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Serotonin, a monoamine neurotransmitter, is important in both the central nervous system (CNS) and the peripheral nervous system. Malfunction of serotonin signaling leads to various disorders. We studied serotonin signaling from serotonergic neurons inside the ventral nerve cord of Drosophila melanogaster. Serotonergic neurons and stimulated release were visualized and achieved with mCherry and channelrhodopsin‐2 (an optogenetically transfected ion channel), respectively, and two electrochemical techniques quantified serotonin release and vesicular content. Mean vesicular serotonin content released during exocytosis from these neurons was 84 %, considerably higher than reported in previous studies regarding octopamine (4.5 %) and glutamate release (31 %). Serotonin content within all vesicles is uniformly changed when serotonin concentration is inhibited or enhanced. However, serotonin release exhibits two Gaussian distributions: higher frequency of small release events, and similar or slightly higher frequency of large events, resulting in differential release fractions ranging from partial (13–18 %) to full (100 %) release after treatment with agents to either enhance or diminish release. This is the first example of consistent full exocytotic release events we have observed in any system. We suggest one pool of vesicles can release significantly diverse fractions of transmitter load during exocytosis, a potentially novel pathway to regulate exocytosis and neuronal signaling. [ABSTRACT FROM AUTHOR]

Mediated processes using a solid material, often called "solid booster", have been proposed to increase the energy density in redox flow batteries (RFB). The strategy alters the energy storage in the dissolved redox species to a solid active material placed in a compartment of the device. Understanding the reaction kinetics of the dissolved redox mediator and the solid booster is crucial for proposing feasible pairs of solid boosters and dissolved redox mediators. We demonstrate a nanoelectrochemical methodology to monitor the reaction between the dissolved species in solution and the solid active material electrodeposited in recessed carbon nanoelectrodes. Our strategy overcomes issues inherent to standard methodologies, such as mass transport limitation, and evaluation of the intrinsic reactivity of the solid material. As a proof of concept, Prussian blue was electrodeposited in a recessed carbon nanoelectrode and used as a confined‐solid material platform to evaluate the reaction between the reduced form of Prussian blue and triiodide, I3- ${{{\rm I}}_{3}^{-}}$. A high conversion rate of the solid booster was observed in the presence of μM concentrations of the dissolved redox species. The proposed nanoelectrode was successfully employed as a potentiometric sensor to monitor the evolution of the reaction with the dissolved active species. [ABSTRACT FROM AUTHOR]

The in‐depth study of single cells requires the dynamically molecular information in one particular nanometer‐sized organelle in a living cell, which is difficult to achieve using current methods. Due to high efficiency of click chemistry, a new nanoelectrode‐based pipette architecture with dibenzocyclooctyne at the tip is designed to realize fast conjugation with azide group‐containing triphenylphosphine, which targets mitochondrial membranes. The covalent binding of one mitochondrion at the tip of the nanopipette allows a small region of the membrane to be isolated on the Pt surface inside the nanopipette. Therefore, the release of reactive oxygen species (ROS) from the mitochondrion is monitored, which is not interfered by the species present in the cytosol. The dynamic tracking of ROS release from one mitochondrion reveals the distinctive "ROS‐induced ROS release" within the mitochondria. Further study of RSL3‐induced ferroptosis using nanopipettes provides direct evidence for supporting the noninvolvement of glutathione peroxidase 4 in the mitochondria during RSL3‐induced ROS generation, which has not previously been observed at the single‐mitochondrion level. Eventually, this established strategy should overcome the existing challenge of the dynamic measurement of one special organelle in the complicated intracellular environment, which opens a new direction for electroanalysis in subcellular analysis. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) is considered as one of the most promising non‐noble‐metal catalysts for hydrogen evolution reaction (HER). To achieve practical application, introducing sulfur (S) vacancies on the inert basal plane of MoS2 is a widely accepted strategy to improve its HER activity. However, probing active sites at the nanoscale and quantitatively analyzing the related electrocatalytic activity in electrolyte aqueous solution are still great challenges. In this work, utilizing high‐resolution scanning electrochemical microscopy, optimized electrodes and newly designed thermal drift calibration software, the HER activity of the S vacancies on an MoS2 inert surface is in situ imaged with less than 20‐nm‐radius sensitivity and the HER kinetic data for S vacancies, including Tafel plot and onset potential, are quantitatively measured. Additionally, the stability of S vacancies over the wide range of pH 0−13 is investigated. This study provides a viable strategy for obtaining the catalytic kinetics of nanoscale active sites on structurally complex electrocatalysts and evaluating the stability of defects in different environments for 2D material‐based catalysts. [ABSTRACT FROM AUTHOR]

Nanoelectrochemistry allows for the investigation of the interaction of per‐ and polyfluoroalkyl substances (PFASs) with silver nanoparticles (AgNPs) and the elucidation of the binding behaviour of PFASs to nanoscale surfaces with high sensitivity. Mechanistic studies supported by single particle collision electrochemistry (SPCE), spectroscopic and density functional theory (DFT) calculations indicate the capability of polyfluorooctane sulfonic acid (PFOS), a representative PFAS, to selectively bind and induce aggregation of AgNPs. Single‐particle measurements provide identification of the "discrete" AgNPs agglomeration (e.g. 2–3 NPs) formed through the inter‐particles F−F interactions and the selective replacement of the citrate stabilizer by the sulfonate of the PFOS. Such interactions are characteristic only for long chain PFAS (‐SO3−) providing a means to selectively identify these substances down to ppt levels. Measuring and understanding the interactions of PFAS at nanoscale surfaces are crucial for designing ultrasensitive methods for detection and for modelling and predicting their interaction in the environment. [ABSTRACT FROM AUTHOR]

Single entity electrochemistry is employed to gain insights into ion solvation in solvent mixtures. To this end, the time required for the oxidation of individual indicator nanoparticles to sparingly soluble products is used to probe ionic diffusion, and hence gain new insights into the solvation properties of solvent mixtures. Herein, water‐ethanol or water‐methanol mixtures of different compositions are analyzed following this new approach, using silver nanoparticle oxidation in the presence of chloride and iodide as a complementary indicator reaction. For increasing concentrations of the bulkier alcohol molecules in the mixtures with water, an increasing content of alcohol molecules in the halide's solvation shell is detected by the observation of hindered halide diffusion. The extent of this solvent replacement is shown to scale with the charge density of the ions and the experimental results are rationalized with respect to literature‐derived thermodynamic data, highlighting the ability of single entity electrochemistry to explore solvation in solvent mixtures. [ABSTRACT FROM AUTHOR]

The transport of molecules and ions through biological nanopores is governed by interaction networks among restricted ions, transported molecules, and residue moieties at pore inner walls. However, identification of such weak ion fluctuations from only few tens of ions inside nanopore is hard to achieve owing to electrochemical measurement limitations. Here, we developed an advanced frequency method to achieve qualitative and spectral analysis of ion interaction networks inside a nanopore. The peak frequency fm reveals the dissociation rate between nanopore and ions; the peak amplitude am depicts the amount of combined ions with the nanopore after interaction equilibrium. A mathematical model for single‐molecule frequency fingerprint achieved the prediction of interaction characteristics of mutant nanopores. This single‐molecule frequency fingerprint is important for classification, characterization, and prediction of synergetic interaction networks inside nanoconfinement. [ABSTRACT FROM AUTHOR]

The nuclear pore complex (NPC) is the proteinaceous nanopore that solely mediates the transport of both small molecules and macromolecules between the nucleus and cytoplasm of a eukaryotic cell to regulate gene expression. In this personal account, we introduce recent progress in our nanoelectrochemical study of molecular transport through the NPC. Our work represents the importance of chemistry in understanding and controlling of NPC‐mediated molecular transport to enable the efficient and safe delivery of genetic therapeutics into the nucleus, thereby fundamentally contributing to human health. Specifically, we employ nanoscale scanning electrochemical microscopy to test our hypothesis that the nanopore of the NPC is divided by transport barriers concentrically into peripheral and central routes to efficiently mediate the bimodal traffic of protein transport and RNA export, respectively, through cooperative hydrophobic and electrostatic interactions. [ABSTRACT FROM AUTHOR]

Electrochemical AFM is a powerful tool for the real‐space characterization of catalysts under realistic electrochemical CO2 reduction (CO2RR) conditions. The evolution of structural features ranging from the micrometer to the atomic scale could be resolved during CO2RR. Using Cu(100) as model surface, distinct nanoscale surface morphologies and their potential‐dependent transformations from granular to smoothly curved mound‐pit surfaces or structures with rectangular terraces are revealed during CO2RR in 0.1 m KHCO3. The density of undercoordinated copper sites during CO2RR is shown to increase with decreasing potential. In situ atomic‐scale imaging reveals specific adsorption occurring at distinct cathodic potentials impacting the observed catalyst structure. These results show the complex interrelation of the morphology, structure, defect density, applied potential, and electrolyte in copper CO2RR catalysts. [ABSTRACT FROM AUTHOR]

The use of renewable energy by means of electrochemical techniques by converting H2O, CO2 and N2 into chemical energy sources and raw materials, is the basis for securing a future sustainable "green" energy supply. Some weaknesses and inconsistencies in the practice of determining the electrocatalytic performance, which prevents a rational bottom‐up catalyst design, are discussed. Large discrepancies in material properties as well as in electrocatalytic activity and stability become obvious when materials are tested under the conditions of their intended use as opposed to the usual laboratory conditions. They advocate for uniform activity/stability correlations under application‐relevant conditions, and the need for a clear representation of electrocatalytic performance by contextualization in terms of functional investigation or progress towards application is emphasized. [ABSTRACT FROM AUTHOR]

Abstract: Lithium (Li) dendrite formation is one of the major hurdles limiting the development of Li‐metal batteries, including Li‐O2 batteries. Herein, we report the first observation of the dendrite‐free epitaxial growth of a Li metal up to 10‐μm thick during charging (plating) in the LiBr‐LiNO3 dual anion electrolyte under O2 atmosphere. This phenomenon is due to the formation of an ultrathin and homogeneous Li2O‐rich solid‐electrolyte interphase (SEI) layer in the preceding discharge (stripping) process, where the corrosive nature of Br− seems to give rise to remove the original incompact passivation layer and NO3− oxidizes (passivates) the freshly formed Li surface to prevent further reactions with the electrolyte. Such reactions keep the SEI thin (<100 nm) and facilitates the electropolishing effect and gets ready for the epitaxial electroplating of Li in the following charge process. [ABSTRACT FROM AUTHOR]

Abstract: An activation step is essential for yielding nitrogen‐doped mesoporous carbon (NMCs) oxygen reduction reaction (ORR) electrocatalysts from biomass. Though many solely KOH or ZnCl2 activated carbon materials have been synthesized with fine ORR activity, there a deep discussion of activated‐carbon‐based electrocatalysts obtained from different activation processes is still lacking. In this paper, we systemically compare radish‐derived NMCs that underwent different activation processes, and reveal the relationship between structure and activity of these activated carbons. We showed that though ZnCl2 is not an effective porogen compared with KOH, owing to a more open pore structure along with effective preservation of nitrogen heteroatoms, ZnCl2 assisted activated carbon could show significantly improved ORR activity, with an onset potential of 0.91 V (vs. RHE), close to benchmark Pt/C catalysts and even better extended operation stability and stronger tolerance to methanol crossover compared with commercial Pt/C catalysts. Thus we proved that ZnCl2 assisted activation is better than exclusively self‐activation or KOH assisted activation in preparing biomass‐derived ORR catalysts. [ABSTRACT FROM AUTHOR]

Abstract: In situ and operando spectroscopic and microscopic methods were used to gain insight into the correlation between the structure, chemical state, and reactivity of size‐ and shape‐controlled ligand‐free Cu nanocubes during CO2 electroreduction (CO2RR). Dynamic changes in the morphology and composition of Cu cubes supported on carbon were monitored under potential control through electrochemical atomic force microscopy, X‐ray absorption fine‐structure spectroscopy and X‐ray photoelectron spectroscopy. Under reaction conditions, the roughening of the nanocube surface, disappearance of the (100) facets, formation of pores, loss of Cu and reduction of CuOx species observed were found to lead to a suppression of the selectivity for multi‐carbon products (i.e. C2H4 and ethanol) versus CH4. A comparison with Cu cubes supported on Cu foils revealed an enhanced morphological stability and persistence of CuI species under CO2RR in the former samples. Both factors are held responsible for the higher C2/C1 product ratio observed for the Cu cubes/Cu as compared to Cu cubes/C. Our findings highlight the importance of the structure of the active nanocatalyst but also its interaction with the underlying substrate in CO2RR selectivity. [ABSTRACT FROM AUTHOR]

Despite significant advancement in preparing various hollow structures by Ostwald ripening, one common problem is the intractable uncontrollability of initiating Ostwald ripening due to the complexity of the reaction processes. Here, a new strategy on Hansen solubility parameter (HSP)-guided solvent selection to initiate Ostwald ripening is proposed. Based on this comprehensive principle for solvent optimization, N, N-dimethylformamide (DMF) was screened out, achieving accurate synthesis of interior space-tunable MoSe2 spherical structures (solid, core-shell, yolk-shell and hollow spheres). The resultant MoSe2 structures exhibit architecture-dependent electrochemical performances towards hydrogen evolution reaction and sodium-ion batteries. This pre-solvent selection strategy can effectively provide researchers great possibility in efficiently synthesizing various hollow structures. This work paves a new pathway for deeply understanding Ostwald ripening. [ABSTRACT FROM AUTHOR]

Hybrid magnetite/carbon quantum dots (MagNP/C-dots) were prepared and their characterization performed by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Because of their suitable magnetization and electrochemical properties, they were used as versatile electrode modifiers after magnetically confining onto screen printed carbon electrodes (SPE), with the aid of a miniature external magnet. The reported strategy introduces a convenient procedure for assembling modified electrodes, since the nanoparticles can be easily released by removing the magnet. The non-enzymatic magnetic biosensor showed excellent performance in the determination of NADH at the concentration range 2×10−7 to 5×10−6 mol L−1, exhibiting a sensitivity of 0.15 μmol L−1 and detection limit of 20 nmol L−1. The MagNP/C-dots/SPE sensor was also successfully applied for the determination of NADH in serum samples. The interference of typical biological molecules has also been investigated. [ABSTRACT FROM AUTHOR]

Near-infrared electrochemiluminescence (ECL) from Au-thiolate nanoclusters is activated by electrode reactions and enhanced by ethylenediamine tetraacetic acid (EDTA). The enhancement effect is higher at pH 7.4 than at more basic or acidic pHs. Magnesium ions are found to modulate the ECL signals through complexation with EDTA and the interaction with the Au nanoclusters. The chemical system and the signal modulation mechanism are believed to be generalizable and advantageous for future sensing and analysis applications with the following merits: 1) Ambient ECL without oxygen removal, 2) high enhancement at physiological pH values, 3) in the near-IR spectrum window with low interference, 4) rich and tunable redox activity of the Au nanoclusters, and 5) EDTA representing other ionophores or chelaters as versatile coreactants. [ABSTRACT FROM AUTHOR]

Single-entity electrochemistry mainly focuses on the properties of single nanoscale systems, which provides a new avenue of studying electrochemical processes at the nanoscale rather than in complex ensemble systems. Stochastic collision nanoelectrochemistry (SCNEC), which has emerged as a convenient and fast single-entity electrochemical analysis method, has gone through significant improvements over the past few years. As a powerful tool for the establishment of multiple analytical strategies, SCNEC has broad applications in electrochemical analysis, catalysis, biosensing, and so forth. This technique is especially promising for the rapid analysis of a single entity with respect to size, concentration, aggregation, and kinetic studies. In this Minireview, we summarize the basic principles and experimental techniques of SCNEC and give a brief overview of the cutting-edge developments in SCNEC over the past 3 years. [ABSTRACT FROM AUTHOR]

Well-controlled functionalization of carbide-based nanocomposite films with noble-metal surface nanoparticles of different sizes may lead to new materials with novel multifunctional properties. In this work, magnetron sputtering was used to deposit nanocomposite films comprising amorphous chromium carbide (a-CrC x), amorphous carbon (a-C), and a minority of silver in the form of embedded nanoclusters. Up to 5⋅1010 surface nanoparticles per cm2 with different size distributions were also found to be formed, owing to the diffusion of silver from the bulk of the film. The influences of these conductive nanoparticles on the electrochemical behavior of the films were investigated in dilute sulfuric acid. Although silver is a noble metal, the oxidation potential of the nanoparticles was about 0.4 V more negative than the Ag+/Ag standard potential, meaning that the nanoparticles were oxidized in the Cr passive potential region. While this effect can mainly be explained by a low concentration of Ag+ in the electrolyte, the sizes of the nanoparticles and interactions with the matrix were also found to be important. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to analyze the surface chemistries. As Ag can be replaced by other noble metals, the concept is of general interest for further studies. [ABSTRACT FROM AUTHOR]

Quantitative theoretical investigations based on a 3D Brownian motion approach established that our previous 'cylindrical' approximation remains valid even for drastically irregular arrays. This result led us to propose a simple analytical equation that can be used to predict the chronoamperometric behavior of such commonly used irregular arrays, taking into account the statistical distributions of the Voronoi cells built around the disk electrodes. [ABSTRACT FROM AUTHOR]

Cover Picture: Nanoelectrochemistry Reveals Selective Interactions of Perfluoroalkyl Substances (PFASs) with Silver Nanoparticles (Angew. Keywords: Detection; Nanoelectrochemistry; Nanoparticles; PFAS; Surface Interactions EN Detection Nanoelectrochemistry Nanoparticles PFAS Surface Interactions 1 1 1 10/14/22 20221017 NES 221017 B Nanoelectrochemistry b using single-particle collisions on microelectrode supported by spectroscopic and theoretical studies provide insights into the molecular interactions of perfluoroalkyl substances (PFAS) at single-particle scale. Detection, Nanoelectrochemistry, Nanoparticles, PFAS, Surface Interactions. [Extracted from the article]

Detection, Nanoelectrochemistry, Nanoparticles, PFAS, Surface Interactions GLO:OL3/17oct22:ange202212561-gra-0003.jpg PHOTO (COLOR): . gl B Donor - Akzeptor-Systeme b In ihrer Zuschrift (e202209225) demonstrieren Christoph Weder, Yoshimitsu Sagara et al. den ersten Cyclophan-Mechanophor, der die Emission von Ladungstransferkomplexen nutzt. Keywords: Detection; Nanoelectrochemistry; Nanoparticles; PFAS; Surface Interactions EN Detection Nanoelectrochemistry Nanoparticles PFAS Surface Interactions 1 1 1 10/13/22 20221017 NES 221017 B Nanoelektrochemie b unter Verwendung von Einzelteilchenkollisionen an Mikroelektroden, unterstützt durch spektroskopische und theoretische Studien, bietet Einblicke in die molekularen Wechselwirkungen von Perfluoralkylsubstanzen (PFAS) auf Einzelpartikelebene. [Extracted from the article]

Electrochemistry at individual metal nanoparticles (NPs) can provide new insights into their electrocatalytic behavior. Herein, the electrochemical activity of single AuNPs attached to the catalytically inert carbon surface is mapped by using extremely small (≥3 nm radius) polished nanoelectrodes as tips in the scanning electrochemical microscope (SECM). The use of such small probes resulted in the spatial resolution significantly higher than in previously reported electrochemical images. The currents produced by either rapid electron transfer or the electrocatalytic hydrogen evolution reaction at a single 10 or 20 nm NP were measured and quantitatively analyzed. The developed methodology should be useful for studying the effects of nanoparticle size, geometry, and surface attachment on electrocatalytic activity in real-world application environment. [ABSTRACT FROM AUTHOR]

Ion solvation, Nanoelectrochemistry, Nano impact electrochemistry, Solvent mixtures, Viscosity of alcohol water mixtures Keywords: Ion solvation; Nanoelectrochemistry; Nano impact electrochemistry; Solvent mixtures; Viscosity of alcohol water mixtures EN Ion solvation Nanoelectrochemistry Nano impact electrochemistry Solvent mixtures Viscosity of alcohol water mixtures 1 1 1 04/14/22 20220411 NES 220411 B The Front Cover b illustrates how the different solvent shells forming in water/alcohol solvent mixtures can be probed by single particle electrochemistry thanks to the resulting difference in diffusion speeds of the solvated ions. Front Cover: Unravelling Anion Solvation in Water-Alcohol Mixtures by Single Entity Electrochemistry (ChemElectroChem 7/2022). [Extracted from the article]

Keywords: ion interaction networks; nanoelectrochemistry; nanopore; single-molecule analysis EN ion interaction networks nanoelectrochemistry nanopore single-molecule analysis 24333 24333 1 11/02/21 20211108 NES 211108 B Like a music box b , in nanopore single-molecule frequency fingerprinting a rotating metal cylinder (an analyte) uses perfectly placed pins (the chemical groups of an analyte) that come up under the comb (the characteristic residue inside the nanopore inner wall) to strike the appropriate prongs or tines of that comb (confined interactions). Ion interaction networks, nanoelectrochemistry, nanopore, single-molecule analysis Cover Picture: Single-Molecule Frequency Fingerprint for Ion Interaction Networks in a Confined Nanopore (Angew. [Extracted from the article]

Ion interaction networks, nanoelectrochemistry, nanopore, single-molecule analysis Keywords: ion interaction networks; nanoelectrochemistry; nanopore; single-molecule analysis EN ion interaction networks nanoelectrochemistry nanopore single-molecule analysis 24537 24537 1 11/02/21 20211108 NES 211108 B Wie bei einem Musikkasten b werden beim Nanoporen-Einzelmolekül-Frequenzfingerprinting ein rotierender Metallzylinder (ein Analyt) und perfekt platzierte Stifte (die chemischen Gruppen eines Analyten) genutzt, welche die Zacken oder Zinken (die charakteristischen Reste in der Nanoporeninnenwand) des Kamms anschlagen. Titelbild: Single-Molecule Frequency Fingerprint for Ion Interaction Networks in a Confined Nanopore (Angew. [Extracted from the article]

Recently, the use of intermetallics as catalysts in various chemical transformations, such as hydrogenation/dehydrogenation, oxidation, and steam reforming, as well as electrocatalysts for oxygen reduction, and their advantages over random alloys in the same composition have been reported. Herein, the effect of atomic ordering on the activity for methanol and formic acid oxidation of low‐temperature fuel cell platinum‐based electrocatalysts is discussed, by comparing ordered and disordered structures with the same Pt/M (in which M is the first and second row transition metal) atomic ratio (3 and 1). [ABSTRACT FROM AUTHOR]

The article presents the back cover of the journal depicting near-infrared electrochemiluminescence from the nanoclusters of gold.