Protein Diffusion in Charged Nanotubes:  “On−Off” Behavior of Molecular Transport

Ku, Jie-Ren; Stroeve, Pieter

doi:10.1021/la0357662

Cited by 98 publications

(89 citation statements)

References 30 publications

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“…The curve illustrates three zones: for pH Յ 7 and pH Ն 9, the diffusion of lectin through the nanochannel is slow, whereas the diffusion is significantly faster for pH values between 7 and 9. Three peaks are visible in this part of the curve, one at pH = 7.5, a second at pH = 8.2, and a third at pH = 8.8, and they can be attributed to the pI values of the three proteins, showing a maximal diffusion coefficient through the nanochannel if they are neutral and do not have electrostatic interactions with channel walls ͑Burns and Zydney, 1999; Chun and Stroeve, 2002;Ku and Stroeve, 2004͒. For pH Ն 9, all three proteins are negatively charged and excluded from the nanochannel according to the EEE ͓Eq.…”

Section: Electrostatic Sieving Of Proteinsmentioning

confidence: 98%

Transport phenomena in nanofluidics

2008

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The transport of fluid in and around nanometer-sized objects with at least one characteristic dimension below 100 nm enables the occurrence of phenomena that are impossible at bigger length scales. This research field was only recently termed nanofluidics, but it has deep roots in science and technology. Nanofluidics has experienced considerable growth in recent years, as is confirmed by significant scientific and practical achievements. This review focuses on the physical properties and operational mechanisms of the most common structures, such as nanometer-sized openings and nanowires in solution on a chip. Since the surface-to-volume ratio increases with miniaturization, this ratio is high in nanochannels, resulting in surface-charge-governed transport, which allows ion separation and is described by a comprehensive electrokinetic theory. The charge selectivity is most pronounced if the Debye screening length is comparable to the smallest dimension of the nanochannel cross section, leading to a predominantly counterion containing nanometer-sized aperture. These unique properties contribute to the charge-based partitioning of biomolecules at the microchannel-nanochannel interface. Additionally, at this free-energy barrier, size-based partitioning can be achieved when biomolecules and nanoconstrictions have similar dimensions. Furthermore, nanopores and nanowires are rooted in interesting physical concepts, and since these structures demonstrate sensitive, label-free, and real-time electrical detection of biomolecules, the technologies hold great promise for the life sciences. The purpose of this review is to describe physical mechanisms on the nanometer scale where new phenomena occur, in order to exploit these unique properties and realize integrated sample preparation and analysis systems.

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Section: Electrostatic Sieving Of Proteinsmentioning

confidence: 98%

Transport phenomena in nanofluidics

2008

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“…Synthetic nanopores of dimensions comparable to the size of biological macromolecules such as proteins 1,2 and DNA ͑Refs. 3-5͒ have potential applications in singleparticle detection, analysis, and separation of biomolecules.…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, the transport problem involves typically ͑at least͒ three length scales: the biomolecule size, the nanopore dimensions, and the screening Debye length. 1,2,6,9 We will consider here, both theoretically and experimentally, the relative roles of the last two length scales for the case of conical nanopores obtained using the track-etching technique. [10][11][12][13][14] Irradiation of polymer films such as polyethylene terephthalate ͑PET͒ with heavy ions and subsequent etching with alkali of the latent particle tracks allow the preparation of synthetic pores with diameters from few nanometers to the micrometer range.…”

Section: Introductionmentioning

confidence: 99%

Ionic conduction, rectification, and selectivity in single conical nanopores

Cervera

Schiedt²,

Neumann³

et al. 2006

The Journal of Chemical Physics

399

539

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Modern track-etching methods allow the preparation of membranes containing a single charged conical nanopore that shows high ionic permselectivity due to the electrical interactions of the surface pore charges with the mobile ions in the aqueous solution. The nanopore has potential applications in electrically assisted single-particle detection, analysis, and separation of biomolecules. We present a detailed theoretical and experimental account of the effects of pore radii and electrolyte concentration on the current-voltage and current-concentration curves. The physical model used is based on the Nernst-Planck and Poisson equations. Since the validity of continuum models for the description of ion transport under different voltages and concentrations is recognized as one of the main issues in the modeling of future applications, special attention is paid to the fundamental understanding of the electrical interactions between the nanopore fixed charges and the mobile charges confined in the reduced volume of the inside solution.

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“…Similar phenomena of the effect of electrostatic interaction on the protein diffusivity have been reported, and the possible reasons have been discussed. [34][35][36][37][38] For example, Salgin et al proposed that the decrease in BSA effective diffusion coefficient is because of the pore narrowing due to the increased adsorption when the membrane and protein had opposite charges. Ku and Stroeve 35 tried to explain from the standpoint of the diffusion potential, which was generated due to the repelling of the counter-ions by the charged membrane, and reduced the protein transport when the protein and the membrane had opposite charge properties.…”

Section: Adsorption Kineticsmentioning

confidence: 99%

Insulin adsorption into porous charged membranes: Effect of the electrostatic interaction

Zhang

Tanioka

Saito

et al. 2009

Biotechnology Progress

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Insulin adsorption into a series of porous charged membranes was investigated by batch adsorption experiments, and the experimental results were analyzed by the homogeneous diffusion model. The membranes used in this study were prepared by pore-surface modification of porous poly(acrylonitrile) (PAN) membranes by grafting with weak acidic and basic functional groups. The amount of insulin adsorbed into the membrane was determined from the material balance of insulin. The insulin partition coefficient K between the membrane and solution was estimated from the equilibrium adsorption amount, and the effective diffusion coefficient D was estimated by matching the model with the experimental data as a fitting parameter. The dependence of K and D on the charge properties of the insulin and membrane is observed and discussed. The partition coefficient K increased when the insulin and the membrane carried opposite charges, on the other hand, the effective diffusion coefficient D was reduced. These results indicate that the electrostatic interaction between the insulin and the membranes played an important role in the insulin adsorption.

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Protein Diffusion in Charged Nanotubes: “On−Off” Behavior of Molecular Transport

Cited by 98 publications

References 30 publications

Transport phenomena in nanofluidics

Transport phenomena in nanofluidics

Ionic conduction, rectification, and selectivity in single conical nanopores

Insulin adsorption into porous charged membranes: Effect of the electrostatic interaction

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