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Vikash Kumar, Pouya Rezai, Vikash Kumar, Pouya Rezai, Vikash Kumar, Pouya Rezai
Sorting of microorganisms and particles from a mixture is critical for numerous biotechnological and medical applications. Several sorting methods such as pinched flow fractionation (PFF), optical sorting, dielectrophoresis, acoustic separation, magnetophoresis and deterministic lateral displacement (DLD) have been reported in literature. But most of these methods lack ideal characteristics of a sorter such as ability to process at high throughput, simple design, non-complicated fabrication method, sheathless operation and high purity in separation...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Hongyao Geng, Jian Feng, Lisa Marie Stabryla, Sung Kwon Cho
Generating, splitting, transporting, and merging droplets are fundamental and critical unit operations for digital (droplet-based) microfluidics. State-of-the-art digital microfluidics performs such operations commonly using electrowetting-on-dielectric (EWOD) in the typical configuration of two parallel channel plates. This paper presents such operations using dielectrowetting (derived from liquid dielectrophoresis), not EWOD, with an array of interdigitated electrodes. The major and unique feature is that the present droplet manipulations are effective for conductive (water with/without surfactant) and non-conductive (propylene carbonate) fluids...
February 20, 2017: Lab on a Chip
Mohammad Hossein Mohammadi, Raquel Obregón, Samad Ahadian, Javier Ramón-Azcón, Milica Radisic
Animal models have been the main resources for drug discovery and prediction of drugs' pharmacokinetic responses in the body. However, noticeable drawbacks associated with animal models include high cost, low reproducibility, low physiological similarity to humans, and ethical problems. Engineered tissue models have recently emerged as an alternative or substitute for animal models in drug discovery and testing and disease modeling. In this review, we focus on skeletal muscle and cardiac muscle tissues by first describing their characterization and physiology...
February 15, 2017: Current Pharmaceutical Design
Foram Ranjeet Madiyar, Sherry Basset, Omer Farooq, Stefan Rothenburg, Christopher Culbertson, Jun Li
This paper reports the capture and detection of vaccinia virus particles based on AC dielectrophoresis (DEP) and electrochemical impedance measurements employing an embedded vertically aligned carbon nanofiber (VACNF) nanoelectrode array (NEA) versus a macroscopic indium-tin-oxide (ITO) transparent electrode in a "points-and-lid" configuration. The nano-DEP device was fabricated by bonding two SU-8 covered electrodes patterned using photolithography. The bottom electrode contains a 200 × 200 μm(2) active region on a randomly distributed NEA and the top electrode contains a microfluidic channel in SU-8 spin-coated on ITO to guide the flow of the virus solution...
February 17, 2017: Electrophoresis
Cynthia Hanson, Elizabeth Vargis
Dielectrophoresis (DEP) uses non-uniform electric fields to cause motion in particles due to the particles' intrinsic properties. As such, DEP is a well-suited label-free means for cell sorting. Of the various methods of implementing DEP, contactless dielectrophoresis (cDEP) is advantageous as it avoids common problems associated with DEP, such as electrode fouling and electrolysis. Unfortunately, cDEP devices can be difficult to fabricate, replicate, and reuse. In addition, the operating parameters are limited by the dielectric breakdown of polydimethylsiloxane (PDMS)...
February 9, 2017: Sensors
Marta Tellez-Gabriel, Céline Charrier, Bénédicte Brounais-Le Royer, Mathilde Mullard, Hannah K Brown, Franck Verrecchia, Dominique Heymann
Gap junctions are transmembrane structures that directly connect the cytoplasm of adjacent cells, making intercellular communications possible. It has been shown that the behaviour of several tumours - such as bone tumours - is related to gap junction intercellular communications (GJIC). Several methodologies are available for studying GJIC, based on measuring different parameters that are useful for multiple applications, such as the study of carcinogenesis for example. These methods nevertheless have several limitations...
February 6, 2017: European Journal of Cell Biology
Barbaros Çetin, S Doğan Öner, Besim Baranoğlu
Dielectrophoresis (DEP) is a very popular technique for microfluidic bio-particle manipulation. For the design of a DEP based microfluidic device, simulation of the particle trajectory within the micro-channel network is crucial. There are basically two approaches: (i) point-particle approach and (ii) finite-sized particle approach. In this study, many aspects of both approaches are discussed for the simulation of DC-DEP, AC-DEP and traveling-wave DEP applications. Point-particle approach is implemented using Lagrangian tracking method, and finite-sized particle is implemented using boundary element method (BEM)...
February 6, 2017: Electrophoresis
Alban J Smith, Richard D O'Rorke, Akshay Kale, Roberts Rimsa, Matthew J Tomlinson, Jennifer Kirkham, A Giles Davies, Christoph Wälti, Christopher D Wood
The ability to isolate specific, viable cell populations from mixed ensembles with minimal manipulation and within intra-operative time would provide significant advantages for autologous, cell-based therapies in regenerative medicine. Current cell-enrichment technologies are either slow, lack specificity and/or require labelling. Thus a rapid, label-free separation technology that does not affect cell functionality, viability or phenotype is highly desirable. Here, we demonstrate separation of viable from non-viable human stromal cells using remote dielectrophoresis, in which an electric field is coupled into a microfluidic channel using shear-horizontal surface acoustic waves, producing an array of virtual electrodes within the channel...
February 2, 2017: Scientific Reports
Anil Koklu, Ahmet C Sabuncu, Ali Beskok
Dielectrophoretic motions of Saccharomyces Cerevisiae (yeast) cells and colloidal gold are investigated using electrochemically modified electrodes exhibiting fractal topology. Electrodeposition of gold on electrodes generated repeated patterns with a fern-leaf type self-similarity. A particle tracking algorithm is used to extract dielectrophoretic particle velocities using fractal and planar electrodes in two different medium conductivities. The results show increased dielectrophoretic force when using fractal electrodes...
January 28, 2017: Electrophoresis
Daniel J Allen, Robert P Accolla, Stuart J Williams
Two dielectrophoresis systems are introduced where the induced dielectrophoretic force is constant throughout the experimental region, resulting in uniform (isomotive) microparticle translation. Isomotive dielectrophoresis (isoDEP) is accomplished through a unique geometry where the gradient of the field-squared (∇Erms2) is constant, a characteristic that is otherwise highly non-uniform in traditional DEP platforms. The governing isoDEP equations were derived herein and applied to two different isoDEP prototypes: (i) one fabricated from deep reactive ion etching (DRIE) of a conductive silicon wafer (1-10 Ω-cm) whose patterned features served as electrodes and microchannel sidewalls simultaneously; (ii) a second where the electric field is applied lengthwise through a PDMS microchannel whose geometry follows a specific curvature...
January 23, 2017: Electrophoresis
Bobby Mathew, Anas Alazzam, Saud Khashan, Mohammad Abutayeh
This short communication presents the proof-of-concept of a novel dielectrophoretic lab-on-chip for identifying/separating circulating tumor cells for purposes of liquid biopsy. The device consists of a polydimethylsiloxane layer, containing a microchannel, bonded on a glass substrate that holds two sets of planar interdigitated transducer electrodes. The lab-on-chip is operated at a frequency that enables dielectrophoretic force to sort cells, based on type, along the lateral direction. The operating frequency ensures attraction force toward the electrodes on cancer cells and repulsion force toward the center of the microchannel on other cells...
March 1, 2017: Talanta
Changbong Yeon, Inyeal Lee, Gil-Ho Kim, Sun Jin Yun
We suggest a unimer-assisted exfoliation method for the exfoliation of van der Waals two-dimensional (2D) materials such as graphene, MoS2, and h-BN and show that the micellar size is a critical parameter for enhancing the exfoliation efficiency. To explain the effectiveness of the unimers in the exfoliation, the influence of the micellar size of a biocompatible block copolymer, Pluronic F-68, is evaluated in view of the yield and thickness of exfoliated 2D flakes. By the addition of water-soluble alcohols, the surfactants exist in the form of a unimer, which facilitates the intercalation into the layered materials and their exfoliation...
January 27, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Coralie Siebman, Orlin D Velev, Vera I Slaveykova
The capability of alternating current (AC) dielectrophoresis (DEP) for on-chip capture and chaining of the three species representative of freshwater phytoplankton was evaluated. The effects of the AC field intensity, frequency and duration on the chaining efficiency and chain lengths of green alga Chlamydomonas reinhardtii, cyanobacterium Synechocystis sp. and diatom Cyclotella meneghiniana were characterized systematically. C. reinhardtii showed an increase of the chaining efficiency from 100 Hz to 500 kHz at all field intensities; C...
January 5, 2017: Biosensors
Georg R Pesch, Fei Du, Michael Baune, Jorg Thöming
Insulator-based dielectrophoresis (iDEP) is a powerful particle analysis technique based on electric field scattering at material boundaries which can be used, for example, for particle filtration or to achieve chromatographic separation. Typical devices consist of microchannels containing an array of posts but large scale application was also successfully tested. Distribution and magnitude of the generated field gradients and thus the possibility to trap particles depends apart from the applied field strength on the material combination between post and surrounding medium and on the boundary shape...
February 3, 2017: Journal of Chromatography. A
Kai Tian, Karl Decker, Aleksei Aksimentiev, Li-Qun Gu
The motion of polarizable particles in a nonuniform electric field (i.e., dielectrophoresis) has been extensively used for concentration, separation, sorting, and transport of biological particles from cancer cells and viruses to biomolecules such as DNAs and proteins. However, current approaches to dielectrophoretic manipulation are not sensitive enough to selectively target individual molecular species. Here, we describe the application of the dielectrophoretic principle for selective detection of DNA and RNA molecules using an engineered biological nanopore...
January 6, 2017: ACS Nano
Anas Alazzam, Bobby Mathew, Falah Alhammadi
We describe the design, microfabrication, and testing of a microfluidic device for separation of cancer cells based on dielectrophoresis. Cancer cells, specifically Green fluorescent protein-labeled MDA-MB-231, are successfully separated from a heterogeneous mixture of the same and normal blood cells. MDA-MB-231 cancer cells are separated with an accuracy that enables precise detection and counting of circulating tumor cells present among normal blood cells. The separation is performed using a set of planar interdigitated transducer electrodes that are deposited on the surface of a glass wafer and slightly protrude into the separation microchannel at one side...
December 30, 2016: Journal of Separation Science
Gabriela B Almeida, Ronei J Poppi, José A Fracassi da Silva
Dielectrophoresis (DEP) is the electrokinetic movement of non-charged particles when they are subjected to a non-uniform electric field. This is a growing area of research, which can be used for trapping, concentrating and separating different particles. Some work has been reported with the intention of trapping metal particles to optimize the surface enhanced Raman spectroscopy (SERS) effect. In this paper, we use DEP with insulating structures (iDEP) to generate a non-uniform electric field for trapping gold nanoparticles (AuNP)...
December 20, 2016: Analyst
Timothy Lannin, Wey-Wey Su, Conor Gruber, Ian Cardle, Chao Huang, Fredrik Thege, Brian Kirby
We used automated electrorotation to measure the cytoplasmic permittivity, cytoplasmic conductivity, and specific membrane capacitance of pancreatic cancer cells under environmental perturbation to evaluate the effects of serum starvation, epithelial-to-mesenchymal transition, and evolution of chemotherapy resistance which may be associated with the development and dissemination of cancer. First, we compared gemcitabine-resistant BxPC3 subclones with gemcitabine-naive parental cells. Second, we serum-starved BxPC3 and PANC-1 cells and compared them to untreated counterparts...
November 2016: Biomicrofluidics
Paul V Jones, Gabriel L Salmon, Alexandra Ros
Separation of nucleic acids has long served as a central goal of analytical research. Innovations in this field may soon enable the development of rapid, on-site sequencing devices that significantly improve both the availability and accuracy of detailed bioinformatics. However, achieving efficient continuous-flow operation and size-based fractionation of DNA still presents considerable challenges. Current methods have not yet satisfied the need for rapid fractionation of size-heterogeneous nucleic acid samples into specific and narrow size distributions...
February 7, 2017: Analytical Chemistry
Alberto Bonanno, Alessandro Sanginario, Simone L Marasso, Beatrice Miccoli, Katarzyna Bejtka, Simone Benetto, Danilo Demarchi
This paper presents a customizable sensing system based on functionalized nanowires (NWs) assembled onto complementary metal oxide semiconductor (CMOS) technology. The Micro-for-Nano (M4N) chip integrates on top of the electronics an array of aluminum microelectrodes covered with gold by means of a customized electroless plating process. The NW assembly process is driven by an array of on-chip dielectrophoresis (DEP) generators, enabling a custom layout of different nanosensors on the same microelectrode array...
November 30, 2016: Sensors
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