Electrochemical analysis based on nanoporous structures

Park, Sangyun; Kim, Hee Chan; Chung, Taek Dong

doi:10.1039/c2an35294j

Cited by 111 publications

(102 citation statements)

References 145 publications

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“…This decrease is attributed to the ionic species in the electrolyte not having sufficient time to fully permeate the nanoporous electrode at high frequencies, limiting the electrochemically active surface area. This result is in agreement with previous experiments demonstrating limited accessibility of the porous surface at comparable scan rates 39,45,46 . In contrast, the rate of increase of SWV signal for planar Au was constant within the same frequency range ( Figure S3d).…”

Section: Swv Signals As a Function Of Frequency For Different Np-au Msupporting

confidence: 93%

Effect of Nanoporous Gold Thin Film Morphology on Electrochemical DNA Sensing

2015

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Advances in materials science and chemistry have led to the development of a wide range of nanostructured materials for building novel electrochemical biosensors. A systematic understanding of the challenges related to electrode morphology involved in designing such sensors is essential for developing effective biosensing tools. In this study, we use nanoporous gold (npAu) thin film electrode coatings with sub-micron thicknesses, as a model system to investigate the influence of nanostructuring on DNA-methylene blue (MB) interactions and their application for DNA biosensors. The interaction of single-and double-stranded DNA immobilized onto morphologically different np-Au films with MB was electrochemically interrogated via square wave voltammetry (SWV). The electrochemical signal from these electrodes in response to MB decayed progressively with each SWV scan. The decay rate was governed by accessibility of the electrochemically-active np-Au surface by the analyte. The optimum frequency for extracting the maximum signal via SWV was influenced by the film morphology, where the optimum frequency was lower for the nanoporous morphology with lower density of molecular access points into the porous coating. Overall, the np-Au electrodes exhibited a 10-fold enhancement in probe grafting density and approximately 10-fold higher electrochemical current upon probetarget hybridization as compared to the planar Au electrodes. The np-Au electrodes enabled sensitive detection with a dynamic range of 10 nM to 100 nM that shifts by an order of magnitude for coarsened np-Au morphology due to increased target penetration into the porous network and hence enhanced hybridization efficiency. These findings provide insight into the influence of nanostructuring on the transport mechanisms of small molecules and nucleic acids, and yield an understanding of diverse sensor performance parameters such as DNA grafting density, hybridization efficiency, sensitivity and dynamic range.

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Section: Swv Signals As a Function Of Frequency For Different Np-au Msupporting

confidence: 93%

Effect of Nanoporous Gold Thin Film Morphology on Electrochemical DNA Sensing

2015

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“…This is important because the electrochemistry that takes place at high surface area nanostructured electrodes is very different from that which takes place at a conventional planar electrode or ultramicroelectrode [14,100]. In a cyclic voltammetry (CV) experiment, the Randles-Sevcik equation predicts that Faradaic current scales linearly with electrode area when all other variables are constant.…”

Section: Electrochemical Methodsmentioning

confidence: 99%

“…High surface area nanostructured electrodes have received considerable attention in recent years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. These materials are conductive, have surface areas that are typically 2-1000 times larger than a planar electrode of similar size, and consist of either oriented, well-defined or random pore morphology.…”

Section: Introductionmentioning

confidence: 99%

“…The reader is referred to other reviews for more information related to the material, engineering and mechanical aspects of nanoporous gold [15,27,28], electroanalysis with macroporous electrodes [16,29], energy applications of nanostructured electrodes [30], electrochemical analysis at nanoporous electrodes [14], and electrocatalysis with nanoporous materials [13]. A book on nanoporous gold by Wittstock et al has also recently been published [31].…”

Section: Introductionmentioning

confidence: 99%

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Nanoporous Gold Electrodes and Their Applications in Analytical Chemistry

Collinson

2013

ISRN Analytical Chemistry

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Nanoporous gold prepared by dealloying Au:Ag alloys has recently become an attractive material in the field of analytical chemistry. This conductive material has an open, 3D porous framework consisting of nanosized pores and ligaments with surface areas that are 10s to 100s of times larger than planar gold of an equivalent geometric area. The high surface area coupled with an open pore network makes nanoporous gold an ideal support for the development of chemical sensors. Important attributes include conductivity, high surface area, ease of preparation and modification, tunable pore size, and a bicontinuous open pore network. In this paper, the fabrication, characterization, and applications of nanoporous gold in chemical sensing are reviewed specifically as they relate to the development of immunosensors, enzyme-based biosensors, DNA sensors, Raman sensors, and small molecule sensors.

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“…181 Because DA has faster electron transfer kinetics than 5-HT, 182-184 most DA molecules are oxidized completely at the outskirts of the pores before they are able to diffuse into the pores, and the effect of the pore-created inner surface on signal output is therefore greatly reduced. 178 In contrast, the large active surface area of our porous gold film is favorable for detecting the slower electron transfer from 5-HT due to the confinement of 5-HT molecules within the pores, 182 generating a higher amplification of 5-HT oxidation relative to DA from mixtures of the two molecules.…”

Section: Resultsmentioning

confidence: 93%

Nanomaterial-Based Electrochemical and Colorimetric Sensors for On-Site Detection of Small-Molecule Targets

Guntupalli¹

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Electrochemical analysis based on nanoporous structures

Cited by 111 publications

References 145 publications

Effect of Nanoporous Gold Thin Film Morphology on Electrochemical DNA Sensing

Effect of Nanoporous Gold Thin Film Morphology on Electrochemical DNA Sensing

Nanoporous Gold Electrodes and Their Applications in Analytical Chemistry

Nanomaterial-Based Electrochemical and Colorimetric Sensors for On-Site Detection of Small-Molecule Targets

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