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Waqas Waheed, Anas Alazzam, Bobby Mathew, Nicolas Christoforou, Eiyad Abu-Nada
This short communication introduces a continuous-flow, dielectrophoresis-based lateral fluid flow fractionation microdevice for detection/isolation of circulating tumor cells in the presence of other haematological cells. The device utilizes two sets of planar interdigitated transducer electrodes micropatterned on top of a glass wafer using standard microfabrication techniques. A microchannel with a single inlet and two outlets, realized in polydimethylsiloxane, is bonded on the glass substrate. The two sets of electrodes slightly protrude into the microchannel...
April 30, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Ugonna Ohiri, C Wyatt Shields, Koohee Han, Talmage Tyler, Orlin D Velev, Nan Jokerst
Locally energized particles form the basis for emerging classes of active matter. The design of active particles has led to their controlled locomotion and assembly. The next generation of particles should demonstrate robust control over their active assembly, disassembly, and reconfiguration. Here we introduce a class of semiconductor microparticles that can be comprehensively designed (in size, shape, electric polarizability, and patterned coatings) using standard microfabrication tools. These custom silicon particles draw energy from external electric fields to actively propel, while interacting hydrodynamically, and sequentially assemble and disassemble on demand...
May 3, 2018: Nature Communications
Ziyi Yu, Christian R Boehm, Julian M Hibberd, Chris Abell, Jim Haseloff, Steven J Burgess, Ivan Reyna-Llorens
Droplet-based microfluidics has been used to facilitate high-throughput analysis of individual prokaryote and mammalian cells. However, there is a scarcity of similar workflows applicable to rapid phenotyping of plant systems where phenotyping analyses typically are time-consuming and low-throughput. We report on-chip encapsulation and analysis of protoplasts isolated from the emergent plant model Marchantia polymorpha at processing rates of >100,000 cells per hour. We use our microfluidic system to quantify the stochastic properties of a heat-inducible promoter across a population of transgenic protoplasts to demonstrate its potential for assessing gene expression activity in response to environmental conditions...
2018: PloS One
O Chmela, J Sadílek, G Domènech-Gil, J Samà, J Somer, R Mohan, A Romano-Rodriguez, J Hubálek, S Vallejos
Gas nanosensors, comprised of arrays of nanoelectrodes with finger-widths of ∼100 nm developed by electron beam lithography and aerosol assisted chemical vapor deposited non-functionalized and Pt-functionalized tungsten oxide nanowires (<100 nm) subsequently integrated across the pairs of electrodes via the dielectrophoresis method, are developed in this work. The functionality of these devices is validated towards various concentrations of NO2 and C2H5OH. The results demonstrate reproducible and consistent responses with better sensitivity and partial selectivity for the non-functionalized systems to NO2, as opposed to the Pt-functionalized systems, which display better sensing properties towards C2H5OH with a loss of response to NO2...
May 2, 2018: Nanoscale
Leilei Shi, Ankit Rana, Leyla Esfandiari
An insulator-based dielectrophoresis (iDEP) is a label-free method that has been extensively utilized for manipulation of nanoparticles, cells, and biomolecules. Here, we present a new iDEP approach that can rapidly trap nanoparticles at the close proximity of a glass nanopipette's tip by applying 10 V/cm direct current (DC) across the pipette's length. The trapping mechanism was systemically studied using both numerical modeling and experimental observations. The results showed that the particle trapping was determined to be controlled by three dominant electrokinetic forces including dielectrophoretic, electrophoretic and electroosmotic force...
April 30, 2018: Scientific Reports
Jian Zhang, Rania Oueslati, Cheng Cheng, Ling Zhao, Jiangang Chen, Raul Almeida, Jayne Wu
Gram-negative bacteria are one of the most common microorganisms in the environment. Their differential detection and recognition from Gram-positive bacteria has been attracting much attention over the years. Using Escherichia coli (E. coli) as a model, we demonstrated on-site detection of Gram-negative bacteria by an AC electrokinetics-based capacitive sensing method using commercial microelectrodes functionalized with an aptamer specific to lipopolysaccharides. Dielectrophoresis effect was utilized to enrich viable bacteria to the microelectrodes rapidly, achieving a detection limit of 102 cells/mL within a 30 s' response time...
April 17, 2018: Biosensors & Bioelectronics
E Du, Yuhao Qiang, Jia Liu
We envision that electrodeformation of biological cells through dielectrophoresis as a new technique to elucidate the mechanistic details underlying membrane failure by electrical and mechanical stresses. Here we demonstrate the full control of cellular uniaxial deformation and tensile recovery in biological cells via amplitude-modified electric field at radio frequency by an interdigitated electrode array in microfluidics. Transient creep and cyclic experiments were performed on individually tracked human erythrocytes...
2018: Applied Sciences
Yuhao Qiang, Jia Liu, E Du
Dielectrophoresis in microfluidics provides a useful tool to test biomechanics of living cells, regardless of surface charges on cell membranes. We have designed an experimental method to characterize the nonlinear viscoelastic behaviors of single cells using dielectrophoresis in a microfluidic channel. This method uses radio frequency, low voltage excitations through interdigitated microelectrodes, allowing probing multiple cells simultaneously with controllable load levels. Dielectrophoretic force was calibrated using a triaxial ellipsoid model...
2018: Micromachines
Meenal Goel, Abhishek Verma, Shalini Gupta
Microarray technology to isolate living cells using external fields is a facile way to do phenotypic analysis at the cellular level. We have used alternating current dielectrophoresis (AC-DEP) to drive the assembly of live pathogenic Salmonella typhi (S.typhi) and Escherichia coli (E.coli) bacteria into miniaturized single cell microarrays. The effects of voltage and frequency were optimized to identify the conditions for maximum cell capture which gave an entrapment efficiency of 90% in 60 min. The chip was used for calibration-free estimation of cellular loads in binary mixtures and further applied for rapid and enhanced testing of cell viability in the presence of drug via impedance spectroscopy...
April 7, 2018: Biosensors & Bioelectronics
Enrique Burzurí, Mariano Vera-Hidalgo, Emerson Giovanelli, Julia Villalva, Andres Castellanos-Gomez, Emilio M Pérez
van der Waals heterostructures (vdWH) are made of different two-dimensional (2D) layers stacked on top of each other, forming a single material with unique properties that differ from those of the individual 2D constituent layers, and that can be modulated through the interlayer interaction. These hetero-materials can be artificially made by mechanical stamping, solution processing or epitaxial growth. Alternatively, franckeite has been recently described as an example of a naturally-occurring vdWH that can be exfoliated down to nanometer thicknesses...
April 4, 2018: Nanoscale
Qingming Chen, Tenghao Li, Yujiao Zhu, Weixing Yu, Xuming Zhang
This paper reports a tunable in-plane optofluidic lens by continuously tuning a silicone oil-air interface from concave to convex using the dielectrophoresis (DEP) force. Two parallel glasses are bonded firmly on two sides by NOA 81(Norland Optical Adhesive 81) spacers, forming an open microfluidic channel. An ITO (indium tin oxide) strip and another unpatterned ITO layer are deposited on two glasses as the top and bottom electrodes. Initially, a capillary concave liquid-air interface is formed at the end of the open channel...
March 19, 2018: Optics Express
Renjie Wang, Yi Xu, Thomas Sors, Joseph Irudayaraj, Wen Ren, Rong Wang
The authors describe a method that can significantly improve the performance of impedimetric detection of bacteria. A multifunctional microfluidic chip was designed consisting of interdigitated microelectrodes and a micro-mixing zone with a Tesla structure. This maximizes the coating of bacterial surfaces with nanoparticles and results in improved impedimetric detection. The method was applied to the detection of Escherichia coli O157:H7 (E. coli). Silver enhancement was accomplished by coating E.coli with the cationic polymer diallyldimethylammonium chloride (PDDA) to form positively charged E...
February 19, 2018: Mikrochimica Acta
Kyuhyun Bang, Sang-Soo Chee, Kangmi Kim, Myungwoo Son, Hanbyeol Jang, Byoung Hun Lee, Kwang Hyeon Baik, Jae-Min Myoung, Moon-Ho Ham
There has been growing interest in developing nanoelectronic devices based on graphene because of its superior electrical properties. In particular, patterning graphene into a nanoribbon can open a bandgap that can be tuned by changing the ribbon width, imparting semiconducting properties. In this study, we report the effect of ribbon width on electrical transport properties of graphene nanoribbons (GNRs). Monolayer graphene sheets and Si nanowires (NWs) were prepared by chemical vapor deposition and a combination of nanosphere lithography and metal-assisted electroless etching from a Si wafer, respectively...
2018: Nano Convergence
Jun Yuan Chan, Aminuddin Bin Ahmad Kayani, Mohd Anuar Md Ali, Chee Kuang Kok, Burhanuddin Yeop Majlis, Susan Ling Ling Hoe, Marini Marzuki, Alan Soo-Beng Khoo, Kostya Ken Ostrikov, Md Ataur Rahman, Sharath Sriram
The recent advancement of dielectrophoresis (DEP)-enabled microfluidic platforms is opening new opportunities for potential use in cancer disease diagnostics. DEP is advantageous because of its specificity, low cost, small sample volume requirement, and tuneable property for microfluidic platforms. These intrinsic advantages have made it especially suitable for developing microfluidic cancer diagnostic platforms. This review focuses on a comprehensive analysis of the recent developments of DEP enabled microfluidic platforms sorted according to the target cancer cell...
January 2018: Biomicrofluidics
Shuailong Zhang, Adele Nikitina, Yujie Chen, Yanfeng Zhang, Lin Liu, Andrew G Flood, Joan Juvert, M Dean Chamberlain, Nazir P Kherani, Steven L Neale, Aaron R Wheeler
Optoelectronic tweezers (OET) are a microsystem actuation technology capable of moving microparticles at mm s-1 velocities with nN forces. In this work, we analyze the behavior of particles manipulated by negative dielectrophoresis (DEP) forces in an OET trap. A user-friendly computer interface was developed to generate a circular rotating light pattern to control the movement of the particles, allowing their force profiles to be conveniently measured. Three-dimensional simulations were carried out to clarify the experimental results, and the DEP forces acting on the particles were simulated by integrating the Maxwell stress tensor...
March 5, 2018: Optics Express
Hitomi Mukaibo, Tonghui Wang, Victor H Perez-Gonzalez, Jirachai Getpreecharsawas, Jack T Wurzer, Blanca Lapizco-Encinas, James L McGrath
Insulator-based dielectrophoresis (iDEP) is a simple, scalable mechanism that can be used for directly manipulating particle trajectories in pore-based filtration and separation processes. However, iDEP manipulation of nanoparticles presents unique challenges as the dielectrophoretic force (&lt;b&gt;&lt;i&gt;F&lt;/i&gt;&lt;/b&gt;&lt;sub&gt;DEP&lt;/sub&gt;) exerted on the nanoparticles can easily be overshadowed by opposing kinetic forces. In this study, a molecularly thin, SiN-based nanoporous membrane (NPN) is explored as a breakthrough technology that enhances &lt;b&gt;&lt;i&gt;F&lt;/i&gt;&lt;/b&gt;&lt;sub&gt;DEP&lt;/sub&gt;...
March 12, 2018: Nanotechnology
Victor H Perez-Gonzalez, Roberto C Gallo-Villanueva, Braulio Cardenas-Benitez, Sergio O Martinez-Chapa, Blanca H Lapizco-Encinas
Insulator based dielectrophoresis (iDEP) is a microfluidic technique used for particle analysis in a wide array of applications. Significant efforts are dedicated to improve iDEP systems by reducing voltage requirements. This study assesses how the performance of an iDEP system, in terms of particle trapping, depends on the number of insulating obstacles longitudinally present in the microchannel. In analogy with Kirchhoff's loop rule, iDEP systems were analyzed as a series combination of electrical resistances, where the equivalent resistance of the post array is composed by a number of individual resistors (columns of insulating posts)...
March 12, 2018: Analytical Chemistry
Danielle V Polniak, Eric Goodrich, Nicole Hill, Blanca H Lapizco-Encinas
Dielectrophoresis (DEP), the migration of particles due to polarization effects under the influence of a nonuniform electric field, was employed for characterizing the behavior and achieving the separation of larger (diameter >5 μm) microparticles by exploiting differences in electrical charge. Usually, electrophoresis (EP) is the method of choice for separating particles based on differences in electrical charge; however, larger particles, which have low electrophoretic mobilities, cannot be easily separated with EP-based techniques...
April 13, 2018: Journal of Chromatography. A
Min Li, Robbyn K Anand
In this review, recent advances that leverage dielectrophoretic approaches to accomplish single-cell analysis (both "on-chip" and "off-chip") are discussed with special emphasis on eukaryotic cells. Dielectrophoresis as an electric-field-induced force utilized for cell manipulation can confer selectivity without labeling. Recent technical improvements have increased the volumetric throughput of the separation of cells from complex mixtures, introduced new strategies for massively parallel single-cell confinement for subsequent on-chip analysis, made possible selective transport of individual cells off-chip, and integrated preconcentration and prefocusing steps to enhance dielectrophoretic performance...
April 2018: Analytical and Bioanalytical Chemistry
Alicia M Boymelgreen, Tov Balli, Touvia Miloh, Gilad Yossifon
Utilization of active colloids to transport both biological and inorganic cargo has been widely examined in the context of applications ranging from targeted drug delivery to sample analysis. In general, carriers are customized to load one specific target via a mechanism distinct from that driving the transport. Here we unify these tasks and extend loading capabilities to include on-demand selection of multiple nano/micro-sized targets without the need for pre-labelling or surface functionalization. An externally applied electric field is singularly used to drive the active cargo carrier and transform it into a mobile floating electrode that can attract (trap) or repel specific targets from its surface by dielectrophoresis, enabling dynamic control of target selection, loading and rate of transport via the electric field parameters...
February 22, 2018: Nature Communications
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