The Influence of Stern Layer Conductance on the Dielectrophoretic Behavior of Latex Nanospheres

Hughes, Michael; Green, Nicolas G.

doi:10.1006/jcis.2002.8324

Cited by 20 publications

(23 citation statements)

References 10 publications

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“…Counterions are more mobile in the diffuse layer than in the Stern layer, and contribute separately to the overall magnitude of K s and thus to the DEP behavior of nanoparticles. [28][29][30][31] A comprehensive study of the ac and dc electrokinetic properties of latex nanoparticles, as a function of suspending medium conductivity and viscosity, has been reported by Ermolina and Morgan, 32 and a theoretical modeling of the DEP force that takes into account the influence of the electrical double layer has been presented by Zhou et al 33 Analysis of the normal and tangential ionic currents that occur around and at the surface of a particle, when its diameter approaches and becomes smaller than the width of its own electrical double layer, indicates that a capacitance effect contributes to the total polarizability of the particle, and exceeds the influence of the surface conductance K s . 34,35 Basuray and Chang 34 also showed that the DEP cross-over frequency for nanocolloids is inversely proportional to the RC time constant of the diffuse layer component of the electrical double layer.…”

Section: ͑15͒mentioning

confidence: 99%

Review Article—Dielectrophoresis: Status of the theory, technology, and applications

2010

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A review is presented of the present status of the theory, the developed technology and the current applications of dielectrophoresis ͑DEP͒. Over the past 10 years around 2000 publications have addressed these three aspects, and current trends suggest that the theory and technology have matured sufficiently for most effort to now be directed towards applying DEP to unmet needs in such areas as biosensors, cell therapeutics, drug discovery, medical diagnostics, microfluidics, nanoassembly, and particle filtration. The dipole approximation to describe the DEP force acting on a particle subjected to a nonuniform electric field has evolved to include multipole contributions, the perturbing effects arising from interactions with other cells and boundary surfaces, and the influence of electrical double-layer polarizations that must be considered for nanoparticles. Theoretical modelling of the electric field gradients generated by different electrode designs has also reached an advanced state. Advances in the technology include the development of sophisticated electrode designs, along with the introduction of new materials ͑e.g., silicone polymers, dry film resist͒ and methods for fabricating the electrodes and microfluidics of DEP devices ͑photo and electron beam lithography, laser ablation, thin film techniques, CMOS technology͒. Around three-quarters of the 300 or so scientific publications now being published each year on DEP are directed towards practical applications, and this is matched with an increasing number of patent applications. A summary of the US patents granted since January 2005 is given, along with an outline of the small number of perceived industrial applications ͑e.g., mineral separation, micropolishing, manipulation and dispensing of fluid droplets, manipulation and assembly of micro components͒. The technology has also advanced sufficiently for DEP to be used as a tool to manipulate nanoparticles ͑e.g., carbon nanotubes, nano wires, gold and metal oxide nanoparticles͒ for the fabrication of devices and sensors. Most efforts are now being directed towards biomedical applications, such as the spatial manipulation and selective separation/enrichment of target cells or bacteria, high-throughput molecular screening, biosensors, immunoassays, and the artificial engineering of three-dimensional cell constructs. DEP is able to manipulate and sort cells without the need for biochemical labels or other bioengineered tags, and without contact to any surfaces. This opens up potentially important applications of DEP as a tool to address an unmet need in stem cell research and therapy.

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Section: ͑15͒mentioning

confidence: 99%

Review Article—Dielectrophoresis: Status of the theory, technology, and applications

2010

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“…Neglecting contributions from the diffusion layer, the total surface conductance of the particle can be modelled as the sum of the Stern layer and diffuse layer conductance [7]. Using this approach, it has been possible to fit dielectrophoretic cross-over data for nanometre-scale latex particles measured at different suspending medium conductivities [27,29,30].…”

Section: Introductionmentioning

confidence: 99%

“…The mobility of the ions that give rise to surface conductance behind the shear plane is unknown, but experiments have shown that it is close to that of the ions in the bulk [7,8,21,30,31]. Therefore, in order to investigate the role of the Stern layer in determining the DEP properties of particles, we also measured the dielectrophoretic cross-over data of latex particles in suspending media of different viscosities.…”

Section: Introductionmentioning

confidence: 99%

The electrokinetic properties of latex particles: comparison of electrophoresis and dielectrophoresis

Ermolina

Morgan

2005

Journal of Colloid and Interface Science

223

255

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A comprehensive study of the AC and DC electrokinetic properties of submicrometre latex particles as a function of particle size and suspending medium conductivity and viscosity is presented. Electrophoretic mobility and dielectrophoretic cross-over results were measured for particle diameters ranging from 44 to 2000 nm. The zeta potentials of the particles were calculated from the electrophoretic mobility data for different suspending medium conductivities, using various models, with and without the inclusion of surface conduction. The dielectrophoretic data was analysed to derive values for the Stern layer conductance and zeta potentials.  2004 Elsevier Inc. All rights reserved.

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“…33 These surface layers have a distinct dielectric behavior which is important in dielectrophoresis. 3,34,35 These induced charges alter the net polarization of a dielectric object. This effect is not treated in this work but has to be considered in an application where a dielectric is surrounded by water.…”

Section: Polarization Forces In Dielectric Materialsmentioning

confidence: 99%

Modeling the Kelvin polarization force actuation of micro- and nanomechanical systems

Schmid

Hierold

Boisen

2010

Journal of Applied Physics

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Polarization forces have become of high interest in micro-and nanomechanical systems. In this paper, an analytical model for a transduction scheme based on the Kelvin polarization force is presented. A dielectric beam is actuated by placing it over the gap of two coplanar electrodes. Finite element method simulations are used to characterize the scheme and to evaluate a field correction factor, which results from simplifying the form of the electric field. The model has been shown to be valid for dielectrics with different permittivities. The presented model facilitates the design of microresonators and nanoresonators with dielectric actuation, which offers a great freedom in the choice of structural material.

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The Influence of Stern Layer Conductance on the Dielectrophoretic Behavior of Latex Nanospheres

Cited by 20 publications

References 10 publications

Review Article—Dielectrophoresis: Status of the theory, technology, and applications

Review Article—Dielectrophoresis: Status of the theory, technology, and applications

The electrokinetic properties of latex particles: comparison of electrophoresis and dielectrophoresis

Modeling the Kelvin polarization force actuation of micro- and nanomechanical systems

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