Ion bridges in microfluidic systems

Park, Sangyun; Chung, Taek Dong; Kim, Hee Chan

doi:10.1007/s10404-008-0391-4

Cited by 19 publications

(9 citation statements)

References 102 publications

(126 reference statements)

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“…Utilizing ionic bridge has been suggested in many microfluidics applications (Park et al 2009). Kim et al (2007) suggested using ionic conductivity of polyelectrolytic gel electrodes for electric field concentration and cell electroporation.…”

Section: Polyelectrolytic Salt Bridgesmentioning

confidence: 99%

Microfluidics cell electroporation

Movahed

2010

Microfluid Nanofluid

130

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Electroporation or electropermeabilization is one of the most powerful biological techniques in cell studies. Applying the high voltage electric field in vicinity of the cells can generate nanopores in cell membrane. Varying with the intensity and the duration of these applied electric field, the created nanopores can be temporary (reversible electroporation) or permanent (irreversible electroporation). Reversible electroporation is usually conducted to insert biological samples into the cells. Cells are also electroporated irreversibly to release their intercellular contents for further biological investigations. In comparison with the conventional electroporation devices, microfluidic (microscale) electroporation devices have some advantages such as higher cell viability rate, high transfection efficiency, lower sample contamination, and smaller Joule heating effect. In this article, the latest advancement in microfluidic cell electroporation is reviewed. First, the underlying theory of membrane permeabilization is reviewed and the leading analytical studies on the cell electroporation are presented. Following that, different experimental methods are compared. Finally, some suggestions are proposed for the future studies.

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Section: Polyelectrolytic Salt Bridgesmentioning

confidence: 99%

Microfluidics cell electroporation

Movahed

2010

Microfluid Nanofluid

130

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“…Daiguji et al (2004) attributed this nonlinear character to mass diffusion becoming the rate-controlling step when the average concentration difference between positive and negative ions inside the nanochannel is much larger than the bulk concentration of the electrolyte solution. However, we would emphasize that this nonlinear current-voltage relationship is mainly due to the occurrence of a concentration polarization effect (Levich 1962;Probstein 1994;Kim et al 2007bKim et al , 2009Ehlert et al 2008;Yossifon et al 2009;Park et al 2009) at the two reservoirs when the nanochannel becomes an ideal ion-selective channel, i.e., ion depletion/ enrichment occurs at inlet/outlet reservoirs or microchannels, respectively (Pu et al 2004;Huang and Yang 2008). In other words, considerable variation in the resistances of two reservoirs is induced once concentration polarization occurs, at which point Ohm's law fails to describe the current-voltage curve.…”

Section: Introductionmentioning

confidence: 99%

Electrokinetic energy conversion in micrometer-length nanofluidic channels

Chang

Yang

2009

Microfluid Nanofluid

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In this study, we present a theoretical and numerical investigation of electrokinetic energy conversion in short-length nanofluidic channels, taking into account reservoir resistance and concentration polarization effects. The concentration polarization effect was demonstrated through numerical modeling using the Poisson-NernstPlanck (PNP) model. In the absence of concentration polarization, the modified Onsager reciprocal relation for the electrokinetic flow through a one-dimensional (1D) nanochannel is derived from both Ohm's law and Kirchhoff's current law while considering the reservoir resistance. Based on this modified Onsager reciprocal relation and the Poisson-Boltzmann (PB) model, a theoretical model for electrokinetic energy conversion is proposed to address the importance of the reservoir resistance effect on electrokinetic energy conversion. The applicability of our proposed model is also verified through numerical modeling of the PNP model. The results calculated from our proposed model are shown to be in good agreement with those from the PNP model when the concentration polarization effect does not occur significantly at the reservoirs. The conversion efficiency and generation power are decreased when the channel resistance is not much larger than the reservoir resistance, especially for a shorter-length nanochannel (e.g., a channel several micrometers in length) with a lower electrolyte concentration and a higher surface charge density. After the concentration polarization effect becomes increased as a larger pressure gradient is applied through an ideal ion-selective nanochannel, the conversion efficiency/generation power is further decreased due to the ion depletion at the inlet reservoir, which increases the electrical resistance of the inlet reservoir or the equivalent electrical resistance of the electrokinetic energy conversion system. The onset pressure difference (or gradient) for a significant concentration polarization is identified both theoretically and numerically. In order to avoid decreases in the conversion efficiency/generation power mentioned above, some key factors such as the length of the nanochannel, the position of electrodes at the reservoirs, and the applied pressure gradient were noticed in this study.

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“…Several studies examined counter‐flow coion pre‐concentration (mostly experimentally) with “T‐junction” configurations (see for example refs. []). These devices deviate from the simple linear micro‐/nanoporous configuration described above because current passes from the sample channel through perpendicular channels containing ion‐exchange materials.…”

Section: Introductionmentioning

confidence: 99%

Highly Selective Current‐Induced Accumulation of Trace Ions at Micro‐/NanoPorous Interfaces

Bondarenko

Bruening

Yaroshchuk

2019

Advcd Theory and Sims

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During application of electrical current through composite micro-/nanoporous membranes, trace-ion accumulation in the microporous layer should vary greatly with the ion diffusion coefficient to allow selective accumulation of specific ions. This study examines the theoretical enrichment factors in the microporous region as a function of current density and trace-ion diffusion coefficient. Trace-ion accumulation relies on charged nanopores that exclude coions, which gives rise to depletion of the dominant salt and high local electric fields in the region next to the nanopores. Trace ions accumulate in this region because convection carries them toward the nanoporous interface, whereas electromigration in the opposite direction is strongest next to the interface. With monovalent coions having 2% difference in diffusion coefficients, calculated accumulation selectivity factors reach >1.2. Such selectivities may prove useful in separating very similar species such as isotopes or equally charged peptides.

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Ion bridges in microfluidic systems

Cited by 19 publications

References 102 publications

Microfluidics cell electroporation

Microfluidics cell electroporation

Electrokinetic energy conversion in micrometer-length nanofluidic channels

Highly Selective Current‐Induced Accumulation of Trace Ions at Micro‐/NanoPorous Interfaces

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