analyzersmentioning

confidence: 99%

Electromagnetic moisture measurement

Hübner¹,

Kaatze²

2016

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XII which we believe to be useful when considering the design of special sensors and appropriate measurement techniques for moisture determination. A chapter dealing with the dielectric properties of water in its different states of interaction is also included. It is intended to provide information concerning the adequate modelling of data derived from the electromagnetic signals when affected by moist materials. Selected applications are discussed in order to introduce some proven examples of electromagnetic moisture sensors and related measurement methods. Finally, a collection of dielectric data for liquids is presented which may serve as reference in calibration procedures. Preferably data obtained from calibration-free methods is given. Additionally, most of it has been measured at different laboratories and the different series of data agree within the limits of experimental uncertainty. A detailed bibliography is provided in order to assist with further reading. We are indebted to Alexander Brandelik, Karlsruhe, who spent much time to critically read the manuscript before publication. We thank Alexander Schaub, Mannheim, for valuable help with editing the book, including proofreading and formatting.

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A bridge technique for measuring the permittivity of a biological solution between 1 and 100 MHz

Cited by 33 publications

References 14 publications

Structure and dynamics of hyaluronic acid semidilute solutions: A dielectric spectroscopy study

Structure and dynamics of hyaluronic acid semidilute solutions: A dielectric spectroscopy study

Determination of the dipole moments of RNAse SA wild type and a basic mutant

Electromagnetic moisture measurement

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