Metal Nanotubule Membranes with Electrochemically Switchable Ion-Transport Selectivity

Nishizawa, Masatoyo; Menon, Vinod P.; Martin, Charles R.

doi:10.1126/science.268.5211.700

Cited by 647 publications

(790 citation statements)

References 16 publications

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“…It can also be viewed as a universal ion exchange membrane, 30 where similar membrane potential modulation has been observed. The experimental results on quasi-statically converting the transmembrane ion gradients into potential validate the voltage regulated selectivity mechanism.…”

mentioning

confidence: 88%

Electric Field Modulation of the Membrane Potential in Solid-State Ion Channels

Guan

Reed

2012

Nano Lett.

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Biological ion channels are molecular devices that allow a rapid flow of ions across the cell membrane. Normal physiological functions, such as generating action potentials for cell-to-cell communication, are highly dependent on ion channels that can open and close in response to external stimuli for regulating ion permeation. Mimicking these biological functions using synthetic structures is a rapidly progressing yet challenging area. Here we report the electric field modulation of the membrane potential phenomena in mechanically and chemically robust solid-state ion channels, an abiotic analogue to the voltage-gated ion channels in living systems. To understand the complex physicochemical processes in the electric field regulated membrane potential behavior, both quasi-static and transient characteristics of converting transmembrane ion gradients into electric potential are investigated. It is found that the transmembrane potential can be adequately tuned by an external electrical stimulation, thanks to the unique properties of the voltage-regulated selective ion transport through a nanoscale channel.

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mentioning

confidence: 88%

Electric Field Modulation of the Membrane Potential in Solid-State Ion Channels

Guan

Reed

2012

Nano Lett.

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“…Perhaps most importantly, we have demonstrated a desirable and readily attainable feature of specifically tailoring transport through a suitable choice of encapsulating ligand chemically absorbed to the NP surface. In this regard, we are able to achieve a desired functionality in a manner similar to, but distinctly different from, those using self-assembled monolayers (SAMs) [35][36][37][38][39][40][41] , b a (1), under the assumption of a fixed membrane charge density, |X|. Deviations to the model are most prevalent at low electrolyte concentration, resulting from the fact that |X| is not a constant, but depends on the electrolyte concentration as shown in the inset.…”

Section: Article Nature Communications | Doi: 101038/ncomms6847mentioning

confidence: 94%

“…Here by utilizing particles encoded a priori with the desired functionality, we are able to bypass the requirement of a favourable surface chemistry in order to bind the molecules to the surface of the porous substrate itself, or any additional steps coating the substrate with a metal such as gold [38][39][40][41] . Owing to the flexibility by which ligated NPs can be synthesized, including both the core materials themselves and the encapsulating ligands 43,44 , we believe the approach outlined here can be generalized to a similar set of functionalities as their SAM counterparts for different core materials.…”

Section: Article Nature Communications | Doi: 101038/ncomms6847mentioning

confidence: 99%

Ion transport controlled by nanoparticle-functionalized membranes

et al. 2014

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From proton exchange membranes in fuel cells to ion channels in biological membranes, the well-specified control of ionic interactions in confined geometries profoundly influences the transport and selectivity of porous materials. Here we outline a versatile new approach to control a membrane's electrostatic interactions with ions by depositing ligand-coated nanoparticles around the pore entrances. Leveraging the flexibility and control by which ligated nanoparticles can be synthesized, we demonstrate how ligand terminal groups such as methyl, carboxyl and amine can be used to tune the membrane charge density and control ion transport. Further functionality, exploiting the ligands as binding sites, is demonstrated for sulfonate groups resulting in an enhancement of the membrane charge density. We then extend these results to smaller dimensions by systematically varying the underlying pore diameter. As a whole, these results outline a previously unexplored method for the nanoparticle functionalization of membranes using ligated nanoparticles to control ion transport.

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“…If the pore walls are made of conductive material, the wall charge can be altered by applying a prescribed potential to the membrane. In this way, the membrane selectivity characteristics can be externally varied and controlled [5,6]. A comprehensive review of charged membranes applications can be found in [7].…”

Section: Introductionmentioning

confidence: 99%

“…The considered electrolyte concentrations were 1 mol/m 3 and lower except the work [24] (the pressure-driven flow was not considered there). However, typical nanofiltration membranes have the pore diameter of a few nanometers and the aspect ratio of order 100-1000, while the electrolyte concentration can be as high as 1000 mol/m 3 [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of electrolyte transport in nanofiltration membranes with constant surface potential/charge density

Ryzhkov

Минаков

2016

Journal of Membrane Science

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Abstract. The pressure-driven ion transport through nanofiltration membrane pores with constant surface potential or charge density is investigated theoretically. Two approaches are employed in the study. The first one is based on one-dimensional Nernst-Planck equation coupled with electroneutrality, zero current, and Donnan equilibrium conditions. This model is extended to account for interfacial effects by using a smooth approximation of step function for the volume charge density. A simplified model for the case of constant surface potential is also proposed. The second approach is based on two-dimensional Nernst-Planck, Poisson, and Navier-Stokes equations, which are solved in a high aspect ratio nanopore connecting two reservoirs with much larger diameter. The modification of equations on the basis of Slotboom transformation is employed to speed up the convergence rate. The distributions of potential, pressure, ion concentrations and fluxes due to convection, diffusion, and migration in the nanopore and reservoirs are discussed and analyzed. It is found that for constant surface charge density, the convective flux of counter-ions in the nanopore is almost completely balanced by the opposite migration flux, while for constant surface potential, the convective flux is balanced by the opposite diffusion and migration fluxes. The co-ions in the nanopore are mainly transported by diffusion. A particular attention is focused on describing the interfacial effects at the nanopore entrance/exit. Detailed comparison between one-and two-dimensional models is performed in terms of rejection, pressure drop, and membrane potential dependence on the surface potential/charge density, volume flux, electrolyte concentration, and pore radius. A good agreement between these models is found when the Debye length is smaller than the pore radius and the surface potential or charge density are sufficiently low.

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Metal Nanotubule Membranes with Electrochemically Switchable Ion-Transport Selectivity

Cited by 647 publications

References 16 publications

Electric Field Modulation of the Membrane Potential in Solid-State Ion Channels

Electric Field Modulation of the Membrane Potential in Solid-State Ion Channels

Ion transport controlled by nanoparticle-functionalized membranes

Theoretical study of electrolyte transport in nanofiltration membranes with constant surface potential/charge density

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