A dielectric-modulated field-effect transistor for biosensing

Im, Hyungsoon; Huang, Xing-Jiu; Gu, Bonsang; Choi, Yang‐Kyu

doi:10.1038/nnano.2007.180

Cited by 524 publications

(249 citation statements)

References 29 publications

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“…E lectrochemical biosensors, which have been widely employed in clinical, environmental, industrial and agricultural applications, recognize biological analytes through a catalytic or binding event occurring at the interface of electrodes [1][2][3][4][5] . Intimate correlation of biosensing performance and the electrocatalytic and structural properties of electrodes has stimulated considerable efforts devoted to innovational materials to coordinate mass-and charge-transport and electron-transfer kinetics for realizing simultaneous minimization of primary resistances in biosensing: electrochemical reaction occurring at electrolyte/electrode interface, mass transport of analyte in electrolyte and electrode, and the electron conduction in electrode and current collector [6][7][8][9] .…”

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confidence: 99%

Nanoporous gold supported cobalt oxide microelectrodes as high-performance electrochemical biosensors

et al. 2013

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Tremendous demands for electrochemical biosensors with high sensitivity and reliability, fast response and excellent selectivity have stimulated intensive research on developing versatile materials with ultrahigh electrocatalytic activity. Here we report flexible and self-supported microelectrodes with a seamless solid/nanoporous gold/cobalt oxide hybrid structure for electrochemical nonenzymatic glucose biosensors. As a result of synergistic electrocatalytic activity of the gold skeleton and cobalt oxide nanoparticles towards glucose oxidation, amperometric glucose biosensors based on the hybrid microelectrodes exhibit multi-linear detection ranges with ultrahigh sensitivities at a low potential of 0.26 V (versus Ag/AgCl). The sensitivity up to 12.5 mA mM À 1 cm À 2 with a short response time of less than 1 s gives rise to ultralow detection limit of 5 nM. The outstanding performance originates from a novel nanoarchitecture in which the cobalt oxide nanoparticles are incorporated into pore channels of the seamless solid/nanoporous Au microwires, providing excellent electronic/ionic conductivity and mass transport for the enhanced electrocatalysis.

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Nanoporous gold supported cobalt oxide microelectrodes as high-performance electrochemical biosensors

et al. 2013

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“…This setup is different from previously reported experiments where nanogaps were used to detect biomolecules through changes in the dielectric constant of the gap, using impedance measurements over the height of the nanogap. 7,8 For electrical detection of immobilized proteins in nanochannels, streptavidin-biotin was chosen as the model receptor-ligand pair. To perform such bindings in nanochannels, surfaces were pre-coated with the commercially available polymer PLL(20)-g[3.5]-PEG(2)/PEG(3.4)-Biotin (50%) (SurfaceSolutionS, Zurich, Switzerland) at 0.1 mg/ml, subsequently referred to PLL-g-PEGbiotin.…”

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Electrical Detection of Fast Reaction Kinetics in Nanochannels with an Induced Flow

2007

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Nanofluidic channels can be used to enhance surface binding reactions, since the target molecules are closely confined to the surfaces that are coated with specific binding partners. Moreover, diffusion-limited binding can be significantly enhanced if the molecules are steered into the nanochannels via either pressure-driven or electrokinetic flow. By monitoring the nanochannel impedance, which is sensitive to surface binding, low analyte concentrations have been detected electrically in nanofluidic channels within response times of 1-2 hours. This represents a ~54 fold reduction in the response time using convective flow compared to diffusion-limited binding. At high flow velocities the presented method of reaction kinetics enhancement is potentially limited by forceinduced dissociations of the receptor-ligand bonds. Optimization of this scheme could be useful for label-free, electrical detection of biomolecule binding reactions within nanochannels on a chip. Keywords NANOFLUIDICS; BINDING KINETICS; ENHANCED MASS TRANSPORT; CONVECTION; ELECTRICAL BIOSENSOR; IMPEDANCE SPECTROSCOPY; FUNCTIONALIZATION; STREPTAVIDIN-BIOTINOne limiting factor for low-abundance analyte detection by immunoassay is the existence of surface diffusion layers, which limits the binding kinetics. In typical ELISA (Enzyme Linked ImmunoSorbent Assays) or bead-based immunoassays, target molecules need to be transported (primarily by diffusion) to the surface-bound antibodies for a binding reaction to occur. The distance for this diffusive transport is roughly corresponding to the average distance between the two target molecules in the sample solution, which can be as large as ~10 µm at lower concentrations (~pM). Diffusive transport at that length scale is relatively slow and inefficient, therefore leading to analyte depletion near the binding surface. This can significantly limit the speed of assays, requiring long incubation times to reach binding equilibrium. 1One way to deal with this problem would be shortening this distance, by confining both target molecules and the antibodies within a nanofluidic channel. Karnik et al. 2 have studied streptavidin-biotin binding in nanochannels, demonstrating the dominance of size and charge effects at high and low ionic strengths, respectively. Largest conductance changes after streptavidin immobilization to biotinylated surfaces were observed at low ionic strength, and *To whom correspondence should be addressed. E-mail: jyhan@mit.edu, Tel: +1-617-253-2290, Fax: +1-617-258-5846 We demonstrate that diffusion-limited reactions can be overcome by performing the detection of analytes in nanochannels with an applied convective flow through them to enhance mass transport. This results in fast reaction kinetics in nanofluidic channels and thus a reduction in the response time to detect a specific target molecule even at low analyte concentrations. Compared to the diffusional transport limit, the response time is decreased by a factor of ~54 by using pressure-driven flow through nanochannels. Surface...

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“…The capacitance in the nanogap affects the current between source and drain. The device has been called dielectricmodulated FET (63 ), and its feasibility with avidinbiotin binding has been demonstrated. The method is not sensitive to the charge of the bound species, as is the case for the standard ion-sensitive FETs.…”

Section: Field-effect Transistor Technologymentioning

confidence: 99%

Discerning Trends in Multiplex Immunoassay Technology with Potential for Resource-Limited Settings

Gordon

Michel

2012

Clinical Chemistry

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BACKGROUND In the search for more powerful tools for diagnoses of endemic diseases in resource-limited settings, we have been analyzing technologies with potential applicability. Increasingly, the process focuses on readily accessible bodily fluids combined with increasingly powerful multiplex capabilities to unambiguously diagnose a condition without resorting to reliance on a sophisticated reference laboratory. Although these technological advances may well have important implications for the sensitive and specific detection of disease, to date their clinical utility has not been demonstrated, especially in resource-limited settings. Furthermore, many emerging technological developments are in fields of physics or engineering, which are not readily available to or intelligible to clinicians or clinical laboratory scientists. CONTENT This review provides a look at technology trends that could have applicability to high-sensitivity multiplexed immunoassays in resource-limited settings. Various technologies are explained and assessed according to potential for reaching relevant limits of cost, sensitivity, and multiplex capability. Frequently, such work is reported in technical journals not normally read by clinical scientists, and the authors make enthusiastic claims for the potential of their technology while ignoring potential pitfalls. Thus it is important to draw attention to technical hurdles that authors may not be publicizing. SUMMARY Immunochromatographic assays, optical methods including those involving waveguides, electrochemical methods, magnetorestrictive methods, and field-effect transistor methods based on nanotubes, nanowires, and nanoribbons reveal possibilities as next-generation technologies.

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A dielectric-modulated field-effect transistor for biosensing

Cited by 524 publications

References 29 publications

Nanoporous gold supported cobalt oxide microelectrodes as high-performance electrochemical biosensors

Nanoporous gold supported cobalt oxide microelectrodes as high-performance electrochemical biosensors

Electrical Detection of Fast Reaction Kinetics in Nanochannels with an Induced Flow

Discerning Trends in Multiplex Immunoassay Technology with Potential for Resource-Limited Settings

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