Electrohydrodynamics of yeast cells in microchannels subjected to travelling electric fields

Nudurupati, Sai; Aubry, Nadine; Singh, Pushpendra

doi:10.1088/0022-3727/39/15/030

Cited by 13 publications

(9 citation statements)

References 33 publications

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“…For certain applications (e.g., mixing), it may be advantageous to use a combination of rotation (rather than translation) and deformation, or even translation, rotation, and deformation. Such combinations should be enabled by the phenomenon of traveling wave dielectrophoresis whose effect on solid particles has been recently studied numerically [43,44].…”

Section: Discussionmentioning

confidence: 99%

Transport and deformation of droplets in a microdevice using dielectrophoresis

Singh¹,

Aubry²

2007

Electrophoresis

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In microfluidic devices the fluid can be manipulated either as continuous streams or droplets. The latter is particularly attractive as individual droplets can not only move but also split and fuse, thus offering great flexibility for applications such as laboratory-on-a-chip. We consider the transport of liquid drops immersed in a surrounding liquid by means of the dielectrophoretic force generated by electrodes mounted at the bottom of a microdevice. The direct numerical simulation (DNS) approach is used to study the motion of droplets subjected to both hydrodynamic and electrostatic forces. Our technique is based on a finite element scheme using the fundamental equations of motion for both the droplets and surrounding fluid. The interface is tracked by the level set method and the electrostatic forces are computed using the Maxwell stress tensor. The DNS results show that the droplets move, and deform, under the action of nonuniform electric stresses on their surfaces. The deformation increases as the drop moves closer to the electrodes. The extent to which the isolated drops deform depends on the electric Weber number. When the electric Weber number is small, the drops remain spherical; otherwise, the drops stretch. Two droplets, however, that are sufficiently close to each other, can deform and coalesce, even if the electric Weber number is small. This phenomenon does not rely on the magnitude of the electric stresses generated by the bulk electric field, but instead is due to the attractive electrostatic drop-drop interaction overcoming the surface tension force. Experimental results are also presented and found to be in agreement with the DNS results.

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Section: Discussionmentioning

confidence: 99%

Transport and deformation of droplets in a microdevice using dielectrophoresis

Singh¹,

Aubry²

2007

Electrophoresis

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“…From late 1980s, several groups of scientists from Europe have conducted intensive investigations on twDEP both theoretically by analytical and numerical solutions (Wang et al 1994;Hughes et al 1996;Morgan et al 2001;Green et al 2002) and experimentally for biological applications (Huang et al 1993;Wang et al 1997;Goater et al 1997;Morgan et al 1997;De Gasperis et al 1999;Cui and Morgan 2000;Gascoyne et al 2002;Cui et al 2002;Pethig et al 2003Pethig et al , 2004. Subsequent works by more researchers in recent years have been focused on modeling and developing more complex twDEP systems and applications (Du et al 2004;Aubry and Singh 2006;Nudurupati et al 2006;Song and Fig. 26 Device structure used in image DEP.…”

Section: Travelling Wave-depmentioning

confidence: 99%

Electrokinetic motion of particles and cells in microchannels

Kang

2009

Microfluid Nanofluid

187

135

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This paper provides an overview of the electrokinetic phenomena associated with particles and cells in microchannel systems. The most important phenomena covered include electrophoresis, dielectrophoresis, and induced-charge electrokinetics. The latest development of these electrokinetic techniques for particle or cell manipulations in microfluidic systems is reviewed, in terms of the basic theories, mathematical models, numerical and experimental methods, and the key results/findings from the published literatures in the most recent decades. Some of the limitations associated with the negative field effects are discussed and the perspectives for the future investigations are summarized.

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“…Similar interactions take place between particles in a nonuniform electric field [27,30,31]. Direct numerical simulations (DNS) conducted using this expression for the interaction force show that two particles subjected to a nonuniform electric field attract each other and orient such that the line joining their centers is parallel to the local electric field direction while they move together toward the location where the electric field strength is locally maximal or minimal, depending on the value of their dielectric constant relative to that of the two fluids [32][33][34]. The extent of this attraction, which, if it is strong, manifests itself in particle chaining, depends on a dimensionless parameter which can also be found in the above references.…”

Section: Dep Forces On Particlesmentioning

confidence: 99%

Concentrating particles on drop surfaces using external electric fields

et al. 2008

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We propose to use an externally applied uniform electric field to alter the distribution of particles on the surface of a drop immersed in another immiscible liquid. Specifically, we seek to generate well-defined concentrated regions at the drop surface while leaving the rest of the surface particle free. Experiments show that when the dielectric constant of the drop is greater than that of the ambient liquid the particles for which the Clausius-Mossotti factor is positive move along the drop surface to the two poles of the drop. Particles with a negative Clausius-Mossotti factor, on the other hand, move along the drop surface to form a ring near the drop equator. The opposite takes place when the dielectric constant of the drop is smaller than that of the ambient liquid, namely particles for which the Clausius-Mossotti factor is positive form a ring near the equator while those for which such a factor is negative move to the poles. This motion is due to the dielectrophoretic force that acts upon particles because the electric field on the surface of the drop is nonuniform, despite the uniformity of the applied electric field. Experiments also show that when small particles collect at the poles of a deformed drop the electric field needed to break the drop is smaller than without particles. These phenomena could be useful to concentrate particles at a drop surface within well-defined regions (poles and equator), separate two types of particles at the surface of a drop or increase the drop deformation to accelerate drop breakup.

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Electrohydrodynamics of yeast cells in microchannels subjected to travelling electric fields

Cited by 13 publications

References 33 publications

Transport and deformation of droplets in a microdevice using dielectrophoresis

Transport and deformation of droplets in a microdevice using dielectrophoresis

Electrokinetic motion of particles and cells in microchannels

Concentrating particles on drop surfaces using external electric fields

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