scholarly journals Development of a Low-Cost Electrical Impedance-Based Microflow Cytometer

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4665-4665
Author(s):  
Darryl Dieujuste ◽  
Jia Liu ◽  
E. Du ◽  
Ofelia A. Alvarez
Keyword(s):  
Integrated Circuit ◽  
Electrical Impedance ◽  
Impedance Measurement ◽  
Physical Space ◽  
Circuit Board ◽  
Concept Design ◽  
Low Oxygen ◽  
Sensors And Actuators ◽  
Sickle Cells ◽  
Microflow Cytometer

Sickle Cell Disease (SCD) is a genetic condition caused by a mutated hemoglobin molecule (HbS) found in red blood cells (RBCs). HbS polymerizes in low oxygen environments and contribute to painful vaso-occlusion in patients. Laboratory diagnosis of SCD is typically made by detection of the presence of sickle cells by peripheral blood smear, and presence of HbS by electrophoresis and high-performance liquid chromatography. Recently, flow cytometry technique in companion with sickling assays has demonstrated the capability in quantitative measurements of sickle cells at single-cell level, using software algorithm for cell-imaging analysis (Van Beers et. al. American Journal of Hematology 2014), and electrical impedance (Liu et. al. Sensors and Actuators B: Chemical 2018). Here, we show a portable, cost-efficient electrical impedance-based sensor and its capability to be used in conjunction with microfluidics-based sickling assay for microflow cytometry of sickle cells. The impedance microflow cytometer is based on a commercially available integrated circuit (IC), the AD5933. Using a microcontroller and additional circuitry on a custom designed printed circuit board, we are able to produce sinusoidal signals of up to 100kHz in frequency and sample up to 200 data points per second, at a cost under $60 in materials to create. The impedance measurement range is optimized to work in companion with microfluidic chips in general. In order to measure sickle cells, the impedance microflow cytometer is used in companion with our unique Polydimethylsiloxane (PDMS) microfluidic cell sickling assay (Du et. al. PNAS 2014). Cells are suspended in phosphate buffered saline (PBS) medium and move in the microchannel using a pressure driven flow. Impedance measurement is achieved using two Ti/Au electrodes embedded in the microchannel as cells flow past the electrodes. Data is captured and made available for post processing using a customized MATLAB script. RBCs from healthy donors and SCD patients were used to demonstrate the capability of the developed system. The results showed that our system can separate between normal RBCs and sickle cells, as well as between sickled and unsickled cells. The performance in detection of sickle cells is comparable to a commercial impedance analyzer. This proof-of-concept design aims to minimize the physical space needed for cytometry as well as bring affordable and reliable cytometry results within its given limitations. Figure Disclosures Alvarez: Forma Therapeutics: Consultancy; Novartis: Consultancy.

scholarly journals Low Cost Instrumentation for Electrical Impedance Tomography in Biomedical Applications

2015 ◽  
Author(s):  
Stewart Smith ◽  
Hancong Wu ◽  
Jiabin Jia
Keyword(s):  
Electrical Impedance Tomography ◽  
Integrated Circuit ◽  
Biomedical Applications ◽  
Electrical Impedance ◽  
Low Cost ◽  
Impedance Measurement ◽  
Impedance Tomography ◽  
Impedance Measurements ◽  
Additional Circuitry ◽  
Initial Results

This poster reports the design, implementation and testing of a portable and inexpensive bio-impedance measurement system intended for electrical impedance tomography (EIT) in cell cultures. The system is based on the AD5933 impedance analyser integrated circuit with additional circuitry to enable four-terminal measurement. Initial results of impedance measurements are reported along with an EIT image reconstructed using the open source EIDORS package.

Application of Lock-in Thermography on PCB for Fault Localization and Validation of Failure Mechanism Due to External Discrete Component Variation

2010 ◽  
Author(s):  
William Ng ◽  
Kevin Weaver ◽  
Zachary Gemmill ◽  
Herve Deslandes ◽  
Rudolf Schlangen
Keyword(s):  
Failure Mechanism ◽  
Integrated Circuit ◽  
Printed Circuit Board ◽  
Hot Spot ◽  
Circuit Board ◽  
Discrete Component ◽  
Printed Circuit ◽  
Thermal Signature ◽  
Lock In

Abstract This paper demonstrates the use of a real time lock-in thermography (LIT) system to non-destructively characterize thermal events prior to the failing of an integrated circuit (IC) device. A case study using a packaged IC mounted on printed circuit board (PCB) is presented. The result validated the failing model by observing the thermal signature on the package. Subsequent analysis from the backside of the IC identified a hot spot in internal circuitry sensitive to varying value of external discrete component (inductor) on PCB.

scholarly journals Practical Precision Electrical Impedance Measurement for the 21st Century – EMPIR Project 17RPT04 VersICal

2019 ◽  
Author(s):  
Oliver Power ◽  
Adam Ziolek ◽  
Andreas Elmholdt Christensen ◽  
Andrei Pokatilov ◽  
Anca Nestor ◽  
...  
Keyword(s):  
21St Century ◽  
Electrical Impedance ◽  
Impedance Measurement ◽  
Research Project ◽  
The Core ◽  
First Results ◽  
Electrical Impedance Measurement ◽  
Measurement Infrastructure

The core objective of EMPIR project 17RPT04 VersICaL is to improve the European measurement infrastructure for electrical impedance, with particular emphasis on the capabilities of developing NMIs and calibration centres. The project will seek to exploit the results of existing research on digital impedance bridges (DIBs) by designing, constructing and validating simple, affordable versions suitable to realise the impedance scale in the range 1 nF to 10 μF and 1 mH to 10 H with relative uncertainties in the range 10-5 to 10-6. The first results of the research project, including the bridge designs and details of a polyphase digitally synthesized multichannel source capable of providing voltage outputs of precise ratio and phase are presented.

scholarly journals Sensitivity Analysis of the Tetrapolar Electrical Impedance Measurement Systems Using COMSOL Multiphysics for the non-uniform and Inhomogeneous Medium

2016 ◽  
Vol 64 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Onic Islam Shuvo ◽  
Md Naimul Islam
Keyword(s):  
Finite Element Method ◽  
Sensitivity Analysis ◽  
Finite Element ◽  
Inhomogeneous Medium ◽  
Electrical Impedance ◽  
Impedance Measurement ◽  
Simulation Software ◽  
Comsol Multiphysics ◽  
Sensitivity Distribution ◽  
Element Method

One of the major problems with Electrical Impedance Tomography (EIT) is the lack of spatial sensitivity within the measured volume. In this paper, sensitivity distribution of the tetrapolar impedance measurement system was visualized considering a cylindrical phantom consisting of homogeneous and inhomogeneous medium. Previously, sensitivity distribution was analysed analytically only for the homogeneous medium considering simple geometries and the distribution was found to be complex1,2. However, for the inhomogeneous volume conductors sensitivity analysis needs to be done using finite element method (FEM). In this paper, the results of sensitivity analysis based on finite element method using COMSOL Multiphysics simulation software are presented. A cylindrical non-uniform, inhomogeneous phantom, which mimics the human upper arm, was chosen to do the experiments by varying different parameters of interest. A successful method for controlling the region of interest was found where the sensitivity was maximum. Refining the finite element mesh size and introducing multifrequency input current (up to 1 MHz) this simulation method can be further improved.Dhaka Univ. J. Sci. 64(1): 7-13, 2016 (January)

Design and Test of a MEMS Accelerometer Array for Submarine Landslide Displacement Monitoring

2021 ◽  
Vol 55 (1) ◽  
pp. 5-16
Author(s):  
Yongqiang Ge ◽  
Jiawang Chen ◽  
Chen Cao ◽  
Jiamin He ◽  
Yan Sheng ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Integrated Circuit ◽  
Slope Failure ◽  
Circuit Board ◽  
Measurement Unit ◽  
Physical Model Test ◽  
Submarine Landslides ◽  
Micro Electro Mechanical Systems ◽  
Mems Accelerometer ◽  
The Difference

AbstractSubmarine landslides in gas hydrate areas are a significant geo-hazard that can cause considerable damage. The processes and mechanism of submarine landslides caused by gas hydrate dissociation are not clearly understood. Therefore, we designed a micro-electro-mechanical systems (MEMS) accelerometer array to study and monitor the deep displacement of submarine landslides. The MEMS accelerometer array consists of several gravity acceleration-sensing units that are protected and positioned using a flexible circuit board and elastic steel tape, such that all the units are connected to an Inter-Integrated Circuit (IIC) communication bus. By sensing the three-axis tilt angles, the direction and magnitude of the displacement for a measurement unit can be calculated; then, the overall displacement of the array is calculated as the difference in the displacements from the initial values. To ensure the accuracy of the tilt angle and displacement calculation, the calibration and verification test of the single MEMS sensor and sensor array is conducted. The MEMS accelerometer array is verified with respect to its principle and arrangement by a laboratory physical model test, and the initial experimentation demonstrated the capacities of the monitoring system for collecting real-time and in-situ information about the dynamic process and propagation of slope failure.

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