Relation between selectivity and conductivity in narrow ion channels

Luchinsky, D. G.; Gibby, William; Kaufman, I. Kh.; McClintock, Peter V. E.; Timuçin, Doǧan A.

doi:10.1109/icnf.2017.7985973

Cited by 12 publications

(17 citation statements)

References 43 publications

(84 reference statements)

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“…The single-file conduction of ions through the pore with a finite number of binding sites K defines the set of energy states of the pore and its total occupancy [12]- [17]. Observing that transitions of ions from the bulk to the pore correspond to small fluctuations in the total energy of the system [11] and canceling out constant terms in the energy Eq.…”

Section: Theory Of Selective Conduction Of Molecular Pore: Role mentioning

confidence: 99%

“…Observing that transitions of ions from the bulk to the pore correspond to small fluctuations in the total energy of the system [11] and canceling out constant terms in the energy Eq. (2) we obtain [12], [13] the free energy of such transitions…”

Section: Theory Of Selective Conduction Of Molecular Pore: Role mentioning

confidence: 99%

“…The current density j i through the pore can be written in general form [19], [23]- [25] as j i = − σi q ∇µ i , where the conductivity σ is defined using the generalised Einstein relation [12], [26], [27]…”

Section: Selectivity Vs Conductivity Trade-offmentioning

confidence: 99%

See 2 more Smart Citations

The Role of Noise in Determining Selective Ionic Conduction Through Nano-Pores

Gibby

Barabash

Guardiani

et al. 2018

2018 IEEE 13th Nanotechnology Materials and Devices Conference (NMDC)

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The problem of predicting selective transport of ions through nano-pores from their structure in the biological and nano-technological systems is addressed. We use a molecular dynamics simulation to provide insight into the key physical parameters of nano-pores and develop a self-consistent analytic theory describing ionic conduction and selectivity through these devices. We analyse the ion's dehydration and excess chemical potential, derive an expression for the conductivity of the nanopore, and emphasize the role of fluctuations in its performance. The theory is verified by comparison of the predicted currentvoltage characteristics with the molecular dynamics results and experimental data obtained for a graphene nano-pore and the KcsA biological channel.

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Section: Theory Of Selective Conduction Of Molecular Pore: Role mentioning

confidence: 99%

Section: Theory Of Selective Conduction Of Molecular Pore: Role mentioning

confidence: 99%

See 1 more Smart Citation

The Role of Noise in Determining Selective Ionic Conduction Through Nano-Pores

Gibby

Barabash

Guardiani

et al. 2018

2018 IEEE 13th Nanotechnology Materials and Devices Conference (NMDC)

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“…The SF entropy-related term TDS n is modeldependent. We use the "single-vacancy" model of the motion [12,27] for which the following result can be derived [28]:…”

Section: Ionic Coulomb Blockade and Concentrationrelated Shiftmentioning

confidence: 99%

“…A complete description of divalent blockade and AMFE should account for statistical and kinetic features of the multi-species solution inside the SF [18,28]. We use a simplified description based on the assumptions: ½Ca ≪ ½Na; t Ca ≫t Na ; P c ð½CaÞ þ P c ð½NaÞ 1; ð7Þ…”

Section: +mentioning

confidence: 99%

Ionic Coulomb blockade and anomalous mole fraction effect in the NaChBac bacterial ion channel and its charge-varied mutants

Kaufman¹,

Fedorenko²,

Luchinsky³

et al. 2017

EPJ Nonlinear Biomed. Phys.

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Abstract. Background. The selectivity of biological cation channels is defined by a short, narrow selectivity filter, having a negative net fixed charge Q f . Voltage gated bacterial channels (NaChBac and some others) are frequently used in biophysics as simplified models of mammalian calcium and sodium channels. We report an experimental, analytic and numerical study of the effects of Q f and bulk ionic concentrations of Ca 2+ and Na + on conduction and selectivity of NaChBac channels, wild type and Q f -varied mutants. Methods. Site-directed mutagenesis and voltage clamp recordings were used to investigate the Na + /Ca 2+ selectivity, divalent blockade and anomalous mole fraction effect (AMFE) for different NaChBac wild type/ mutants channels and the properties dependence on Q f . Experimental results were compared with Brownian dynamics simulations and with analytic predictions of the ionic Coulomb blockade (ICB) model, which was extended to encompass bulk concentration effects. Results. It was shown that changing of Q f from -4e (for LESWAS wild type) to -8e (for LEDWAS mutant) leads to strong divalent blockade of the Na + current by micromolar amounts of Ca 2+ ions, similar to the effects seen in mammalian calcium channels. The BD simulations revealed a concentration-related logarithmic shift of the conduction bands. These results were shown to be consistent with ICB model predictions. Conclusions. The extended ICB model explains the experimental (divalent blockade and AMFE) and simulated (multi-ion bands and their concentration-related shifts) selectivity phenomena of NaChBac channel and its charge-varied mutants. These results extend the understanding of ion channel selectivity and may also be applicable to biomimetic nanopores with charged walls.

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Ionic Coulomb blockade as a fractional Wien effect

et al. 2019

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Recent advances in nanofluidics have allowed exploration of ion transport down to molecular scale confinement, yet artificial porins are still far from reaching the advanced functionalities of biological ion machinery. Achieving single ion transport that is tuneable by an external gate -the ionic analogue of electronic Coulomb blockade (CB) -would open new avenues in this quest. However, an understanding of ionic CB beyond the electronic analogy is still lacking. Here we show that the many-body dynamics of ions in a charged nanochannel result in a quantised and strongly nonlinear ionic transport, in full agreement with molecular simulations. We find that ionic CB occurs when, upon sufficient confinement, oppositely charged ions form 'Bjerrum pairs', and the conduction proceeds through a mechanism reminiscent of Onsager's Wien effect. Our findings open the way to novel nanofluidic functionalities, such as an ionic-CB-based ion pump inspired by its electronic counterpart.arXiv:2005.05199v1 [cond-mat.soft]

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Relation between selectivity and conductivity in narrow ion channels

Cited by 12 publications

References 43 publications

The Role of Noise in Determining Selective Ionic Conduction Through Nano-Pores

The Role of Noise in Determining Selective Ionic Conduction Through Nano-Pores

Ionic Coulomb blockade and anomalous mole fraction effect in the NaChBac bacterial ion channel and its charge-varied mutants

Ionic Coulomb blockade as a fractional Wien effect

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