Resistive-Pulse Studies of Proteins and Protein/Antibody Complexes Using a Conical Nanotube Sensor

Sexton, L.; Horne, Lloyd P.; Sherrill, Stefanie A.; Bishop, Gregory W.; Baker, Lane A.; Martin, Charles R.

doi:10.1021/ja0739943

Cited by 218 publications

(245 citation statements)

References 67 publications

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“…The fully electrical molecular detection is also unique compared with technologies such as Biacore, a surface plasmon resonancebased bioanalyzer (28), in that it works without optical signal readout. For such electrical detection, a nanoporous structure is known to be suitable, especially when it is used in resistive-pulse mode (29,30). In this study we showed another practical option using functionalized glass nanopipettes in which antibodies of interest were immobilized on the surface of individual nanopipettes rather than dispersed in the bulk solution.…”

Section: Discussionmentioning

confidence: 96%

Label-free biosensing with functionalized nanopipette probes

Umehara

Karhánek

Davis

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

155

148

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Nanopipette technology can uniquely identify biomolecules such as proteins based on differences in size, shape, and electrical charge. These differences are determined by the detection of changes in ionic current as the proteins interact with the nanopipette tip coated with probe molecules. Here we show that electrostatic, biotin-streptavidin, and antibody-antigen interactions on the nanopipette tip surface affect ionic current flowing through a 50-nm pore. Highly charged polymers interacting with the glass surface modulated the rectification property of the nanopipette electrode. Affinity-based binding between the probes tethered to the surface and their target proteins caused a change in the ionic current due to a partial blockade or an altered surface charge. These findings suggest that nanopipettes functionalized with appropriate molecular recognition elements can be used as nanosensors in biomedical and biological research.biomolecules ͉ biosensor ͉ immunoassay ͉ current rectification ͉ nanopore N anopipettes, characterized by the submicron to nanoscale size of the pore at the tip, are of great interest because of their unique physicochemical properties and potential for various biomedical and biological applications. By pulling a single glass capillary, one can easily and cost-effectively create a pair of nanopipettes that can be used for molecular deposition onto a solid surface (1, 2), for delivery to the surface of a single cell (3) and its inner compartments (4, 5), or for biomolecular sensing as described hereafter. These applications can be optimized by an enhanced understanding of the physical and chemical interactions at the pore region, which has been a subject of theoretical studies (6). Advances in both technical and theoretical fronts will further demonstrate the utility of nanopipettebased devices for many purposes.Biomolecule sensing with a nanopipette probe has been performed with and without the aid of optical methods. Fluorescence-based pH sensing (7) shows the submicron spatial resolution and millisecond time resolution of such sensors. Fully-electrical detection of DNA-conjugated gold nanoparticles (8) uses resistive pulses caused by the translocation of fairly large (10 nm) particles, the underlying principle identical to that of nanopore biosensors (9) and DNA sequencers (10). Unlike other nanostructure-based chemical sensors (11), which often require access to semiconductor facilities, nanopipette biosensors can be created and tailored at the bench, thereby reducing turnaround time. Nanopipettes also have enormous potential for detecting a small number of molecules from a tiny amount of clinical samples or live single cells, a feature useful for medical diagnostics and molecular and cellular biology research.A key challenge for nanopipette biosensors is adapting to applications where specific molecules can be targeted. One approach would be to separate the sensing and actuating functions, an idea embodied by an engineered ion channel fused with a surface receptor protein responsible f...

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Section: Discussionmentioning

confidence: 96%

Label-free biosensing with functionalized nanopipette probes

Umehara

Karhánek

Davis

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

155

148

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“…For example, if a receptor is immobilized to the nanopore surface, then the presence of the target will cause a change in ion current as long as the target is bound. There is a growing arsenal of techniques for chemically modifying the surface of nanopores (Nguyen et al, 2011, Sexton, et al, 2007, Wanunu&Meller, 2007. There is nothing about this particular sensing mechanism that requires nanoscale pores.…”

Section: Ion Current Modulation Methodsmentioning

confidence: 99%

“…These applications require no labelling of the protein, which can sometimes change binding properties. For example, the Martin group has shown that the electrical signature of a protein can be distinguished from that of the protein bound to an antibody fragment (Sexton et al, 2007). In that report, tracketched nanopores were coated with gold to make a conical nanotube of tip opening 9 to 27 nm in diameter.…”

Section: Resistive-pulse Sensingmentioning

confidence: 99%

Immunoassays Using Artificial Nanopores

Actis¹,

Vilozny²,

Pourmand³

2012

Advances in Immunoassay Technology

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“…But even covalent bonding can be used for attachment if appropriate functional groups exist on the etched surface. This is a starting point for biospecific single-channel sensors [51][52][53][54][55][56][57][58][59][60].…”

Section: Asymmetric Single Poresmentioning

confidence: 99%

Controlled fabrication of ion track nanowires and channels

Spohr

Zet

Fischer

et al. 2010

Nuclear Instruments and Methods in Physics Research Section B:

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We describe a system for fabricating prescribed numbers of ion track nanochannels and nanowires from a few hundred down to one. It consists of two parts: First, a mobile TAPE TRANSPORT SYSTEM, which, in connection with an ion beam from a heavy-ion accelerator (nuclear charge Z above 18 and specific energy between 1 and 10 MeV/nucleon) tuned down to low flux density by means of defocusing and a set of sensitive fluorescence screens, can fabricate a series of equidistant irradiation spots on a tape, whereby each spot corresponds to a preset number of ion tracks. The tape transport system uses films of 36 mm width and thicknesses between 5 and 100 µm. The aiming precision the system depends on the diameter of the installed beam defining aperture, which is between 50 and 500 µm. The distance between neighboring irradiation spots on the tape is variable and typically set to 25 mm. After reaching the preset number of ion counts the irradiation is terminated, the tape is marked and moved to the next position. The irradiated frames are punched out to circular membranes with the irradiation spot in the center. The second part of the setup is a compact CONDUCTOMETRIC SYSTEM with 10 picoampere resolution consisting of a computer controlled conductometric cell, sealing the membrane hermetically between two chemically inert half-chambers containing electrodes and filling/flushing openings, and is encased by an electrical shield and a thermal insulation. The ion tracks can be etched to a preset diameter and the system can be programmed to electroreplicate nanochannels in a prescribed sequence of magnetic/nonmagnetic metals, alloys or semiconductors. The goal of our article is to make the scientific community aware of the special features of single ion fabrication and to demonstrate convincingly the significance of controlled etching and electroreplication.

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Resistive-Pulse Studies of Proteins and Protein/Antibody Complexes Using a Conical Nanotube Sensor

Cited by 218 publications

References 67 publications

Label-free biosensing with functionalized nanopipette probes

Label-free biosensing with functionalized nanopipette probes

Immunoassays Using Artificial Nanopores

Controlled fabrication of ion track nanowires and channels

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