Noise Properties of Rectifying Nanopores

Powell, Matthew R.; Sa, Niya; Davenport, Matt; Healy, Ken; Vlassiouk, Ivan; Létant, Sonia E.; Baker, Lane A.; Siwy, Zuzanna S.

doi:10.1021/jp2016038

Cited by 35 publications

(48 citation statements)

References 46 publications

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“…In fact, as described in Supporting Information, section SI-2, we further incorporated electro-osmotic flow into our finite element simulations, and found negligible effect on the ion current. 44,45 Thus, electro-osmotic effects play no part in surfaceinduced ICR phenomenon under the conditions of these experiments (tip size, bias, and electrolyte concentration).…”

Section: Approach Curvesmentioning

confidence: 89%

Surface Charge Mapping with a Nanopipette

et al. 2014

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Nanopipettes are emerging as simple but powerful tools for probing chemistry at the nanoscale.In this contribution the use of nanopipettes for simultaneous surface charge mapping and topographical imaging is demonstrated, using a scanning ion conductance microscopy (SICM) format. When a nanopipette is positioned close to a surface in electrolyte solution the direct ion current (DC), driven by an applied bias between a quasi-reference counter electrode (QRCE) in the nanopipette and a second QRCE in the bulk solution is sensitive to surface charge. The charge sensitivity arises because the diffuse double layers at the nanopipette and the surface interact, creating a perm-selective region which becomes increasingly significant at low ionic strengths (10 mM 1:1 aqueous electrolyte herein). This leads to a polarity-dependent ion current and surface-induced rectification as the bias is varied. Using distance-modulated SICM, which induces an alternating ion current component (AC) by periodically modulating the distance between the nanopipette and the surface, the effect of surface charge on the DC and AC is explored and rationalized. The impact of surface charge on the AC phase (with respect to the driving sinusoidal signal) is highlighted in particular; this quantity shows a shift that is highly sensitive to interfacial charge and provides the basis for visualizing charge simultaneously with topography. The studies herein highlight the use of nanopipettes for functional imaging with applications from cell biology to materials characterization where understanding surface charge is of key importance.3

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Section: Approach Curvesmentioning

confidence: 89%

Surface Charge Mapping with a Nanopipette

et al. 2014

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“…There has been recent interest in the preparation of asymmetric pores in membranes of various thicknesses, thus we investigated the dependence of the current-voltage curves of conically shaped pores on the pore length 36,51,52 . The corresponding rectification degrees were calculated based on currents recorded at ± 1 V for 0.1 M KCl.…”

Section: Influence Of the Pore Length On The Rectification Behaviormentioning

confidence: 99%

Rectification properties of conically shaped nanopores: consequences of miniaturization

Pietschmann

Wolfram

Burger

et al. 2013

Phys. Chem. Chem. Phys.

116

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Nanopores attracted a great deal of scientific interest as templates for biological sensors as well as model systems to understand transport phenomena at the nanoscale. The experimental and theoretical analysis of nanopores has been so far focused on understanding the effect of the pore opening diameter on ionic transport. In this article we present systematic studies on the dependence of ion transport properties on the pore length. Particular attention was given to the effect of ion current rectification exhibited for conically shaped nanopores with homogeneous surface charges. We found that reducing the length of conically shaped nanopores significantly lowered their ability to rectify ion current. However, rectification properties of short pores can be enhanced by tailoring the surface charge and the shape of the narrow opening. Furthermore we analyze the relationship of the rectification behavior and ion selectivity for different pore lengths. All simulations were performed using MsSimPore, a software package for solving the Poisson-Nernst-Planck (PNP) equations. It is based on a novel finite element solver and allows for simulations up to surface charge densities of -2 e/nm 2 . MsSimPore is based on 1D reduction of the PNP model, but allows for a direct treatment of the pore with bulk electrolyte reservoirs, a feature which was previously used in higher dimensional models only. MsSimPore includes these reservoirs in the calculations; a property especially important for short pores, where the ionic concentrations and the electric potential vary strongly inside the pore as well as in the regions next to pore entrance.

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“…While this is an effective means of noise reduction, it is unavoidably accompanied by a degradation of the measurement time resolution , which distorts the signal and masks structural information that can reveal DNA sequence and other important molecular features that can be measured in an experiment. The behavior of noise in nanopores has been studied extensively [23–31], highlighting its importance for progress in the field.…”

Section: Introductionmentioning

confidence: 99%

Nanopores: A journey towards DNA sequencing

Wanunu

2012

Physics of Life Reviews

558

557

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Much more than ever, nucleic acids are recognized as key building blocks in many of life's processes, and the science of studying these molecular wonders at the single-molecule level is thriving. A new method of doing so has been introduced in the mid 1990's. This method is exceedingly simple: a nanoscale pore that spans across an impermeable thin membrane is placed between two chambers that contain an electrolyte, and voltage is applied across the membrane using two electrodes. These conditions lead to a steady stream of ion flow across the pore. Nucleic acid molecules in solution can be driven through the pore, and structural features of the biomolecules are observed as measurable changes in the trans-membrane ion current. In essence, a nanopore is a high-throughput ion microscope and a single-molecule force apparatus. Nanopores are taking center stage as a tool that promises to read a DNA sequence, and this promise has resulted in overwhelming academic, industrial, and national interest. Regardless of the fate of future nanopore applications, in the process of this 16-year-long exploration, many studies have validated the indispensability of nanopores in the toolkit of single-molecule biophysics. This review surveys past and current studies related to nucleic acid biophysics, and will hopefully provoke a discussion of immediate and future prospects for the field.

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Noise Properties of Rectifying Nanopores

Cited by 35 publications

References 46 publications

Surface Charge Mapping with a Nanopipette

Surface Charge Mapping with a Nanopipette

Rectification properties of conically shaped nanopores: consequences of miniaturization

Nanopores: A journey towards DNA sequencing

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