scholarly journals Editorial for the Special Issue on AC Electrokinetics in Microfluidic Devices

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 345
Author(s):  
Antonio Ramos ◽  
Pablo García-Sánchez
Keyword(s):  
Electric Fields ◽  
Microfluidic Devices ◽  
Special Issue ◽  
Small Particles ◽  
Ac Electrokinetics ◽  
Ac Electric Fields

The use of AC electric fields for manipulating and/or characterizing liquids and small particles in suspension is well-known [...]

AC Electrokinetics for Biosensors

2004 ◽  
Author(s):  
M. Sigurdson ◽  
C. Meinhart ◽  
D. Wang
Keyword(s):  
Electric Fields ◽  
Dna Hybridization ◽  
Fluid Motion ◽  
Diffusive Transport ◽  
Analyte Concentration ◽  
Ac Electrokinetics ◽  
Ac Electric Fields ◽  
Binding Rate ◽  
Electrothermal Flow ◽  
Biosensor Device

We develop here tools for speeding up binding in a biosensor device through augmenting diffusive transport, applicable to immunoassays as well as DNA hybridization, and to a variety of formats, from microfluidic to microarray. AC electric fields generate the fluid motion through the well documented but unexploited phenomenon, Electrothermal Flow, where the circulating flow redirects or stirs the fluid, providing more binding opportunities between suspended and wall-immobilized molecules. Numerical simulations predict a factor of up to 8 increase in binding rate for an immunoassay under reasonable conditions. Preliminary experiments show qualitatively higher binding after 15 minutes. In certain applications, dielectrophoretic capture of passing molecules, when combined with electrothermal flow, can increase local analyte concentration and further enhance binding.

scholarly journals Dipolophoresis and Travelling-Wave Dipolophoresis of Metal Microparticles

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 259
Author(s):  
Jose Eladio Flores-Mena ◽  
Pablo García-Sánchez ◽  
Antonio Ramos
Keyword(s):  
Electric Fields ◽  
Particle Motion ◽  
Numerical Solutions ◽  
Particle Surface ◽  
Travelling Wave ◽  
Aqueous Electrolytes ◽  
Small Particles ◽  
Ac Electric Fields ◽  
Induced Charge ◽  
Analytical Expressions

We study theoretically and numerically the electrokinetic behavior of metal microparticles immersed in aqueous electrolytes. We consider small particles subjected to non-homogeneous ac electric fields and we describe their motion as arising from the combination of electrical forces (dielectrophoresis) and the electroosmotic flows on the particle surface (induced-charge electrophoresis). The net particle motion is known as dipolophoresis. We also study the particle motion induced by travelling electric fields. We find analytical expressions for the dielectrophoresis and induced-charge electrophoresis of metal spheres and we compare them with numerical solutions. This validates our numerical method, which we also use to study the dipolophoresis of metal cylinders.

Highly conductive multi-walled carbon nanotube/polydimethylsiloxane (MWCNT/PDMS) nanocomposite for microfluidic applications

2020 ◽  
pp. 002199832097764
Author(s):  
Nasim Jan Mohammadi Dashtaki ◽  
Amir Hossein Nassajpour-Esfahani ◽  
Morteza Bayareh ◽  
Pouya Rezai ◽  
Ali Doostmohammadi
Keyword(s):  
Electric Fields ◽  
Microfluidic Devices ◽  
Microstructural Properties ◽  
Elemental Mapping ◽  
Conductive Materials ◽  
Ac Electric Fields ◽  
Ac Electric Field ◽  
Multi Walled Carbon Nanotube ◽  
Measured Field ◽  
Scanning Electron

Conductive materials are required for sensing and actuation purposes in microfluidic devices. Electrical and mechanical properties of aligned CNTs/PDMS nanocomposites fabricated in AC and quasi-AC electric fields were measured. Field emission scanning electron microscope and elemental mapping were used to evaluate the microstructural properties of fabricated specimens. Results showed that nanocomposite properties were dependent on CNT concentration. A homogenized and nonagglomerated composite was obtained using a quasi-AC electric field with the voltage of 1075 V zero to peak at a frequency of 100 Hz and current of 35 milliamps when applied to suspension for 2 hours at 80 °C. The aligned nanocomposite with 1 wt% of CNT exhibited an electrical conductivity, Young’s modulus, and tensile strength of 10-6 S/cm, 7.23 MPa, and 1.02 MPa, respectively.

Fabrication of ZrO 2 /rGO nanocomposites by flash sintering under AC electric fields

2021 ◽  
Author(s):  
Xinghua Su ◽  
Mengying Fu ◽  
Gai An ◽  
Zhihua Jiao ◽  
Qiang Tian ◽  
...  
Keyword(s):  
Electric Fields ◽  
Ac Electric Fields ◽  
Flash Sintering

scholarly journals Spinning Janus doublets driven in uniform ac electric fields

2014 ◽  
Vol 89 (1) ◽  
Author(s):  
Alicia Boymelgreen ◽  
Gilad Yossifon ◽  
Sinwook Park ◽  
Touvia Miloh
Keyword(s):  
Electric Fields ◽  
Ac Electric Fields

scholarly journals Micropipette-Based Microfluidic Device for Monodisperse Microbubbles Generation

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 387
Author(s):  
Carlos Toshiyuki Matsumi ◽  
Wilson José da Silva ◽  
Fábio Kurt Schneider ◽  
Joaquim Miguel Maia ◽  
Rigoberto E. M. Morales ◽  
...  
Keyword(s):  
Electric Fields ◽  
Microfluidic Device ◽  
Soft Lithography ◽  
Low Cost ◽  
Characteristic Curve ◽  
Microfluidic Devices ◽  
Average Diameter ◽  
Internal Diameter ◽  
Medical Diagnostic ◽  
Average Size

Microbubbles have various applications including their use as carrier agents for localized delivery of genes and drugs and in medical diagnostic imagery. Various techniques are used for the production of monodisperse microbubbles including the Gyratory, the coaxial electro-hydrodynamic atomization (CEHDA), the sonication methods, and the use of microfluidic devices. Some of these techniques require safety procedures during the application of intense electric fields (e.g., CEHDA) or soft lithography equipment for the production of microfluidic devices. This study presents a hybrid manufacturing process using micropipettes and 3D printing for the construction of a T-Junction microfluidic device resulting in simple and low cost generation of monodisperse microbubbles. In this work, microbubbles with an average size of 16.6 to 57.7 μm and a polydispersity index (PDI) between 0.47% and 1.06% were generated. When the device is used at higher bubble production rate, the average diameter was 42.8 μm with increased PDI of 3.13%. In addition, a second-order polynomial characteristic curve useful to estimate micropipette internal diameter necessary to generate a desired microbubble size is presented and a linear relationship between the ratio of gaseous and liquid phases flows and the ratio of microbubble and micropipette diameters (i.e., Qg/Ql and Db/Dp) was found.

Anomalous Particle Rotation and Resulting Microstructure of Colloids in AC Electric Fields

Langmuir ◽  
2008 ◽  
Vol 24 (22) ◽  
pp. 12842-12848 ◽  
Author(s):  
Pushkar P. Lele ◽  
Manish Mittal ◽  
Eric M. Furst
Keyword(s):  
Electric Fields ◽  
Particle Rotation ◽  
Ac Electric Fields ◽  
Anomalous Particle
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