Bioelectric profiling of Rickettsia montanensis in Vero cells utilizing dielectrophoresis.

Rickettsia is an intracellular bacteria transmitted to humans through ticks, lice, fleas, or their feces, causing acute symptoms such as fever, headache, rashes, and muscle aches. Detecting rickettsial diseases is challenging due to limitations in current methods such as negative results, low sensitivity, and high cost. These limitations highlight the need for improved detection methods.

A Comprehensive Review of Organ-on-a-Chip Technology and Its Applications.

Organ-on-a-chip (OOC) is an emerging technology that simulates an artificial organ within a microfluidic cell culture chip. Current cell biology research focuses on in vitro cell cultures due to various limitations of in vivo testing. Unfortunately, in-vitro cell culturing fails to provide an accurate microenvironment, and in vivo cell culturing is expensive and has historically been a source of ethical controversy.

Dielectrophoretic profiling of erythrocytes to study the impacts of metabolic stress, temperature, and storage duration utilizing a point-and-planar microdevice.

Dielectrophoresis (DEP) is widely utilized for trapping and sorting various types of cells, including live and dead cells and healthy and infected cells. This article focuses on the dielectric characterization of erythrocytes (red blood cells or RBCs) by quantifying DEP crossover frequency using a novel point-and-planar microwell device platform. Numerical simulations using COMSOL Multiphysics software demonstrate that the distribution of the DEP force is influenced by factors such as the shape of the point electrode, spacing between the point and planar electrodes, and the type of bioparticle being investigated.

Dielectric characterization of Babesia bovis using the dielectrophoretic crossover frequency.

Coinfection with the tick-transmitted pathogen Babesia spp. is becoming a serious health problem because of the erythrocyte invasion through Ixodes scapularis tick. The transmission of this protozoan by blood transfusion often results in high morbidity and mortality in recipients.

Comparative Study and Simulation of Capacitive Sensors in Microfluidic Channels for Sensitive Red Blood Cell Detection.

Microfluidics provides an indispensable platform for combining analytical operations such as sample preparation, mixing, separation/enrichment, and detection onto a single compact platform, defined as a lab-on-a-chip (LOC) device with applicability in biomedical and life science applications. Due to its ease of integration, 1D interdigital capacitive (IDC) sensors have been used in microfluidic platforms to detect particles of interest. This paper presents a comparative study on the use of capacitive sensors for microfluidic devices to detect bioparticles, more specifically red blood cells (RBCs).

Dielectrophoretic Characterization of Tenogenically Differentiating Mesenchymal Stem Cells.

Tendons are collagenous musculoskeletal tissues that connect muscles to bones and transfer the forces necessary for movement. Tendons are susceptible to injury and heal poorly, with long-term loss of function. Mesenchymal stem cell (MSC)-based therapies are a promising approach for treating tendon injuries but are challenged by the difficulties of controlling stem cell fate and of generating homogenous populations of stem cells optimized for tenogenesis (differentiation toward tendon).

Dielectrophoresis as a tool for electrophysiological characterization of stem cells.

Dielectrophoresis (DEP), a nonlinear electrokinetic technique caused by Maxwell-Wagner interfacial polarization of neutral particles in an electrolyte solution, is a powerful cell manipulation method used widely for various applications such as enrichment, trapping, and sorting of heterogeneous cell populations. While conventional cell characterization and sorting methods require tagging or labeling of cells, DEP has the potential to manipulate cells in a label-free way. Due to its unique ability to characterize and sort cells without the need of labeling, there is renewed interest in using DEP for stem cell research and regenerative medicine.

Application of dielectrophoresis towards characterization of rare earth elements biosorption by Cupriavidus necator.

This work presents the dielectric characterization of rare earth elements (REEs) biosorption by Cupriavidus necator using dielectrophoretic crossover frequency measurements. Traditional means of characterizing biomass for biosorption is limited and time consuming. In this research we are presenting, for the first time, an electrokinetic method termed as dielectrophoresis (DEP) for the characterization of biosorption (uptake) of rare earth elements (REEs) by gram negative bacteria - Cupriavidus necator.

Dielectric Characterization and Separation Optimization of Infiltrating Ductal Adenocarcinoma via Insulator-Dielectrophoresis.

The dielectrophoretic separation of infiltrating ductal adenocarcinoma cells (ADCs) from isolated peripheral blood mononuclear cells (PBMCs) in a ~1.4 mm long Y-shaped microfluidic channel with semi-circular insulating constrictions is numerically investigated. In this work, ADCs (breast cancer cells) and PBMCs' electrophysiological properties were iteratively extracted through the fitting of a single-shell model with the frequency-conductivity data obtained from AC microwell experiments.

Electro-osmotic surface effects generation in an electrokinetic-based transport device: A comparison of RF and MW plasma generating sources.

It is a common practice in insulator-based dielectrophoretic separation to use and reuse PDMS-constructed microdevice for an extended period of time while performing biological and technical replicate experiments. This is usually done to rule out any effects of device variation on separation efficiency. Ensuring that all experimental conditions remain the same is critical to the conclusion that can be drawn from such repeated experiments.

Dimethyl adenosine transferase (KsgA) contributes to cell-envelope fitness in Salmonella Enteritidis.

We previously reported that inactivation of a universally conserved dimethyl adenosine transferase (KsgA) attenuates virulence and increases sensitivity to oxidative and osmotic stress in Salmonella Enteritidis. Here, we show a role of KsgA in cell-envelope fitness as a potential mechanism underlying these phenotypes in Salmonella. We assessed structural integrity of the cell-envelope by transmission electron microscopy, permeability barrier function by determining intracellular accumulation of ethidium bromide and electrophysical properties by dielectrophoresis, an electrokinetic tool, in wild-type and ksgA knock-out mutants of S.

Insulator-based dielectrophoretic diagnostic tool for babesiosis.

Babesia species are obligate intraerythrocytic tick-borne protozoan parasites that are the etiologic agents of babesiosis, a potentially life-threatening, malaria-like illness in humans and animals. Babesia-infected people have been known to suffer from complications including liver problems, severe hemolytic anemia, and kidney failure. As reported by the Food and Drug Administration, 38% of mortality cases observed in transfusion recipients were associated with transfusion transmitted diseases of which babesiosis is the chief culprit.

Dielectrophoretic applications for disease diagnostics using lab-on-a-chip platforms.

Dielectrophoresis is a powerful technique used to distinguish distinct cellular identities in heterogeneous cell populations and to monitor changes in the cell state without the need for biochemical tags, including live and dead cells. Recent studies in the past decade have indicated that dielectrophoresis can be used to discriminate the disease state of cells by exploring the differences in the dielectric polarizabilities of the cells. Factors controlling the dielectric polarizability are dependent on the conductivity and permittivity of the cell and the suspending medium, the cell morphology, the internal structure, and the electric double layer effects associated with the charges on the cell surface.

Dielectrophoretic separation of bioparticles in microdevices: a review.

In recent years, dielectrophoretic force has been used to manipulate colloids, inert particles, and biological microparticles, such as red blood cells, white blood cells, platelets, cancer cells, bacteria, yeast, microorganisms, proteins, DNA, etc. This specific electrokinetic technique has been used for trapping, sorting, focusing, filtration, patterning, assembly, and separating biological entities/particles suspended in a buffer medium. Dielectrophoretic forces acting on particles depend on various parameters, for example, charge of the particle, geometry of the device, dielectric constant of the medium and particle, and physiology of the particle.

Direct current insulator-based dielectrophoretic characterization of erythrocytes: ABO-Rh human blood typing.

A microfluidic platform developed for quantifying the dependence of erythrocyte (red blood cell, RBC) responses by ABO-Rh blood type via direct current insulator dielectrophoresis (DC-iDEP) is presented. The PDMS DC-iDEP device utilized a 400 x 170 μm² rectangular insulating obstacle embedded in a 1.46-cm long, 200-μm wide inlet channel to create spatial non-uniformities in direct current (DC) electric field density realized by separation into four outlet channels.

Direct current dielectrophoretic simulation of proteins using an array of circular insulating posts.

This paper presents a mathematical model for the manipulation of proteins using insulator-based dielectrophoresis (iDEP) and direct current (DC) electric fields. Simulations via COMSOL v4.1 Multiphysics software are implemented to study the response of moderately sized proteins on a lab-on-a-chip platform.

A continuous DC-insulator dielectrophoretic sorter of microparticles.

A lab-on-a-chip device is described for continuous sorting of fluorescent polystyrene microparticles utilizing direct current insulating dielectrophoresis (DC-iDEP) at lower voltages than previously reported. Particles were sorted by combining electrokinetics and dielectrophoresis in a 250 μm wide PDMS microchannel containing a rectangular insulating obstacle and four outlet channels. The DC-iDEP particle flow behaviors were investigated with 3.

DC insulator dielectrophoretic applications in microdevice technology: a review.

Dielectrophoresis is a noninvasive, nondestructive, inexpensive, and fast technique for the manipulation of bioparticles. Recent advances in the field of dielectrophoresis (DEP) have resulted in new approaches for characterizing the behavior of particles and cells using direct current (DC) electric fields. In such approaches, spatial nonuniformities are created in the channel by embedding insulating obstacles in the channel or flow field in order to perform separation or trapping.

Dielectrophoretic characterization of erythrocytes: positive ABO blood types.

Dielectrophoretic manipulation of erythrocytes/red blood cells is investigated as a tool to identify blood type for medical diagnostic applications. Positive blood types of the ABO typing system (A+, B+, AB+ and O+) were tested and cell responses quantified. The dielectrophoretic response of each blood type was observed in a platinum electrode microdevice, delivering a field of 0.

QSAR analysis of 1,3-diaryl-4,5,6,7-tetrahydro-2H-isoindole derivatives as selective COX-2 inhibitors.

Quantitative structure-activity relationship (QSAR) analysis was performed on a series of 1,3-diaryl-4,5,6,7-tetrahydro-2H-isoindole for their cyclooxygenase-2 (COX-2) inhibition. QSAR investigations were based on Hansch's extra thermodynamic multi-parameter approach and receptor surface analysis (RSA). QSAR investigations reveal that steric and electrostatic interactions are primarily responsible for COX-2 enzyme-ligand interaction.