Measurements of Nonlinear Electrical Impedances by Virtue of Induced Conformational Changes in DNAs

2010 ◽  
Vol 22 (5) ◽  
pp. 601-607 ◽  
Author(s):  
Takatoki Yamamoto ◽  
◽  
Sangwook Lee ◽  
Teruo Fujii ◽  
Keyword(s):  
Aqueous Solution ◽  
Conformational Changes ◽  
Electrical Impedance ◽  
Dna Analysis ◽  
Electrical Impedance Spectroscopy ◽  
Label Free ◽  
Impedance Sensing ◽  
Fully Integrated ◽  
Impedance Response ◽  
Strength Dependence

A method for label-free electrical impedance sensing of DNA is proposed, and experimentally demonstrated using a micro Electrical Impedance Spectroscopy (µ- EIS) device. The method features not only the detection of DNA without any labelling, but also the control of the conformation that would enhance the electrical impedance signal. In order to conduct semiautomated measurements controlled by an external PC, a microfluidic chip made of a silicone elastomer of polydimethylsiloxane (PDMS), a measurement chip embedded with micro-electrodes, and a micropump chip are fully integrated in the µ-EIS device. The µ-EIS device is capable of detecting DNA concentrations of a few nM in aqueous solution of a few pL in volume by virtue of the conformation-enhanced nonlinear impedance response. As a first demonstration of conformational-change-induced DNA analysis, the frequency and the electric field strength dependence of various lengths of DNA are evaluated.

Role of direct and inverted undoped spiro-OMeTAD–perovskite architectures in determining solar cells performances: an investigation via electrical impedance spectroscopy

2019 ◽  
Vol 21 (12) ◽  
pp. 6613-6621 ◽  
Author(s):  
Marianna Ambrico ◽  
Paolo F. Ambrico ◽  
Luisa De Marco ◽  
Rosabianca Iacobellis ◽  
Arianna D’Abramo ◽  
...  
Keyword(s):  
Solar Cells ◽  
Impedance Spectroscopy ◽  
Electrical Impedance ◽  
Electrical Impedance Spectroscopy ◽  
Impedance Response ◽  
Inverse Structure

Spiro-OMeTAD/perovskite direct and inverse structure architectures’ influence on the performance of solar cells are elucidated via the analysis of the structure impedance response.

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

Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 11
Author(s):  
Leilei Shi ◽  
Leyla Esfandiari
Keyword(s):  
Electrical Impedance ◽  
Disease Diagnosis ◽  
Electrical Impedance Spectroscopy ◽  
Label Free ◽  
Early Disease ◽  
Non Invasive ◽  
Diagnosis And Prognosis ◽  
Rapid Characterization ◽  
Impedance Sensor

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.

scholarly journals Dielectrophoretic and Electrical Impedance Differentiation of Cancerous Cells Based on Biophysical Phenotype

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 401
Author(s):  
Ina Turcan ◽  
Iuliana Caras ◽  
Thomas Gabriel Schreiner ◽  
Catalin Tucureanu ◽  
Aurora Salageanu ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Tumor Cells ◽  
Cancer Cell ◽  
Primary Tumor ◽  
Electrical Impedance ◽  
Mononuclear Cells ◽  
Equivalent Circuit Model ◽  
Electrical Impedance Spectroscopy ◽  
Label Free ◽  
Peripheral Blood Mononuclear

Here, we reported a study on the detection and electrical characterization of both cancer cell line and primary tumor cells. Dielectrophoresis (DEP) and electrical impedance spectroscopy (EIS) were jointly employed to enable the rapid and label-free differentiation of various cancer cells from normal ones. The primary tumor cells that were collected from two colorectal cancer patients and cancer cell lines (SW-403, Jurkat, and THP-1), and healthy peripheral blood mononuclear cells (PBMCs) were trapped first at the level of interdigitated microelectrodes with the help of dielectrophoresis. Correlation of the cells dielectric characteristics that was obtained via electrical impedance spectroscopy (EIS) allowed evident differentiation of the various types of cell. The differentiations were assigned to a “dielectric phenotype” based on their crossover frequencies. Finally, Randles equivalent circuit model was employed for highlighting the differences with regard to a series group of charge transport resistance and constant phase element for cancerous and normal cells.

scholarly journals Real-Time Monitoring of Dissection Events of Single Budding Yeast in a Microfluidic Cell-Culturing Device Integrated With Electrical Impedance Biosensor

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhen Zhu ◽  
Yangye Geng ◽  
Yingying Wang ◽  
Ke Liu ◽  
Zhenxiang Yi ◽  
...  
Keyword(s):  
Single Cell ◽  
Real Time ◽  
Microfluidic Device ◽  
Electrical Impedance ◽  
Budding Yeast ◽  
Impedance Measurement ◽  
Microfluidic Devices ◽  
Electrical Impedance Spectroscopy ◽  
Label Free ◽  
Yeast Aging

Microfluidic devices in combination with fluorescent microscopy offer high-resolution and high-content platforms to study single-cell morphology, behavior and dynamic process in replicative aging of budding yeast, Saccharomyces cerevisiae. However, a huge mass of recorded images makes the data processing labor-intensive and time-consuming to determine yeast replicative lifespan (RLS), a primary criterion in yeast aging. To address this limitation and pursue label-free RLS assays, electrical impedance spectroscopy (EIS) that can be easily functionalized through microelectrodes in microfluidic devices, was introduced to monitor cell growth and division of budding yeast. Herein, a microfluidic device integrated with EIS biosensor was proposed to perform in-situ impedance measurement of yeast proliferation in single-cell resolution so as to identify the momentary events of daughter dissection from its mother. Single yeast cells were reliably immobilized at the bottleneck-like traps for continuous culturing, during which daughter cells were effectively detached from their mother cells by hydraulic shear forces. Time-lapse impedance measurement was performed every 2 min to monitor the cellular process including budding, division and dissection. By using the K-means clustering algorithm to analyze a self-defined parameter “Dissection Indicator,” to our knowledge for the first time, the momentary event of a daughter removing from its mother cell was accurately extracted from EIS signals. Thus, the identification of daughter dissection events based on impedance sensing technology has been validated. With further development, this microfluidic device integrated with electrical impedance biosensor holds promising applications in high-throughput, real-time and label-free analysis of budding yeast aging and RLS.

scholarly journals Investigating Electrical Impedance Spectroscopy for Estimating Blood Flow-Induced Variations in Human Forearm

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5333
Author(s):  
Gautam Anand ◽  
Andrew Lowe
Keyword(s):  
Blood Flow ◽  
Impedance Spectroscopy ◽  
Electrical Impedance ◽  
Electrical Impedance Spectroscopy ◽  
Impedance Response ◽  
Arterial Impedance ◽  
Hemodynamic Assessment ◽  
Ultrasound Measurements ◽  
Human Forearm ◽  
Commercial Device

This work aims to investigate the feasibility of employing multi-frequency bioimpedance analysis for hemodynamic assessment. Towards this, we aim to explore one of its implementations, electrical impedance spectroscopy (EIS), for estimating changes in radial artery diameter due to blood flow. Following from our previous investigations, here, we use a commercial device—the Quadra® Impedance Spectroscopy device—for impedance measurements of the forearm of three subjects under normal conditions and occluding the artery with a cuff. This was performed simultaneously with ultrasound measurements as a reference. The impedance spectra were measured over time, yielding waveforms reflecting changes due to blood flow. Contributions from the fat/muscle domains were accounted for using the occluded impedance response, resulting in arterial impedance. A modified relationship was approximated to calculate the diameter from the arterial impedance, which showed a similarity with ultrasound measurements. Comparison with the ultrasound measurements revealed differences in phase and amplitude, primarily due to the approximated relationship between impedance and diameter and neglecting the impedance phase analysis. This work shows the potential of EIS, with improvements, towards estimating blood flow-induced variation in arteries. Further analysis and improvements could help place this technology in mainstream clinical practice for hemodynamic monitoring.

scholarly journals Electric Cell-Substrate Impedance Sensing of Cellular Effects under Hypoxic Conditions and Carbonic Anhydrase Inhibition

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Luciana Stanica ◽  
Mihnea Rosu-Hamzescu ◽  
Mihaela Gheorghiu ◽  
Miruna Stan ◽  
Loredana Antonescu ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Real Time ◽  
Ph Regulation ◽  
Electrical Impedance Spectroscopy ◽  
High Temporal Resolution ◽  
Label Free ◽  
Human Colon Cancer ◽  
Impedance Sensing ◽  
Hypoxic Conditions ◽  
Cell Substrate

Tumor hypoxia provides a dynamic environment for the cancer cells to thrive and metastasize. Evaluation of cell growth, cell-cell, and cell surface interactions in hypoxic conditions is therefore highly needed in the establishment of treatment options. Electric cell-substrate impedance sensing (ECIS) has been traditionally used in the evaluation of cellular platforms as a real-time, label-free impedance-based method to study the activities of cells grown in tissue cultures, but its application for hypoxic environments is seldom reported. We present real-time evaluation of hypoxia-induced bioeffects with a focus on hypoxic pH regulation of tumor environment. To this end, multiparametric real-time bioanalytical platform using electrical impedance spectroscopy (EIS) and human colon cancer HT-29 cells is advanced. A time series of EIS data enables monitoring with high temporal resolution the alterations occurring within the cell layer, especially at the cell-substrate level. We reveal the dynamic changes of cellular processes during hypoxic conditions and in response to application of acetazolamide (AZA), a carbonic anhydrase inhibitor. Optical evaluation and pH assessment complemented the electrical analysis towards establishing a pattern of cellular changes. The proposed bioanalytical platform indicates wide applicability towards evaluation of bioeffects of hypoxia at cellular level.

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