The kinetics of several fast heterogeneous electron-transfer reactions were investigated by steady-state voltammetry at nanoelectrodes and scanning electrochemical microscopy (SECM). disk-type, polished Pt (3.7-400-nm radius) characterized a combination voltammetry, electron microscopy, SECM. A number experimental curves obtained the same nanoelectrode to attain accuracy reproducibility similar those reported previously for micrometer-sized probes. new analytical approximation was developed...

The production of reactive oxygen and nitrogen species (ROS RNS) in human cells is implicated various diseases, including cancer. Micrometer-sized electrodes coated with Pt black platinized nanoelectrodes have previously been used for the detection primary ROS RNS biological systems. In this Article, we report development carbon well-characterized geometry use them as scanning electrochemical microscopy (SECM) tips to measure inside noncancerous metastatic breast cells. By performing...

Anion exchange membrane fuel cells are limited by the slow kinetics of alkaline hydrogen oxidation reaction (HOR). Here, we establish HOR catalytic activities single-atom and diatomic sites as a function *H *OH binding energies to screen optimal active for HOR. As result, Ru-Ni one is identified best center. Guided theoretical finding, subsequently synthesize catalyst with supported on N-doped porous carbon, which exhibits excellent activity, CO tolerance, stability also superior single-site...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTScanning Electrochemical Microscopy. 31. Application of SECM to the Study Charge Transfer Processes at Liquid/Liquid InterfaceChang Wei, Allen J. Bard, and Michael V. MirkinCite this: Phys. Chem. 1995, 99, 43, 16033–16042Publication Date (Print):October 1, 1995Publication History Published online1 May 2002Published inissue 1 October 1995https://pubs.acs.org/doi/10.1021/j100043a050https://doi.org/10.1021/j100043a050research-articleACS...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTScanning electrochemical microscopy. 12. Theory and experiment of the feedback mode with finite heterogeneous electron-transfer kinetics arbitrary substrate sizeAllen J. Bard, Michael V. Mirkin, Patrick R. Unwin, David O. WipfCite this: Phys. Chem. 1992, 96, 4, 1861–1868Publication Date (Print):February 1, 1992Publication History Published online1 May 2002Published inissue 1 February...

Nanometer-sized glass-sealed metal ultramicroelectrodes (UMEs) have been prepared using a laser-based micropipet puller. The tip was exposed to solution either by etching away small portion of glass insulator or micropolishing. characterization the UMEs carried out combination steady-state voltammetry, scanning electron microscopy (SEM), and electrochemical (SECM). cyclic voltammograms obtained regular shape with very capacitive resistive background. effective electrode radii from...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSimple analysis of quasi-reversible steady-state voltammogramsMichael V. Mirkin and Allen J. BardCite this: Anal. Chem. 1992, 64, 19, 2293–2302Publication Date (Print):October 1, 1992Publication History Published online1 May 2002Published inissue 1 October 1992https://pubs.acs.org/doi/10.1021/ac00043a020https://doi.org/10.1021/ac00043a020research-articleACS PublicationsRequest reuse permissionsArticle Views2757Altmetric-Citations222LEARN ABOUT...

Reactive oxygen and nitrogen species (ROS RNS) produced by macrophages are essential for protecting a human body against bacteria viruses. Micrometer-sized electrodes coated with Pt black have previously been used selective sensitive detection of ROS RNS in biological systems. To determine inside macrophages, one needs smaller (i.e., nanometer-sized) sensors. In this article, the methodologies extended to fabrication characterization Pt/Pt nanoelectrodes. Electrodes metal surface flush glass...

There is a significant current interest in development of new techniques for direct characterization the intracellular redox state and high-resolution imaging living cells. We used nanometer-sized amperometric probes combination with scanning electrochemical microscope (SECM) to carry out spatially resolved experiments cultured human breast With tip radius approximately 1,000 times smaller than that cell, an probe can penetrate cell travel inside it without apparent damage membrane. The data...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTScanning electrochemical microscopy. 19. Ion-selective potentiometric microscopyBenjamin R. Horrocks, Michael V. Mirkin, David T. Pierce, Allen J. Bard, Geza. Nagy, and Klara. TothCite this: Anal. Chem. 1993, 65, 9, 1213–1224Publication Date (Print):May 1, 1993Publication History Published online1 May 2002Published inissue 1 1993https://pubs.acs.org/doi/10.1021/ac00057a019https://doi.org/10.1021/ac00057a019research-articleACS PublicationsRequest...

New approaches have been developed for measuring the rates of electron transfer (ET) across self-assembled molecular monolayers by scanning electrochemical microscopy (SECM). The models can be used to independently measure ET mediated monolayer-attached redox moieties and direct through film as well rate a bimolecular reaction between attached dissolved species. By using high concentration mediator in solution, very fast heterogeneous (108 s-1) (1011 mol-1 cm3 constants measured. measured...

The multistage process of borohydride oxidation in an reaction to borate at a Au electrode has been studied by means fast‐scan cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM). total irreversibility this observed previously is shown be result the presence very unstable intermediates. CV measurements showed that least two stages are quasi‐reversible, coupled homogeneous chemical was proved SECM. rate constant for as well kinetic parameters first stage evaluated using...

Nanoelectrochemical approaches were used to investigate adsorption/desorption of hydrogen on Pt electrodes. These processes, which have been extensively studied over the last century, remain current interest because their applications in energy storage systems. The effective surface area a nanoelectrode was found be much larger than its geometric due diffusion adsorbed redox species at Pt/glass interface. An additional peak desorption observed and attributed spillover from into glass....

The ability to manipulate ultrasmall volumes of liquids is essential in such diverse fields as cell biology, microfluidics, capillary chromatography, and nanolithography. In it often necessary inject material high molecular weight (e.g., DNA, proteins) into living cells because their membranes are impermeable molecules. All techniques currently used for microinjection plagued by two common problems: the relatively large injector size volume injected fluid, poor control amount material. Here...

Electrochemistry at individual metal nanoparticles (NPs) can provide new insights into their electrocatalytic behavior. Herein, the electrochemical activity of single AuNPs attached to catalytically inert carbon surface is mapped by using extremely small (≥3 nm radius) polished nanoelectrodes as tips in scanning microscope (SECM). The use such probes resulted spatial resolution significantly higher than previously reported images. currents produced either rapid electron transfer or hydrogen...

Electrochemical experiments were carried out in a nanometer-sized cylindrical thin layer cell (TLC) formed by etching the surface of disk-type platinum nanoelectrode (5- to 150-nm radius). Using high frequency ac voltage, such an electrode was etched remove very (> or = 1-nm-thick) Pt. The resulting zeptoliter-scale cavity inside glass sheath filled with aqueous solution containing redox species, and immersed dry (no external solution) pool mercury produce TLC. Several approaches based on...

This Perspective is an update to our more extensive survey of scanning electrochemical microscopy (SECM) published in 2007. During this time, the SECM field retained its momentum by expanding into new areas and meeting emerging scientific technological challenges. Here we focus on most prominent developments such as high-resolution imaging, investigation structures processes nanoscale, alternative energy applications, approaches solving “real world” problems. The fabrication novel probes...

The release of reactive oxygen and nitrogen species (ROS/RNS) by macrophages undergoing phagocytosis is crucial for the efficiency immune system. In this work, platinized carbon nanoelectrodes were used to detect, characterize, quantify first time intracellular production rates four primary ROS/RNS (i.e., H2O2, ONOO–, NO•, NO2–) inside single phagolysosomes living RAW 264.7 murine stimulated interferon-γ lipopolysaccharide (IFN-γ/LPS) mimic an in vivo inflammatory activation. time-dependent...

ConspectusElectrochemistry at metal nanoparticles (NPs) is of significant current interest because its applications in catalysis, energy conversion and storage, sensors. The electrocatalytic activity NPs depends strongly on their size, shape, surface attachment. use a large number particles most reported kinetic experiments obscured the effects these factors polydispersity different NP orientations. Recent efforts to probe electrochemistry single included recording catalytically amplified...