Liquid dielectrophoresis and surface microfluidics

Kaler, K.V.I.S.; Prakash, Ravi; Chugh, Dipankar

doi:10.1063/1.3411003

Cited by 44 publications

(39 citation statements)

References 34 publications

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“…9 For example, precise control of droplet motion/manipulation via external electric fields has been employed in works. 4,5,10 a Author to whom correspondence should be addressed. Electronic mail: pribylm@vscht.cz, Tel.…”

Section: Introductionmentioning

confidence: 99%

“…Various methods of complex liquid and particle treatment such as AC and DC electroosmosis, 1, 2 electrophoresis, 3 dielectrophoresis, 4 digital addressing, 5 electrocoalescence 6 or electrochemical sensing 7 are driven by external electric fields imposed on specific parts of the microfluidic systems. For example, charged water droplets dispersed in an oil phase can be addressed by means of DC electric field into specific parts of a microfluidic structure.…”

Section: Introductionmentioning

confidence: 99%

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Oscillatory motion of water droplets in kerosene above co-planar electrodes in microfluidic chips

et al. 2014

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We experimentally observed oscillatory motion of water droplets in microfluidic systems with coplanar microelectrodes under imposed DC electric fields. Two-electrode arrangement with no bipolar electrode and eight-electrode arrangement with six bipolar microelectrodes were investigated. Kerosene was used as the continuous phase. We studied the dependences of the oscillation frequency on the electric field intensity and ionic strength of the water phase. We found that the electric field dependence is strongly nonlinear and discussed possible reasons of this phenomenon, e.g., the droplet deformation at electrode edges that affects the charge transfer between the electrode and droplet or the interplay between the Coulomb force on free charge and the dielectrophoretic force. Our experiments further revealed that the oscillation frequency decreases with growing salt concentration in the two-electrode arrangement, but increases in the eight-electrode arrangement, which was attributed to surface tension related processes and electrochemical processes on the bipolar electrodes. Finally, we analyzed the effects of the electric field on the oscillatory motion by means of a simplified mathematical model. It was shown that the electric force imposed on the droplet charge is the key factor to induce the oscillations and the dielectrophoretic force significantly contributes to the momentum transfer at the electrode edges. For the same electric field strength, the model is able to predict the same oscillation frequency as that observed in the experiments.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oscillatory motion of water droplets in kerosene above co-planar electrodes in microfluidic chips

et al. 2014

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“…Figure 3a shows the continuous, bi-directional actuation of a 10 μL PCR droplet following the EW based dispensing and mixing. The electrostatic/D-DEP actuation [11,23,24] is facilitated by an AC voltage (50-60 Vpp, 40 Hz), applied across a pair of herringbone electrodes upon which the droplet is electrically confined and transported. The droplet track is switched with a 50 V DC voltage applied across the top and bottom herringbone electrode pair to facilitate droplet transfer between the two temperature zones.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, our work has demonstrated that a continuous droplet transport scheme, which enables droplet transport and thermal cycling without the requirement of active electrode switching [11], can be an effective solution for a PCR micro-device with reduced electrical overhead requirement for a multiplexed diagnosis system. Here active droplet transport is facilitated by electrostatic or, droplet-dielectrophoresis (D-DEP) based electro-actuation technique, which utilizes herring-bone shaped electrode arrays to facilitate droplet transport and thermal cycling [11,23,24].…”

Section: Introductionmentioning

confidence: 99%

Multiplex, Quantitative, Reverse Transcription PCR Detection of Influenza Viruses Using Droplet Microfluidic Technology

Prakash

Wong

et al. 2014

Micromachines

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Quantitative, reverse transcription, polymerase chain reaction (qRT-PCR) is facilitated by leveraging droplet microfluidic (DMF) system, which due to its precision dispensing and sample handling capabilities at microliter and lower volumes has emerged as a popular method for miniaturization of the PCR platform. This work substantially improves and extends the functional capabilities of our previously demonstrated single qRT-PCR micro-chip, which utilized a combination of electrostatic and electrowetting droplet actuation. In the reported work we illustrate a spatially multiplexed micro-device that is capable of conducting up to eight parallel, real-time PCR reactions per usage, with adjustable control on the PCR thermal cycling parameters (both process time and temperature set-points). This micro-device has been utilized to detect and quantify the presence of two clinically relevant respiratory viruses, Influenza A and Influenza B, in human samples (nasopharyngeal swabs, throat swabs). The device performed accurate detection and quantification of the two respiratory viruses, over several orders of RNA copy counts, in unknown (blind) panels of extracted patient samples with acceptably high PCR efficiency (>94%). The multi-stage qRT-PCR assays on eight panel patient samples OPEN ACCESSMicromachines 2015, 6 64 were accomplished within 35-40 min, with a detection limit for the target Influenza virus RNAs estimated to be less than 10 RNA copies per reaction.

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“…The electrodes create a non-uniform electrical field under AC voltage and the DEP force attracts the polarizable liquid into regions of higher electrical field. One of the identified issues related to LDEP actuation is the required actuation voltage which is usually above 200 V RMS for a single-plate open microfluidic device, together with a frequency range of 1 kHz to 1 MHz [18][19][20]. Such high voltages may lead to the chip dielectric layer breakdown and liquid electrolysis.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Liquid DiElectroPhoresis (LDEP) Digital Microfluidic Transduction for Biomedical Applications

et al. 2011

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Digital microfluidic has recently been under intensive study, as an effective method to carry out liquid manipulation in Lab-On-a-Chip (LOC) systems. Among droplet actuation forces, ElectroWetting on Dielectric (EWOD) and Liquid DiElectroPhoresis (LDEP) are powerful tools, used in many LOC platforms. Such digital microfluidic transductions do not require integration of complex mechanical components such as pumps and valves to perform the fluidic operations. However, although LDEP has been proved to be efficient to carry and manipulate biological components in insulating liquids, this microfluidic transduction requires several hundreds of volts at relatively high frequencies (kHz to MHz). With the purpose to develop integrated microsystems µ-TAS (Micro Total Analysis System) or Point of Care systems, the goal here is to reduce such high actuation voltage, the power consumption, though using standard dielectric materials. This paper gives key rules to determine the best tradeoff between liquid manipulation efficiency, low-power consumption and robustness of microsystems using LDEP actuation. This study leans on an electromechanical model to describe liquid manipulation that is applied to an experimental setup, and provides precise quantification of both actuation voltage V th and OPEN ACCESSMicromachines 2011, 2 259 frequency f c thresholds between EWOD and LDEP regimes. In particular, several parameters will be investigated to quantify V th and f c , such as the influence of the chip materials, the electrodes size and the device configurations. Compared to current studies in the field, significant reduction of both V th and f c is achieved by optimization of the aforementioned parameters.

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Liquid dielectrophoresis and surface microfluidics

Cited by 44 publications

References 34 publications

Oscillatory motion of water droplets in kerosene above co-planar electrodes in microfluidic chips

Oscillatory motion of water droplets in kerosene above co-planar electrodes in microfluidic chips

Multiplex, Quantitative, Reverse Transcription PCR Detection of Influenza Viruses Using Droplet Microfluidic Technology

Optimization of Liquid DiElectroPhoresis (LDEP) Digital Microfluidic Transduction for Biomedical Applications

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