Dielectrophoresis for the manipulation of nanobioparticles

Lapizco‐Encinas, Blanca H.; Rito‐Palomares, Marco

doi:10.1002/elps.200700303

Cited by 191 publications

(180 citation statements)

References 59 publications

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“…As a versatile tool, dielectrophoresis (DEP) has been widely used to focus, trap, concentrate and separate cells, viruses, and biomolecules in microfluidic devices for various lab-ona-chip applications [1][2][3]. DEP refers to the induced motion of particles (either charged or non-charged) in a nonuniform electric field [4].…”

Section: Introductionmentioning

confidence: 99%

Joule heating effects on electroosmotic flow in insulator‐based dielectrophoresis

et al. 2011

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Joule heating effects on electroosmotic flow in insulator-based dielectrophoresisInsulator-based dielectrophoresis (iDEP) is an emerging technology that has been successfully used to manipulate a variety of particles in microfluidic devices. However, due to the locally amplified electric field around the in-channel insulator, Joule heating often becomes an unavoidable issue that may disturb the electroosmotic flow and affect the particle motion. This work presents the first experimental study of Joule heating effects on electroosmotic flow in a typical iDEP device, e.g. a constriction microchannel, under DC-biased AC voltages. A numerical model is also developed to simulate the observed flow pattern by solving the coupled electric, energy, and fluid equations in a simplified two-dimensional geometry. It is observed that depending on the magnitude of the DC voltage, a pair of counter-rotating fluid circulations can occur at either the downstream end alone or each end of the channel constriction. Moreover, the pair at the downstream end appears larger in size than that at the upstream end due to DC electroosmotic flow. These fluid circulations, which are reasonably simulated by the numerical model, form as a result of the action of the electric field on Joule heatinginduced fluid inhomogeneities in the constriction region.

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Section: Introductionmentioning

confidence: 99%

Joule heating effects on electroosmotic flow in insulator‐based dielectrophoresis

et al. 2011

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“…The ability to selectively manipulate bio-particles such as cells, 1 DNA, 2 and proteins, 3 as well as nanomaterials, such as nanofibers, 4 nanotubes, 5 and nanowires 6 at localized fluid/device interfaces, within media of a wide range of conductivity, is fundamental to many applications in biomedicine and nanofabrication. Electrokinetic methodologies are uniquely poised for particle manipulation, 7 since they are based on the inherent charge distributions within the manipulated materials, their scaling laws are highly compatible with microfluidic systems, and their instrumentation is relatively simple to assemble.…”

Section: Introductionmentioning

confidence: 99%

Floating-electrode enhanced constriction dielectrophoresis for biomolecular trapping in physiological media of high conductivity

et al. 2012

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We present an electrokinetic framework for designing insulator constriction-based dielectrophoresis devices with enhanced ability to trap nanoscale biomolecules in physiological media of high conductivity, through coupling short-range dielectrophoresis forces with long-range electrothermal flow. While a 500-fold constriction enables field focusing sufficient to trap nanoscale biomolecules by dielectrophoresis, the extent of this high-field region is enhanced through coupling the constriction to an electrically floating sensor electrode at the constriction floor. However, the enhanced localized fields due to the constriction and enhanced current within saline media of high conductivity (1 S/m) cause a rise in temperature due to Joule heating, resulting in a hotspot region midway within the channel depth at the constriction center, with temperatures of $8 -10 K above the ambient. While the resulting vortices from electrothermal flow are directed away from the hotspot region to oppose dielectrophoretic trapping, they also cause a downward and inward flow towards the electrode edges at the constriction floor. This assists biomolecular trapping at the sensor electrode through enabling long-range fluid sampling as well as through localized stirring by fluid circulation in its vicinity.

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“…24,25 Indeed, classical DEP theory for homogeneous particles in solution predicts that extremely high field gradients are necessary to achieve DEP forces significant for manipulation of biomolecules a few nm in size. However, the manipulation of proteins by DEP has recently been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Tuning direct current streaming dielectrophoresis of proteins

et al. 2012

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Dielectrophoresis (DEP) of biomolecules has large potential to serve as a novel selectivity parameter for bioanalytical methods such as (pre)concentration, fractionation, and separation. However, in contrast to well-characterized biological cells and (nano)particles, the mechanism of protein DEP is poorly understood, limiting bioanalytical applications for proteins. Here, we demonstrate a detailed investigation of factors influencing DEP of diagnostically relevant immunoglobulin G (IgG) molecules using insulator-based DEP (iDEP) under DC conditions. We found that the pH range in which concentration of IgG due to streaming iDEP occurs without aggregate formation matches the pH range suitable for immunoreactions. Numerical simulations of the electrokinetic factors pertaining to DEP streaming in this range further suggested that the protein charge and electroosmotic flow significantly influence iDEP streaming. These predictions are in accordance with the experimentally observed pH-dependent iDEP streaming profiles as well as the determined IgG molecular properties. Moreover, we observed a transition in the streaming behavior caused by a change from positive to negative DEP induced through micelle formation for the first time experimentally, which is in excellent qualitative agreement with numerical simulations. Our study thus relates molecular immunoglobulin properties to observed iDEP, which will be useful for the future development of protein (pre)concentration or separation methods based on DEP.

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Dielectrophoresis for the manipulation of nanobioparticles

Cited by 191 publications

References 59 publications

Joule heating effects on electroosmotic flow in insulator‐based dielectrophoresis

Joule heating effects on electroosmotic flow in insulator‐based dielectrophoresis

Floating-electrode enhanced constriction dielectrophoresis for biomolecular trapping in physiological media of high conductivity

Tuning direct current streaming dielectrophoresis of proteins

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