Electric impedance of aqueous KCl and NaCl solutions: Salt concentration dependence on components of the equivalent electric circuit

Lima, Lisandra F.; Vieira, Admilson Lopes; Mukai, H.; Andrade, Cid Marcos Gonçalves; Fernandes, P. R. G.

doi:10.1016/j.molliq.2017.06.069

Cited by 53 publications

(24 citation statements)

References 35 publications

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“…Finally, the functionality of the electrodes was verified by measuring the impedance between 100 and 40 MHz of NaCl dissolved in milli-Q water. In accordance with the literature [ 50 ], the Bode plot of the impedance measurements Z’( f ) showed a large plateau between 100 and 10 4 Hz, with the value of the plateau increasing with a decreasing salt concentration. Furthermore, the Nyquist plot displayed a characteristic shape of Randle equivalent circle and the expected trend as the electrolyte charge transfer resistance (represented by the semi-circle part of the plot) increased linearly with the increased salt concentration.…”

Section: Resultssupporting

confidence: 90%

An Approach to Ring Resonator Biosensing Assisted by Dielectrophoresis: Design, Simulation and Fabrication

et al. 2020

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The combination of extreme miniaturization with a high sensitivity and the potential to be integrated in an array form on a chip has made silicon-based photonic microring resonators a very attractive research topic. As biosensors are approaching the nanoscale, analyte mass transfer and bonding kinetics have been ascribed as crucial factors that limit their performance. One solution may be a system that applies dielectrophoretic forces, in addition to microfluidics, to overcome the diffusion limits of conventional biosensors. Dielectrophoresis, which involves the migration of polarized dielectric particles in a non-uniform alternating electric field, has previously been successfully applied to achieve a 1000-fold improved detection efficiency in nanopore sensing and may significantly increase the sensitivity in microring resonator biosensing. In the current work, we designed microring resonators with integrated electrodes next to the sensor surface that may be used to explore the effect of dielectrophoresis. The chip design, including two different electrode configurations, electric field gradient simulations, and the fabrication process flow of a dielectrohoresis-enhanced microring resonator-based sensor, is presented in this paper. Finite element method (FEM) simulations calculated for both electrode configurations revealed ∇E2 values above 1017 V2m−3 around the sensing areas. This is comparable to electric field gradients previously reported for successful interactions with larger molecules, such as proteins and antibodies.

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Section: Resultssupporting

confidence: 90%

An Approach to Ring Resonator Biosensing Assisted by Dielectrophoresis: Design, Simulation and Fabrication

et al. 2020

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“…Our results using various electrolytes emulated previous data [34][35][36] and validated the experimental setup for further analysis.…”

Section: Validation Of Parallel-plate Contact Device To Measure Dielesupporting

confidence: 84%

Investigation of the Electrical Properties of Microtubule Ensembles under Cell-Like Conditions

et al. 2020

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Microtubules are hollow cylindrical polymers composed of the highly negatively-charged (~23e), high dipole moment (1750 D) protein α, β- tubulin. While the roles of microtubules in chromosomal segregation, macromolecular transport, and cell migration are relatively well-understood, studies on the electrical properties of microtubules have only recently gained strong interest. Here, we show that while microtubules at physiological concentrations increase solution capacitance, free tubulin has no appreciable effect. Further, we observed a decrease in electrical resistance of solution, with charge transport peaking between 20–60 Hz in the presence of microtubules, consistent with recent findings that microtubules exhibit electric oscillations at such low frequencies. We were able to quantify the capacitance and resistance of the microtubules (MT) network at physiological tubulin concentrations to be 1.27 × 10−5 F and 9.74 × 104 Ω. Our results show that in addition to macromolecular transport, microtubules also act as charge storage devices through counterionic condensation across a broad frequency spectrum. We conclude with a hypothesis of an electrically tunable cytoskeleton where the dielectric properties of tubulin are polymerisation-state dependent.

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“…In this model, the channel impedance Z ch is in series with an electrical double layer capacitance C dl and is in parallel with a stray capacitance C stray [ 34 , 35 , 36 ]. In addition, a lead inductance ( L ld ) was included in the equivalent circuit, which is associated with the electrodes and the cables connecting the device to the impedance analyzer [ 37 , 38 ]. The values of C dl , C stray , and L ld were obtained via measurements on electrolyte solutions with well-known electrical properties, followed by fitting into the combination of constant phase element and Cole–Cole model [ 38 , 39 ].…”

Section: Methodsmentioning

confidence: 99%

An Electrokinetically-Driven Microchip for Rapid Entrapment and Detection of Nanovesicles

Shi

Esfandiari

2020

Micromachines

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Electrical Impedance Spectroscopy (EIS) has been widely used as a label-free and rapid characterization method for the analysis of cells in clinical research. However, the related work on exosomes (40–150 nm) and the particles of similar size has not yet been reported. In this study, we developed a new Lab-on-a-Chip (LOC) device to rapidly entrap a cluster of sub-micron particles, including polystyrene beads, liposomes, and small extracellular vesicles (exosomes), utilizing an insulator-based dielectrophoresis (iDEP) scheme followed by measuring their impedance utilizing an integrated electrical impedance sensor. This technique provides a label-free, fast, and non-invasive tool for the detection of bionanoparticles based on their unique dielectric properties. In the future, this device could potentially be applied to the characterization of pathogenic exosomes and viruses of similar size, and thus, be evolved as a powerful tool for early disease diagnosis and prognosis.

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Electric impedance of aqueous KCl and NaCl solutions: Salt concentration dependence on components of the equivalent electric circuit

Cited by 53 publications

References 35 publications

An Approach to Ring Resonator Biosensing Assisted by Dielectrophoresis: Design, Simulation and Fabrication

An Approach to Ring Resonator Biosensing Assisted by Dielectrophoresis: Design, Simulation and Fabrication

Investigation of the Electrical Properties of Microtubule Ensembles under Cell-Like Conditions

An Electrokinetically-Driven Microchip for Rapid Entrapment and Detection of Nanovesicles

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