Experimental demonstration of charge inversion in a protein channel in the presence of monovalent cations

López, María Esther Álvarez; Queralt-Martín, María; Alcaraz, Antonio

doi:10.1016/j.elecom.2014.08.006

Cited by 8 publications

(1 citation statement)

References 16 publications

(27 reference statements)

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“…Finally, note that experiments at high concentrations of LiCl lead to positive values of RP that for ccis > ctrans imply anion-selective pores 62 showing selectivity inversion. This result is very significant in the context of charge inversion with monovalent ions 67 , an effect that cannot be described using the strongly correlated liquid theory 68 .…”

Section: Biphasic Concentration Patternsmentioning

confidence: 96%

Biphasic concentration patterns in ionic transport under nanoconfinement revealed in steady-state and time-dependent properties

Queralt-Martín

Perez-Grau

Alvero-González

et al. 2023

The Journal of Chemical Physics

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Ion permeation across nanoscopic structures differs considerably from microfluidics because of strong steric constraints, transformed solvent properties and charge-regulation effects revealed mostly in diluted solutions. However, little is known about nanofluidics in moderately concentrated solutions, which are critically important for industrial applications and living systems. Here we show that nanoconfinement triggers general biphasic concentration patterns in a myriad of ion transport properties using two contrasting systems: a biological ion channel and a much larger synthetic nanopore. Our findings show a low concentration regime ruled by classical Debye screening and another one where ion-ion correlations and enhanced ion-surface interactions contribute differently to each electrophysiological property. Thus, different quantities (e.g., conductance vs noise) measured under the same conditions may appear contradictory because they belong to different concentration regimes. In addition, non-linear effects that are barely visible in bulk conductivity only in extremely concentrated solutions become apparent in nanochannels around physiological conditions.

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Section: Biphasic Concentration Patternsmentioning

confidence: 96%

Biphasic concentration patterns in ionic transport under nanoconfinement revealed in steady-state and time-dependent properties

Queralt-Martín

Perez-Grau

Alvero-González

et al. 2023

The Journal of Chemical Physics

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Structural analysis of confined monovalent salts: Combined effects of steric hindrance, surface charge representation, and dielectric response

Wang

Yang

Wang

2020

Electrochimica Acta

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Nanopore charge inversion and current-voltage curves in mixtures of asymmetric electrolytes

Ramı́rez

Manzanares

Cervera

et al. 2018

Journal of Membrane Science

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We consider the screening of the negative charges (carboxylic acid groups) fixed on the surface of a conical-shaped track-etched nanopore by divalent magnesium (Mg 2+) and trivalent lanthanum (La 3+). The experimental current (I)voltage (V) curves and current rectification ratios allow discussing fundamental questions about the overcompensation of spatially-fixed charges by multivalent ions over nanoscale volumes. The effects of charge inversion or reversal on nanopore transport are discussed in mixtures of asymmetric electrolytes (LaCl 3 and MgCl 2 with KCl). In particular, pore charge inversion is demonstrated for La 3+ as well as for mixtures of this trivalent ion at low concentrations with monovalent potassium (K +) and divalent Mg 2+ ions at biologically relevant concentrations. It is found that small concentrations of multivalent ions can modulate the nanopore rectification and the transport of other majority ions in the solution. We study also the kinetics of the nanopore electrical recovery when the electrolyte solutions bathing the single-pore membrane are changed and show the hysteretic effects observed in the IV curves. Finally, we describe the hysteresis observed in the IV curves of CaCl 2 , MgCl 2, and BaCl 2 and mixtures. We also give a qualitative description of the effects of charge reversal on the pore rectification using the Nernst-Planck flux equations for multivalent ion mixtures.

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Experimental demonstration of charge inversion in a protein channel in the presence of monovalent cations

Cited by 8 publications

References 16 publications

Biphasic concentration patterns in ionic transport under nanoconfinement revealed in steady-state and time-dependent properties

Biphasic concentration patterns in ionic transport under nanoconfinement revealed in steady-state and time-dependent properties

Structural analysis of confined monovalent salts: Combined effects of steric hindrance, surface charge representation, and dielectric response

Nanopore charge inversion and current-voltage curves in mixtures of asymmetric electrolytes

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