Dual Microelectrodes for Distance Control and Detection of Nitric Oxide from Endothelial Cells by Means of Scanning Electrochemical Microscope

Işık, Sonnur; Etienne, Mathieu; Oni, Joshua; Blöchl, Andrea; Reiter, Sabine; Schuhmann, Wolfgang

doi:10.1021/ac049182w

Cited by 67 publications

(47 citation statements)

References 34 publications

(50 reference statements)

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“…The topographic and chemical information about the electrochemical processes taking place at a given site of a single-cell can be obtained from the faradaic currents measured at the working ultramicroelectrode directly or after additional modification using redox mediators. Main requirements for the successful accomplishment of such electrochemical measurements are accurate placement of the tip of microelectrode(s), precise determination of the tip-to-cell distance, and the appropriate selectivity of the ultramicroelectrodes for species that may change in concentration as a result of various cellular actions [58,59].…”

Section: Electrochemistrymentioning

confidence: 99%

Redox regulation of calcium ion channels: Chemical and physiological aspects

et al. 2011

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a b s t r a c tReactive oxygen species (ROS) are increasingly recognized as second messengers in many cellular processes. While high concentrations of oxidants damage proteins, lipids and DNA, ultimately resulting in cell death, selective and reversible oxidation of key residues in proteins is a physiological mechanism that can transiently alter their activity and function. Defects in ROS producing enzymes cause disturbed immune response and disease.Changes in the intracellular free Ca 2+ concentration are key triggers for diverse cellular functions. Ca 2+ homeostasis thus needs to be precisely tuned by channels, pumps, transporters and cellular buffering systems. Alterations of these key regulatory proteins by reversible or irreversible oxidation alter the physiological outcome following cell stimulation. It is therefore necessary to understand which proteins are regulated and if this regulation is relevant in a physiological-and/or pathophysiological context. Because ROS are inherently difficult to identify and to measure, we first review basic oxygen redox chemistry and methods of ROS detection with special emphasis on electron paramagnetic resonance (EPR) spectroscopy. We then focus on the present knowledge of redox regulation of Ca 2+ permeable ion channels such as voltage-gated (CaV) Ca 2+ channels, transient receptor potential (TRP) channels and Orai channels.© 2011 Elsevier Ltd. All rights reserved. Basic redox chemistry of oxygenMany chemical processes are linked to the exchange of electrons between two or more molecular entities. The transfer of one (or more) electron(s) is associated with oxidation (loss of electron) and reduction (gain of electron) of the components. Such reactions are also known as redox reactions. The processes of reactive oxygen species (ROS) formation and elimination are exclusively of redox nature.Molecular oxygen is the precursor of all ROS. It contains two unpaired electrons in separate (antibonding) orbitals in its outer electron sphere and is thus, by definition, a radical. Radicals have at least one unpaired electron in their orbital system and usually show high reactivity; transition metal ions also may have unpaired electrons, but are not called radicals. Although having radical character, molecular oxygen is chemically rather inert (luckily!), because high * Corresponding authors at: Institut für Biophysik, Gebäude 58, Universität des Saarlandes, D-66421 Homburg/Saar, Germany. Tel.: +49 6841 1626453; fax: +49 6841 1626060.E-mail addresses: ivan.bogeski@uks.eu (I. Bogeski), barbara.niemeyer@uks.eu (B.A. Niemeyer).

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Section: Electrochemistrymentioning

confidence: 99%

Redox regulation of calcium ion channels: Chemical and physiological aspects

et al. 2011

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“…Außerdem wurde die Positionierung mithilfe eines optischen Mikroskops ausgeführt, [349,363,364] oder Zellen wurden in speziellen Kavitäten kultiviert, mit deren oberen Rand sie nach dem Anwachsen eine ebene Fläche bildeten. [365][366][367][368] Alternativ kommen auch Doppelmikroelektroden zum Einsatz, bei denen eine UME einen Mediator umsetzt, der nicht mit der Probe wechselwirkt und eine Abstandsbestimmung nach Gleichung (3) ermöglicht.…”

Section: Untersuchungen Zum Metabolismus Von Geweben Und Zellenunclassified

“…Zur Detektion kam ein elektrokatalytischer Sensor basierend auf substituierten Nickelporphyrinen mit einem Durchmesser von 50 mm zum Einsatz. [364] Der Sensor wurde mit einer konventionellen Pt-UME (1 10 mm) zu einer Doppelmikroelektrode kombiniert. Mithilfe der Pt-UME wurde die Sonde unter Verwendung der O 2 -Reduktion sowie von Gleichung (3) über den Zellen positioniert.…”

Section: Abgabe Von Botenstoffenunclassified

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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“…Many enzyme-based microelectrodes have been developed by immobilizing enzymes for the detection of glucose, 4,5 lactate, 6,7 glutamate, 8 acetylcholine, 9 cholesterol, 10,11 and nitric oxide (NO). 12,13 Recently, miniaturized biosensors modified with glucose oxidase or lactate oxidase were used as SECM probes, demonstrating the ability of this approach to be applied to probe cellular metabolism. 14 Previously, we have fabricated microelectrodes modified with glucose oxidase (GOx) for the determination of the apparent Michaelis constant with respect to oxygen.…”

Section: Introductionmentioning

confidence: 99%

Microsensors with Detection Range of Glucose to Higher Concentrations by Regulating Oxygen Concentration with the Electrolysis of Water

2012

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We describe an improvement of the detectable range of glucose oxidase (GOx)-based microsensors to higher concentrations. Oxygen consumed by the enzyme reaction of GOx was detected cathodically by the microelectrode modified with poly(dimethylsiloxane) (PDMS) and GOx layers. PDMS was used to prevent the permeation of hydrogen peroxide that was produced by the enzyme reaction. The prepared microsensors were positioned above microband electrodes which were used to produce oxygen by the electrolysis of water, allowing a high oxygen concentration (0.8 mM) to be maintained around the microsensors. By applying this system, the detectable concentration range for glucose was extended up to 20 mM.

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Dual Microelectrodes for Distance Control and Detection of Nitric Oxide from Endothelial Cells by Means of Scanning Electrochemical Microscope

Cited by 67 publications

References 34 publications

Redox regulation of calcium ion channels: Chemical and physiological aspects

Redox regulation of calcium ion channels: Chemical and physiological aspects

Elektrochemische Rastermikroskopie zur direkten Abbildung von Reaktionsgeschwindigkeiten

Microsensors with Detection Range of Glucose to Higher Concentrations by Regulating Oxygen Concentration with the Electrolysis of Water

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