TU Darmstadt / ULB / TUbiblio

Membrane potential of single asymmetric nanopores: Divalent cations and salt mixtures

Ramirez, Patricio and Cervera, Javier and Gomez, Vicente and Ali, Mubarak and Nasir, Saima and Ensinger, Wolfgang and Mafe, Salvador (2019):
Membrane potential of single asymmetric nanopores: Divalent cations and salt mixtures.
573, In: Journal of Membrane Science, ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, pp. 579-587, ISSN 03767388, DOI: 10.1016/j.memsci.2018.12.043,
[Online-Edition: https://doi.org/10.1016/j.memsci.2018.12.043],
[Article]

Abstract

We study the electric potential difference (membrane potential) that arises across a single-pore membrane which separates two aqueous solutions at different salt concentrations. This potential difference is obtained here as the reversal potential of a conical nanopore, defined as the applied voltage needed to obtain a zero current through the membrane. To this end, different monovalent (LiCl, NaCl, KCl, and CsCl) and divalent (CaCl2, MgCl2, and BaCl2) cations are considered over a wide range of concentrations and salt mixtures for the two asymmetric nanostructure directionalities. The experimental data allows discussing fundamental questions on the interaction of the charges fixed to the pore surface with the mobile ions in solution over nanoscale volumes. In particular, we describe the effects due to (i) the relative orientation of the axial charge distribution along the pore and the externally imposed concentration gradient, (ii) the different screening of the pore negative charges by the monovalent and divalent cations, and (iii) the non-zero bi-ionic potential arising between two salts of distinct cations with a common anion at the same concentration. We have also given a quantitative description of the experimental data obtained with monovalent cations on the basis of the Poisson-Nernst-Planck formalism. In the case of the divalent cations, however, we could give only a qualitative description of the observed phenomena. Taken together, the results can contribute to the understanding of electrochemical and bioelectrical membrane processes which are regulated by the interplay between the membrane asymmetry and the ionic concentration and electrical potential gradients.

Item Type: Article
Erschienen: 2019
Creators: Ramirez, Patricio and Cervera, Javier and Gomez, Vicente and Ali, Mubarak and Nasir, Saima and Ensinger, Wolfgang and Mafe, Salvador
Title: Membrane potential of single asymmetric nanopores: Divalent cations and salt mixtures
Language: English
Abstract:

We study the electric potential difference (membrane potential) that arises across a single-pore membrane which separates two aqueous solutions at different salt concentrations. This potential difference is obtained here as the reversal potential of a conical nanopore, defined as the applied voltage needed to obtain a zero current through the membrane. To this end, different monovalent (LiCl, NaCl, KCl, and CsCl) and divalent (CaCl2, MgCl2, and BaCl2) cations are considered over a wide range of concentrations and salt mixtures for the two asymmetric nanostructure directionalities. The experimental data allows discussing fundamental questions on the interaction of the charges fixed to the pore surface with the mobile ions in solution over nanoscale volumes. In particular, we describe the effects due to (i) the relative orientation of the axial charge distribution along the pore and the externally imposed concentration gradient, (ii) the different screening of the pore negative charges by the monovalent and divalent cations, and (iii) the non-zero bi-ionic potential arising between two salts of distinct cations with a common anion at the same concentration. We have also given a quantitative description of the experimental data obtained with monovalent cations on the basis of the Poisson-Nernst-Planck formalism. In the case of the divalent cations, however, we could give only a qualitative description of the observed phenomena. Taken together, the results can contribute to the understanding of electrochemical and bioelectrical membrane processes which are regulated by the interplay between the membrane asymmetry and the ionic concentration and electrical potential gradients.

Journal or Publication Title: Journal of Membrane Science
Volume: 573
Publisher: ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Uncontrolled Keywords: Conical nanopore, Membrane potential, Divalent cations, Bi-ionic potential
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Material Analytics
Date Deposited: 23 Jan 2019 10:30
DOI: 10.1016/j.memsci.2018.12.043
Official URL: https://doi.org/10.1016/j.memsci.2018.12.043
Funders: Hessen State Ministry of Higher Education, Research and the Arts (Germany), LOEWE project iNAPO, Ministerio de Ciencia, Innovacion y Universidades (Spain), European Regional Development Funds (FEDER), Grant Number MAT2018
Export:
Suche nach Titel in: TUfind oder in Google
Send an inquiry Send an inquiry

Options (only for editors)

View Item View Item