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https://www.readbyqxmd.com/read/28434715/separation-of-janus-droplets-and-oil-droplets-in-microchannels-by-wall-induced-dielectrophoresis
#1
Mengqi Li, Dongqing Li
The continuous separation of different types of droplets from a mixture is important in industrial and research applications. Currently researches for droplet separation focus on homogeneous emulsion droplets, and there is no study on the separation of heterogeneous droplets. The wall-induced dielectrophoresis, which originates from the non-uniform electrical field around a sphere nearby a planar wall, can be applied to separate dielectric particle and cells. In this work, the continuous separations of oil droplets and the electrically induced Janus droplets (EIJDs) in a microchannel by using the wall-induced dielectrophoresis method were presented...
April 14, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28432530/an-integrated-microsystem-with-dielectrophoresis-enrichment-and-impedance-detection-for-detection-of-escherichia-coli
#2
Renjie Wang, Yi Xu, Haitao Liu, Jinlan Peng, Joseph Irudayaraj, Feiyun Cui
An integrated microsystem device with matched interdigitated microelectrode chip was fabricated for enrichment and detection of Escherichia coli O157:H7. The microsystem has integrated with positive dielectrophoresis (pDEP) enrichment and in situ impedance detection, whose total volume is only 3.0 × 10(-3) m(3), and could provide impedance testing voltages of 0 ~ 10 V, detection frequencies of 1 KHz ~ 1 MHz, DEP excitation signals with amplitude of 0 ~ 10 Vpp and frequencies of 1KHz ~ 1 MHz, which fully meets the demands of pDEP enrichment and impedance detection for bacteria...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28429819/effects-of-dielectrophoresis-on-thrombogenesis-in-human-whole-blood
#3
Steven Kinio, James Mills
Thrombogenesis (blood clot formation) is a major barrier to the development of biomedical devices that interface with blood. Although state-of-the-art chemically and pharmacologically mediated clot mitigation strategies are effective, some limitations of such approaches include depletion of active agents, or adverse reactions in patients. Increased clotting protein adsorption and platelet adhesion, which occurs when artificial surfaces are exposed to blood, results in enhanced clot formation on artificial surfaces...
April 21, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28417250/impact-of-surface-roughness-on-dielectrophoretically-assisted-concentration-of-microorganisms-over-pcb-based-platforms
#4
Geeta Bhatt, Rishi Kant, Keerti Mishra, Kuldeep Yadav, Deepak Singh, Ramanathan Gurunath, Shantanu Bhattacharya
This article presents a PCB based microfluidic platform for performing a dielectrophoretic capture of live microorganisms over inter-digitated electrodes buried under layers of different surface roughness values. Although dielectrophoresis has been extensively studied earlier over silicon and polymer surfaces with printed electrodes the issue of surface roughness particularly in case of buried electrodes has been seldom investigated. We have addressed this issue through a layer of spin coated PDMS (of various surface roughness) that is used to cover the printed electrodes over a printed circuit board...
June 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28408395/high-throughput-low-loss-low-cost-and-label-free-cell-separation-using-electrophysiology-activated-cell-enrichment
#5
Shabnam A Faraghat, Kai F Hoettges, Max K Steinbach, Daan R van der Veen, William J Brackenbury, Erin A Henslee, Fatima H Labeed, Michael P Hughes
Currently, cell separation occurs almost exclusively by density gradient methods and by fluorescence- and magnetic-activated cell sorting (FACS/MACS). These variously suffer from lack of specificity, high cell loss, use of labels, and high capital/operating cost. We present a dielectrophoresis (DEP)-based cell-separation method, using 3D electrodes on a low-cost disposable chip; one cell type is allowed to pass through the chip whereas the other is retained and subsequently recovered. The method advances usability and throughput of DEP separation by orders of magnitude in throughput, efficiency, purity, recovery (cells arriving in the correct output fraction), cell losses (those which are unaccounted for at the end of the separation), and cost...
April 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28403214/antibody-independent-capture-of-circulating-tumor-cells-of-non-epithelial-origin-with-the-apostream%C3%A2-system
#6
Priya Balasubramanian, Robert J Kinders, Shivaani Kummar, Vishal Gupta, David Hasegawa, Anoop Menachery, Scott M Lawrence, Lihua Wang, Katherine Ferry-Galow, Darren Davis, Ralph E Parchment, Joseph E Tomaszewski, James H Doroshow
Circulating tumor cells (CTCs) are increasingly employed for research and clinical monitoring of cancer, though most current methods do not permit the isolation of non-epithelial tumor cells. Furthermore, CTCs isolated with antibody-dependent methods are not suitable for downstream experimental uses, including in vitro culturing and implantation in vivo. In the present study, we describe the development, validation, and transfer across laboratories of a new antibody-independent device for the enrichment of CTCs from blood samples of patients with various cancer diagnoses...
2017: PloS One
https://www.readbyqxmd.com/read/28401635/electrokinetic-device-design-and-constraints-for-use-in-high-conductance-solutions
#7
D P Heineck, J M Lewis, M J Heller
The quest for new cell-free DNA and exosome biomarker-based molecular diagnostics require fast and efficient sample preparation techniques. Conventional methods for isolating these biomarkers from blood are both time-consuming and laborious. New electrokinetic microarray devices using dielectrophoresis (DEP) to isolate cell-free DNA and exosome biomarkers have now greatly improved the sample preparation process. Nevertheless, these devices still have some limitations when used with high conductance biological fluids, e...
April 12, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28401227/in-situ-mrna-isolation-from-a-microfluidic-single-cell-array-using-an-external-afm-nanoprobe
#8
Xuan Li, Yinglei Tao, Do-Hyun Lee, Hemantha K Wickramasinghe, Abraham P Lee
We present an in situ mRNA extraction platform to quantify marker-genes' expression levels of single target cells within high-density microfluidic trapping arrays. This platform enables single-cell transcriptomic analysis to reveal in-depth information of cellular mechanisms and population heterogeneity. Although microfluidic technology enables the automation of single-cell sorting, trapping and identification, most developed microfluidic devices are closed off and prevent single-cell access by external analytical equipment...
April 12, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28394391/refinement-of-insulator-based-dielectrophoresis
#9
Claire V Crowther, Mark A Hayes
The ability to separate analytes with increasingly similar properties drives the field of separation science. One way to achieve such separations is using trapping and streaming dielectrophoresis (DEP), which directly exploits the subtle differences in the electrophysical properties of analytes. The non-uniform fields necessary for DEP can be formed using various insulator shapes in microchannels. Current insulator shapes include triangles, diamonds, circles, and rectangles. However, all of these insulators pose problems for trapping, streaming, and sorting (deflection) as the induced fields/gradients are not behaviorally consistent across the lateral dimension...
April 10, 2017: Analyst
https://www.readbyqxmd.com/read/28376803/characterization-of-biomechanical-properties-of-cells-through-dielectrophoresis-based-cell-stretching-and-actin-cytoskeleton-modeling
#10
Guohua Bai, Ying Li, Henry K Chu, Kaiqun Wang, Qiulin Tan, Jijun Xiong, Dong Sun
BACKGROUND: Cytoskeleton is a highly dynamic network that helps to maintain the rigidity of a cell, and the mechanical properties of a cell are closely related to many cellular functions. This paper presents a new method to probe and characterize cell mechanical properties through dielectrophoresis (DEP)-based cell stretching manipulation and actin cytoskeleton modeling. METHODS: Leukemia NB4 cells were used as cell line, and changes in their biological properties were examined after chemotherapy treatment with doxorubicin (DOX)...
April 4, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28372723/review-microbial-analysis-in-dielectrophoretic-microfluidic-systems
#11
REVIEW
Renny E Fernandez, Ali Rohani, Vahid Farmehini, Nathan S Swami
Infections caused by various known and emerging pathogenic microorganisms, including antibiotic-resistant strains, are a major threat to global health and well-being. This highlights the urgent need for detection systems for microbial identification, quantification and characterization towards assessing infections, prescribing therapies and understanding the dynamic cellular modifications. Current state-of-the-art microbial detection systems exhibit a trade-off between sensitivity and assay time, which could be alleviated by selective and label-free microbial capture onto the sensor surface from dilute samples...
May 8, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28370028/a-novel-dielectrophoresis-potential-spectroscopy-for-colloidal-nanoparticles
#12
Hao Huang, H Daniel Ou-Yang
Dielectrophoresis (DEP) has been widely used to manipulate nanoparticles in microfluidic applications. However, determination of the DEP force of nanoparticles by theoretical models is not easy due to complications caused by the polarization of electrical double layer. Additionally, there is a lack of suitable experimental techniques to quantify the DEP force of nanoparticles. This article reports a statistical mechanics-based experimental method to determine the DEP potential energy of a single particle by measuring the equilibrium number density of particles in a DEP force field...
March 29, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28358942/negative-dielectrophoresis-spectroscopy-for-rare-analyte-quantification-in-biological-samples
#13
Syed Abdul Mannan Kirmani, Fleming Dackson Gudagunti, Logeeshan Velmanickam, Dharmakeerthi Nawarathna, Ivan T Lima
No abstract text is available yet for this article.
March 1, 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28342274/a-feasibility-study-for-enrichment-of-highly-aggressive-cancer-subpopulations-by-their-biophysical-properties-via-dielectrophoresis-enhanced-with-synergistic-fluid-flow
#14
Temple Anne Douglas, Jaka Cemazar, Nikita Balani, Daniel C Sweeney, Eva M Schmelz, Rafael V Davalos
A common problem with cancer treatment is the development of treatment resistance and tumor recurrence that result from treatments that kill most tumor cells yet leave behind aggressive cells to repopulate. Presented here is a microfluidic device that can be used to isolate tumor subpopulations to optimize treatment selection. Dielectrophoresis (DEP) is a phenomenon where particles are polarized by an electric field and move along the electric field gradient. Different cell subpopulations have different DEP responses depending on their bioelectrical phenotype, which, we hypothesize, correlate with aggressiveness...
March 25, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28328089/capacitive-dna-sensor-for-rapid-and-sensitive-detection-of-whole-genome-human-herpesvirus-1-dsdna-in-serum
#15
Cheng Cheng, Rania Oueslati, Jayne Wu, Jiangang Chen, Shigetoshi Eda
This work presents a rapid, highly sensitive, low-cost, and specific capacitive DNA sensor for detection of whole genome human herpesvirus-1 DNA. This sensor is capable of direct DNA detection with a response time of 30 s, and it can be used to test standard buffer or serum samples. The sensing approach for DNA detection is based on alternating current (AC) electrokinetics. By applying an inhomogeneous AC electric field on sensor electrodes, positive dielectrophoresis is induced to accelerate DNA hybridization...
March 22, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28328070/modeling-and-simulation-of-dielectrophoretic-collective-dynamics-in-a-suspension-of-polarizable-particles-under-the-action-of-a-gradient-ac-electric-field
#16
Shigeru Tada, Yan Shen, Zhiyong Qiu
When a suspension of polarizable particles is subjected to a gradient AC electric field, the particles exhibit collective motion due to an interaction between the dipole induced in the particles and the spatial gradient of the electric field; this is known as dielectrophoresis. In the present study, the collective dynamics of suspended particles in a parallel-plate electric chamber was investigated by simulating numerically the trajectories of individual particles under the action of combined dielectrophoretic and dipole-dipole interparticle forces...
March 22, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28314101/dielectrophoresis-system-for-testing-antimicrobial-susceptibility-of-gram-negative-bacteria-to-%C3%AE-lactam-antibiotics
#17
I-Hsiu Su, Wen-Chien Ko, Chung-Hsin Shih, Fang-Hao Yeh, Yung-Nien Sun, Jung-Chih Chen, Po-Lin Chen, Hsien-Chang Chang
Gram-negative bacteria (GNBs) are common pathogens causing severe sepsis. Rapid evaluation of drug susceptibility would guide effective antibiotic treatment and promote life-saving. A total of 78 clinical isolates of 13 Gram-negative species collected between April 2013 and November 2013 from two medical centers in Tainan were tested. Bacterial morphology changes in different concentrations of antibiotics were observed under the electric field of a quadruple electrode array using light microscopy. The minimal inhibitory concentrations (MICs) of four antimicrobial agents, namely, cefazolin, ceftazidime, cefepime, and doripenem, were determined by the dielectrophoretic antimicrobial susceptibility testing (dAST) and by the conventional broth dilution testing (BDT)...
March 31, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28306161/dna-dielectrophoresis-theory-and-applications-a-review
#18
REVIEW
Martina Viefhues, Ralf Eichhorn
Dielectrophoresis is the migration of an electrically polarizable particle in an inhomogeneous electric field. This migration can be exploited for several applications with (bio)molecules or cells. Dielectrophoresis is a non-invasive technique; therefore, it is very convenient for (selective) manipulation of (bio)molecules or cells. In this review, we will focus on DNA dielectrophoresis as this technique offers several advantages in trapping and immobilization, separation and purification, and analysis of DNA molecules...
March 17, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28301054/dipole-and-multipole-models-of-dielectrophoresis-for-a-non-negligible-particle-size-simulations-and-experiments
#19
Tomáš Michálek, Jiří Zemánek
Mathematical models of dielectrophoresis play an important role in the design of experiments, analysis of results, and even operation of some devices. In this paper, we test the accuracy of existing models in both simulations and laboratory experiments. We test the accuracy of the most common model that involves a point-dipole approximation of the induced field, when the small-particle assumption is broken. In simulations, comparisons against a model based on the Maxwell stress tensor show that even the point-dipole approximation provides good results for a large particle close to the electrodes...
March 16, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28295737/dielectrophoresis-assisted-integration-of-1024-carbon-nanotube-sensors-into-a-cmos-microsystem
#20
Florent Seichepine, Jörg Rothe, Alexandra Dudina, Andreas Hierlemann, Urs Frey
Carbon-nanotube (CNT)-based sensors offer the potential to detect single-molecule events and picomolar analyte concentrations. An important step toward applications of such nanosensors is their integration in large arrays. The availability of large arrays would enable multiplexed and parallel sensing, and the simultaneously obtained sensor signals would facilitate statistical analysis. A reliable method to fabricate an array of 1024 CNT-based sensors on a fully processed complementary-metal-oxide-semiconductor microsystem is presented...
March 15, 2017: Advanced Materials
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