Electrochemical Principles for Active Control of Liquids on Submillimeter Scales

Gallardo, Benedict S.; Gupta, Vinay; Eagerton, Franklin D.; Jong, Lana I.; Craig, Vincent S. J.; Shah, Rahul R.; Abbott, Nicholas L.

doi:10.1126/science.283.5398.57

Cited by 432 publications

(323 citation statements)

References 32 publications

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“…Because each droplet can be independently controlled, highly integrated, scalable and flexible architectures can be implemented. 10 A number of techniques have been described for the actuation of droplets on solid surfaces including the use of thermocapillary effects, 14 photochemical effects, 15 electrochemical gradients, 16 surface tension gradients, 17 temperature gradients, 18 air pressure, 19 structured surfaces, 20 dielectrophoresis, 21 and electrostatic methods. 8 An extension of this approach is a liquid-liquid microfluidic system for manipulating freely suspended microliter or nanoliter droplets.…”

Section: Introductionmentioning

confidence: 99%

Local Heating of Discrete Droplets Using Magnetic Porous Silicon-Based Photonic Crystals

et al. 2006

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This paper describes a method for local heating of discrete micro-liter scale liquid droplets. The droplets are covered with magnetic porous Si microparticles, and heating is achieved by application of an external alternating electromagnetic field. The magnetic porous Si microparticles consist of two layers: the top layer contains a photonic code and it is hydrophobic, with surfacegrafted dodecyl moieties. The bottom layer consists of a hydrophilic Si oxide host layer that is infused with Fe 3 O 4 nanoparticles. The amphiphilic microparticles spontaneously align at the interface of a water droplet immersed in mineral oil, allowing manipulation of the droplets by application of a magnetic field. Application of an oscillating magnetic field (338 kHz, 18A RMS current in a coil surrounding the experiment) generates heat in the superparamagnetic particles that can raise the temperature of the enclosed water droplet to >80 °C within 5 min.A simple microfluidics application is demonstrated: combining complementary DNA strands contained in separate droplets and then thermally inducing dehybridization of the conjugate. The complementary oligonucleotides were conjugated with the cyanine dye fluorophores Cy3 and Cy5 to quantify the melting/re-binding reaction by fluorescence resonance energy transfer (FRET). The magnetic porous Si microparticles were prepared as photonic crystals, containing spectral codes that allowed the identification of the droplets by reflectivity spectroscopy. The technique demonstrates the feasibility of tagging, manipulating, and heating small volumes of liquids without the use of conventional microfluidic channel and heating systems.

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Section: Introductionmentioning

confidence: 99%

Local Heating of Discrete Droplets Using Magnetic Porous Silicon-Based Photonic Crystals

et al. 2006

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“…As a ubiquitous phenomenon in nature, droplet motion on solid substrates has attracted great attention for decades because of the fundamental physics involved [1][2][3][4][5][6][7][8][9][10] and its relevance to a wide range of applications in chemistry, biology, and industry [11][12][13][14][15]. Though there has been extensive work on the subject, many aspects of this seemingly simple phenomenon remain issues of interest to fundamental research.…”

Section: Introductionmentioning

confidence: 99%

Thermal singularity and droplet motion in one-component fluids on solid substrates with thermal gradients

Qian

2012

Phys. Rev. E

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Using a continuum model capable of describing the one-component liquid-gas hydrodynamics down to the contact line scale, we carry out numerical simulation and physical analysis for the droplet motion driven by thermal singularity. For liquid droplets in one-component fluids on heated or cooled substrates, the liquid-gas interface is nearly isothermal. Consequently, a thermal singularity occurs at the contact line and the Marangoni effect due to temperature gradient is suppressed. Through evaporation or condensation in the vicinity of the contact line, the thermal singularity makes the contact angle increase with the increasing substrate temperature. This effect on the contact angle can be used to move the droplets on substrates with thermal gradients. Our numerical results for this kind of droplet motion are explained by a simple fluid dynamical model at the droplet length scale. Since the mechanism for droplet motion is based on the change of contact angle, a separation of length scales is exhibited through a comparison between the droplet motion induced by a wettability gradient and that by a thermal gradient. It is shown that the flow field at the droplet length scale is independent of the statics or dynamics at the contact line scale.

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“…A number of methods for manipulating microfluidic droplets have been proposed in the literature [13][14][15]. Of these, electrical methods to actuate droplets appear to be the most promising [8,9,19].…”

Section: Droplet-based Microfluidicsmentioning

confidence: 99%

Automated Design of Microfluidics-Based Biochips: Connecting Biochemistry to Electronics CAD

Chakrabarty

2006

2006 International Conference on Computer Design

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Electrochemical Principles for Active Control of Liquids on Submillimeter Scales

Cited by 432 publications

References 32 publications

Local Heating of Discrete Droplets Using Magnetic Porous Silicon-Based Photonic Crystals

Local Heating of Discrete Droplets Using Magnetic Porous Silicon-Based Photonic Crystals

Thermal singularity and droplet motion in one-component fluids on solid substrates with thermal gradients

Automated Design of Microfluidics-Based Biochips: Connecting Biochemistry to Electronics CAD

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