An SECM Detection Scheme with Improved Sensitivity and Lateral Resolution: Detection of Galactosidase Activity with Signal Amplification by Glucose Dehydrogenase

Zhao, Chuan; Wittstock, Günther

doi:10.1002/anie.200454261

Cited by 38 publications

(20 citation statements)

References 21 publications

(14 reference statements)

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“…Examples are p -aminophenyl phosphate (PAPP) for alkaline phosphatase (ALP), hydrogen peroxide (H 2 O 2 ) for glucose oxidase (GOx), p -aminophenyl-β- d -galactopyranoside (PAPG) for galactosidase and ferrocene derivatives for horseradish peroxidase (HRP). 5 – 8 The electroactive species can cycle between the enzyme and tip in the FB mode. Alternatively, the SECM tip can detect the flux of electroactive species initially not present, being the product of an enzymatic reaction at the substrate (substrate generation/tip collection (SG/TC) mode, Fig.…”

Section: Electrochemical Imaging Techniquesmentioning

confidence: 99%

Electrochemical imaging of cells and tissues

et al. 2018

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Section: Electrochemical Imaging Techniquesmentioning

confidence: 99%

Electrochemical imaging of cells and tissues

et al. 2018

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“…Re‐activation of the diffusing species in the presence of a second electrode providing an opposing reducing or oxidizing potential, as is performed in scanning electrochemical microscopy (SECM) and in nanofluidic devices, provides a significant amplification of the faradaic current due to redox cycling. This concept has been exploited for biodetection with increased sensitivity . Alternatively, if the second electrode is sufficiently close to the surface to get in contact with the electrochemically active layer, the electrode can take the role of the mediator by replenishing the oxidized/reduced species directly.…”

Section: Introductionmentioning

confidence: 99%

Electron Transfer Mediated by Surface‐Tethered Redox Groups in Nanofluidic Devices

Steentjes

Sarkar

Jonkheijm

et al. 2016

Small

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Electrochemistry provides a powerful sensor transduction and amplification mechanism that is highly suited for use in integrated, massively parallelized assays. Here, the cyclic voltammetric detection of flexible, linear poly(ethylene glycol) polymers is demonstrated, which have been functionalized with redox-active ferrocene (Fc) moieties and surface-tethered inside a nanofluidic device consisting of two microscale electrodes separated by a gap of <100 nm. Diffusion of the surface-bound polymer chains in the aqueous electrolyte allows the redox groups to repeatedly shuttle electrons from one electrode to the other, resulting in a greatly amplified steady-state electrical current. Variation of the polymer length provides control over the current, as the activity per Fc moiety appears to depend on the extent to which the polymer layers of the opposing electrodes can interpenetrate each other and thus exchange electrons. These results outline the design rules for sensing devices that are based on changing the polymer length, flexibility, and/or diffusivity by binding an analyte to the polymer chain. Such a nanofluidic enabled configuration provides an amplified and highly sensitive alternative to other electrochemical detection mechanisms.

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“…In other work glucose dehydrogenase could be bound to strepavidin modified magnetic microbeads, deposited on a surface and the resultant microarray imaged by SECM [6,7]. Multiple enzyme arrays have also been studied; galactoxidase and glucose dehydrogenase have, for example, previously been combined in microspots and imaged by SECM [8]. SECM and AFM techniques have also been combined using a single probe to enable both topographic and electrochemical imaging of a patterned enzyme surface [9].…”

Section: Introductionmentioning

confidence: 99%

Construction and interrogation of enzyme microarrays using scanning electrochemical microscopy – optimisation of adsorption and determination of enzymatic activity

Roberts

Davis

Collyer

et al. 2011

Analyst

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Scanning electrochemical microscopy (SECM) has been used to image and study the catalytic activity of horseradish peroxidase (HRP) immobilised in a patterned fashion onto glass slides. Microarrays of HRP islands could be deposited on amino-modified glass slides using glutaraldehyde crosslinking combined with the SECM being used as a micro-deposition device. The enzymatic activity of the immobilised enzyme on the surface was in the presence of its substrate observed to give rise to substantial positive feedback between the slide and the SECM microelectrode tip. Conversely when either blank slides - or slides coated with HRP which had been subsequently thermally denatured were utilised, these showed negative feedback effects. Various conditions such as enzyme concentration, incubation time and substrate concentration were systematically varied to optimise sensitivity. Regular arrays of HRP could be assembled and when imaged, displayed lower limits of detection of 1.2 × 10(-12) mol ml(-1) of benzoquinone.

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An SECM Detection Scheme with Improved Sensitivity and Lateral Resolution: Detection of Galactosidase Activity with Signal Amplification by Glucose Dehydrogenase

Cited by 38 publications

References 21 publications

Electrochemical imaging of cells and tissues

Electrochemical imaging of cells and tissues

Electron Transfer Mediated by Surface‐Tethered Redox Groups in Nanofluidic Devices

Construction and interrogation of enzyme microarrays using scanning electrochemical microscopy – optimisation of adsorption and determination of enzymatic activity

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