Micrometer-spaced platinum interdigitated array electrode:  fabrication, theory, and initial use

Chidsey, Christopher E. D.; Feldman, B. J.; Lundgren, Cynthia A.; Murray, Royce W.

doi:10.1021/ac00294a026

Cited by 214 publications

(114 citation statements)

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“…Paired microbands have been developed by an epoxied thin mica sheet with sputtered gold on both sides [11] or by sealing of two metalized glass slides separated with a plastic spacer [12] . Photolithography has also been employed to fabricate microbands [13][14][15] and interdigited array electrodes [16] by metal evaporation [17] , sputtering [18,19] and chemical vapour deposition [7,20,21] . Boron doped diamond ultramicroband electrodes have been realised based on lithography and chemical vapour deposition [22,23] .…”

Section: Introductionmentioning

confidence: 99%

Arrays of Screen‐Printed Graphite Microband Electrodes as a Versatile Electroanalysis Platform

et al. 2014

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Arrays of microband electrodes were developed by screen printing followed by cutting, which enabled the realization of microband arrays at the cut edge. Microband arrays of different designs were characterised with physical and electrochemical methods. In both cases the methods showed that the microband width was around 5 m. Semi-steady-state cyclic voltammetry responses were observed for redox probes.Chronocoulometric measurements showed the establishment of convergent diffusion regimes characterized by current densities similar to those of a single microelectrode.The analytical performance of the elaborated electrode system and its versatility were illustrated with two electrochemical assays: detection of ascorbic acid via direct oxidation and a mediated glucose biosensor fabricated via dip coating. Due to convergent mass transport both systems showed enhancement of the analytical characteristics. The developed approach can be adapted to automated electrode recovery.

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Section: Introductionmentioning

confidence: 99%

Arrays of Screen‐Printed Graphite Microband Electrodes as a Versatile Electroanalysis Platform

et al. 2014

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“…Unlike RRDEs, no rotation is required in IDAs, and the reaction with oxygen and the detection of PROS are diffusion-limited processes. IDAs have previously been used (11)(12)(13)(14) to assess the formation of PROS with reduction catalysts (13). The study presents here a report of the detection of PROS on IDAs as a function of eT through SAMs functionalized with hemoprotein models.…”

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confidence: 99%

Role of a distal pocket in the catalytic O ₂ reduction by cytochrome c oxidase models immobilized on interdigitated array electrodes

Collman

Decréau

Lin

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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Five iron porphyrins with different superstructures were immobilized on self-assembled-monolayer (SAM)-coated interdigitatedarray (IDAs) gold-platinum electrodes. The selectivity of the catalysts i.e., limited formation of partially reduced oxygen species (PROS) in the electrocatalytic reduction of dioxygen, is a function of 2 rates: (i) the rate of electron transfer from the electrode to the catalyst, which is controlled by the length, and conjugation of the linker from the catalyst to the electrode and (ii) the rate of bound oxygen (superoxide) hydrolysis, which correlates with the presence of a water cluster in the gas-binding pocket influencing the rate of oxygen binding; these factors are controlled by the nature of the porphyrin superstructure. The structurally biomimetic Trisimidazole model is the most selective.electron transfer rate ͉ oxygen binding rates ͉ water cluster ͉ oxygen complex stabilization ͉ partially reduced oxygen species A recent report showed that water may inhibit oxygen binding in hemoprotein models (1). This echoes the ''water displacement model'' proposed for oxygen binding in myoglobin (2-4). This finding is relevant to cytochrome c oxidase (CcO) for 2 reasons: (i) CcO binds and reduces oxygen to form water (5) and (ii) the hydrolysis of the oxygen complex in CcO and in other enzymes is an issue and occurs when water, protons, and electrons are present (6, 7). This reaction releases partially reduced oxygen species (PROS) that are toxic to organisms (Fig. 1). The study herein examines the formation of PROS during the electrocatalytic reduction of oxygen by several site-isolated CcO models ( Fig. 2) as a function of (i) the oxygen association rate [k on (O 2 )] and the rate of hydrolysis, both associated with the presence of water in the gas binding pocket, and (ii) the availability of electrons at the oxygen reduction site associated with the rate of electron arrival from the electrode to the catalyst [k(eT)] and/or the presence of redox active species in the vicinity of the heme. The latter aspects were specifically addressed in previous studies by immobilizing the active-site models onto self-assembled-monolayer (SAM)-coated rotating ring disk gold electrodes (RRDE) (8-10): k(eT) was controlled by the length and conjugated character of the linker between the catalyst and the gold electrode, and immobilization allowed site isolation. To get better collection efficiencies for the detection of PROS and to prevent damage to the SAM associated with high rotation rates, the present study used Au-Pt interdigitated array electrodes (IDAs). The collection efficiency of these IDA electrodes is in the 65-90% range as compared with Ͻ20% in RRDE (8).IDAs have 2 sets of alternating arrays of electrodes. The electrode widths and spacing are on similar dimensions, and this distance is within diffusion layers for typical electroactive species in solution. This results in diffusion gradients of adjacent microband electrodes that overlap with each other. Redox products created at the Au generator ...

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“…However, this technique has limited collection efficiencies (CE, i.e., percentage of the PROS generated being detected on the ring). Interdigitated array (IDA) Electrodes provide an alternative to rotating ring disc techniques for detecting products/byproducts of unstirred electrochemical reactions (40). IDAs have 2 sets of alternate arrays of electrodes (10 m wide) spaced 5-10 m apart (Fig.…”

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confidence: 99%

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex

Collman

Dey

Yang

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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O2 reactivity of a functional NOR model is investigated by using electrochemistry and spectroscopy. The electrochemical measurements using interdigitated electrodes show very high selectivity for 4e O2 reduction with minimal production of partially reduced oxygen species (PROS) under both fast and slow electron flux. Intermediates trapped at cryogenic temperatures and characterized by using resonance Raman spectroscopy under single-turnover conditions indicate that an initial bridging peroxide intermediate undergoes homolytic OOO bond cleavage generating a trans heme/nonheme bis-ferryl intermediate. This bis ferryl species can oxygenate 2 equivalents of a reactive substrate.C ytochrome c oxidase (CcO) and nitric oxide reductase (NOR) belong to the heme copper oxidase superfamily of enzymes (1, 2). CcO is the terminal enzyme in the respiratory chain of higher organisms, located in their mitochondrial membrane, that reduces O 2 to H 2 O as source of energy. The O 2 reduction process in CcO generates a pH gradient across the bilayer membrane, which provides the driving force for ATP synthesis. The bimetallic active site of CcO has a heme ligated to the protein by a proximal histidine ligand and a distal Cu B site coordinated by 3 histidine ligands ( Fig. 1) (3). In addition to the bimetallic site, there is a conserved tyrosine ligand covalently attached to one of the histidines coordinated to Cu B (4, 5). The NORs are the older member of the family and are found in bacteria using NO 3 Ϫ as source of energy instead of O 2 (2, 6, 7). Although there are no high-resolution crystal structures of NOR, biochemical studies and computer modeling indicate that these enzymes have a histidine-ligated heme, quite like the CcOs, and a distal Fe B , unlike Cu B in CcO, coordinated by 3 histidines ( Fig. 1) (8-10). NORs do not have the conserved tyrosine residue of CcO but have a few conserved key glutamate residues (11,12). Although the NOR enzymes are proposed to have specific proton channels, they are probably not involved in generating proton gradients (13-16).These 2 enzymes exhibit complementary reactivity toward 2 very significant diatomic molecules in nature; O 2 and NO. In eukaryotes CcO (aa 3 type) reduces O 2 to H 2 O and is reversibly but strongly inhibited by [17][18][19][20]. Several other CcOs (ba 3 , caa 3 , cbb 3 ) are reported to exhibit limited (Ͻ1%) NOR activity, i.e., reduce NO to N 2 O (7, 21). On the other hand, NORs that reduce NO to N 2 O are reversibly but strongly inhibited by O 2 , and some of them show modest (Ϸ10%) O 2 reduction activity (12). The parallels in their reactivities toward O 2 and NO and similarities in their secondary structures have led to a hypotheses regarding NOR's and CcO's similar evolutionary origins (6,22).Electrochemistry is a very powerful technique that can provide fundamental insights into reaction mechanisms of redox catalysts (23-27). Conventionally, a catalyst is deposited on a conducting electrode material (e.g., graphite); however, this approach does not allow site isola...

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Micrometer-spaced platinum interdigitated array electrode: fabrication, theory, and initial use

Cited by 214 publications

References 41 publications

Arrays of Screen‐Printed Graphite Microband Electrodes as a Versatile Electroanalysis Platform

Arrays of Screen‐Printed Graphite Microband Electrodes as a Versatile Electroanalysis Platform

Role of a distal pocket in the catalytic O ₂ reduction by cytochrome c oxidase models immobilized on interdigitated array electrodes

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex

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Micrometer-spaced platinum interdigitated array electrode: fabrication, theory, and initial use

Cited by 214 publications

References 41 publications

Arrays of Screen‐Printed Graphite Microband Electrodes as a Versatile Electroanalysis Platform

Arrays of Screen‐Printed Graphite Microband Electrodes as a Versatile Electroanalysis Platform

Role of a distal pocket in the catalytic O 2 reduction by cytochrome c oxidase models immobilized on interdigitated array electrodes

O 2 reduction by a functional heme/nonheme bis-iron NOR model complex

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Product

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Role of a distal pocket in the catalytic O ₂ reduction by cytochrome c oxidase models immobilized on interdigitated array electrodes

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex