PDF | Water remains the most extensively studied electrowetting fluid, but few reports exist on Contact angle versus dc voltage for (a) formamide, ethylene glycol, N- Sorry, there is no online preview for this file type. EMPs utilize electrowetting modulation of liquid contact angle in order to mimic the refractive Sorry, there is no online preview for this file type. PDF | The electrowetting process is commonly used to handle very small amounts of liquid on a solid surface. Sorry, there is no online preview for this file type. Capillary surfaces [15, 26] of variable contact angle, e.g., not equal to
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A simple and efficient device for density-based particle sorting is in high demand for the purification of specific cells, bacterium, or environmental particles for medical, biochemical, and industrial applications.
Here we present microfluidic systems to achieve size- and density-based particle separation by adopting the sedimentation effect for a size-based particle sorting technique utilizing microscale hydrodynamics, called pinched-flow fractionation PFF. Two schemes are presented: This article introduces a novel magnetic bead-based DNA extraction and purification device using active magnetic mixing approach.
Mixing and separation steps are performed using functionalised superparamagnetic beads suspended in cell lysis buffer in a circular chamber that is sandwiched between two external magnetic coils. Non-uniform nature of magnetic field causes temporal and spatial distribution of beads within the chamber. This process efficiently mixes the lysis buffer and whole blood in order to extract DNA from target cells. Functionalized surface of the This paper reports both experimental and numerical investigations of the formation process of ferrofluid droplets in a flow focusing configuration with and without an applied magnetic field.
In the experiment, the homogenous magnetic field was generated using an electromagnet. The magnetic field in the flow direction affects the formation process and changes the size of the droplets. The change in the droplet size depends on the magnetic field strength and the flow rates.
A numerical model was used to investigate the Solute deposition patterns of peptides are studied on dried droplet deposits from engineered droplet shapes using surface assisted laser desorption ionization mass spectrometric imaging. Strong pinning of the contact line to the edges of the hydrophilic area causes the solutes to deposit mostly to the perimeter of the hydrophilic area on simple circular and square shaped spots.
More complex geometries resulted in unique deposition patterns, showing potential for spotting and chemical The simulated results confirm This work demonstrates an optofluidic system, where dielectrophoretically controlled suspended nanoparticles are used to manipulate the properties of an optical waveguide.
This optofluidic device is composed of a multimode polymeric rib waveguide and a microfluidic channel as its upper cladding. This channel integrates dielectrophoretic DEP microelectrodes and is infiltrated with suspended silica and tungsten trioxide nanoparticles.
By applying electrical signals with various intensities and frequencies to the DEP microelectrodes, the nanoparticles can be concentrated close to the waveguide surface significantly altering Even at low Reynolds numbers, momentum can impact the shape of hydrodynamically focused flow. A series of symmetric and asymmetric microfluidic channels with two converging streams were fabricated with different angles of confluence at the junction.
The channels were used to study the characteristics of Y-type microchannels for flow-focusing.
CiteULike: Microfluidics and Nanofluidics (Online First™)
Computational analysis and experimental results gathered We demonstrate a robust method to produce monodisperse femtoliter to attoliter droplets by using a nano-microfluidic device. Two immiscible liquids are forced through a nanochannel where a steady nanoscopic liquid filament forms, thinning close to the nanochannel exit to a microchannel due to the capillary focusing.
When the nanoscopic filament enters the microchannel, monodisperse droplets are formed by capillary instability. In a certain range of physical parameters and geometrical configurations, the droplet size is only determined by the nanochannel height and The internal motions inside a liquid meniscus in the so-called liquid cone-jet mode, which can occur upon stimulation by a coflowing gas sheath in flow focusing, are explored by both numerical simulation and experimental visualization.
The results for low viscosity liquids show that, as in previous numerical simulations, a recirculating cell inside the meniscus appears when the injected liquid flow rate is reduced.
Thus, as the flow rate is reduced not only the average residence time of particles in the meniscus The tangential momentum accommodation coefficient TMAC was investigated experimentally from the mass flow rate through a single microtube under the slip flow and the early part of the transition regime. The measurements were carried out by the constant-volume method under the mean Knudsen number smaller than 0.
To measure TMACs on various materials, quite large microtube was employed, We present a microfluidic network-based combinatorial dilution device to generate on-demand combinatorial dilutions of all input samples in the range of a 3D simplex-centroid. The device consists of an initial concentration control module and a combinatorial dilution module. In the initial concentration control module, the concept of using a single common channel has been incorporated to generate desirable concentrations of each sample, diluted independently in response to variable input flow.
Then, the diluted samples flow into the combinatorial dilution module to Microfluidic technologies are gaining elwctrowetting importance due to their capability of manipulating fluids at the microscale that should allow to synthesize many products with surprisingly high yields and short reaction times.
In the lab-on-chip field researchers have developed microfluidic apparatuses to provide special equipments for producing positron emission tomography PET radiopharmaceuticals in a quicker, safer, and more reliable way compared to traditional vessel-based approaches. A chemically powered channelless microfluidic device was designed, fabricated, and characterized. The device consists of an asymmetric silver—gold bimetallic catalytic junction fabricated on a silicon dioxide surface.
The decomposition of hydrogen peroxide at the silver—gold interface generates a proton gradient and an associated electric field which in turn drives electroosmosis and electrophoresis when a charged particle is present in the vicinity of the field. By engineering an asymmetric device consisting of an isolated junction, continuous electroosmotic fluid flow across the device The effects of rib-patterned surfaces and surface wettability on liquid flow in microchannels were experimentally investigated in this study.
Microchannels were fabricated on single-crystal silicon wafers by photolithographic and wet-etching techniques. Rib structures were patterned in the silicon microchannel, and filwtype surface was chemically treated filetyp trichlorosilane to create hydrophobic condition. Experiments with water as the working fluid were performed with these microchannels over a wide range of Reynolds numbers between and The results for the wlectrowetting microchannels showed This paper reports the findings of a numerical investigation on the droplet break-up in a microfluidic T-junction.
The numerical flow visualization of the droplet formation process is validated with the experimental flow visualization. From the computational results, we show that the pressure profile of the dispersed phase and the continuous phase in the squeezing regime changes as the droplet break-up process proceeds.
The assumption taken by other researchers that the dispersed phase pressure profile, during the droplet formation process at a It is found that the motions of water molecules inside the CNTs of diameter smaller than Initially, the water diffusion exhibits a long-time super- or sub-diffusion mechanism, and thereafter it transits to the single-file type inside the 6, 6 CNT and shifts to the Fickian type inside the larger CNTs.
Although several applications of electrowetting on dielectric digital lab-on-a-chips are reported in literature, there is still a lack of knowledge about the influence of operational and design parameters on the performance of an analytical assay.
This paper investigates how droplet size variability, introduced by droplet dispensing and splitting, influences the assay performance with respect to repeatability and accuracy and presents a novel method to reduce this variability. Both a theoretical and experimental approach were followed. Monte Carlo simulations were applied to The motion of the magnetic bead was simulated based on Lagrangian tracking method and the separation efficiency was calculated according to the trajectories.
Impact parameters including geometrical configuration, fluid velocity, magnetic flux density, magnetic bead size, and temperature on separation efficiency were discussed. The results show that both the L- and T-microchannel Ethanol consumption is associated with the risk of breast cancer progression; however, the mechanism of relationship has not yet been fully explained. Research on breast cancer cell migration after ethanol stimulation may give hope for a better understanding of the disease and oncotherapy.
Conventional cell migration assays such as Boyden chamber and wound-healing assays are easy to conduct for this purpose; however, these assays have inherent limitations. In this study, we quantified the effect of ethanol on MCF-7 hunam breast cancer This study describes an analytical model and experimental verifications of transport of non-magnetic spherical microparticles in ferrofluids in a microfluidic system that consists of a microchannel and a permanent magnet.
The permanent magnet produces a spatially non-uniform magnetic field that gives rise to a magnetic buoyancy force on particles within ferrofluid-filled microchannel. We obtained trajectories of particles in the ciletype by 1 calculating magnetic buoyancy force through the use of an analytical expression of magnetic field distributions and a nonlinear magnetization A low voltage electroosmotic eo pump suitable for high density fieltype into microfabricated fluidic systems has been developed.
The high density integration of the eo pump required a small footprint as well as a specific on-chip design to ventilate the electrolyzed gases emerging at the platinum Pt electrodes. For this purpose, a novel liquid—gas lg separator was invented. This lg-separator separated the gas bubbles from the liquid and guided them away from the electroweetting pump.
Electrowetting of a 3D drop: numerical modelling with electrostatic vector fields
Its operational principle was solely based Microscale bioparticle analysis has advanced significantly providing advantages over bench-scale studies such as the use of a reduced amount of sample and reagents, higher sensitivity, faster response, and portability. Insulator-based dielectrophoresis iDEP is a microscale technique where particles are driven by polarization effects under a non-uniform electrical field created by the inclusion of insulators between two electrodes.
We present a new method for aliquoting liquids on the centrifugal microfluidic platform. Our method is a two-stage process with an initial metering phase and a subsequent transport phase initiated by switching a centrifugo-pneumatic valve. The method enables aliquoting liquids into completely separated reaction cavities. It includes precise metering that is An excimer laser incorporating a reconfigurable intelligent pinhole mask IPM is demonstrated for the fabrication of microfluidic geometries on a poly methyl methacrylate substrate.
Beam reconfiguration techniques are used to overcome some of the drawbacks associated with traditional scanning laser ablation through a static mask.
The production of zero lead-in ZLI features are described, where the ramp lead-in angle—inherent to scanning laser ablation—is reduced to be in line with the cross-sectional side-wall angle of the microchannel itself.
The technique is applied to An acoustically activated micropump is fabricated and demonstrated using a single step lithography process and an off-chip acoustic energy source. Using angled lateral cavities with trapped air bubbles, acoustic energy is used to oscillate the liquid—air interface to create a fluidic driving force.
The angled lateral cavity design allows for fluid rectification from the first-order pulsatile flow of the oscillating bubbles. The fluid rectification is achieved through the asymmetrical flow produced by the oscillating interface generating fluid flow away from the The dynamic contact line behavior of water on nanotextured rough hydrophobic and superhydrophobic surfaces is studied and contrasted to smooth hydrophobic surfaces for application in immersion lithography.
This unexpected increase in critical velocity is observed for both sticky We present a simple, versatile method for the in-situ fabrication of membranes inside a microfluidic channel during a chip manufacturing process using only two extra slanted angle holographic exposure steps. This method combines the strengths of both inclined UV exposure and holographic lithography to produce micrometer-sized three-dimensional sieving structures.
Using a common chip material, the photoresist material SU-8, together with this method, a leak-free membrane-channel connection is obtained.