A Circuit Model of Human Whole Blood in a Microfluidic Dielectric Sensor

Suster, Michael A.; Vitale, Nicholas; Maji, Debnath; Mohseni, Pedram

doi:10.1109/tcsii.2016.2607718

Cited by 13 publications

(11 citation statements)

References 15 publications

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“…The ClotChip featured a parallel-plate capacitive sensor to extract the dielectric permittivity of whole blood within a microfluidic channel [12]. Two planar sensing electrodes were separated from a floating electrode through a microfluidic channel to form a three-dimensional capacitive sensing area.…”

Section: Methodsmentioning

confidence: 99%

“…Calibration of the measurement setup was performed daily to implement quality control and ensure accurate electrical measurement of the blood sample. This step was performed using a custom printed-circuit board in the form of the ClotChip sensor that contained an equivalent circuit model of whole blood [12]. Additional quality control was implemented by testing a control sample from a pool of known healthy volunteer donors on each day that patient samples were examined.…”

Section: Methodsmentioning

confidence: 99%

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Assessment of whole blood coagulation with a microfluidic dielectric sensor

Maji

Fuente

Kucukal

et al. 2018

Journal of Thrombosis and Haemostasis

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Background Rapid point-of-care (POC) assessment of hemostasis is clinically important in patients with a variety of coagulation factor and platelet defects who have bleeding disorders. Objective To evaluate a novel dielectric microsensor, termed ClotChip, which is based on the electrical technique of dielectric spectroscopy for rapid, comprehensive assessment of whole blood coagulation. Methods The ClotChip is a three-dimensional, parallel-plate, capacitive sensor integrated into a single-use microfluidic channel with miniscule sample volume (< 10 μL). The ClotChip readout is defined as the temporal variation in the real part of dielectric permittivity of whole blood at 1 MHz. Results The ClotChip readout exhibits two distinct parameters, namely, the time to reach a permittivity peak (T ) and the maximum change in permittivity after the peak (Δε ), which are, respectively, sensitive towards detecting non-cellular (i.e. coagulation factor) and cellular (i.e. platelet) abnormalities in the hemostatic process. We evaluated the performance of ClotChip using clinical blood samples from 15 healthy volunteers and 12 patients suffering from coagulation defects. The ClotChip T parameter exhibited superior sensitivity at distinguishing coagulation disorders as compared with conventional screening coagulation tests. Moreover, the ClotChip Δε parameter detected platelet function inhibition induced by aspirin and exhibited strong positive correlation with light transmission aggregometry. Conclusions This study demonstrates that ClotChip assesses multiple aspects of the hemostatic process in whole blood on a single disposable cartridge, highlighting its potential as a POC platform for rapid, comprehensive hemostatic analysis.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Assessment of whole blood coagulation with a microfluidic dielectric sensor

Maji

Fuente

Kucukal

et al. 2018

Journal of Thrombosis and Haemostasis

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“…As the MUT passes through this capacitive sensing area, the sensor impedance changes based on the dielectric permittivity of the MUT. At the measurement frequency, ω, the complex impedance, Z S , of the capacitive sensing area can be expressed as [34]:

Z_{S} = \frac{1}{j ω C_{0} false(ε_{r}^{'} - j ε_{r}^{"} false)},

where C 0 is the nominal, series-connected, air-gap capacitance of the parallel-plate capacitive sensing area.

ε_{r}^{'}

and

ε_{r}^{"}

are the real and imaginary parts, respectively, of ε r of the MUT and can be calculated from the measurements of Z S using:

ε_{r}^{'} = \frac{italicimag false(Z_{S}^{- 1} false)}{ω C_{0}},

and

ε_{r}^{"} = \frac{italicreal false(Z_{S}^{- 1} false)}{ω C_{0}} .

The permittivity of human whole blood in a microfluidic dielectric sensor exhibits several distinct frequency-dependent regions.…”

Section: Sensor Design and Methodsmentioning

confidence: 99%

“…Finally,

ε_{r}^{"}

is dominated by a combination of the CDL effect and the bulk solution conductivity of blood over the entire frequency range. A detailed analysis of ε r for human whole blood in a microfluidic dielectric sensor and a corresponding circuit model is previously reported in [34]. In this work, we aim to capture the blood coagulation dynamics, including aggregation of RBCs in a fibrin clot and their subsequent shape change as a result of contractile forces from activated platelets.…”

Section: Sensor Design and Methodsmentioning

confidence: 99%

“…Dielectric coagulometry measurements with human whole blood were first performed using a first-generation (Gen-1) ClotChip that was based on a commercially available printed-circuit board (PCB) for the substrate and sensing electrodes, as previously reported in [32], [34]. To minimize the potential for artificial contact activation of the coagulation process, we subsequently manufactured a second-generation (Gen-2) ClotChip that was based on a biocompatible, chemically inert, polymethyl methacrylate (PMMA) plastic substrate and cap [33].…”

Section: Sensor Design and Methodsmentioning

confidence: 99%

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ClotChip: A Microfluidic Dielectric Sensor for Point-of-Care Assessment of Hemostasis

Maji

Suster

Kucukal

et al. 2017

IEEE Trans. Biomed. Circuits Syst.

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This paper describes the design, fabrication, and testing of a microfluidic sensor for dielectric spectroscopy (DS) of human whole blood during coagulation. The sensor, termed ClotChip, employs a three-dimensional (3D), parallel-plate, capacitive sensing structure with a floating electrode integrated into a microfluidic channel. Interfaced with an impedance analyzer, the ClotChip measures the complex relative dielectric permittivity, εr, of human whole blood in a frequency range of 40Hz to 100MHz. The temporal variation in the real part of the blood dielectric permittivity at 1MHz features a time to reach a permittivity peak, Tpeak, as well as a maximum change in permittivity after the peak, Δεr,max, as two distinct parameters of ClotChip readout. The ClotChip performance was benchmarked against rotational thromboelastometry (ROTEM) to evaluate the clinical utility of its readout parameters in capturing the clotting dynamics arising from coagulation factors and platelet activity. Tpeak exhibited a very strong positive correlation (r = 0.99, p < 0.0001) with the ROTEM clotting time (CT) parameter, whereas Δεr,max exhibited a strong positive correlation (r = 0.85, p < 0.001) with the ROTEM maximum clot firmness (MCF) parameter. This work demonstrates the ClotChip potential as a point-of-care (POC) platform to assess the complete hemostatic process using <10μL of human whole blood.

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Lensless light intensity model for quasi-spherical cell size measurement

Dai

et al. 2022

Biomed Microdevices

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A Circuit Model of Human Whole Blood in a Microfluidic Dielectric Sensor

Cited by 13 publications

References 15 publications

Assessment of whole blood coagulation with a microfluidic dielectric sensor

Assessment of whole blood coagulation with a microfluidic dielectric sensor

ClotChip: A Microfluidic Dielectric Sensor for Point-of-Care Assessment of Hemostasis

Lensless light intensity model for quasi-spherical cell size measurement

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