Detection of Hydrogen Peroxide at Mesoporous Platinum Microelectrodes

Evans, Stuart A. G.; Elliott, Joanne; Andrews, Lynn M.; Bartlett, Philip N.; Doyle, Peter J.; Denuault, Guy

doi:10.1021/ac011052p

Cited by 362 publications

(249 citation statements)

References 23 publications

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“…In the literature, reduction of hydrogen peroxide at platinized electrodes is observed at similar potentials. 41 The anodic response is free from complications due to oxygen and the limiting response (at 500 mV) can be seen to be linear with concentration.…”

Section: Resultsmentioning

confidence: 98%

Electrochemical Nanoprobes for Single-Cell Analysis

et al. 2014

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The measurement of key molecules in individual cells with minimal disruption to the biological milieu is the next frontier in single-cell analyses. Nanoscale devices are ideal analytical tools because of their small size and their potential for high spatial and temporal resolution recordings. Here, we report the fabrication of disk-shaped carbon nanoelectrodes whose radius can be precisely tuned within the range 5-200 nm. The functionalization of the nanoelectrode with platinum allowed the monitoring of oxygen consumption outside and inside a brain slice. Furthermore, we show that nanoelectrodes of this type can be used to impale individual cells to perform electrochemical measurements within the cell with minimal disruption to cell function. These nanoelectrodes can be fabricated combined with scanning ion conductance microcopy probes which should allow high resolution electrochemical mapping of species on or in living cells.

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Section: Resultsmentioning

confidence: 98%

Electrochemical Nanoprobes for Single-Cell Analysis

et al. 2014

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“…Platinum black or other nano-porous films (e.g. iridium oxide, titanium nitride) can be used to increase the effective area of the electrode surface [99,100].…”

Section: Modelling and Simulationmentioning

confidence: 99%

Single cell dielectric spectroscopy

Morgan

Sun²,

Holmes³

et al. 2006

J. Phys. D: Appl. Phys.

395

313

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Over the last century a number of techniques have been developed which allow the measurement of the dielectric properties of biological particles in fluid suspension. The majority of these techniques are limited by the fact that they only provide an average value for the dielectric properties of a collection of particles. More recently, with the advent of microfabrication techniques and the Lab-on-a-chip, it has been possible to perform dielectric spectroscopic experiments on single biological particles suspended in physiological media. In this paper we review current methods for single cell dielectric spectroscopy. We also discuss alternative single cell dielectric measurement techniques, specifically the ac electrokinetic methods of dielectrophoresis and electrorotation. Single cell electrical impedance spectroscopy is also discussed with relevance to a microfabricated flow cytometer. We compare impedance spectroscopy data obtained from measurements made using a microfabricated flow cytometer with simulation data obtained using an equivalent circuit model for the device.

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“…24 The mean value of ipeak at 0.55 V ( Figure 3C) was 46 ± 16 pA corresponding reasonably well to that expected for the diffusion-controlled steady-state current (iss) predicted for a NP on a surface, based on the NP size distribution ( Figure 2C): 25 (1) where n is the number of electrons transferred per H2O2 (2), F is the Faraday constant (96485 C mol -1 ), DH2O2 is the diffusion coefficient of H2O2 in 0.1 M phosphate buffer solution (1.46×10 -5 cm 2 s -1 ), 27 CH2O2 is the concentration of H2O2 (0.5 mM). This simple analysis yields iss = 38 ± 10 pA.…”

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confidence: 99%

Time-Resolved Detection and Analysis of Single Nanoparticle Electrocatalytic Impacts

et al. 2015

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ABSTRACT:There is considerable interest in understanding the interaction and activity of single entities, such as (electro)catalytic nanoparticles (NPs), with (electrode) surfaces. Through the use of a high bandwidth, high signal/noise measurement system, NP impacts on an electrode surface are detected and analyzed in unprecedented detail, revealing considerable new mechanistic information on the process. Taking the electrocatalytic oxidation of H2O2 at ruthenium oxide (RuOx) NPs as an example, the rise time of currenttime transients for NP impacts is consistent with a hydrodynamic trapping model for the arrival of a NP with a distancedependent NP diffusion-coefficient. NP release from the electrode appears to be aided by propulsion from the electrocatalytic reaction at the NP. High frequency NP impacts, orders of magnitude larger than can be accounted for by a single pass diffusive flux of NPs, are observed that indicate the repetitive trapping and release of an individual NP that has not previously recognized. The experiments and models described could readily be applied to other systems and serve as a powerful platform for detailed analysis of NP impacts.An important frontier in electrochemistry is measuring the behavior of individual nano-entities such as nanoparticles (NPs), nanowires and nanorods and relating this to other properties such as size, structure and electronic characteristics, so as to develop fundamental understanding and rational applications. 1-3 An interesting approach for observing the electrochemical properties of catalytic NPs is to monitor their impact (or landing) from solution onto a collector electrode, as introduced by Bard et al.,4,5 and developed by several groups. [6][7][8][9][10][11][12] In order to resolve such impacts, the use of a small-sized ultramicroelectrode (UME) is mandatory to reduce both background currents and the impact frequency. To enhance the impact signal to background current, electrode surfaces have been modified with Hg or Bi 7 and borondoped diamond 12 has also been used as an UME material. Alternatively, scanning electrochemical cell microscopy (SECCM) functioning as an ultramicro-electrochemical cell system offers particularly low background currents by reducing the area of the collector electrode, as well as offering the widest range of support electrodes. This is because the electrochemical cell is formed by meniscus confinement, rather than electrode encapsulation (Figure 1). 13 Despite these innovations, detailed analysis of the form of the current-time profile which is the primary signal for the landing (and detachment) of a single NP on an electrode has not yet been forthcoming, but would represent a huge advance towards understanding the impact process. Herein, we are able to analyze this process as never before and deduce key information on the NP arrival and release process from individual impact transients. Moreover, we show that impact frequencies can be orders of magnitude higher than expected based on single pass diffusion due to the repetitiv...

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Detection of Hydrogen Peroxide at Mesoporous Platinum Microelectrodes

Cited by 362 publications

References 23 publications

Electrochemical Nanoprobes for Single-Cell Analysis

Electrochemical Nanoprobes for Single-Cell Analysis

Single cell dielectric spectroscopy

Time-Resolved Detection and Analysis of Single Nanoparticle Electrocatalytic Impacts

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