Conductive and Biphasic Pulses in Tunable Resistive Pulse Sensing

Weatherall, Eva; Willmott, Geoff R.

doi:10.1021/acs.jpcb.5b00344

Cited by 32 publications

(67 citation statements)

References 44 publications

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“…The observation of rectification behaviour does illustrate that the enriched ion zone at the pore mouth used to describe the rectification properties of smaller pores 24,42 sufficiently exerts an influence across the larger opening, even when the electrical DL is much shorter than the opening D s . This effect has also been attributed to biphasic pulse behaviour in TRPS 49 .…”

Section: Please Do Not Adjust Marginsmentioning

confidence: 75%

“…This effect is seen to a greater extent within conical pores, and typically recorded for pore openings where the diameter, D s , is equivalent to the electrical double layer, DL, thickness, 24,48 although the DL does not need to fully extend across the pore opening 24 , and larger pores exhibit current rectification effects 23,49 .…”

Section: Assay 1 -Measuring Translocation Times From Resistive Pulsesmentioning

confidence: 85%

“…Tunable pores fabricated from PU have a small negative surface charge 29,49 at pH > 5, and are conical in shape. The unmodified pores used here had an approx.…”

Section: Assay 1 -Measuring Translocation Times From Resistive Pulsesmentioning

confidence: 99%

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Protein detection using tunable pores: resistive pulses and current rectification

et al. 2016

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We present the first comparison between assays that use resistive pulses or rectification ratios on a tunable pore platform. We compare their ability to quantify the cancer biomarker Vascular Endothelial Growth Factor (VEGF). The first assay measures the electrophoretic mobility of aptamer modified nanoparticles as they traverse the pore. By controlling the aptamer loading on the particle surface, and measuring the speed of each translocation event we are able to observe a change in velocity as low as 18 pM. A second non-particle assay exploits the current rectification properties of conical pores. We report the first use of Layer-by-Layer (LbL) assembly of polyelectrolytes onto the surface of the polyurethane pore. The current rectification ratios demonstrate the presence of the polymers, producing pH and ionic strength-dependent currents. The LbL assembly allows the facile immobilisation of DNA aptamers onto the pore allowing a specific dose response to VEGF. Monitoring changes to the current rectification allows for a rapid detection of 5 pM VEGF. Each assay format offers advantages in their setup and ease of preparation but comparable sensitivities.

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Section: Please Do Not Adjust Marginsmentioning

confidence: 75%

Section: Assay 1 -Measuring Translocation Times From Resistive Pulsesmentioning

confidence: 85%

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Protein detection using tunable pores: resistive pulses and current rectification

et al. 2016

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“…High aspect ratio nanopores are available to researchers with a product called qNano. [73][74][75][76][77] This measurement system dynamically adjusts the diameter of the through-hole made in the polymer. With high aspect ratio nanopores, the particle diameter and zeta potential of the analyte are obtained by utilizing the fact that Ip and td have information on the volume, particle velocity, and surface charge of the analyte.…”

Section: •2 Flow Dynamics Of High Aspect Ratio Nanoporesmentioning

confidence: 99%

Analysis Method of the Ion Current-Time Waveform Obtained from Low Aspect Ratio Solid-state Nanopores

Taniguchi

2019

ANAL. SCI.

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Low aspect ratio nanopores are expected to be applied to the detection of viruses and bacteria because of their high spatial resolution. Multiphysics simulations have revealed that the ion current-time waveform obtained from low aspect ratio nanopores contains information on not only the volume of viruses and bacteria, but also the structure, surface charge, and flow dynamics. Analysis using machine learning extracts information about these analytes from the ion current-time waveform. The combination of low aspect ratio nanopores, multiphysics simulation, and machine learning has made it possible to distinguish different types of viruses and bacteria with high accuracy.

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“…Studies have shown that ionic strength, off-axial translocation, the pore wall charge density and applied potential can affect the pulse size and width. [29][30][31][32] In cases where the charge double layers around the particles and pore walls interact, conductive pulses and ion current rectification can also be observed. 21,33,34 To help understand how the charge density effects the sensitivity of Aptamer RPS assays here we choose two known aptamers to heavy metal ions.…”

Section: Introductionmentioning

confidence: 99%

The Design and Characterization of Multifunctional Aptamer Nanopore Sensors

et al. 2018

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Aptamer-modified nanomaterials provide a simple, yet powerful sensing platform when combined with resistive pulse sensing technologies. Aptamers adopt a more stable tertiary structure in the presence of a target analyte, which results in a change in charge density and velocity of the carrier particle. In practice the tertiary structure is specific for each aptamer and target, and the strength of the signal varies with different applications and experimental conditions. Resistive pulse sensors (RPS) have single particle resolution, allowing for the detailed characterization of the sample. Measuring the velocity of aptamer-modified nanomaterials as they traverse the RPS provides information on their charge state and densities. To help understand how the aptamer structure and charge density effects the sensitivity of aptamer-RPS assays, here we study two metal binding aptamers. This creates a sensor for mercury and lead ions that is capable of being run in a range of electrolyte concentrations, equivalent to river to seawater conditions. The observed results are in excellent agreement with our proposed model. Building on this we combine two aptamers together in an attempt to form a dual sensing strand of DNA for the simultaneous detection of two metal ions. We show experimental and theoretical responses for the aptamer which creates layers of differing charge densities around the nanomaterial. The density and diameter of these zones effects both the viability and sensitivity of the assay. While this approach allows the interrogation of the DNA structure, the data also highlight the limitations and considerations for future assays.

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Conductive and Biphasic Pulses in Tunable Resistive Pulse Sensing

Cited by 32 publications

References 44 publications

Protein detection using tunable pores: resistive pulses and current rectification

Protein detection using tunable pores: resistive pulses and current rectification

Analysis Method of the Ion Current-Time Waveform Obtained from Low Aspect Ratio Solid-state Nanopores

The Design and Characterization of Multifunctional Aptamer Nanopore Sensors

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