scholarly journals Thermal Shock Response of Yeast Cells Characterised by Dielectrophoresis Force Measurement

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5304
Author(s):  
García-Diego Fernando-Juan ◽  
Mario Rubio-Chavarría ◽  
Pedro Beltrán ◽  
Francisco J. Espinós
Keyword(s):  
Cell Membrane ◽  
Yeast Cell ◽  
Electric Fields ◽  
Force Measurement ◽  
Cell Structure ◽  
Biological Properties ◽  
Yeast Cells ◽  
Uniform Electric Field ◽  
Membrane Conductivity ◽  
Conductivity Cell

Dielectrophoresis is an electric force experienced by particles subjected to non-uniform electric fields. Recently, several technologies have been developed focused on the use of dielectrophoretic force (DEP) to manipulate and detect cells. On the other hand, there is no such great development in the field of DEP-based cell discrimination methods. Despite the demand for methods to differentiate biological cell states, most DEP developed methods have been focused on differentiation through geometric parameters. The novelty of the present work relies upon the point that a DEP force cell measurement is used as a discrimination method, capable of detecting heat killed yeast cells from the alive ones. Thermal treatment is used as an example of different biological state of cells. It comes from the fact that biological properties have their reflection in the electric properties of the particle, in this case a yeast cell. To demonstrate such capability of the method, 279 heat-killed cells were measured and compared with alive cells data from the literature. For each cell, six speeds were taken at different points in its trajectory inside a variable non-uniform electric field. The electric parameters in cell wall conductivity, cell membrane conductivity, cell membrane permittivity of the yeast cell from bibliography explains the DEP experimental force measured. Finally, alive and heat-treated cells were distinguished based on that measure. Our results can be explained through the well-known damage of cell structure characteristics of heat-killed cells.

scholarly journals Characterization of Simple and Double Yeast Cells Using Dielectrophoretic Force Measurement

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3813 ◽  
Author(s):  
Fernando-Juan García-Diego ◽  
Mario Rubio-Chavarría ◽  
Pedro Beltrán ◽  
Francisco J. Espinós
Keyword(s):  
Electric Fields ◽  
Force Measurement ◽  
Point Of View ◽  
Yeast Cells ◽  
Instrumental Method ◽  
Particle Characterization ◽  
Dielectrophoretic Force ◽  
Cell Velocity ◽  
First Time

Dielectrophoretic force is an electric force experienced by particles subjected to non-uniform electric fields. In recent years, plenty of dielectrophoretic force (DEP) applications have been developed. Most of these works have been centered on particle positioning and manipulation. DEP particle characterization has been left in the background. Likewise, these characterizations have studied the electric properties of particles from a qualitative point of view. This article focuses on the quantitative measurement of cells’ dielectric force, specifically yeast cells. The measures are obtained as the results of a theoretical model and an instrumental method, both of which are developed and described in the present article, based on a dielectrophoretic chamber made of two V-shaped placed electrodes. In this study, 845 cells were measured. For each one, six speeds were taken at different points in its trajectory. Furthermore, the chamber design is repeatable, and this was the first time that measurements of dielectrophoretic force and cell velocity for double yeast cells were accomplished. To validate the results obtained in the present research, the results have been compared with the dielectric properties of yeast cells collected in the pre-existing literature.

Magnetic and Electric Manipulation of a Single Cell in Fluid

2004 ◽  
Vol 820 ◽  
Author(s):  
Hakho Lee ◽  
Tom P. Hunt ◽  
Robert M. Westervelt
Keyword(s):  
Yeast Cell ◽  
Single Cell ◽  
Electric Fields ◽  
Magnetic Beads ◽  
Microfluidic Channel ◽  
Yeast Cells ◽  
Length Scales

AbstractMagnetic and electric manipulation of a single cell in a microfluidic channel was demonstrated using a microelectromagnet matrix and a micropost matrix. The microelectromagnet matrix is two perpendicular arrays of straight wires that are separated and topped by insulating layers. The micropost matrix is an array of post-shaped electrodes embedded in an insulting layer. By controlling the current in each wire of the microelectromagnet matrix or the voltage on each electrode of the micropost matrix, versatile magnetic or electric fields were created on micrometer length scales, controlling the motion of individual cells in fluid. Single or multiple yeast cells attached to magnetic beads were trapped and moved by the microelectromagnet matrix; a single yeast cell was directly trapped and moved by the micropost matrix.

scholarly journals S. cerevisiae Outer and Inner Membranes are Compromised upon Benzyl Alcohol Treatment

2021 ◽  
Vol 8 (2) ◽  
pp. 35-39
Author(s):  
Ergüden Bengü
Keyword(s):  
Cell Wall ◽  
Cell Membrane ◽  
Yeast Cell ◽  
Benzyl Alcohol ◽  
Cell Membranes ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
New Drugs ◽  
Yeast Cells ◽  
Fungal Cell

Although there are innovations in the treatment of diseases caused by fungi and medicines with multiple targets have been developed, the search for a drug with a broad spectrum and without any side effects continues to date. It is generally accepted that determining the cellular target responsible for the toxic effect opens up new possibilities for the development of new drugs. Especially the effects of antifungal agents on the surface components of the fungal cell, on cell wall synthesis and the identification of the target site are crucial in antifungal drug development. Thus studies on the fungal cell membranes in connection with the antifungal agents, aim to develop new strategies for the therapy of fungal infections. Antifungal agents targeting fungal cell wall and cell membrane components have increased in importance in clinical studies. In this study, understanding the mechanism of action of benzyl alcohol, a known membrane fluidizer, and the determination of its cellular targets are aimed. We have shown that in the presence of sorbitol, the osmotic stabilizer, benzyl alcohol becomes less effective against yeast cell. Moreover, benzyl alcohol disrupts cell membrane, causing leakage of ions to the extracellular medium. Nuclear membrane is distorted upon treatment of yeast cells with benzyl alcohol. Thus, we conclude that both outer and inner yeast cell membranes are compromised by the action of benzyl alcohol.

Electrorotation of lymphocytes—The influence of membrane events and nucleus

1986 ◽  
Vol 6 (11) ◽  
pp. 973-982 ◽  
Author(s):  
Heiko Ziervogel ◽  
Roland Glaser ◽  
Dieter Schadow ◽  
Stephan Heymann
Keyword(s):  
Electrical Properties ◽  
Cell Membrane ◽  
Electric Fields ◽  
Concanavalin A ◽  
High Frequency ◽  
Human Peripheral Blood ◽  
Peripheral Blood Lymphocytes ◽  
Cell Interior ◽  
Membrane Conductivity ◽  
Human Peripheral Blood Lymphocytes

Electrorotation—the spin of cells in rotating high frequency electric fields—has been used to investigate properties of human peripheral blood lymphocytes. The rotation spectra of lymphocytes deviate from those of single shell spheres. The deviations are caused by the electrical properties of the nucleus in the cell interior. Electrorotation allows the distinction between successfully stimulated lymphocytes and unstimulated cells after application of concanavalin A. Notwithstanding the fact that only a proportion of the cells will be mitogenically stimulated we detected an enhanced cell membrane conductivity for the whole cell population immediately after the addition of mitogen.

scholarly journals Deformation but not migration and rotation – a model study on vesicle biomechanics in a uniform DC electric field

2016 ◽  
Vol 3 (1) ◽  
pp. 18
Author(s):  
Hui Ye ◽  
Austen Curcuru
Keyword(s):  
Cell Membrane ◽  
Electric Field ◽  
Electric Fields ◽  
Radial Pressure ◽  
Biological Properties ◽  
Phospholipid Bilayer ◽  
Biological Cell ◽  
Biological Cells ◽  
Giant Vesicles ◽  
Dc Electric Field

Background: Biological cells migrate, deform and rotate in various types of electric fields, which have significant impact on the normal cellular physiology. To investigate electrically-induced deformation, researchers have used artificial giant vesicles that mimic the phospholipid bilayer cell membrane. Containing primarily the neutral molecule phosphatidylcholine, these vesicles deformed under evenly distributed, strong direct current (DC) electric fields. Interestingly, they did not migrate or rotate. A biophysical mechanism underlying the kinematic differences between the biological cells and the vesicles under electric stimulation has not been worked out. Methods: We modeled the vesicle as a leaky, dielectric sphere and computed the surface pressure, rotation torques and translation forces applied on the vesicle by a DC electric field. We compared these measurements with those in a biological cell that contains non-zero, intrinsic charges (carried by the functional groups on the membrane). Results: For both the vesicle and the cell, the electrically-induced charges interacted with the local electric field to generate radial pressure for deformation. However, due to the symmetrical distribution of both the charges and the electric field on the vesicle/cell surface, the electric field could not generate net translation force or rotational torques. For a biological cell, the intrinsic charges carried by the cell membrane could account for its migration and rotation in a DC electric field. Conclusions: Results from this work suggests an interesting control diagram of cellular kinematics and movements by the electric field: cell deformation and migration can be manipulated by directly targeting different charged groups on the membrane. Fate of the cell in an electric field depends not only on the delicately controlled field parameters, but also on the biological properties of the cell.

scholarly journals Optimizing Transformation Frequency of Cryptococcus neoformans and Cryptococcus gattii Using Agrobacterium tumefaciens

2021 ◽  
Vol 7 (7) ◽  
pp. 520
Author(s):  
Jianmin Fu ◽  
Nohelli E. Brockman ◽  
Brian L. Wickes
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Yeast Cell ◽  
Transformation Efficiency ◽  
Transformation Frequency ◽  
Yeast Cells ◽  
Agar Concentration ◽  
Genetic Tool ◽  
Number Of Factors ◽  
Cryptococcus Spp ◽  
Transformation Systems

The transformation of Cryptococcus spp. by Agrobacterium tumefaciens has proven to be a useful genetic tool. A number of factors affect transformation frequency. These factors include acetosyringone concentration, bacterial cell to yeast cell ratio, cell wall damage, and agar concentration. Agar concentration was found to have a significant effect on the transformant number as transformants increased with agar concentration across all four serotypes. When infection time points were tested, higher agar concentrations were found to result in an earlier transfer of the Ti-plasmid to the yeast cell, with the earliest transformant appearing two h after A. tumefaciens contact with yeast cells. These results demonstrate that A. tumefaciens transformation efficiency can be affected by a variety of factors and continued investigation of these factors can lead to improvements in specific A. tumefaciens/fungus transformation systems.

The vibration of electrified water drops

1971 ◽  
Vol 322 (1551) ◽  
pp. 523-534 ◽  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Axial Ratio ◽  
Uniform Electric Field ◽  
Interferometric Technique ◽  
Photographic Analysis ◽  
Wide Range ◽  
Water Drops ◽  
Strength And Deformation ◽  
A Charge

Pressure has been used as the principal parameter in calculations of the fundamental vibrational frequencies of spherical drops of radius R , density ρ, and surface tension T carrying a charge Q or uncharged spheroidal drops of axial ratio a / b situated in a uniform electric field of strength E . Freely vibrating charged drops have a frequency f = f 0 ( 1 - Q 2 /16π R 3 T ) ½ , as shown previously by Rayleigh (1882) using energy considerations; f 0 is the vibrational frequency of non-electrified drops (Rayleigh 1879). The fundamental frequency of an uncharged drop in an electric field will decrease with increasing field strength and deformation a / b and will equal zero when E ( R )/ T ) ½ = 1.625 and a / b = 1.86; these critical values correspond to the disintegration conditions derived by Taylor (1964). An interferometric technique involving a laser confirmed the accuracy of the calculations concerned with charged drops. The vibration of water drops of radius around 2 mm was studied over a wide range of temperatures as they fell through electric fields either by suspending them in a vertical wind tunnel or allowing them to fall between a pair of vertical electrodes. Photographic analysis of the vibrations revealed good agreement between theory and experiment over the entire range of conditions studied even though the larger drops were not accurately spheroidal and the amplitude of the vibrations was large.

scholarly journals Universal intracellular biomolecule delivery with precise dosage control

2018 ◽  
Vol 4 (10) ◽  
pp. eaat8131 ◽  
Author(s):  
Y. Cao ◽  
H. Chen ◽  
R. Qiu ◽  
M. Hanna ◽  
E. Ma ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Electric Fields ◽  
Low Voltage ◽  
Intracellular Delivery ◽  
Cell Types ◽  
Controlled Delivery ◽  
Biological Research ◽  
Biological Applications ◽  
Primary Cells ◽  
Cell Densities

Intracellular delivery of mRNA, DNA, and other large macromolecules into cells plays an essential role in an array of biological research and clinical therapies. However, current methods yield a wide variation in the amount of material delivered, as well as limitations on the cell types and cargoes possible. Here, we demonstrate quantitatively controlled delivery into a range of primary cells and cell lines with a tight dosage distribution using a nanostraw-electroporation system (NES). In NES, cells are cultured onto track-etched membranes with protruding nanostraws that connect to the fluidic environment beneath the membrane. The tight cell-nanostraw interface focuses applied electric fields to the cell membrane, enabling low-voltage and nondamaging local poration of the cell membrane. Concurrently, the field electrophoretically injects biomolecular cargoes through the nanostraws and into the cell at the same location. We show that the amount of material delivered is precisely controlled by the applied voltage, delivery duration, and reagent concentration. NES is highly effective even for primary cell types or different cell densities, is largely cargo agnostic, and can simultaneously deliver specific ratios of different molecules. Using a simple cell culture well format, the NES delivers into >100,000 cells within 20 s with >95% cell viability, enabling facile, dosage-controlled intracellular delivery for a wide variety of biological applications.

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