Direct detection of antibody–antigen binding using an on-chip artificial pore

Saleh, Omar A.; Sohn, Lydia L.

doi:10.1073/pnas.0337563100

Cited by 166 publications

(133 citation statements)

References 31 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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“…It is a classic flow cytometer based on the electronic detection method that employs the modulation of electrical resistance in an electrical ion current for label-free biological sample identification and analysis. Resistive pulse sensing method has been widely applied for sensing microparticles, such as polystyrene particles (Xu et al 2007), single DNA molecules (Saleh and Sohn 2003a), proteins (Wharton et al 2007), antigen and antibody (Saleh and Sohn 2003b;Carbonaro and Sohn 2005). The sensitivity of resistive pulse approach depends on the volume ratio of the sample and has a much lower manufacturing and operational cost.…”

Section: Introductionmentioning

confidence: 99%

Optical microflow cytometer for particle counting, sizing and fluorescence detection

Chen

Wang

2008

Microfluid Nanofluid

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A novel on-chip optical flow cytometer concept is reported for fluorescence detection, enumeration, and sizing of microparticles in a poly-dimethylsiloxane (PDMS) microchip. The detection system integrates a pair of external optical fibers and other optical components for particle counting, sizing and fluorescence analysis in each measurement simultaneously. The scattered light signal indicates the total number and the size of the particles passing through the detection window, whereas the concurrent backward fluorescence signal shows only the number of fluorescence particles. In the experiments, microparticles of four different sizes with diameters ranging from 3.2 to 10.2 lm were discriminated and counted based on the fluorescence and scattered light intensity. The relative percentage of the fluorescence-labeled particles can be analyzed by the ratio of the events of fluorescence signals to forward scattered signals.

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“…1 The immunoassay is an antibody-based detecting technique for a specific antigen; 2 it exploits highly sensitive and specific binding interactions between an antigen and an antibody. 3,4 Depending on the assay format, immunoassays can be used qualitatively and quantitatively, and the application of immunoassays has been extended to various research fields, such as environmental monitoring, medical diagnostics, proteomics, pharmaceutical drug screening research, and basic cellular analytical research. 5,6 Enzyme-linked immunosorbent assays (ELISAs) are the most fundamental and basic immunoassay for clinical diagnostic and biological research fields, due to their high sensitivity and versatility.…”

Section: Introductionmentioning

confidence: 99%

Computational study on the interactions and orientation of monoclonal human immunoglobulin G on a polystyrene surface

Javkhlantugs¹,

Bayar²,

Ganzorig³

et al. 2013

IJN

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Abstract:Having a theoretical understanding of the orientation of immunoglobulin on an immobilized solid surface is important in biomedical pathogen-detecting systems and cellular analysis. Despite the stable adsorption of immunoglobulin on a polystyrene (PS) surface that has been applied in many kinds of immunoassays, there are many uncertainties in antibodybased clinical and biological experimental methods. To understand the binding mechanism and physicochemical interactions between immunoglobulin and the PS surface at the atomic level, we investigated the binding behavior and interactions of the monoclonal immunoglobulin G (IgG) on the PS surface using the computational method. In our docking simulation with the different arrangement of translational and rotational orientation of IgG onto the PS surface, three typical orientation patterns of the immunoglobulin G on the PS surface were found. We precisely analyzed these orientation patterns and clarified how the immunoglobulin G interacts with the PS surface at atomic scale in the beginning of the adsorption process. Major driving forces for the adsorption of IgG onto the PS surface come from serine (Ser), aspartic acid (Asp), and glutamic acid (Glu) residues.

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Direct detection of antibody–antigen binding using an on-chip artificial pore

Cited by 166 publications

References 31 publications

Label-free biosensing with functionalized nanopipette probes

Label-free biosensing with functionalized nanopipette probes

Optical microflow cytometer for particle counting, sizing and fluorescence detection

Computational study on the interactions and orientation of monoclonal human immunoglobulin G on a polystyrene surface

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