Designing of a dual channel impedance analyzer for biological measurements
01 Dec 2014-pp 1-5
TL;DR: The current study describes the development of two channel impedance analyzer, which was acquired in a computer using USB6009 and recorded the data in a text file for analysis that a later stage.
Abstract: The current study describes the development of two channel impedance analyzer. The signals from the impedance analyzer were acquired in a computer using USB6009 [1]. A LabVIEW program was made to connect the hardware with the software. A provision was made in the software such that the impedance data from both the channels may either be acquired individually or by subtracting the channel one data from the channel two data. Additionally, a provision was made to recorded the data in a text file for analysis that a later stage.
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Patent•
08 Dec 2008
TL;DR: Methods and systems are provided for the noninvasive measurement of the subepithelial impedance of the breast and for assessing the risk that a substantially asymptomatic female patient will develop or be at substantially increased risk of developing proliferative or pre-cancerous changes in the breast, or may be at subsequent risk for the development of pre- cancerous or cancerous changes.
Abstract: Methods and systems are provided for the noninvasive measurement of the subepithelial impedance of the breast and for assessing the risk that a substantially asymptomatic female patient will develop or be at substantially increased risk of developing proliferative or pre-cancerous changes in the breast, or may be at subsequent risk for the development of pre-cancerous or cancerous changes. A plurality of electrodes are used to measure subepithelial impedance of parenchymal breast tissue of a patient at one or more locations and at least one frequency, particularly moderately high frequencies. The risk of developing breast cancer is assessed according to measured and expected or estimated values of subepithelial impedance for the patient and according to one or more experienced-based algorithms. Devices for practicing the disclosed methods are also provided.
2 citations
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TL;DR: In this article, a trap-and-measure device is used to analyze the characteristics of electrochemical materials for biomedical applications, and four kinds of cell (HeLa, A549, MCF-7, and MDA-MB-231) are analyzed and characterized based on their impedance.
Abstract: Electrical impedance spectroscopy (EIS) is used to analyze the characteristics of electrochemical materials for biomedical applications. This paper presents a method for differentiating four kinds of cell using impedance measurements at various voltages and frequencies. Four kinds of cell (HeLa, A549, MCF-7, and MDA-MB-231) are analyzed and characterized based on their impedance by a trap-and-measure device. The impedance spectra are obtained by the impedance analyzer at an operating voltage of 0.2–1.0 V and frequency of 20–101 kHz. According to the impedance measurements, HeLa, A549, and MCF-7 cells and the pathological stages of a given cancer cell line (MCF-7 and MDA-MB-231) can be distinguished. The equivalent circuit is modeled as a cell impedance in parallel with the impedance of the culture medium, a cell impedance that contains the cell membrane capacitance, and a cytoplasm resistance. With an increase in the operating voltage, the cytoplasm resistance decreases due to the opening of the ionic channel. For A549, MDA-MB-231, MCF-7, and HeLa cells, the maximum variation of the resistance was obtained in the voltage ranges of 0.8–1.0 V, 0.8–1.0 V, 0.6–0.8 V, and 0.4–0.6 V, respectively. The results reveal that different kinds of cell have different tolerances to an electric field.
101 citations
"Designing of a dual channel impedan..." refers methods in this paper
...Hence, this device may help in drug screening, toxicological and antimicrobial assay [3, 5, 7]....
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...Lite the correlation between proliferation measu based technique and conventional methodo [1, 5-6]....
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TL;DR: A procedure to fit the proposed model to microelectrode electrical performance is presented, enabling the decoding of empirical measurements and its interpretation in terms of number of cells, and the results are promising.
Abstract: This work proposes a cell–microelectrode model to be used on cell culture assays as an alternative to end-point protocols employed in cell growth and cell biometry applications. The microelectrode model proposed is based on the area overlap between the microelectrode sensor and the living cells as main parameter. This model can be applied to cell size identification, cell count, and their extension to cell growth, motility and dosimetry protocols. A procedure to fit the proposed model to microelectrode electrical performance is presented, enabling the decoding of empirical measurements and its interpretation in terms of number of cells. This fitting procedure depends on three parameters: microelectrode geometry, gap resistance between substrate attached cells and microelectrode and, mainly, on microelectrode area covered by cells. The model has been implemented employing Analog Hardware Descriptions Language (AHDL) to be incorporated also to mixed-mode simulation processes during circuit design flow. Experiments performed with commercial electrodes are described, illustrating a procedure to obtain cell number in real time in both, growth and dosimetry assays, employing an established cell line (AA8). The results are displayed in the form of growth curves (cells were growing during a week), as well as dosimetric response after treatment with MG132, a proteasome inhibitor. The results agree with the expected performances, with errors around 10–20% in the number of cells measured, therefore we think that these results are promising.
55 citations
Additional excerpts
...Hence, this device may help in drug screening, toxicological and antimicrobial assay [3, 5, 7]....
[...]
...Stainless steel electrodes were used [7]....
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Patent•
08 Dec 2008
TL;DR: In this paper, a plurality of electrodes are used to measure subepithelial impedance of parenchymal breast tissue of a patient at one or more locations and at at least one frequency, particularly moderately high frequencies.
Abstract: Methods and systems are provided for the noninvasive measurement of the subepithelial impedance of the breast and for assessing the risk that a substantially asymptomatic female patient will develop or be at substantially increased risk of developing proliferative or pre-cancerous changes in the breast, or may be at subsequent risk for the development of pre-cancerous or cancerous changes. A plurality of electrodes are used to measure subepithelial impedance of parenchymal breast tissue of a patient at one or more locations and at at least one frequency, particularly moderately high frequencies. The risk of developing breast cancer is assessed according to measured and expected or estimated values of subepithelial impedance for the patient and according to one or more experienced-based algorithms. Devices for practicing the disclosed methods are also provided.
50 citations
01 Jan 2004
TL;DR: The main idea of the proposed approach is that the use of a rather specific signal system makes it possible to separate responses to different excitations from the measured summary signals by means of a quite simple filter and different (under) sampling rates.
Abstract: The paper focuses on principles of designing of a multichannel bioimpedance analyzer based on simultaneous multisine measurement. The measurement task arises due to the need to monitor patients during and after heart surgery operation performing MIMO (multiple-input-multiple-output) bioimpedance measurement. Frequencies of the simultaneously applied sinusoidal excitations must be close but simultaneously varied in a larger range (e.g. from 1 kHz up to 10 MHz). The main idea of the proposed approach is that the use of a rather specific signal system (frequencies of sinusoidal excitations are related as integers and sampling frequencies are properly related/adapted to them) makes it possible to separate responses to different excitations from the measured summary signals by means of a quite simple filter and different (under) sampling rates.
18 citations
"Designing of a dual channel impedan..." refers methods in this paper
...Lite the correlation between proliferation measu based technique and conventional methodo [1, 5-6]....
[...]
...Provisions were made to visualize structures into a graph in a front panel (fi control was made to record the signals as per [6]....
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TL;DR: The design and evaluation of a multi-electrode design that improves upon the statistical significance and spatial resolution of cellular impedance data measured using commercial electric cell-substrate impedance sensing (ECIS) systems was reported and the importance of multiple measurements within a cell culture was demonstrated.
Abstract: This paper reports the design and evaluation of a multi-electrode design that improves upon the statistical significance and spatial resolution of cellular impedance data measured using commercial electric cell-substrate impedance sensing (ECIS) systems. By evaluating cellular impedance using eight independent sensing electrodes, position-dependent impedance measurements can be recorded across the device and compare commonly used equivalent circuit and mathematical models for extraction of cell parameters. Data from the 8-electrode device was compared to data taken from commercial electric cell-substrate impedance sensing (ECIS) system by deriving a relationship between equivalent circuit and mathematically modelled parameters. The impedance systems were evaluated and compared by investigating the effects of arsenic trioxide (As2O3), a well-established chemotherapeutic agent, on ovarian cancer cells. Impedance spectroscopy, a non-destructive, label-free technique, was used to continuously measure the frequency-dependent cellular properties, without adversely affecting the cells. The importance of multiple measurements within a cell culture was demonstrated; and the data illustrated that the non-uniform response of cells within a culture required redundant measurements in order to obtain statistically significant data, especially for drug discovery applications. Also, a correlation between equivalent circuit modelling and mathematically modelled parameters was derived, allowing data to be compared across different modelling techniques.
6 citations
Additional excerpts
...To minimize this prob the globe are trying to use impedance ana proliferation [2-3]....
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