Controlling ion transport through nanopores: modeling transistor behavior

Mádai, Eszter; Matejczyk, Bartłomiej; Dallos, András; Valiskó, Mónika; Boda, Dezső

doi:10.1039/c8cp03918f

Cited by 29 publications

(61 citation statements)

References 89 publications

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“…The electrolyte is modeled in the implicit solvent framework, an approximation common in nanopore modeling studies [1,12,13,14,15,16] and one that captures the device-level physics [17,18]. This work was inspired by our previous study in which we found the presence of scaling [19]. A symmetric charge pattern was used in that study for a model nanofluidic transistor, where current was modulated with the surface charge of the central region.…”

Section: Introductionmentioning

confidence: 99%

Scaling Behavior of Bipolar Nanopore Rectification with Multivalent Ions

et al. 2019

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We present a scaling behavior of a rectifying bipolar nanopore as a function of the parameter ξ = R P /(λ z if ), where R P is the radius of the pore, λ is the characteristic screening length of the electrolyte filling the pore, and z if = z + |z − | is a scaling factor that makes scaling work for electrolytes containing multivalent ions (z + and z − are cation and the anion valences). By scaling we mean that the rectification of the pore (defined as the ratio of currents in the forward and reversed biased states) depends on pore radius, concentration, c, and ion valences via the parameter ξ implicitly. This feature is based on the fact that rectification depends on the voltage-sensitive appearance of depletion zones that, in turn, depend on the relation of R P to the rescaled screening length λ z if . In this modeling study, we use the Poisson-Nernst-Planck (PNP) theory and a particle simulation method, the Local Equilibrium Monte Carlo (LEMC). The latter can compute ion correlations that are ignored in the mean-field treatment of PNP and that are very important for multivalent ions (we show results for 1:1, 2:1, 3:1, and 2:2 electrolytes). In addition to the z if factor, we show that one must choose a screening length appropriate to the system, in our case the Debye length for λ for PNP and the screening length given by the Mean Spherical Approximation for LEMC.

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Section: Introductionmentioning

confidence: 99%

Scaling Behavior of Bipolar Nanopore Rectification with Multivalent Ions

et al. 2019

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“…This, however, can be prevented by using an appropriately chosen concentration. As we have seen in our previous study [47] for a nanopore transistor, the relevant parameter is R pore /λ D , where R pore is the pore radius somewhere along the pore and λ D is the Debye length. In that paper [47] we showed that device functions scale with the R pore /λ D parameter.…”

Section: Discussionmentioning

confidence: 76%

“…The bulk value is experimental (D bulk K + = 1.849 × 10 −9 m 2 s −1 and D bulk Cl − = D bulk X = 2.032 × 10 −9 m 2 s −1 ), while D pore i just scales the current without influencing the I/I 0 ratio. Following our previous studies [45,8,46,47] here we set the relation D…”

Section: Interparticle Potentialsmentioning

confidence: 99%

“…Thus, the NP and the continuity equations together with LEMC form a self-consistent system. The advantage over the widely used Poisson-Nernst-Planck theory is that the statistical mechanical component is an accurate particle simulation method instead of an approximate mean-field theory (Poisson-Boltzmann) [45,47,48]. Details are found in earlier papers [39,41].…”

Section: Np+lemcmentioning

confidence: 99%

“…We apply the Nernst-Planck (NP) transport equation and couple it to LEMC resulting in a hybrid method, called NP+LEMC. This method was successfully applied for various problems in the last couple of years such as particle transport through model membranes [39,40], ion channels [41,42,43], and nanopores [44,45,8,46,47,1,48].…”

Section: Introductionmentioning

confidence: 99%

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Application of a bipolar nanopore as a sensor: rectification as an additional device function

Mádai

Valiskó

Boda

2019

Phys. Chem. Chem. Phys.

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We model and simulate a nanopore sensor that selectively binds analyte ions. This binding leads to the modulation of the local concentrations of the ions of the background electrolyte (KCl), and, thus, to the modulation of the ionic current flowing through the pore. The nanopore's wall carries a bipolar charge pattern with a larger positive buffer region determining the anions as the main charge carriers and the smaller negative binding region containing binding sites. This charge pattern proved to be an appropriate one as shown by a previous comparative study of varying charge patterns (Mádai et al. J. Mol. Liq., 2019, 283, 391-398.). Binding of the positive analyte ions attracts more anions in the pore thus increasing the current. The asymmetric nature of the pore results in an additional device function, rectification. Our model, therefore, is a dual response device. Using a reduced model of the nanopore studied by a hybrid computer simulation method (Local Equilibrium Monte Carlo coupled to the Nernst-Planck equation) we show that we can create a sensor whose underlying mechanisms are based on the changes of the local electric field as a response to changing thermodynamic conditions. The change of the electric field results in changes in the local ionic concentrations (depletion zones), and, thus, changes in ionic currents.

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Electrical Circuit Modeling of Nanofluidic Systems

Sebastian

Green

2023

Advanced Physics Research

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Nanofluidic systems exhibit transport characteristics that have made technological marvels such as desalination and energy harvesting possible by virtue of their ability to influence small currents due to selective ion transport. Traditionally, these applications have relied on nanoporous membranes whose complicated geometry impedes a comprehensive understanding of the underlying physics. To bypass the associated difficulties, The authors consider the simpler nanochannel array and elucidate the effects of interchannel interactions on the Ohmic response. It is demonstrated that a nanochannel array is equivalent to an array of mutually independent but identical unit‐cells whereby the array can be represented by an equivalent electrical circuit of resistances connected in a parallel configuration. The model is validated using numerical simulations and experiments. The approach to modeling nanofluidic systems by their equivalent electrical circuit provides an invaluable tool for analyzing and interpreting experimental measurements.

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Controlling ion transport through nanopores: modeling transistor behavior

Cited by 29 publications

References 89 publications

Scaling Behavior of Bipolar Nanopore Rectification with Multivalent Ions

Scaling Behavior of Bipolar Nanopore Rectification with Multivalent Ions

Application of a bipolar nanopore as a sensor: rectification as an additional device function

Electrical Circuit Modeling of Nanofluidic Systems

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