scholarly journals Lab-On-A-Chip Device for Yeast Cell Characterization in Low-Conductivity Media Combining Cytometry and Bio-Impedance

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3366 ◽  
Author(s):  
Julien Claudel ◽  
Arthur Luiz Alves De Araujo ◽  
Mustapha Nadi ◽  
Djilali Kourtiche
Keyword(s):  
Electrical Properties ◽  
Tap Water ◽  
Single Cells ◽  
Short Circuit ◽  
Impedance Measurement ◽  
Lab On A Chip ◽  
Yeast Cells ◽  
Pass Band ◽  
Internal Cell ◽  
Conductivity Medium

This paper proposes a simple approach to optimize the operating frequency band of a lab-on-a-chip based on bio-impedance cytometry for a single cell. It mainly concerns applications in low-conductivity media. Bio-impedance allows for the characterization of low cell concentration or single cells by providing an electrical signature. Thus, it may be necessary to perform impedance measurements up to several tens of megahertz in order to extract the internal cell signature. In the case of single cells, characterization is performed in a very small volume down to 1 pL. At the same time, measured impedances increase from tens of kilo-ohms for physiological liquids up to several mega-ohms for low conductivity media. This is, for example, the case for water analysis. At frequencies above hundreds of kilohertz, parasitic effects, such as coupling capacitances, can prevail over the impedance of the sample and completely short-circuit measurements. To optimize the sensor under these conditions, a complete model of a cytometry device was developed, including parasitic coupling capacitances of the sensor to take into account all the impedances. It appears that it is possible to increase the pass band by optimizing track geometries and placement without changing the sensing area. This assumption was obtained by measuring and comparing electrical properties of yeast cells in a low-conductivity medium (tap water). Decreased coupling capacitance by a factor higher than 10 was obtained compared with a previous non-optimized sensor, which allowed for the impedance measurement of all electrical properties of cells as small as yeast cells in a low-conductivity medium.

Measurement of Electrical Properties of Sickle Cells From Electrical Impedance of Cell Suspension

2017 ◽  
Author(s):  
Jia Liu ◽  
Yuhao Qiang ◽  
E. Du
Keyword(s):  
Electrical Properties ◽  
Cell Suspension ◽  
Sickle Cell ◽  
Electrical Impedance ◽  
Single Cells ◽  
Impedance Measurement ◽  
Mixture Theory ◽  
Electrical Impedance Spectroscopy ◽  
Electrical Impedance Measurement ◽  
Characteristic Features

Analysis of the electrical properties of a biological cell can provide useful information about its characteristic features, such as the intracellular composition, charge distribution and composition changes in cell membrane, as well as the extracellular environment. Electrical impedance spectroscopy of a cell suspension can be used to extract an average measure of the electrical properties of single cells. In sickle cell disease, the disease state of a sickle red blood cell is closely related to the intracellular hemoglobin composition and concentration. This study presents an electrical impedance measurement of sickle cell suspension with normal red blood cells as control. Electrical impedance spectra of cell suspensions are obtained in the range of 1000 Hz to 1MHz. Based on Maxwell’s mixture theory, average values of membrane capacitance and cytoplasm resistance of single cells are extracted for both normal and sickle blood samples. Comparing to traditional parallel-plate setup for cell suspension subjected to frequency sweep, this method requires low quantity of blood specimens and can be potentially valuable for patients that are already anemic.

scholarly journals 3D printed microfluidic lab-on-a-chip device for fiber-based dual beam optical manipulation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haoran Wang ◽  
Anton Enders ◽  
John-Alexander Preuss ◽  
Janina Bahnemann ◽  
Alexander Heisterkamp ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Single Cells ◽  
Lab On A Chip ◽  
Cost Effective ◽  
Optical Manipulation ◽  
Hydrodynamic Focusing ◽  
Trapping Region ◽  
Dual Beam ◽  
3D Printed ◽  
On Chip

Abstract3D printing of microfluidic lab-on-a-chip devices enables rapid prototyping of robust and complex structures. In this work, we designed and fabricated a 3D printed lab-on-a-chip device for fiber-based dual beam optical manipulation. The final 3D printed chip offers three key features, such as (1) an optimized fiber channel design for precise alignment of optical fibers, (2) an optically clear window to visualize the trapping region, and (3) a sample channel which facilitates hydrodynamic focusing of samples. A square zig–zag structure incorporated in the sample channel increases the number of particles at the trapping site and focuses the cells and particles during experiments when operating the chip at low Reynolds number. To evaluate the performance of the device for optical manipulation, we implemented on-chip, fiber-based optical trapping of different-sized microscopic particles and performed trap stiffness measurements. In addition, optical stretching of MCF-7 cells was successfully accomplished for the purpose of studying the effects of a cytochalasin metabolite, pyrichalasin H, on cell elasticity. We observed distinct changes in the deformability of single cells treated with pyrichalasin H compared to untreated cells. These results demonstrate that 3D printed microfluidic lab-on-a-chip devices offer a cost-effective and customizable platform for applications in optical manipulation.

scholarly journals Photocurrent density and electrical properties of Bi0.5Na0.5TiO3-BaNi0.5Nb0.5O3 ceramics

2021 ◽  
Author(s):  
Mingqiang Zhong ◽  
Qin Feng ◽  
Changlai Yuan ◽  
Xiao Liu ◽  
Baohua Zhu ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Photocurrent Density ◽  
Open Circuit ◽  
Light Conditions ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray

AbstractIn this work, the (1−x)Bi0.5Na0.5TiO3-xBaNi0.5Nb0.5O3 (BNT-BNN; 0.00 ⩽ x ⩽ 0.20) ceramics were prepared via a high-temperature solid-state method. The crystalline structures, photovoltaic effect, and electrical properties of the ceramics were investigated. According to X-ray diffraction, the system shows a single perovskite structure. The samples show the normal ferroelectric loops. With the increase of BNN content, the remnant polarization (Pr) and coercive field (Ec) decrease gradually. The optical band gap of the samples narrows from 3.10 to 2.27 eV. The conductive species of grains and grain boundaries in the ceramics are ascribed to the double ionized oxygen vacancies. The open-circuit voltage (Voc) of ∼15.7 V and short-circuit current (Jsc) of ∼1450 nA/cm2 are obtained in the 0.95BNT-0.05BNN ceramic under 1 sun illumination (AM1.5G, 100 mW/cm2). A larger Voc of 23 V and a higher Jsc of 5500 nA/cm2 are achieved at the poling field of 60 kV/cm under the same light conditions. The study shows this system has great application prospects in the photovoltaic field.

CHANGES IN THE RESTING POTENTIAL OF SKELETAL MUSCLE IN RATS WITH COLD ACCLIMATION

1966 ◽  
Vol 44 (5) ◽  
pp. 791-802 ◽  
Author(s):  
M. H. Sherebrin ◽  
A. C. Burton
Keyword(s):  
Skeletal Muscle ◽  
Electrical Properties ◽  
Cold Acclimation ◽  
White Muscle ◽  
Single Cells ◽  
Temperature Gradients ◽  
Resting Potential ◽  
The Mean ◽  
Shivering Thermogenesis ◽  
Main Factor

The resting potential of single cells in the flexor thigh muscles of rats was measured in an attempt to find a change in the electrical properties of the cell membrane with cold acclimation, in order to identify and relate metabolic changes occurring with non-shivering thermogenesis. The mean resting potential of cells in cold-acclimated rats was found to be slightly but significantly higher than in the controls. A larger temperature gradient with depth was measured in the cold-acclimated animals than in the controls. If the Q10 of resting potential with temperature is as great as 1.16, the higher potential in the cold-acclimated rats may be accounted for by this temperature difference. The resting potential was also found to vary with depth in both groups of rats. This could not be attributed to temperature gradients, and change from red to white muscle cells with depth is thought to be the main factor for the increase of potential with depth.

Lower Limits of Detection for Single Biological Particles Using Impedance Spectroscopy

2005 ◽  
Author(s):  
Pahnit Seriburi ◽  
Ashutosh Shastry ◽  
Angelique Van’t Wout ◽  
John Mittler ◽  
Shih-Hui Chao ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Impedance Spectroscopy ◽  
Minimally Invasive ◽  
Limit Of Detection ◽  
Single Cells ◽  
Lab On A Chip ◽  
Minimally Invasive Approach ◽  
Invasive Approach ◽  
Membrane Bound ◽  
Lower Limits

Single-cell impedance spectroscopy integrated with lab-on-a-chip systems provides a direct and minimally invasive approach for monitoring and characterizing properties of individual cells in real-time. Here we investigate the theoretical potential and limitations of this technique for analyzing single membrane-bound particles as small as 100 nm in diameter. Our theoretical model suggests a lower limit of detection for single cells on the order of a few microns.

Short-circuit impedance measurement

2003 ◽  
Vol 150 (2) ◽  
pp. 169 ◽  
Author(s):  
K.O.H. Pedersen ◽  
A.H. Nielsen ◽  
N.K. Poulsen
Keyword(s):  
Short Circuit ◽  
Impedance Measurement ◽  
Circuit Impedance

scholarly journals Safety Analysis of Solar Module under Partial Shading

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Wei He ◽  
Fengshou Liu ◽  
Jie Ji ◽  
Shengyao Zhang ◽  
Hongbing Chen
Keyword(s):  
Solar Cells ◽  
Power Dissipation ◽  
Hot Spot ◽  
Single Cells ◽  
Short Circuit ◽  
Heating Power ◽  
Maximum Point ◽  
Solar Module ◽  
Partial Shading ◽  
Efficient Alternative

Hot spot often occurs in a module when the qualities of solar cells mismatch and bypass diodes are proved to be an efficient alternative to reduce the effect of hot spot. However, these principles choosing a diode are based on the parameters of bypass diodes and PV cells without consideration of the maximum heating power of the shaded cell, which may cause serious consequences. On this basis, this paper presents a new approach to investigate partially shaded cells in different numbers of PV cells and different shading scenarios, including inhomogeneous illumination among solar cells and incomplete shading in one cell, which innovatively combines the same cells or divides one affected cell into many small single cells and then combines the same ones, and analyzes the shaded cell. The results indicate that the maximum power dissipation of the shaded cell occurs at short-circuit conditions. With the number of solar cells increasing, the shaded cell transfers from generating power to dissipating power and there is a maximum point of power dissipation in different shading situations that may lead to severe hot spot. Adding up the heat converted from solar energy, the heating power can be higher. In this case, some improvements about bypass diodes are proposed to reduce hot spot.

scholarly journals Extensive Regulation of Metabolism and Growth during the Cell Division Cycle

2014 ◽  
Author(s):  
Nikolai Slavov ◽  
David Botstein ◽  
Amy Caudy
Keyword(s):  
Gene Expression ◽  
Oxygen Consumption ◽  
Cell Division ◽  
Single Cell ◽  
Single Cells ◽  
Emergent Behavior ◽  
Yeast Cells ◽  
Physiological Data ◽  
Synchronized Cultures ◽  
Metabolic Cycle

Yeast cells grown in culture can spontaneously synchronize their respiration, metabolism, gene expression and cell division. Such metabolic oscillations in synchronized cultures reflect single-cell oscillations, but the relationship between the oscillations in single cells and synchronized cultures is poorly understood. To understand this relationship and the coordination between metabolism and cell division, we collected and analyzed DNA-content, gene-expression and physiological data, at hundreds of time-points, from cultures metabolically-synchronized at different growth rates, carbon sources and biomass densities. The data enabled us to extend and generalize our mechanistic model, based on ensemble average over phases (EAP), connecting the population-average gene-expression of asynchronous cultures to the gene-expression dynamics in the single-cells comprising the cultures. The extended model explains the carbon-source specific growth-rate responses of hundreds of genes. Our physiological data demonstrate that the frequency of metabolic cycling in synchronized cultures increases with the biomass density, suggesting that this cycling is an emergent behavior, resulting from the entraining of the single-cell metabolic cycle by a quorum-sensing mechanism, and thus underscoring the difference between metabolic cycling in single cells and in synchronized cultures. Measurements of constant levels of residual glucose across metabolically synchronized cultures indicate that storage carbohydrates are required to fuel not only the G1/S transition of the division cycle but also the metabolic cycle. Despite the large variation in profiled conditions and in the scale of their dynamics, most genes preserve invariant dynamics of coordination with each other and with the rate of oxygen consumption. Similarly, the G1/S transition always occurs at the beginning, middle or end of the high oxygen consumption phases, analogous to observations in human and drosophila cells. These results highlight evolutionary conserved coordination among metabolism, cell growth and division.

scholarly journals YeastSpotter: accurate and parameter-free web segmentation for microscopy images of yeast cells

2019 ◽  
Vol 35 (21) ◽  
pp. 4525-4527 ◽  
Author(s):  
Alex X Lu ◽  
Taraneh Zarin ◽  
Ian S Hsu ◽  
Alan M Moses
Keyword(s):  
Image Analysis ◽  
Web Application ◽  
Single Cells ◽  
Yeast Cells ◽  
Supplementary Information ◽  
Supplementary Data ◽  
User Friendly ◽  
Microscopy Images

Abstract Summary We introduce YeastSpotter, a web application for the segmentation of yeast microscopy images into single cells. YeastSpotter is user-friendly and generalizable, reducing the computational expertise required for this critical preprocessing step in many image analysis pipelines. Availability and implementation YeastSpotter is available at http://yeastspotter.csb.utoronto.ca/. Code is available at https://github.com/alexxijielu/yeast_segmentation. Supplementary information Supplementary data are available at Bioinformatics online.

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