Conductance-Based Determination of Solid-State Nanopore Size and Shape: An Exploration of Performance Limits

Frament, Cameron M.; Dwyer, Jason R.

doi:10.1021/jp305381j

Cited by 43 publications

(79 citation statements)

References 32 publications

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“…(1), Supporting Information Fig. 2 and associated discussion)—but this straightforward conductance model provides a tractable and useful framework with good agreement with the measured conductance of nanopores across a range of experimentally determined sizes and shapes . As a species of interest passes through the nanopore, or is entrained therein, it perturbs the open‐pore flow of ions, and frequently generates an analyte‐specific current blockage (or enhancement) .…”

Section: Introductionmentioning

confidence: 86%

“…We simulated the experimental conductances using the experimentally supported Eq. in conjunction with experimentally supported nanopore profiles, and then fit the data using candidate nanopore profiles . The focus was whether including either defects or double pores would negatively affect the feasibility of the approach augured by the formalism.…”

Section: Methodsmentioning

confidence: 99%

“…Application of suitable voltages, typically ≤200 mV, across the impermeable support membrane drives ion passage through the nanopore. The resulting open‐pore ionic conductance, G , is determined by the bulk solution conductivity, K , by the size and shape of the nanopore (here captured in volume and surface integrals,

A = {(\int \frac{d z}{π {false(r (z) false)}^{2}})}^{- 1}

and

B = {(\int \frac{d z}{2 π r false(z false)})}^{- 1}

, respectively), and by properties of the nanopore‐solution interface

G = K \cdot A (r, L) + μ |σ| \cdot B (r, L) = G_{bulk} + G_{surface}

where σ is the nanopore surface charge density that attracts counterions of mobility, μ. The pore has a radius, r(z) , that can vary along length, L , of the pore (aligned with the z ‐axis as shown in Supporting Information Fig.…”

Section: Introductionmentioning

confidence: 99%

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Conductance‐based profiling of nanopores: Accommodating fabrication irregularities

et al. 2017

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Solid-state nanopores are nanoscale channels through otherwise impermeable membranes. Single molecules or particles can be passed through electrolyte-filled nanopores by, e.g. electrophoresis, and then detected through the resulting physical displacement of ions within the nanopore. Nanopore size, shape, and surface chemistry must be carefully controlled, and on extremely challenging <10 nm-length scales. We previously developed a framework to characterize nanopores from the time-dependent changes in their conductance as they are being formed through solution-phase nanofabrication processes with the appeal of ease and accessibility. We revisited this simulation work, confirmed the suitability of the basic conductance equation using the results of time-dependent experimental conductance measurements during nanopore fabrication by Yanagi et al., and then deliberately relaxed the model constraints to allow for (i) the presence of defects; and (ii) the formation of two small pores instead of one larger one. Our simulations demonstrated that the time-dependent conductance formalism supports the detection and characterization of defects, as well as the determination of pore number, but with implementation performance depending on the measurement context and results. In some cases, the ability to discriminate numerically between the correct and incorrect nanopore profiles was slight, but with accompanying differences in candidate nanopore dimensions that could yield to post-fabrication conductance profiling, or be used as convenient uncertainty bounds. Time-dependent nanopore conductance thus offers insight into nanopore structure and function, even in the presence of fabrication defects.

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Section: Introductionmentioning

confidence: 86%

Section: Methodsmentioning

confidence: 99%

A = {(\int \frac{d z}{π {false(r (z) false)}^{2}})}^{- 1}

and

B = {(\int \frac{d z}{2 π r false(z false)})}^{- 1}

, respectively), and by properties of the nanopore‐solution interface

G = K \cdot A (r, L) + μ |σ| \cdot B (r, L) = G_{bulk} + G_{surface}

Section: Introductionmentioning

confidence: 99%

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Conductance‐based profiling of nanopores: Accommodating fabrication irregularities

et al. 2017

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“…The nanopore conductance magnitude is determined by the solution conductivity (and solution pH, through its effect on surface charges), nanopore size and shape, and also by the nanopore's surface charge. 24,113,[217][218][219][220][221] Passage of an analyte through the nanopore can generate a perturbation in the measured current that arises from physical displacement of solution ions by the analyte and from more complex interactions between charges in solution and on the surface of the analyte and nanopore. 24,28,52,[221][222][223] It is convenient to generically refer to the current perturbations as ''blockages,'' although analyte properties and sensing conditions may lead even to current enhancements.…”

Section: Nanofluidic Sample Cellsmentioning

confidence: 99%

Through a Window, Brightly: A Review of Selected Nanofabricated Thin-Film Platforms for Spectroscopy, Imaging, and Detection

Dwyer

Harb

2017

Appl Spectrosc

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We present a review of the use of selected nanofabricated thin films to deliver a host of capabilities and insights spanning bioanalytical and biophysical chemistry, materials science, and fundamental molecular-level research. We discuss approaches where thin films have been vital, enabling experimental studies using a variety of optical spectroscopies across the visible and infrared spectral range, electron microscopies, and related techniques such as electron energy loss spectroscopy, X-ray photoelectron spectroscopy, and single molecule sensing. We anchor this broad discussion by highlighting two particularly exciting exemplars: a thin-walled nanofluidic sample cell concept that has advanced the discovery horizons of ultrafast spectroscopy and of electron microscopy investigations of in-liquid samples; and a unique class of thin-film-based nanofluidic devices, designed around a nanopore, with expansive prospects for single molecule sensing. Free-standing, low-stress silicon nitride membranes are a canonical structural element for these applications, and we elucidate the fabrication and resulting features-including mechanical stability, optical properties, X-ray and electron scattering properties, and chemical natureof this material in this format. We also outline design and performance principles and include a discussion of underlying material preparations and properties suitable for understanding the use of alternative thin-film materials such as graphene.

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“…161 Geometric parameters of solid state nanopores, such as pore diameter, are estimated by conductance measurements. 162 …”

Section: Conductance-based Detectionmentioning

confidence: 99%

Conductivity-based detection techniques in nanofluidic devices

Harms

Haywood

Kneller

et al. 2015

Analyst

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This review covers conductivity detection in fabricated nanochannels and nanopores. Improvements in nanoscale sensing are a direct result of advances in fabrication techniques, which produce devices with channels and pores with reproducible dimensions and in a variety of materials. Analytes of interest are detected by measuring changes in conductance as the analyte accumulates in the channel or passes transiently through the pore. These detection methods take advantage of phenomena enhanced at the nanoscale, such as ion current rectification, surface conductance, and dimensions comparable to the analytes of interest. The end result is the development of sensing technologies for a broad range of analytes, e.g., ions, small molecules, proteins, nucleic acids, and particles.

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Conductance-Based Determination of Solid-State Nanopore Size and Shape: An Exploration of Performance Limits

Cited by 43 publications

References 32 publications

Conductance‐based profiling of nanopores: Accommodating fabrication irregularities

Conductance‐based profiling of nanopores: Accommodating fabrication irregularities

Through a Window, Brightly: A Review of Selected Nanofabricated Thin-Film Platforms for Spectroscopy, Imaging, and Detection

Conductivity-based detection techniques in nanofluidic devices

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