Immobilized Diaphorase Surfaces Observed by Scanning Electrochemical Microscope with Shear Force Based Tip−Substrate Positioning

Yamada, Hiroshi; Fukumoto, Hideo; Yokoyama, Tetsuya; Koike, Takao

doi:10.1021/ac048582g

Cited by 53 publications

(39 citation statements)

References 31 publications

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“…35,[41][42][43][44][45][46] Since the shear forces have to be measured in a viscous liquid, the signal change upon approach is rather small. Because long integration times have to be used, lateral translation rates are restricted.…”

Section: -25mentioning

confidence: 99%

Soft Stylus Probes for Scanning Electrochemical Microscopy

Cortés‐Salazar

Träuble

et al. 2009

Anal. Chem.

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A soft stylus microelectrode probe has been developed to carry out scanning electrochemical microscopy (SECM) of rough, tilted, and large substrates in contact mode. It is fabricated by first ablating a microchannel in a polyethylene terephthalate thin film and filling it with a conductive carbon ink. After curing the carbon track and lamination with a polymer film, the V-shaped stylus was cut thereby forming a probe, with the cross section of the carbon track at the tip being exposed either by UVphotoablation machining or by blade cutting followed by polishing to produce a crescent moon-shaped carbon microelectrode. The probe properties have been assessed by cyclic voltammetry, approach curves, and line scans over electrochemically active and inactive substrates of different roughness. The influence of probe bending on contact mode imaging was then characterized using simple patterns. Boundary element method simulations were employed to rationalize the distance-dependent electrochemical response of the soft stylus probes.Scanning electrochemical microscopy (SECM) is a scanning probe technique that provides spatially resolved detection of electrochemical and chemical surface reactivity.1,2 Typically, the probe is an amperometric disk-shaped ultramicroelectrode (UME) enclosed in an insulating sheath, e.g. glass. Due to the hemispherical diffusion occurring at the microdisc electrode, a steadystate current can be monitored as a function of the horizontal (x, y) and vertical (z) probe positions. SECM has found many applications ranging from surface reactivity imaging 3-13 to the study of the kinetics of homogeneous and heterogeneous reactions at solid/liquid, gas/liquid, and liquid/liquid interfaces. 14-20 Because the response of a SECM probe can be described by continuum models of mass transport coupled to electrochemical kinetics, quantitative kinetic information can be extracted by comparing experimental and simulated curves in many practically relevant situations. 21-25The response of a SECM probe depends on the surface reactivity of the sample and the distance d between the surface and the active area of the probe electrode. In order to obtain a reactivity image that is not influenced by topography, d must be kept constant. In conventional SECM operations, this is achieved by working on samples with a roughness that is considerably smaller than the radius r T of the UME and by leveling the plane of the sample surface with respect to the x,y-scanning plane of the positioning system. However, this approach becomes inappropriate on rough surfaces of large aspect ratios or when large scan areas (in the mm 2 range) have to be investigated so that leveling becomes a major obstacle. Similar limitations apply when imaging curved samples. This drawback has been recognized for a long time. In the case of a small r T , a constant d can be maintained by combining

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Section: -25mentioning

confidence: 99%

Soft Stylus Probes for Scanning Electrochemical Microscopy

Cortés‐Salazar

Träuble

et al. 2009

Anal. Chem.

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“…[415] Alternativ kann eine UME an ein Bein eines stimmgabelförmigen Quarzresonators angebracht werden. [258,397,413,414,416,417] Das Resonanzverhalten des Systems wird in diesem Fall vor allem durch den Quarzresonator bestimmt, wodurch die Elektronik für einen engeren Frequenzbereich ausgelegt werden kann als bei der oben besprochenen Variante. Da die Masse der UME wegen der seitlichen Isolierung wesentlich größer ist als die des Quarzresonators, bestehen auch hier Empfindlichkeitsprobleme.…”

Section: Enzymmarkierungenunclassified

Elektrochemische Rastermikroskopie zur direkten Abbildung von Reaktionsgeschwindigkeiten

Wittstock¹,

Burchardt²,

Pust³

et al. 2007

Angewandte Chemie

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Eine entscheidende Rolle in der Elektrochemie, aber auch in biologischen Systemen oder beim Transport durch Membranen, spielen lokale Prozesse an Fest‐flüssig‐Grenzflächen oder Flüssig‐flüssig‐Grenzflächen, die z. B. an Defektstellen, an Poren oder an einzelnen Zellen ablaufen und sich durch integrale Untersuchungsverfahren nur schwer erfassen lassen. Mit der elektrochemischen Rastermikroskopie steht eine Untersuchungsmethode für lokale Grenzflächenreaktionen zur Verfügung, die nach zwei Jahrzehnten Entwicklung eine solide theoretische Basis und eine große Zahl von Anwendungen aufweist. Sie bietet die Möglichkeit, Geschwindigkeiten heterogener Reaktionen direkt abzubilden und Oberflächen durch elektrochemisch erzeugte Reaktanten lokal zu modifizieren. Die Vielfalt der Anwendungen reicht von klassischen elektrochemischen Fragestellungen bei der Untersuchung lokaler Korrosionsphänomene und elektrokatalytischer Reaktionen in Brennstoffzellen, von Sensoroberflächen, Biochips und mikrostrukturierten Analysesystemen bis hin zum Massentransport durch synthetische Membranen, Haut und Gewebe sowie interzellulären Kommunikationsprozessen. Außerdem können Prozesse an Flüssigkeitsoberflächen oder an Flüssig‐flüssig‐Grenzflächen untersucht werden.

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“…30 The probe was moved up and down vertically by 0.1 -3.0 μm to reduce the damage to the samples at collection of each data point. This feedback mode, defined as "standing approach (STA) mode", 31 permits extensive applications of the probe to samples with large height differences on the surface or fragile biomaterials including microbeads or living cells.…”

Section: ·2 Imaging Of Biological Materials With Secmmentioning

confidence: 99%

Bioimaging with Micro/Nanoelectrode Systems

Matsue

2013

ANAL. SCI.

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Immobilized Diaphorase Surfaces Observed by Scanning Electrochemical Microscope with Shear Force Based Tip−Substrate Positioning

Cited by 53 publications

References 31 publications

Soft Stylus Probes for Scanning Electrochemical Microscopy

Soft Stylus Probes for Scanning Electrochemical Microscopy

Elektrochemische Rastermikroskopie zur direkten Abbildung von Reaktionsgeschwindigkeiten

Bioimaging with Micro/Nanoelectrode Systems

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