Pressure-Dependent Ion Current Rectification in Conical-Shaped Glass Nanopores

Lan, Wen−How; Holden, Deric A.; White, Henry S.

doi:10.1021/ja205773a

Cited by 216 publications

(250 citation statements)

References 37 publications

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“…1c), consistent with the rectification behavior observed in negatively charged conical geometries. [28][29][30][31] The nanopipettes were filled with (5 kbp or 10 kbp) double-stranded DNA solution and Ag/AgCl electrodes were fitted both in the nanopipette (patch electrode) and in the external reservoir containing only buffer (bath/ground electrode). Under these conditions, the negatively charged DNA molecules inside the nanopipette migrate toward the inner electrode under positive applied potentials and toward the tip of the nanopipette under negative potentials.…”

Section: Resultsmentioning

confidence: 99%

On-Demand Delivery of Single DNA Molecules Using Nanopipets

et al. 2015

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Understanding the behavioral properties of single molecules or larger scale populations interacting with single molecules is currently a hotly pursued topic in nanotechnology. This arises from the potential such techniques have in relation to applications such as targeted drug delivery, early stage detection of disease, and drug screening. Although label and label-free single molecule detection strategies have existed for a number of years, currently lacking are efficient methods for the controllable delivery of single molecules in aqueous environments. In this article we show both experimentally and from simulations that nanopipets in conjunction with asymmetric voltage pulses can be used for label-free detection and delivery of single molecules through the tip of a nanopipet with "on-demand" timing resolution. This was demonstrated by controllable delivery of 5 kbp and 10 kbp DNA molecules from solutions with concentrations as low as 3 pM.

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Section: Resultsmentioning

confidence: 99%

On-Demand Delivery of Single DNA Molecules Using Nanopipets

et al. 2015

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“…Nanofluidic devices have been attracting great interest owing to the unique ionic transport properties, [1][2][3][4] such as ionic selectivity, [5][6][7][8] ionic rectification, [9][10][11][12] local ion depletion/enrichment, [13][14][15][16][17] etc. Of these, electrostatic interactions between ionic species and surface charge of channel play important roles because the electrical double layer (EDL), which can extend as far as 100 nm to only a few angstroms, occupies a non-negligible fraction of nanofluidic channel.…”

mentioning

confidence: 99%

Tuning Transport Selectivity of Ionic Species by Phosphoric Acid Gradient in Positively Charged Nanochannel Membranes

Yang

Wang

et al. 2015

Anal. Chem.

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The transport of ionic species through a nanochannel plays important roles in fundamental research and practical applications of the nanofluidic device. Here, we demonstrated that ionic transport selectivity of a positively charged nanochannel membrane can be tuned under a phosphoric acid gradient. When phosphoric acid solution and analyte solution were connected by the positively charged nanochannel membrane, the faster-moving analyte through the positively charged nanochannel membrane was the positively charged dye (methylviologen, MV(2+)) instead of the negatively charged dye (1,5-naphthalene disulfonate, NDS(2-)). In other words, a reversed ion selectivity of the nanochannel membranes can be found. It can be explained as a result of the combination of diffusion, induced electroosmosis, and induced electrophoresis. In addition, the influencing factors of transport selectivity, including concentration of phosphoric acid, penetration time, and volume of feed solution, were also investigated. The results showed that the transport selectivity can further be tuned by adjusting these factors. As a method of tuning ionic transport selectivity by establishing phosphoric acid gradient, it will be conducive to improving the separation of ionic species.

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“…It has been reported that nanopores with radii of 200 nm rectified the current based on the gas pressure, 24,46 Figure 5 CO2 activation of ion current rectification in nanochannels Y Xu et al whereas the geometrical structure of the nanopores with radii less than~30 nm will have a negligible effect on the current. Thus, the possible mechanism of the physical gas pressures induced by CO 2 can be excluded for our smart chemical-driven nanopores because the radii of the nanopores in our system are o30 nm (Supplementary Figure S12).…”

Section: Co2 Activation Of Ion Current Rectification In Nanochannelsmentioning

confidence: 98%

“…Nevertheless, most previous studies on rectification have been based on liquid-solid interactions. [18][19][20][21][22][23] The gas phase in the nanofluidic system was not recognized until it was reported in 2011 that the physical loading of gas pressure also influences the rectification property of the nanofluidic system, 24 although this work considered physically driven rectification, and it is hard to distinguish the components of the gas.…”

Section: Introductionmentioning

confidence: 99%

Mimicking how plants control CO2 influx: CO2 activation of ion current rectification in nanochannels

Zhang

Tong

et al. 2015

NPG Asia Mater

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One of the key processes of photosynthesis is to control the influx of atmospheric carbon dioxide (CO 2 ). Ion channels fulfill this process by regulating the opening and closing of stomatal pores in plants' leaves. Inspired by this natural process, we have developed an amidine-modified gas-responsive system that closely mimics stomatal pores: CO 2 rather than the variation in the pH value directly modulates the conductance state of the channel. The CO 2 -activated chemical reaction of amidine groups is reversible and produces an excess surface charge on the pore walls of asymmetric nanochannels, which makes the ions pass preferentially through the nanochannels in one direction relative to the conductance in the other direction, resulting in a significant ion current rectification. Furthermore, the influence of the different molecular conformation of the amidine-containing molecules on the current is investigated and discussed. The conclusive simulation of our system based on the Poisson and Nernst-Planck (PNP) model is also in good agreement with the experimental results. Accordingly, we have successfully mimicked the mechanism of stomatal closure in plants with our gas-activated nanosystem.

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Pressure-Dependent Ion Current Rectification in Conical-Shaped Glass Nanopores

Cited by 216 publications

References 37 publications

On-Demand Delivery of Single DNA Molecules Using Nanopipets

On-Demand Delivery of Single DNA Molecules Using Nanopipets

Tuning Transport Selectivity of Ionic Species by Phosphoric Acid Gradient in Positively Charged Nanochannel Membranes

Mimicking how plants control CO2 influx: CO2 activation of ion current rectification in nanochannels

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