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Plačkić A, Neubert TJ, Patel K, Kuhl M, Watanabe K, Taniguchi T, Zurutuza A, Sordan R, Balasubramanian K. Electrochemistry at the Edge of a van der Waals Heterostructure. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306361. [PMID: 38109121 DOI: 10.1002/smll.202306361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/19/2023] [Indexed: 12/19/2023]
Abstract
Artificial van der Waals heterostructures, obtained by stacking two-dimensional (2D) materials, represent a novel platform for investigating physicochemical phenomena and applications. Here, the electrochemistry at the one-dimensional (1D) edge of a graphene sheet, sandwiched between two hexagonal boron nitride (hBN) flakes, is reported. When such an hBN/graphene/hBN heterostructure is immersed in a solution, the basal plane of graphene is encapsulated by hBN, and the graphene edge is exclusively available in the solution. This forms an electrochemical nanoelectrode, enabling the investigation of electron transfer using several redox probes, e.g., ferrocene(di)methanol, hexaammineruthenium, methylene blue, dopamine and ferrocyanide. The low capacitance of the van der Waals edge electrode facilitates cyclic voltammetry at very high scan rates (up to 1000 V s-1), allowing voltammetric detection of redox species down to micromolar concentrations with sub-second time resolution. The nanoband nature of the edge electrode allows operation in water without added electrolyte. Finally, two adjacent edge electrodes are realized in a redox-cycling format. All the above-mentioned phenomena can be investigated at the edge, demonstrating that nanoscale electrochemistry is a new application avenue for van der Waals heterostructures. Such an edge electrode will be useful for studying electron transfer mechanisms and the detection of analyte species in ultralow sample volumes.
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Affiliation(s)
- Aleksandra Plačkić
- L-NESS, Department of Physics, Politecnico di Milano, Via Anzani 42, Como, 22100, Italy
- BioSense Institute, University of Novi Sad, Dr Zorana Đinđića 1, Novi Sad, 21000, Serbia
| | - Tilmann J Neubert
- School of Analytical Sciences Adlershof (SALSA), IRIS Adlershof & Department of Chemistry, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099, Berlin, Germany
| | - Kishan Patel
- L-NESS, Department of Physics, Politecnico di Milano, Via Anzani 42, Como, 22100, Italy
| | - Michel Kuhl
- School of Analytical Sciences Adlershof (SALSA), IRIS Adlershof & Department of Chemistry, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099, Berlin, Germany
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Amaia Zurutuza
- Graphenea Semiconductor SLU, Mikeletegi Pasealekua 83, San Sebastián, 20009, Spain
| | - Roman Sordan
- L-NESS, Department of Physics, Politecnico di Milano, Via Anzani 42, Como, 22100, Italy
| | - Kannan Balasubramanian
- School of Analytical Sciences Adlershof (SALSA), IRIS Adlershof & Department of Chemistry, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099, Berlin, Germany
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2
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Karbarz M. Editorial. J Electroanal Chem (Lausanne) 2023. [DOI: 10.1016/j.jelechem.2023.117313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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3
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Zaleskaya-Hernik M, Karbarz M, Romański J. The use of microelectrodes to study ion recognition by a squaramide-based ion pair receptor consisting of a ferrocene reporter. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.117058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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4
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A highly sensitive, easy-and-rapidly-fabricable microfluidic electrochemical cell with an enhanced three-dimensional electric field. Anal Chim Acta 2022; 1232:340488. [DOI: 10.1016/j.aca.2022.340488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 09/21/2022] [Accepted: 10/04/2022] [Indexed: 11/20/2022]
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5
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Vannoy KJ, Krushinski LE, Kong EF, Dick JE. Reagentless Voltammetric Identification of Cocaine from Complex Powders. Anal Chem 2022; 94:12638-12644. [PMID: 36066582 DOI: 10.1021/acs.analchem.2c01630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cocaine is one of the most commonly trafficked and abused drugs in the United States, and deployable field tests are important for rapid identification in nonlaboratory settings. At present, colorimetric tests exist for in-field determination, but these fundamentally suffer from interferent effects. Cocaine is an organic salt that is readily water soluble as a cation and almost insoluble in the deprotonated neutral form. Here, we take advantage of the electrochemical window of water to increase the pH at the electrode surface by driving water reduction, effectively electroprecipitating the cocaine base. The precipitate on the electrode surface is then electrochemically oxidized by a voltammetric sweep through sufficiently positive potentials. We demonstrate excellent selectivity to cocaine compared to common adulterants, such as procaine, lidocaine, benzocaine, caffeine, and levamisole. Finally, we detect cocaine on a carbon fiber microelectrode, demonstrating miniaturizability and allowing access to low-resistance media (e.g., tap water).
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Affiliation(s)
- Kathryn J Vannoy
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Lynn E Krushinski
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Edgar F Kong
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jeffrey E Dick
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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6
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Enhancement of the Negative Capacitance Associated with the Dissolution of Silver by Salt Concentrations by Means of Anodic Stripping Voltammetry. ELECTROCHEM 2022. [DOI: 10.3390/electrochem3030027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The amount of anodically dissolved charge of silver by linear sweep stripping voltammetry has been observed to be smaller than that of the potentiostatically deposited charge. The imbalance in the charge is opposite to the participation in the double-layer capacitance. This can be explained in terms of the negative capacitive current, which is caused by dipoles of generated redox charge (Ag+) with counterions (NO3−). Lower concentrations of counterions may suppress the capacitance to retain the equality of the charge. This prediction is examined in this work by the oxidation of silver film at various concentrations of NO3− by anodic stripping voltammetry. The capacitance decreased with a decrease in the salt concentrations less than 0.05 mol dm−3. Low concentrations of salts prevent loss of the anodic charge in electroanalysis. This dependence was related with the lifespan of generated silver nitrate dipoles and is described theoretically.
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7
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Dumitrescu E, Deshpande A, Wallace KN, Andreescu S. Time-Dependent Monitoring of Dopamine in the Brain of Live Embryonic Zebrafish Using Electrochemically Pretreated Carbon Fiber Microelectrodes. ACS MEASUREMENT SCIENCE AU 2022; 2:261-270. [PMID: 36785866 PMCID: PMC9838818 DOI: 10.1021/acsmeasuresciau.1c00051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Neurotransmitters are involved in functions related to signaling, stress response, and pathological disorder development, and thus, their real-time monitoring at the site of production is important for observing the changes related to these disorders. Here, we demonstrate the first time-dependent quantification of dopamine in the brains of live zebrafish embryos using electrochemically pretreated carbon fiber microelectrodes (CFMEs) utilizing differential pulse voltammetry as the measurement technique. The pretreatment of the CFMEs in 0.1 M NaOH held at a potential of +1.0 V for 600 s improves the sensitivity toward dopamine and allows for reliable measurements in low ionic strength media. We demonstrate the measurement of extracellular dopamine concentrations in the zebrafish brain during late embryogenesis. The extracellular dopamine concentration in the tectum of zebrafish varies between 200 and 400 nM. The conventional pharmacological manipulation of neurotransmitter levels in the brain demonstrates the selective detection of dopamine at the implantation site. Exposure to the dopamine transporter inhibitor nomifensine induces an increase in extracellular dopamine from 201.9 (±34.9) nM to 352.2 (±20.0) nM, while exposure to the norepinephrine transporter inhibitor desipramine does not lead to a significant modulation of the measured signal. Furthermore, we report the quantitative assessment of the catecholamine stress response of embryos to tricaine, an anesthetic frequently used in zebrafish assays. Exposure to tricaine induces a short-lived increase in brain dopamine from 198.6 (±15.7) nM to a maximum of 278.8 (±14.0) nM. Thus, in vivo electrochemistry can detect real-time changes in zebrafish neurochemical physiology resulting from drug exposure.
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Affiliation(s)
- Eduard Dumitrescu
- Department
of Chemistry and Biomolecular Science, Clarkson
University, 8 Clarkson Avenue, Potsdam, New York 13699-5810, United States
| | - Aaditya Deshpande
- Department
of Chemistry and Biomolecular Science, Clarkson
University, 8 Clarkson Avenue, Potsdam, New York 13699-5810, United States
| | - Kenneth N. Wallace
- Department
of Biology, Clarkson University, 8 Clarkson Avenue, Potsdam, New York 13699-5805, United States
| | - Silvana Andreescu
- Department
of Chemistry and Biomolecular Science, Clarkson
University, 8 Clarkson Avenue, Potsdam, New York 13699-5810, United States
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Bird MJ, Pearson MA, Asaoka S, Miller JR. General Method for Determining Redox Potentials without Electrolyte. J Phys Chem A 2020; 124:5487-5495. [PMID: 32437607 DOI: 10.1021/acs.jpca.0c02948] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel method to determine redox potentials without electrolyte is presented. The method is based on a new ability to determine the dissociation constant, K°d, for ion pairs formed between any radical anion and any inert electrolyte counterion. These dissociation constants can be used to determine relative shifts of redox potential as a function of electrolyte concentration, connecting referenced potentials determined with electrochemistry (with 0.1 M electrolyte) to electrolyte-free values. Pulse radiolysis created radical anions enabling determination of equilibrium constants for electron transfer between anions of donor and acceptor molecules as a function of electrolyte concentration in THF. The measurements determined "composite equilibrium constants", KeqC, which contain information about the dissociation constant for the electrolyte cations, X+, with the radical anions of both the donor, K°d(D-•,X+) and the acceptor, K°d(A-•,X+). Dissociation constants were obtained for a selection of radical anions with tetrabutylammonium (TBA+). The electrolyte was found to shift the reduction potentials of small molecules 1-methylpyrene and trans-stilbene by close to +130 mV whereas oligo-fluorenes and polyfluorenes experienced shifts of only (+25 ± 6) mV due to charge delocalization weakening the ion pair. These shifts for reduction of aromatic hydrocarbon molecules are smaller than shifts of +232 and +451 mV seen previously for benzophenone radical anion with TBA+ and Na+ respectively where the charge on the radical anion is localized largely on one C═O bond, thus forming a more tightly bound ion pair.
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Affiliation(s)
- Matthew J Bird
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793-5000, United States
| | - Matthew A Pearson
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Sadayuki Asaoka
- Department of Biomolecular Engineering, Kyoto Institute of Technology, Matsugaskaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - John R Miller
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793-5000, United States
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Koklu A, Giuliani J, Monton C, Beskok A. Rapid and Sensitive Detection of Nanomolecules by an AC Electrothermal Flow Facilitated Impedance Immunosensor. Anal Chem 2020; 92:7762-7769. [DOI: 10.1021/acs.analchem.0c00890] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Anil Koklu
- Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Jason Giuliani
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Carlos Monton
- General Atomics, P.O. Box 85608, San Diego, California 92186 United States
| | - Ali Beskok
- Department of Mechanical Engineering, Southern Methodist University, Dallas, Texas 75205, United States
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10
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Guo Y, Yang M, Batchelor-McAuley C, Compton RG. Metal deposition and stripping under self-supported conditions: Experiment and simulation. J Electroanal Chem (Lausanne) 2019. [DOI: 10.1016/j.jelechem.2019.113370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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11
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Pecchielan G, Baldo MA, Fabris S, Daniele S. A preliminary voltammetric investigation of silver ions in food simulants. J Electroanal Chem (Lausanne) 2019. [DOI: 10.1016/j.jelechem.2019.05.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Ghosh Dastider S, Abdullah A, Jasim I, Yuksek NS, Dweik M, Almasri M. Low concentration E. coli O157:H7 bacteria sensing using microfluidic MEMS biosensor. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:125009. [PMID: 30599553 DOI: 10.1063/1.5043424] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
This paper reports the design, fabrication, and testing of a microfluidic MEMS biosensor for rapid sensing of low concentration Escherichia coli O157:H7. It consists of a specially designed focusing and sensing region, which enables the biosensor to detect low concentration of bacterial cells. The focusing region consists of a ramped vertical electrode pair made of electroplated gold along with tilted thin film finger pairs (45°) embedded inside a microchannel. The focusing region generates positive dielectrophoresis force, which moves the cells towards the edges of the tilted thin film electrode fingers, located at the center of the microchannel. The fluidic drag force then carries the focused cells to the sensing region, where three interdigitated electrode arrays (IDEAs) with 30, 20, and 10 pairs, respectively, are embedded inside the microchannel. This technique resulted in highly concentrated samples in the sensing region. The sensing IDEAs are functionalized with the anti-E. coli antibody for specific sensing of E. coli 0157:H7. As E. coli binds to the antibody, it results in an impedance change, which is measured across a wide frequency range of 100 Hz-10 MHz. The biosensor was fabricated on a glass substrate using the SU8 epoxy resist to form the microchannel, gold electroplating to form the vertical focusing electrode pair, a thin gold film to form the sensing electrode, the finger electrodes, traces and bonding pads, and polydimethylsiloxane to seal the device. The microfluidic impedance biosensor was tested with various low concentration bacterial samples and was able to detect bacterial concentration, as low as 39 CFU/ml with a total sensing time of 2 h.
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Affiliation(s)
- Shibajyoti Ghosh Dastider
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65211, USA
| | - Amjed Abdullah
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65211, USA
| | - Ibrahem Jasim
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65211, USA
| | - Nuh S Yuksek
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65211, USA
| | - Majed Dweik
- Department of Co-operative Research, Lincoln University, Jefferson City, Missouri 65101, USA
| | - Mahmoud Almasri
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65211, USA
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13
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Anodic stripping voltammetry of silver in the absence of electrolytes: Theory and experiment. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2018.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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15
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Chan C, Kätelhön E, Compton RG. Theoretical prediction of a transient accumulation of nanoparticles at a well-defined distance from an electrified liquid-solid interface. NANOSCALE 2018; 10:19459-19468. [PMID: 30318525 DOI: 10.1039/c8nr05055d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The Brownian motion of nanoparticles near liquid-solid interfaces is at the heart of evolving technologies: recent developments in the sensing of nano-objects and energy storages based on electro-active colloidal solutions crucially rely on the understanding and, even more, on the control of particle transport near charged surfaces. On the basis of the Nernst-Planck equation, the Gouy-Chapman model, and an established model of near-wall hindered diffusion, this work predicts transient and highly-localised accumulations of nanoparticles at a well-defined distance from an electrified surface following a potential being applied. The interplay of electrostatics and near-wall hindered diffusion yields entirely unexpected effects: nanoobjects temporarily accumulate near the interface while even small electric potentials applied at the surface can dramatically enhance the mass transport of nano-objects towards it.
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Affiliation(s)
- Crystal Chan
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, UK.
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16
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Volgin VM, Davydov AD. Effect of migration on homogeneous redox electrocatalysis at rotating disk electrode. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2017.10.150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Li X, Batchelor-McAuley C, Laborda E, Compton RG. Aqueous Voltammetry in the Near Absence of Electrolyte. Chemistry 2017; 23:15222-15226. [PMID: 28876501 DOI: 10.1002/chem.201703525] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Indexed: 11/09/2022]
Abstract
In order to minimize the incidence of the CO2 hydrolysis and conduct aqueous electrochemistry in the virtual absence of electrolyte, a novel methodology is developed to achieve the near minimum conductivity (≈60 nS cm-1 ) for an aqueous solution through in situ deionization with ion exchange resin beads. Aqueous electrochemistry studying the oxidations of platinum, ferrocenemethanol, and hydrogen (H2 ) were conducted in the near complete absence of trace ionic species at a platinum microelectrode (d=10 μm). Both surface and solution phase electrochemical reactions were clearly observed, indicating that under these conditions there is a sufficiently compressed double layer for an interfacial electron transfer to be driven and the iR effects are significantly smaller than theoretically expected.
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Affiliation(s)
- Xiuting Li
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, Oxford, OX1 3QZ, UK
| | | | - Eduardo Laborda
- Departamento de Química Física, Facultad de Química, Universidad de Murcia, 30100, Murcia, Spain
| | - Richard G Compton
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, Oxford, OX1 3QZ, UK
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18
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Ma C, Xu W, Wichert WRA, Bohn PW. Ion Accumulation and Migration Effects on Redox Cycling in Nanopore Electrode Arrays at Low Ionic Strength. ACS NANO 2016; 10:3658-64. [PMID: 26910572 DOI: 10.1021/acsnano.6b00049] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Ion permselectivity can lead to accumulation in zero-dimensional nanopores, producing a significant increase in ion concentration, an effect which may be combined with unscreened ion migration to improve sensitivity in electrochemical measurements, as demonstrated by the enormous current amplification (∼2000-fold) previously observed in nanopore electrode arrays (NEA) in the absence of supporting electrolyte. Ionic strength is a key experimental factor that governs the magnitude of the additional current amplification (AFad) beyond simple redox cycling through both ion accumulation and ion migration effects. Separate contributions from ion accumulation and ion migration to the overall AFad were identified by studying NEAs with varying geometries, with larger AFad values being achieved in NEAs with smaller pores. In addition, larger AFad values were observed for Ru(NH3)6(3/2+) than for ferrocenium/ferrocene (Fc(+)/Fc) in aqueous solution, indicating that coupling efficiency in redox cycling can significantly affect AFad. While charged species are required to observe migration effects or ion accumulation, poising the top electrode at an oxidizing potential converts neutral species to cations, which can then exhibit current amplification similar to starting with the cation. The electrical double layer effect was also demonstrated for Fc/Fc(+) in acetonitrile and 1,2-dichloroethane, producing AFad up to 100× at low ionic strength. The pronounced AFad effects demonstrate the advantage of coupling redox cycling with ion accumulation and migration effects for ultrasensitive electrochemical measurements.
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Affiliation(s)
- Chaoxiong Ma
- Department of Chemistry and Biochemistry and ‡Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Wei Xu
- Department of Chemistry and Biochemistry and ‡Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - William R A Wichert
- Department of Chemistry and Biochemistry and ‡Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Paul W Bohn
- Department of Chemistry and Biochemistry and ‡Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
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Capozzi B, Xia J, Adak O, Dell EJ, Liu ZF, Taylor JC, Neaton JB, Campos LM, Venkataraman L. Single-molecule diodes with high rectification ratios through environmental control. NATURE NANOTECHNOLOGY 2015; 10:522-527. [PMID: 26005998 DOI: 10.1038/nnano.2015.97] [Citation(s) in RCA: 219] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 04/14/2015] [Indexed: 06/04/2023]
Abstract
Molecular electronics aims to miniaturize electronic devices by using subnanometre-scale active components. A single-molecule diode, a circuit element that directs current flow, was first proposed more than 40 years ago and consisted of an asymmetric molecule comprising a donor-bridge-acceptor architecture to mimic a semiconductor p-n junction. Several single-molecule diodes have since been realized in junctions featuring asymmetric molecular backbones, molecule-electrode linkers or electrode materials. Despite these advances, molecular diodes have had limited potential for applications due to their low conductance, low rectification ratios, extreme sensitivity to the junction structure and high operating voltages. Here, we demonstrate a powerful approach to induce current rectification in symmetric single-molecule junctions using two electrodes of the same metal, but breaking symmetry by exposing considerably different electrode areas to an ionic solution. This allows us to control the junction's electrostatic environment in an asymmetric fashion by simply changing the bias polarity. With this method, we reliably and reproducibly achieve rectification ratios in excess of 200 at voltages as low as 370 mV using a symmetric oligomer of thiophene-1,1-dioxide. By taking advantage of the changes in the junction environment induced by the presence of an ionic solution, this method provides a general route for tuning nonlinear nanoscale device phenomena, which could potentially be applied in systems beyond single-molecule junctions.
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Affiliation(s)
- Brian Capozzi
- Department of Applied Physics and Applied Mathematics, New York, New York 10027, USA
| | - Jianlong Xia
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Olgun Adak
- Department of Applied Physics and Applied Mathematics, New York, New York 10027, USA
| | - Emma J Dell
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Zhen-Fei Liu
- Molecular Foundry, Lawrence Berkeley National Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA
| | - Jeffrey C Taylor
- Department of Applied Physics and Applied Mathematics, New York, New York 10027, USA
| | - Jeffrey B Neaton
- 1] Molecular Foundry, Lawrence Berkeley National Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA [2] Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720, USA
| | - Luis M Campos
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Latha Venkataraman
- 1] Department of Applied Physics and Applied Mathematics, New York, New York 10027, USA [2] Department of Chemistry, Columbia University, New York, New York 10027, USA
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Antonietta Baldo M, Oliveri P, Simonetti R, Daniele S. Voltammetric behaviour of ferrocene in olive oils mixed with a phosphonium-based ionic liquid. J Electroanal Chem (Lausanne) 2014. [DOI: 10.1016/j.jelechem.2014.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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Guo C, Yu Y, Liu J. Rapidly patterning conductive components on skin substrates as physiological testing devices via liquid metal spraying and pre-designed mask. J Mater Chem B 2014; 2:5739-5745. [PMID: 32262017 DOI: 10.1039/c4tb00660g] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The newly emerging skin-electronic devices with flexible features are usually fabricated on a very thin substrate, which do not directly contact the skin. This may generate large coupling impedance with the skin and a high signal noise for a sensitive detection of weak physiological signals. Here, in an alternative manner, we propose a method to directly pattern liquid metal conductive components as sensors on skin through a spray-printing strategy. This quick way of making flexible electronics on skin is enabled via a stainless mask that is pre-designed by chemical etching with line width resolution of 100 μm and can be used to deposit desired electrical components. Several typical geometric metal graphics, spanning from simple to complex structures, which serve to compose complex electrical circuits or devices, are fabricated in a moment. Particularly, GaIn24.5-based liquid metal wires deposited on pig skin under different conditions were quantified, and the mechanisms for the spray-printing of bioelectronics were interpreted. Further, stretching experiments were performed, which show that the resistance of the printed film would take a square growth with the tensile length of the pig skin in a specific range. Finally, an inter-digital array (IDA) electrode sensor with the distance between two inter-digital fingers of 0.5 mm and the length of the finger of 11 mm was fabricated and applied to measure impedance spectroscopy of pig skin. This study demonstrates the unique value of the present Lab on Skin for physiological measurement. It illustrates a promising route for directly printing electronics pattern on skin that will be very useful for a wide variety of practical situations such as skin sensors, actuators, skin electrical circuits, etc.
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Affiliation(s)
- Cangran Guo
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084, China.
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Gong Z, Guo Y, Sun X, Cao Y, Wang X. Acetylcholinesterase biosensor for carbaryl detection based on interdigitated array microelectrodes. Bioprocess Biosyst Eng 2014; 37:1929-34. [PMID: 24770986 DOI: 10.1007/s00449-014-1195-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 02/28/2014] [Indexed: 10/25/2022]
Abstract
In this study, an acetylcholinesterase (AChE) biosensor with superior accuracy and sensitivity was successfully developed based on interdigitated array microelectrodes (IAMs). IAMs have a series of parallel microband electrodes with alternating microbands connected together. Chitosan was used as the enzyme immobilization material, and AChE was used as the model enzyme for carbaryl detection to fabricate AChE biosensor. Electrochemical impedance spectroscopy was used in conjunction with the fabricated biosensor to detect pesticide residues. Based on the inhibition of pesticides on the AChE activity, using carbaryl as model compounds, the biosensor exhibited a wide range, low detection limit, and high stability. Moreover, the biosensor can also be used as a new promising tool for pesticide residue analysis.
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Affiliation(s)
- Zhili Gong
- School of Agricultural and Food Engineering, Shandong University of Technology, No.12, Zhangzhou Road, Zibo, 255049, Shandong, People's Republic of China
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23
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Hamon M, Hong JW. New tools and new biology: recent miniaturized systems for molecular and cellular biology. Mol Cells 2013; 36:485-506. [PMID: 24305843 PMCID: PMC3887968 DOI: 10.1007/s10059-013-0333-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 11/14/2013] [Indexed: 01/09/2023] Open
Abstract
Recent advances in applied physics and chemistry have led to the development of novel microfluidic systems. Microfluidic systems allow minute amounts of reagents to be processed using μm-scale channels and offer several advantages over conventional analytical devices for use in biological sciences: faster, more accurate and more reproducible analytical performance, reduced cell and reagent consumption, portability, and integration of functional components in a single chip. In this review, we introduce how microfluidics has been applied to biological sciences. We first present an overview of the fabrication of microfluidic systems and describe the distinct technologies available for biological research. We then present examples of microsystems used in biological sciences, focusing on applications in molecular and cellular biology.
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Affiliation(s)
- Morgan Hamon
- Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, AL 36849,
USA
| | - Jong Wook Hong
- Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, AL 36849,
USA
- College of Pharmacy, Seoul National University, Seoul 151-741,
Korea
- Department of Bionano Engineering, Hanyang University, Ansan 426-791,
Korea
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24
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Zhang C, Aoki KJ, Chen J, Nishiumi T. Blocking of two-electron reduction of non-charged species in the absence of supporting electrolyte at nanoelectrodes. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2013.09.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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25
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26
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Voltammetry in low concentration of electrolyte supported by ionic latex suspensions. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2013.03.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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27
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28
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Heterogeneous electron transfer and diffusivities of ferrocene/ferrocenium couple in toluene/phosphonium-based ionic liquid solutions. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2012.12.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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29
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Aguilar D, Parat C, Galceran J, Companys E, Puy J, Authier L, Potin-Gautier M. Determination of free metal ion concentrations with AGNES in low ionic strength media. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2012.11.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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30
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Rapid bacterial detection with an interdigitated array electrode by electrochemical impedance spectroscopy. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2012.05.131] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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31
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YAN XF, WANG MH, AN D. Progress of Interdigitated Array Microelectrodes Based Impedance Immunosensor. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2012. [DOI: 10.3724/sp.j.1096.2011.01601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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32
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Differential pulse techniques in weakly supported media: Changes in the kinetics and thermodynamics of electrode processes resulting from the supporting electrolyte concentration. J Electroanal Chem (Lausanne) 2012. [DOI: 10.1016/j.jelechem.2012.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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33
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Wang H, Pilon L. Physical interpretation of cyclic voltammetry for measuring electric double layer capacitances. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2011.12.118] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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34
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Monticelli D, Pozzi A, Credaro A, Dossi C. An Electroanalytical Approach to the Understanding of Copper Exportation in Glaciated Catchments. ELECTROANAL 2012. [DOI: 10.1002/elan.201100560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Belding SR, Laborda E, Compton RG. Steady-state voltammetry at a microdisc electrode in the absence of excess supporting electrolyte for reversible, quasi-reversible and irreversible electrode kinetics. Phys Chem Chem Phys 2012; 14:14635-49. [DOI: 10.1039/c2cp42533e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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SENTHAMARAI R, RAJENDRAN L. A COMPARISON OF DIFFUSION-LIMITED CURRENT AT MICROELECTRODES OF VARIOUS GEOMETRIES. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2011. [DOI: 10.1142/s0219633608003721] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this paper, we present a critical evaluation of the influence of geometry on the behavior of the transient current at all ultramicroelectrodes. The nonsteady-state chronoamperometric diffusion limited current of various microelectrodes (circular disc, circular ring, elliptical disc, elliptical ring, band, hemicylinder, hemisphere, hemioblate and hemiprolate electrodes) are compared. Here, the area of the entire electrode is fixed and time variables are also normalized with respect to area. The chronoamperometric current for short and long time for all microelectrodes are given in tabular as well as graphical form also.
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Affiliation(s)
- R. SENTHAMARAI
- SMSV Higher Secondary School, Karaikudi 630 001, Tamilnadu, India
| | - L. RAJENDRAN
- SMSV Higher Secondary School, Karaikudi 630 001, Tamilnadu, India
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37
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Batchelor-McAuley C, Dickinson EJF, Rees NV, Toghill KE, Compton RG. New Electrochemical Methods. Anal Chem 2011; 84:669-84. [DOI: 10.1021/ac2026767] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christopher Batchelor-McAuley
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Edmund J. F. Dickinson
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Neil V. Rees
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Kathryn E. Toghill
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Richard G. Compton
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
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38
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YAN XF, WANG MH, AN D. Progress of Interdigitated Array Microelectrodes Based Impedance Immunosensor. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2011. [DOI: 10.1016/s1872-2040(10)60478-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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39
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Huang H, Wang Q, Cha CS, Lu J, Zhuang L. A Reference Electrode System for Electrochemical Measurements in Pure Water. ELECTROANAL 2011. [DOI: 10.1002/elan.201000589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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40
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Abstract
Exploration of electrochemical properties in ultrasmall volumes is still an emerging area. It is not only of great importance for the fundamental research, but also endowed with practical significance in the area of bioanalysis and medicine. Microelectrodes with superior electrochemical characteristics and versatile configurations are suitable tools for the investigation in confined geometries, and remarkable progress involving both preparation methods and theoretical interpretation has been made during the last few decades. Despite this success, electrochemical studies in nanoscopic volumes are still highly challenging due to the less predictable situations in very limited spatial and temporal domains, as well as difficulty in micromanipulation at the nanoscale. In this mini-review, we will summarize the main strategies for this topic, briefly look through the recent advances, and specifically introduce the design and application of a new kind of on-chip ultrasmall electrochemical cells based on micro- and nanogap electrodes, which are prepared by photolithographic method with volume ranging from femtolitre to attolitre. Finally, the limits of current systems and the future perspectives of this field are discussed.
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Affiliation(s)
- Tao Li
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
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41
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Cyclic voltammetry in weakly supported media: The reduction of the cobaltocenium cation in acetonitrile – Comparison between theory and experiment. J Electroanal Chem (Lausanne) 2010. [DOI: 10.1016/j.jelechem.2010.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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42
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Belding SR, Limon-Petersen JG, Dickinson EJF, Compton RG. Cyclic Voltammetry in the Absence of Excess Supporting Electrolyte Offers Extra Kinetic and Mechanistic Insights: Comproportionation of Anthraquinone and the Anthraquinone Dianion in Acetonitrile. Angew Chem Int Ed Engl 2010; 49:9242-5. [DOI: 10.1002/anie.201004874] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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43
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Belding SR, Limon-Petersen JG, Dickinson EJF, Compton RG. Cyclic Voltammetry in the Absence of Excess Supporting Electrolyte Offers Extra Kinetic and Mechanistic Insights: Comproportionation of Anthraquinone and the Anthraquinone Dianion in Acetonitrile. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201004874] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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44
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Arya SK, Chornokur G, Venugopal M, Bhansali S. Antibody functionalized interdigitated μ-electrode (IDμE) based impedimetric cortisol biosensor. Analyst 2010; 135:1941-6. [DOI: 10.1039/c0an00242a] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Cyclic voltammetry at microelectrodes. Influence of natural convection on diffusion layers as characterized by in situ mapping of concentration profiles. Electrochem commun 2009. [DOI: 10.1016/j.elecom.2009.04.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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46
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Varshney M, Li Y. Interdigitated array microelectrodes based impedance biosensors for detection of bacterial cells. Biosens Bioelectron 2008; 24:2951-60. [PMID: 19041235 DOI: 10.1016/j.bios.2008.10.001] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 10/02/2008] [Accepted: 10/03/2008] [Indexed: 11/16/2022]
Abstract
Impedance spectroscopy is a sensitive technique to characterize the chemical and physical properties of solid, liquid, and gas phase materials. In recent years this technique has gained widespread use in developing biosensors for monitoring the catalyzed reaction of enzymes; the bio-molecular recognition events of specific proteins, nucleic acids, whole cells, antibodies or antibody-related substances; growth of bacterial cells; or the presence of bacterial cells in the aqueous medium. Interdigitated array microelectrodes (IDAM) have been integrated with impedance detection in order to miniaturize the conventional electrodes, enhance the sensitivity, and use the flexibility of electrode fabrication to suit the conventional electrochemical cell format or microfluidic devices for variety of applications in chemistry and life sciences. This article limits its discussion to IDAM based impedance biosensors for their applications in the detection of bacterial cells. It elaborates on different IDAM geometries their fabrication materials and design parameters, and types of detection techniques. Additionally, the shortcomings of the current techniques and some upcoming trends in this area are also mentioned.
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Affiliation(s)
- Madhukar Varshney
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
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47
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Donten M, Bak E, Gniadek M, Stojek Z, Scholz F. Three-phase electrochemistry with a hanging drop of water-insoluble liquid. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2008.02.099] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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48
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Donten M, Nowicka A, Palys M, Szydlowska J, Stojek Z. Voltammetry of Undiluted Red-Ox Systems. Electrochemical ESR- and Electrochemical Impedance Spectroscopy Evidence for Formation of Ionic Liquid at Microelectrode Surface. ELECTROANAL 2008. [DOI: 10.1002/elan.200704062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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49
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Hyk W, Karbarz M, Misterkiewicz B, Stojek Z. Voltammetric Studies of Diffusional and Migrational Transport of Ferrocene Derivative of Tripeptide Glutathione. J Phys Chem B 2007; 111:13090-6. [DOI: 10.1021/jp073363v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wojciech Hyk
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland, and Department of Chemistry, Technical University of Radom, Chrobrego 27, 26-600 Radom, Poland
| | - Marcin Karbarz
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland, and Department of Chemistry, Technical University of Radom, Chrobrego 27, 26-600 Radom, Poland
| | - Boguslaw Misterkiewicz
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland, and Department of Chemistry, Technical University of Radom, Chrobrego 27, 26-600 Radom, Poland
| | - Zbigniew Stojek
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland, and Department of Chemistry, Technical University of Radom, Chrobrego 27, 26-600 Radom, Poland
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50
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Horvath J, Nagy M. Role of linear charge density and counterion quality in thermodynamic properties of strong acid type polyelectrolytes: divalent transition metal cations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:10963-71. [PMID: 17154572 DOI: 10.1021/la061642o] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Thermodynamic properties of aqueous solutions of poly[(vinyl alcohol)-co-(vinyl sulfate)] (PVAS) copolymer polyelectrolytes with divalent transition metal (Co(II), Ni(II), and Cu(II)) counterions have been determined by the gel deswelling method in the concentration range of 0.0005-0.12 mol of counterion/kg of water (0.09-9 w/w% of the polymer). The influence of the chemical nature of the counterion as well as the effect of the composition of the copolymer from small to medium linear charge density have been systematically studied. Solvent activity, reduced osmotic pressure, the Flory-Huggins pair interaction parameter, rational osmotic coefficients, and degrees of dissociation were calculated from the measured data. No difference could have been observed between the three counterions. Reduced osmotic pressure curves are found to be convex from above, as for Na+ counterions studied previously, which is contrary to the usual behavior of neutral polymers. Intercepts are increasing, and the calculated apparent molar masses and degrees of dissociation at infinite dilution are decreasing with increasing linear charge density of the polyelectrolytes. The pair interaction parameters show a considerable negative deviation from linearity, except for the high volume fraction region. From the differences, concentration dependence of degrees of dissociation could have been calculated. The values at infinite dilution are in good agreement with those obtained from the intercepts of the reduced osmotic pressure curves. Degrees of dissociation seem to decrease approximately linearly with increasing concentration and reach zero at finite concentrations. Rational osmotic coefficients have been calculated in three different ways, both regarding and neglecting the change in the degrees of dissociation.
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Affiliation(s)
- Judit Horvath
- Institute of Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518 Budapest 112, Hungary.
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