Characterization of small noble metal microelectrodes by voltammetry and energy-dispersive x-ray analysis

Strein, Timothy G.; Ewing, Andrew G.

doi:10.1021/ac00057a017

Cited by 13 publications

(12 citation statements)

References 21 publications

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“…The previous study has demonstrated that the electrochemical behavior of gold microelectrodes was similar to that of small platinum electrodes in DA solution. 38 Furthermore, the surface morphologies of native platinum and Au-NP deposited platinum plates were observed by AFM images, as shown in Fig. 2(C) and (D).…”

Section: Sensitivity Improvement Of Da Detections Upon Au-np Depositionmentioning

confidence: 98%

Microelectrodes with gold nanoparticles and self-assembled monolayers for in vivo recording of striatal dopamine

Tsai

Guo

Han

et al. 2012

Analyst

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Electrochemical determination of in vivo dopamine (DA) using implantable microelectrodes is essential for monitoring the DA depletion of an animal model of Parkinson's disease (PD), but faces substantial interference from ascorbic acid (AA) in the brain area due to similar electroactive characteristics. This study utilizes gold nanoparticles (Au-NPs) and self-assembled monolayers (SAMs) to modify platinum microelectrodes for improving sensitivity and specificity to DA and alleviating AA interference. With appropriate choice of ω-mercaptoalkane carboxylic acid chain length, our results show that a platinum microelectrode coated with Au-NPs and 3-mercaptopropionic acid (MPA) has approximately an 881-fold specificity to AA. During amperometric measurements, Au-NP/MPA reveals that the responsive current is linearly dependent on DA over the range of 0.01-5 μM with a correlation coefficient of 0.99 and the sensitivity is 2.7-fold that of a conventional Nafion-coated electrode. Other important features observed include fast response time (below 2 s), resistance to albumin adhesion and low detection limit (7 nM) at a signal to noise ratio of 3. Feasibility of in vivo DA recording with the modified microelectrodes is verified by real-time monitoring of electrically stimulated DA release in the striatum of anesthetized rats with various stimulation parameters and administration of a DA uptake inhibitor. The developed microelectrodes present an attractive alternative to the traditional options for continuous electrochemical in vivo DA monitoring.

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Section: Sensitivity Improvement Of Da Detections Upon Au-np Depositionmentioning

confidence: 98%

Microelectrodes with gold nanoparticles and self-assembled monolayers for in vivo recording of striatal dopamine

Tsai

Guo

Han

et al. 2012

Analyst

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“…The current gold standard microelectrode material are the noble metals, which exhibit fast electron-transfer kinetics and adequate sensitivity. [7,8] Unfortunately, the versatility of metal microelectrodes is tempered by increased background noise, surface oxidation and surface fouling. This results in rapid loss of analyte signals with time.…”

Section: Introductionmentioning

confidence: 99%

The effect of electrode size and surface heterogeneity on electrochemical properties of ultrananocrystalline diamond microelectrode

Dutta

Siddiqui

Zeng

et al. 2015

Journal of Electroanalytical Chemistry

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We report here the effect of electrode size on electrochemical properties of boron-doped ultrananocrystalline diamond (UNCD) microelectrodes using electrochemical impedance spectroscopy (EIS). By reducing microelectrode size from 250-μm to 10-μm diameter (D), the shape of impedance spectra changes from linear line to two-arcs. The fitting of experimental data to electrochemical circuit model suggest that each arc likely corresponds to UNCD grains and grain boundaries phases. The two phases become separable as a result of microelectrode size reduction. In addition, for D≤100-μm, microstructural and morphological defects/ heterogeneities of grain boundaries and the presence of surface oxygen are also revealed in the spectra. The microelectrode size reduction specifically affect the impedance of the grain boundaries, e.g. for ultramicroelectrodes, UMEs (D≤25-μm), as the grain boundaries impedance increases by 30-fold. Thus, at UMEs, the grains-grain boundaries properties are revealed more sensitively in the spectra. Atomic force microscopy, scanning electron microscopy, Raman spectroscopy and surface profilometry measurements were performed to study the influence of microfabrication on surface properties. A significant increase in surface roughness after microfabrication shows that heterogeneities as observed in the spectra are not only due to intrinsic UNCD properties but also arises from microfabrication.

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“…13,14 Although several techniques have been developed in fabricating nanoprobes having electroactive areas with characteristic dimensions down to a few nanometers at the apex, these existing nanoelectrode probes have a tapered shape and, correspondingly, a relatively large total structure, except for the very end of the probe, [15][16][17][18][19][20][21][22][23][24] limiting their range of applicability for nonintrusive electrochemical studies in isolated microenvironments. [25][26][27][28] Due to their well-defined nanoscale geometry and excellent mechanical, electrical, and chemical properties, nanotubes have recently been explored as electrodes for electrochemistry, overcoming the aforementioned problems in nanoelectrode fabrication. Campbell et al 29 reported the direct use of individual multiwall carbon nanotubes having diameters of ϳ150 nm for electrochemistry.…”

mentioning

confidence: 99%

Individual Nanotube-Based Needle Nanoprobes for Electrochemical Studies in Picoliter Microenvironments

Yum

Cho

et al. 2007

ACS Nano

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We report the fabrication and characterization of individual nanotube-based, long and straight needle nanoprobes for electrochemistry and the study of their applicability and behavior in microenvironments. The needle nanoprobe, with a nanoscale ring-shaped Au electrode at the tip of the needle serving as the active electrode, was characterized by electrochemical current measurement and cyclic voltammetry and analyzed with electrochemical models. Such a needle nanoprobe, in combination with another metal-coated nanowire as a reference electrode, was further used, for the first time, for local electrochemical sensing inside microdroplets having volumes down to a few picoliters. We explain the acquired voltammetric behaviors of redox-active molecules in confined microscale environments and reveal a unique electrochemical mechanism which allows the regeneration of the redox-active molecules and the establishment of a stable reference potential in the microenvironments.

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Characterization of small noble metal microelectrodes by voltammetry and energy-dispersive x-ray analysis

Cited by 13 publications

References 21 publications

Microelectrodes with gold nanoparticles and self-assembled monolayers for in vivo recording of striatal dopamine

Microelectrodes with gold nanoparticles and self-assembled monolayers for in vivo recording of striatal dopamine

The effect of electrode size and surface heterogeneity on electrochemical properties of ultrananocrystalline diamond microelectrode

Individual Nanotube-Based Needle Nanoprobes for Electrochemical Studies in Picoliter Microenvironments

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