1
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Atomic force microscopy - Scanning electrochemical microscopy (AFM-SECM) for nanoscale topographical and electrochemical characterization: Principles, applications and perspectives. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2019.135472] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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2
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Wu T, Alharbi A, Kiani R, Shahrjerdi D. Quantitative Principles for Precise Engineering of Sensitivity in Graphene Electrochemical Sensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1805752. [PMID: 30548684 PMCID: PMC6823930 DOI: 10.1002/adma.201805752] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/11/2018] [Indexed: 05/15/2023]
Abstract
A major difficulty in implementing carbon-based electrode arrays with high device-packing density is to ensure homogeneous and high sensitivities across the array. Overcoming this obstacle requires quantitative microscopic models that can accurately predict electrode sensitivity from its material structure. Such models are currently lacking. Here, it is shown that the sensitivity of graphene electrodes to dopamine and serotonin neurochemicals in fast-scan cyclic voltammetry measurements is strongly linked to point defects, whereas it is unaffected by line defects. Using the physics of point defects in graphene, a microscopic model is introduced that explains how point defects determine sensitivity. The predictions of this model match the empirical observation that sensitivity linearly increases with the density of point defects. This model is used to guide the nanoengineering of graphene structures for optimum sensitivity. This approach achieves reproducible fabrication of miniaturized sensors with extraordinarily higher sensitivity than conventional materials. These results lay the foundation for new integrated electrochemical sensor arrays based on nanoengineered graphene.
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Affiliation(s)
- Ting Wu
- Electrical and Computer Engineering, New York University, Brooklyn, NY, 11201, USA
| | - Abdullah Alharbi
- Electrical and Computer Engineering, New York University, Brooklyn, NY, 11201, USA
| | - Roozbeh Kiani
- Center for Neural Science, New York University, New York, NY, 10003, USA
- Neuroscience Institute, New York University Langone Medical Center, New York, NY, 10016, USA
| | - Davood Shahrjerdi
- Electrical and Computer Engineering, New York University, Brooklyn, NY, 11201, USA
- Center for Quantum Phenomena, Physics Department, New York University, New York, NY, 10003, USA
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3
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Velmurugan J, Agrawal A, An S, Choudhary E, Szalai VA. Fabrication of Scanning Electrochemical Microscopy-Atomic Force Microscopy Probes to Image Surface Topography and Reactivity at the Nanoscale. Anal Chem 2017; 89:2687-2691. [PMID: 28192901 DOI: 10.1021/acs.analchem.7b00210] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Concurrent mapping of chemical reactivity and morphology of heterogeneous electrocatalysts at the nanoscale allows identification of active areas (protrusions, flat film surface, or cracks) responsible for productive chemistry in these materials. Scanning electrochemical microscopy (SECM) can map surface characteristics, record catalyst activity, and identify chemical products at solid-liquid electrochemical interfaces. It lacks, however, the ability to distinguish topographic features where surface reactivity occurs. Here, we report the design and fabrication of scanning probe tips that combine SECM with atomic force microscopy (AFM) to perform measurements at the nanoscale. Our probes are fabricated by integrating nanoelectrodes with quartz tuning forks (QTFs). Using a calibration standard fabricated in our lab to test our probes, we obtain simultaneous topographic and electrochemical reactivity maps with a lateral resolution of 150 nm.
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Affiliation(s)
- Jeyavel Velmurugan
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology (NIST) , Gaithersburg, Maryland 20899, United States.,Maryland NanoCenter, University of Maryland , College Park, Maryland 20742, United States
| | - Amit Agrawal
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology (NIST) , Gaithersburg, Maryland 20899, United States.,Maryland NanoCenter, University of Maryland , College Park, Maryland 20742, United States
| | - Sangmin An
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology (NIST) , Gaithersburg, Maryland 20899, United States.,Maryland NanoCenter, University of Maryland , College Park, Maryland 20742, United States
| | - Eric Choudhary
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology (NIST) , Gaithersburg, Maryland 20899, United States
| | - Veronika A Szalai
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology (NIST) , Gaithersburg, Maryland 20899, United States
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4
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Unwin PR, Güell AG, Zhang G. Nanoscale Electrochemistry of sp(2) Carbon Materials: From Graphite and Graphene to Carbon Nanotubes. Acc Chem Res 2016; 49:2041-8. [PMID: 27501067 DOI: 10.1021/acs.accounts.6b00301] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Carbon materials have a long history of use as electrodes in electrochemistry, from (bio)electroanalysis to applications in energy technologies, such as batteries and fuel cells. With the advent of new forms of nanocarbon, particularly, carbon nanotubes and graphene, carbon electrode materials have taken on even greater significance for electrochemical studies, both in their own right and as components and supports in an array of functional composites. With the increasing prominence of carbon nanomaterials in electrochemistry comes a need to critically evaluate the experimental framework from which a microscopic understanding of electrochemical processes is best developed. This Account advocates the use of emerging electrochemical imaging techniques and confined electrochemical cell formats that have considerable potential to reveal major new perspectives on the intrinsic electrochemical activity of carbon materials, with unprecedented detail and spatial resolution. These techniques allow particular features on a surface to be targeted and models of structure-activity to be developed and tested on a wide range of length scales and time scales. When high resolution electrochemical imaging data are combined with information from other microscopy and spectroscopy techniques applied to the same area of an electrode surface, in a correlative-electrochemical microscopy approach, highly resolved and unambiguous pictures of electrode activity are revealed that provide new views of the electrochemical properties of carbon materials. With a focus on major sp(2) carbon materials, graphite, graphene, and single walled carbon nanotubes (SWNTs), this Account summarizes recent advances that have changed understanding of interfacial electrochemistry at carbon electrodes including: (i) Unequivocal evidence for the high activity of the basal surface of highly oriented pyrolytic graphite (HOPG), which is at least as active as noble metal electrodes (e.g., platinum) for outer-sphere redox processes. (ii) Demonstration of the high activity of basal plane HOPG toward other reactions, with no requirement for catalysis by step edges or defects, as exemplified by studies of proton-coupled electron transfer, redox transformations of adsorbed molecules, surface functionalization via diazonium electrochemistry, and metal electrodeposition. (iii) Rationalization of the complex interplay of different factors that determine electrochemistry at graphene, including the source (mechanical exfoliation from graphite vs chemical vapor deposition), number of graphene layers, edges, electronic structure, redox couple, and electrode history effects. (iv) New methodologies that allow nanoscale electrochemistry of 1D materials (SWNTs) to be related to their electronic characteristics (metallic vs semiconductor SWNTs), size, and quality, with high resolution imaging revealing the high activity of SWNT sidewalls and the importance of defects for some electrocatalytic reactions (e.g., the oxygen reduction reaction). The experimental approaches highlighted for carbon electrodes are generally applicable to other electrode materials and set a new framework and course for the study of electrochemical and interfacial processes.
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Affiliation(s)
- Patrick R. Unwin
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Aleix G. Güell
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
- School
of Engineering and Built Environment, Glasgow Caledonian University, Glasgow G4 0BA, United Kingdom
| | - Guohui Zhang
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
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5
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Zhang G, Tan SY, Patel AN, Unwin PR. Electrochemistry of Fe3+/2+ at highly oriented pyrolytic graphite (HOPG) electrodes: kinetics, identification of major electroactive sites and time effects on the response. Phys Chem Chem Phys 2016; 18:32387-32395. [DOI: 10.1039/c6cp06472h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Electron transfer kinetics of Fe3+/2+ on HOPG is as fast as on metals, with the electroactivity dominated by basal plane.
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Affiliation(s)
- Guohui Zhang
- Department of Chemistry
- University of Warwick
- Coventry CV4 7AL
- UK
| | - Sze-yin Tan
- Department of Chemistry
- University of Warwick
- Coventry CV4 7AL
- UK
| | - Anisha N. Patel
- Department of Chemistry
- University of Warwick
- Coventry CV4 7AL
- UK
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6
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Maddar FM, Lazenby RA, Patel AN, Unwin PR. Electrochemical oxidation of dihydronicotinamide adenine dinucleotide (NADH): comparison of highly oriented pyrolytic graphite (HOPG) and polycrystalline boron-doped diamond (pBDD) electrodes. Phys Chem Chem Phys 2016; 18:26404-26411. [DOI: 10.1039/c6cp05394g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
NADH electro-oxidation is faster, but more prone to fouling, at HOPG compared to pBDD.
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Affiliation(s)
| | | | - Anisha N. Patel
- Department of Chemistry
- University of Warwick
- Coventry
- UK
- Interfaces, Traitements, Organisation et Dynamique des Systèmes Laboratory
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7
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Velický M, Bissett MA, Toth PS, Patten HV, Worrall SD, Rodgers ANJ, Hill EW, Kinloch IA, Novoselov KS, Georgiou T, Britnell L, Dryfe RAW. Electron transfer kinetics on natural crystals of MoS2 and graphite. Phys Chem Chem Phys 2015; 17:17844-53. [PMID: 26088339 DOI: 10.1039/c5cp02490k] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Here, we evaluate the electrochemical performance of sparsely studied natural crystals of molybdenite and graphite, which have increasingly been used for fabrication of next generation monolayer molybdenum disulphide and graphene energy storage devices. Heterogeneous electron transfer kinetics of several redox mediators, including Fe(CN)6(3-/4-), Ru(NH3)6(3+/2+) and IrCl6(2-/3-) are determined using voltammetry in a micro-droplet cell. The kinetics on both materials are studied as a function of surface defectiveness, surface ageing, applied potential and illumination. We find that the basal planes of both natural MoS2 and graphite show significant electroactivity, but a large decrease in electron transfer kinetics is observed on atmosphere-aged surfaces in comparison to in situ freshly cleaved surfaces of both materials. This is attributed to surface oxidation and adsorption of airborne contaminants at the surface exposed to an ambient environment. In contrast to semimetallic graphite, the electrode kinetics on semiconducting MoS2 are strongly dependent on the surface illumination and applied potential. Furthermore, while visibly present defects/cracks do not significantly affect the response of graphite, the kinetics on MoS2 systematically accelerate with small increase in disorder. These findings have direct implications for use of MoS2 and graphene/graphite as electrode materials in electrochemistry-related applications.
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Affiliation(s)
- Matěj Velický
- School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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8
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Güell AG, Cuharuc AS, Kim YR, Zhang G, Tan SY, Ebejer N, Unwin PR. Redox-dependent spatially resolved electrochemistry at graphene and graphite step edges. ACS NANO 2015; 9:3558-71. [PMID: 25758160 DOI: 10.1021/acsnano.5b00550] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The electrochemical (EC) behavior of mechanically exfoliated graphene and highly oriented pyrolytic graphite (HOPG) is studied at high spatial resolution in aqueous solutions using Ru(NH3)6(3+/2+) as a redox probe whose standard potential sits close to the intrinsic Fermi level of graphene and graphite. When scanning electrochemical cell microscopy (SECCM) data are coupled with that from complementary techniques (AFM, micro-Raman) applied to the same sample area, different time-dependent EC activity between the basal planes and step edges is revealed. In contrast, other redox couples (ferrocene derivatives) whose potential is further removed from the intrinsic Fermi level of graphene and graphite show uniform and high activity (close to diffusion-control). Macroscopic voltammetric measurements in different environments reveal that the time-dependent behavior after HOPG cleavage, peculiar to Ru(NH3)6(3+/2+), is not associated particularly with any surface contaminants but is reasonably attributed to the spontaneous delamination of the HOPG with time to create partially coupled graphene layers, further supported by conductive AFM measurements. This process has a major impact on the density of states of graphene and graphite edges, particularly at the intrinsic Fermi level to which Ru(NH3)6(3+/2+) is most sensitive. Through the use of an improved voltammetric mode of SECCM, we produce movies of potential-resolved and spatially resolved HOPG activity, revealing how enhanced activity at step edges is a subtle effect for Ru(NH3)6(3+/2+). These latter studies allow us to propose a microscopic model to interpret the EC response of graphene (basal plane and edges) and aged HOPG considering the nontrivial electronic band structure.
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Affiliation(s)
- Aleix G Güell
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Anatolii S Cuharuc
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Yang-Rae Kim
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Guohui Zhang
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Sze-yin Tan
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Neil Ebejer
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Patrick R Unwin
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
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9
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Nioradze N, Chen R, Kurapati N, Khvataeva-Domanov A, Mabic S, Amemiya S. Organic Contamination of Highly Oriented Pyrolytic Graphite As Studied by Scanning Electrochemical Microscopy. Anal Chem 2015; 87:4836-43. [DOI: 10.1021/acs.analchem.5b00213] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Nikoloz Nioradze
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Ran Chen
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Niraja Kurapati
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | | | | | - Shigeru Amemiya
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
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10
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Bosshart PD, Engel A, Fotiadis D. High-resolution atomic force microscopy imaging of rhodopsin in rod outer segment disk membranes. Methods Mol Biol 2015; 1271:189-203. [PMID: 25697525 DOI: 10.1007/978-1-4939-2330-4_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Atomic force microscopy (AFM) is a powerful imaging technique that allows recording topographical information of membrane proteins under near-physiological conditions. Remarkable results have been obtained on membrane proteins that were reconstituted into lipid bilayers. High-resolution AFM imaging of native disk membranes from vertebrate rod outer segments has unveiled the higher-order oligomeric state of the G protein-coupled receptor rhodopsin, which is highly expressed in disk membranes. Based on AFM imaging, it has been demonstrated that rhodopsin assembles in rows of dimers and paracrystals and that the rhodopsin dimer is the fundamental building block of higher-order structures.
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Affiliation(s)
- Patrick D Bosshart
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, Bern, CH-3012, Switzerland
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11
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Zhang G, Cuharuc AS, Güell AG, Unwin PR. Electrochemistry at highly oriented pyrolytic graphite (HOPG): lower limit for the kinetics of outer-sphere redox processes and general implications for electron transfer models. Phys Chem Chem Phys 2015; 17:11827-38. [DOI: 10.1039/c5cp00383k] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron transfer kinetics for outer-sphere redox couples is fast on the basal surface of highly oriented pyrolytic graphite (HOPG).
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Affiliation(s)
- Guohui Zhang
- Department of Chemistry
- University of Warwick
- Coventry
- UK
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12
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O’Connell MA, Wain AJ. Mapping Electroactivity at Individual Catalytic Nanostructures Using High-Resolution Scanning Electrochemical–Scanning Ion Conductance Microcopy. Anal Chem 2014; 86:12100-7. [DOI: 10.1021/ac502946q] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
| | - Andrew J. Wain
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
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13
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Mashaghi A, Mashaghi S, Reviakine I, Heeren RMA, Sandoghdar V, Bonn M. Label-free characterization of biomembranes: from structure to dynamics. Chem Soc Rev 2014; 43:887-900. [PMID: 24253187 DOI: 10.1039/c3cs60243e] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We review recent progress in the study of the structure and dynamics of phospholipid membranes and associated proteins, using novel label-free analytical tools. We describe these techniques and illustrate them with examples highlighting current capabilities and limitations. Recent advances in applying such techniques to biological and model membranes for biophysical studies and biosensing applications are presented, and future prospects are discussed.
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Affiliation(s)
- Alireza Mashaghi
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
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14
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Zhang G, Kirkman PM, Patel AN, Cuharuc AS, McKelvey K, Unwin PR. Molecular Functionalization of Graphite Surfaces: Basal Plane versus Step Edge Electrochemical Activity. J Am Chem Soc 2014; 136:11444-51. [DOI: 10.1021/ja505266d] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Guohui Zhang
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Paul M. Kirkman
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Anisha N. Patel
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Anatolii S. Cuharuc
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Kim McKelvey
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Patrick R. Unwin
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
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15
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Wain AJ, Pollard AJ, Richter C. High-Resolution Electrochemical and Topographical Imaging Using Batch-Fabricated Cantilever Probes. Anal Chem 2014; 86:5143-9. [DOI: 10.1021/ac500946v] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Andrew J. Wain
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW United Kingdom
| | - Andrew J. Pollard
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW United Kingdom
| | - Christoph Richter
- NanoWorld Services GmbH, Schottkystraße
10, Erlangen, Bavaria 91058, Germany
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16
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Güell AG, Meadows KE, Dudin PV, Ebejer N, Byers JC, Macpherson JV, Unwin PR. Selection, characterisation and mapping of complex electrochemical processes at individual single-walled carbon nanotubes: the case of serotonin oxidation. Faraday Discuss 2014; 172:439-55. [DOI: 10.1039/c4fd00054d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The electrochemical (EC) oxidation of the neurotransmitter, serotonin, at individual single-walled carbon nanotubes (SWNTs) is investigated at high resolution using a novel platform that combines flow-aligned SWNTs with atomic force microscopy, Raman microscopy, electronic conductance measurements, individual SWNT electrochemistry and high-resolution scanning electrochemical cell microscopy (SECCM). SECCM has been used to visualise the EC activity along side-wall sections of metallic SWNTs to assess the extent to which side-walls promote the electrochemistry of this complex multi-step process. Uniform and high EC activity is observed that is consistent with significant reaction at the side-wall, rather than electrochemistry being driven by defects alone. By scanning forward and reverse (trace and retrace) over the same region of a SWNT, it is also possible to assess any blocking of EC activity by serotonin oxidation reaction products. At a physiologically relevant concentration (5 μM), there is no detectable blocking of SWNTs, which can be attributed, at least in part, to the high diffusion rate to an individual, isolated SWNT in the SECCM format. At higher serotonin concentration (2 mM), oligomer formation from oxidation products is much more significant and major blocking of the EC process is observed from line profiles recorded as the SECCM meniscus moves over an SWNT. The SECCM line profile morphology is shown to be highly diagnostic of whether blocking occurs during EC processes. The studies herein add to a growing body of evidence that various EC processes at SWNTs, from simple outer sphere redox reactions to complex multi-step processes, occur readily at pristine SWNTs. The platform described is of general applicability to various types of nanostructures and nanowires.
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Affiliation(s)
- Aleix G. Güell
- Department of Chemistry
- University of Warwick
- Coventry, United Kingdom
| | - Katherine E. Meadows
- Department of Chemistry
- University of Warwick
- Coventry, United Kingdom
- Molecular Organisation and Assembly in Cells Doctoral Training Centre
- University of Warwick
| | - Petr V. Dudin
- Department of Chemistry
- University of Warwick
- Coventry, United Kingdom
| | - Neil Ebejer
- Department of Chemistry
- University of Warwick
- Coventry, United Kingdom
| | - Joshua C. Byers
- Department of Chemistry
- University of Warwick
- Coventry, United Kingdom
| | | | - Patrick R. Unwin
- Department of Chemistry
- University of Warwick
- Coventry, United Kingdom
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17
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Abstract
This contribution provides a personal overview and summary of Faraday Discussion 172 on “Carbon in Electrochemistry”, covering some of the key points made at the meeting within the broader context of other recent developments on carbon materials for electrochemical applications. Although carbon electrodes have a long history of use in electrochemistry, methods and techniques are only just becoming available that can test long-established models and identify key features for further exploration. This Discussion has highlighted the need for a better understanding of the impact of surface structure, defects, local density of electronic states, and surface functionality and contamination, in order to advance fundamental knowledge of various electrochemical processes and phenomena at carbon electrodes. These developments cut across important materials such as graphene, carbon nanotubes, conducting diamond and high surface area carbon materials. With more detailed pictures of structural and electronic controls of electrochemistry at carbon electrodes (and electrodes generally), will come rational advances in various technological applications, from sensors to energy technology (particularly batteries, supercapacitors and fuel cells), that have been well-illustrated at this Discussion.
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Affiliation(s)
- Patrick R. Unwin
- Department of Chemistry
- University of Warwick
- Coventry CV4 7AL, UK
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18
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Patel AN, Tan SY, Miller TS, Macpherson JV, Unwin PR. Comparison and Reappraisal of Carbon Electrodes for the Voltammetric Detection of Dopamine. Anal Chem 2013; 85:11755-64. [DOI: 10.1021/ac401969q] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Anisha N. Patel
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Sze-yin Tan
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Thomas S. Miller
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | | | - Patrick R. Unwin
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
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19
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Local control of protein binding and cell adhesion by patterned organic thin films. Anal Bioanal Chem 2013; 405:3673-91. [DOI: 10.1007/s00216-013-6748-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 01/08/2013] [Accepted: 01/14/2013] [Indexed: 12/18/2022]
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20
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Patel AN, Tan SY, Unwin PR. Epinephrine electro-oxidation highlights fast electrochemistry at the graphite basal surface. Chem Commun (Camb) 2013; 49:8776-8. [DOI: 10.1039/c3cc45022h] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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21
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Patel AN, McKelvey K, Unwin PR. Nanoscale Electrochemical Patterning Reveals the Active Sites for Catechol Oxidation at Graphite Surfaces. J Am Chem Soc 2012; 134:20246-9. [DOI: 10.1021/ja3095894] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Anisha N. Patel
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Kim McKelvey
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Patrick R. Unwin
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, United Kingdom
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22
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Patel AN, Collignon MG, O’Connell MA, Hung WOY, McKelvey K, Macpherson JV, Unwin PR. A New View of Electrochemistry at Highly Oriented Pyrolytic Graphite. J Am Chem Soc 2012; 134:20117-30. [DOI: 10.1021/ja308615h] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Anisha N. Patel
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, U.K
| | - Manon Guille Collignon
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, U.K
| | - Michael A. O’Connell
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, U.K
| | - Wendy O. Y. Hung
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, U.K
| | - Kim McKelvey
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, U.K
| | - Julie V. Macpherson
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, U.K
| | - Patrick R. Unwin
- Department
of Chemistry and ‡MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, U.K
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23
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Roberts NA, Noh JH, Lassiter MG, Guo S, Kalinin SV, Rack PD. Synthesis and electroplating of high resolution insulated carbon nanotube scanning probes for imaging in liquid solutions. NANOTECHNOLOGY 2012; 23:145301. [PMID: 22433664 PMCID: PMC3362830 DOI: 10.1088/0957-4484/23/14/145301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
High resolution and isolated scanning probe microscopy (SPM) is in demand for continued development of energy storage and conversion systems involving chemical reactions at the nanoscale as well as an improved understanding of biological systems. Carbon nanotubes (CNTs) have large aspect ratios and, if leveraged properly, can be used to develop high resolution SPM probes. Isolation of SPM probes can be achieved by depositing a dielectric film and selectively etching at the apex of the probe. In this paper the fabrication of a high resolution and isolated SPM tip is demonstrated using electron beam induced etching of a dielectric film deposited onto an SPM tip with an attached CNT at the apex.
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Affiliation(s)
- N A Roberts
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA
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24
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Avdic A, Lugstein A, Wu M, Gollas B, Pobelov I, Wandlowski T, Leonhardt K, Denuault G, Bertagnolli E. Fabrication of cone-shaped boron doped diamond and gold nanoelectrodes for AFM-SECM. NANOTECHNOLOGY 2011; 22:145306. [PMID: 21368355 DOI: 10.1088/0957-4484/22/14/145306] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We demonstrate a reliable microfabrication process for a combined atomic force microscopy (AFM) and scanning electrochemical microscopy (SECM) measurement tool. Integrated cone-shaped sensors with boron doped diamond (BDD) or gold (Au) electrodes were fabricated from commercially available AFM probes. The sensor formation process is based on mature semiconductor processing techniques, including focused ion beam (FIB) machining, and highly selective reactive ion etching (RIE). The fabrication approach preserves the geometry of the original AFM tips resulting in well reproducible nanoscaled sensors. The feasibility and functionality of the fully featured tips are demonstrated by cyclic voltammetry, showing good agreement between the measured and calculated currents of the cone-shaped AFM-SECM electrodes.
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Affiliation(s)
- A Avdic
- Solid State Electronics Institute, Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria
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25
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Leonhardt K, Avdic A, Lugstein A, Pobelov I, Wandlowski T, Wu M, Gollas B, Denuault G. Atomic Force Microscopy-Scanning Electrochemical Microscopy: Influence of Tip Geometry and Insulation Defects on Diffusion Controlled Currents at Conical Electrodes. Anal Chem 2011; 83:2971-7. [DOI: 10.1021/ac103083y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kelly Leonhardt
- School of Chemistry, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Amra Avdic
- Solid State Electronics Institute, Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria
| | - Alois Lugstein
- Solid State Electronics Institute, Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria
| | - Ilya Pobelov
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Thomas Wandlowski
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Ming Wu
- CEST Competence Centre for Electrochemical Surface Technology, Viktor-Kaplan-Strasse 2, Wiener Neustadt, Austria
| | - Bernhard Gollas
- CEST Competence Centre for Electrochemical Surface Technology, Viktor-Kaplan-Strasse 2, Wiener Neustadt, Austria
- Institute for Chemistry and Technology of Materials, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Guy Denuault
- School of Chemistry, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, United Kingdom
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26
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Engel A. Imaging and interrogating native membrane proteins using the atomic force microscope. Methods Mol Biol 2011; 736:153-167. [PMID: 21660727 DOI: 10.1007/978-1-61779-105-5_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Membrane proteins exist in a lipid bilayer and provide for cell-cell communication, transport solutes, and convert energies. Detergents are used to extract membrane proteins and keep them in solution for purification and subsequent analyses. The atomic force microscope (AFM) is a powerful tool for imaging and manipulating membrane proteins in their native state without the necessity to solubilize them. It allows membranes that are adsorbed to flat solid supports to be raster-scanned in physiological solutions with an atomically sharp tip. Therefore, AFM is capable of observing biological molecular machines at work. Superb images of native membranes have been recorded, and a quantitative interpretation of the data acquired using the AFM tip has become possible. In addition, multifunctional probes to simultaneously acquire information on the topography and electrical properties of membrane proteins have been produced. This progress is discussed here and fosters expectations for future developments and applications of AFM and single-molecule force spectroscopy.
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Affiliation(s)
- Andreas Engel
- Maurice E. Müller Institute for Structural Biology, Biozentrum, University of Basel, Basel, Switzerland.
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27
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Bergner S, Palatzky P, Wegener J, Matysik FM. High-Resolution Imaging of Nanostructured Si/SiO2 Substrates and Cell Monolayers Using Scanning Electrochemical Microscopy. ELECTROANAL 2010. [DOI: 10.1002/elan.201000446] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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Cortés-Salazar F, Momotenko D, Lesch A, Wittstock G, Girault HH. Soft Microelectrode Linear Array for Scanning Electrochemical Microscopy. Anal Chem 2010; 82:10037-44. [DOI: 10.1021/ac1019304] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fernando Cortés-Salazar
- Laboratoire d’Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland, and Department of Pure and Applied Chemistry, Center of Interface Science (CIS), Faculty of Mathematics and Natural Sciences, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany
| | - Dmitry Momotenko
- Laboratoire d’Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland, and Department of Pure and Applied Chemistry, Center of Interface Science (CIS), Faculty of Mathematics and Natural Sciences, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany
| | - Andreas Lesch
- Laboratoire d’Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland, and Department of Pure and Applied Chemistry, Center of Interface Science (CIS), Faculty of Mathematics and Natural Sciences, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany
| | - Gunther Wittstock
- Laboratoire d’Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland, and Department of Pure and Applied Chemistry, Center of Interface Science (CIS), Faculty of Mathematics and Natural Sciences, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany
| | - Hubert H. Girault
- Laboratoire d’Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland, and Department of Pure and Applied Chemistry, Center of Interface Science (CIS), Faculty of Mathematics and Natural Sciences, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany
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29
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Noh JH, Nikiforov M, Kalinin SV, Vertegel AA, Rack PD. Nanofabrication of insulated scanning probes for electromechanical imaging in liquid solutions. NANOTECHNOLOGY 2010; 21:365302. [PMID: 20702930 PMCID: PMC3018872 DOI: 10.1088/0957-4484/21/36/365302] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In this paper, the fabrication and electrical and electromechanical characterization of insulated scanning probes have been demonstrated in liquid solutions. The silicon cantilevers were sequentially coated with chromium and silicon dioxide, and the silicon dioxide was selectively etched at the tip apex using focused-electron-beam-induced etching (FEBIE) with XeF(2). The chromium layer acted not only as the conductive path from the tip, but also as an etch-resistant layer. This insulated scanning probe fabrication process is compatible with any commercial AFM tip and can be used to easily tailor the scanning probe tip properties because FEBIE does not require lithography. The suitability of the fabricated probes is demonstrated by imaging of a standard topographical calibration grid as well as piezoresponse force microscopy (PFM) and electrical measurements in ambient and liquid environments.
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Affiliation(s)
- Joo Hyon Noh
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996-2200
| | - Maxim Nikiforov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Sergei V. Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Alexey A. Vertegel
- Department of Bioengineering, Clemson University, Clemson, SC 29634-0905
| | - Philip D. Rack
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996-2200
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831
- Corresponding author: PD Rack:
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30
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Pust SE, Salomo M, Oesterschulze E, Wittstock G. Influence of electrode size and geometry on electrochemical experiments with combined SECM-SFM probes. NANOTECHNOLOGY 2010; 21:105709. [PMID: 20160335 DOI: 10.1088/0957-4484/21/10/105709] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Gold electrodes integrated into silicon scanning force microscopy (SFM) probes allow the acquisition of spatially correlated data for sample morphology (via SFM) and local electrochemical reactivity via scanning electrochemical microscopy (SECM). The lateral resolution of both techniques is controlled by different properties of the integrated probes. The topographic tracking provided by the SFM mechanism allows the realization of very small working distances for the SECM measurements. Microfabrication technology was used in order to reduce the size of the active electrode area of the tip into the sub-100 nm regime. The functionality of the probes was tested using electrochemical methods. Experiments revealed that the response could be quantitatively compared to numerical simulation. The low working distance, in combination with the small size of the active electrode area, allows for high lateral resolution in the SECM images. This is illustrated with different model substrates that cover a range of different rate constants and illustrate the dependence of the SECM contrast on the local kinetics of the sample in the sub-micrometre size range.
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Affiliation(s)
- Sascha E Pust
- Faculty of Mathematics and Science, Department of Pure and Applied Chemistry, Carl von Ossietzky University of Oldenburg, Center of Interface Science, D-26111 Oldenburg, Germany
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31
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Anne A, Cambril E, Chovin A, Demaille C, Goyer C. Electrochemical atomic force microscopy using a tip-attached redox mediator for topographic and functional imaging of nanosystems. ACS NANO 2009; 3:2927-2940. [PMID: 19769340 DOI: 10.1021/nn9009054] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We describe the development of a new type of high-resolution atomic force electrochemical microscopy (AFM-SECM), labeled Tarm (for tip-attached redox mediator)/AFM-SECM, where the redox mediator, a ferrocene (Fc), is tethered to the AFM-SECM probe via nanometer long, flexible polyethylene glycol (PEG) chains. It is demonstrated that the tip-attached ferrocene-labeled PEG chains effectively shuttle electrons between the tip and substrate, thus acting as molecular sensors probing the local electrochemical reactivity of a planar substrate. Moreover the Fc-PEGylated AFM-SECM probes can be used for tapping mode imaging, allowing simultaneous recording of electrochemical feedback current and of topography, with a vertical and a lateral resolution in the nanometer range. By imaging the naturally nanostructured surface of HOPG, we demonstrate that Tarm/AFM-SECM microscopy can be used to probe the reactivity of nanometer-sized active sites on surfaces. This new type of SECM microscopy, being, by design, free of the diffusional constraints of classical SECM, is expected to, in principle, enable functional imaging of redox nanosystems such as individual redox enzyme molecules.
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Affiliation(s)
- Agnès Anne
- Laboratoire d'Electrochimie Moleculaire, Unite Mixte de Recherche Universite, CNRS No. 7591, Universite Paris Diderot, Paris 7, 15 rue Jean-Antoine de Baif, 75205 Paris Cedex 13, France
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32
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Ghorbal A, Grisotto F, Charlier J, Palacin S, Goyer C, Demaille C. Localized Electrografting of Vinylic Monomers on a Conducting Substrate by Means of an Integrated Electrochemical AFM Probe. Chemphyschem 2009; 10:1053-7. [DOI: 10.1002/cphc.200800803] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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33
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Atomic force microscopy of biological membranes. Biophys J 2009; 96:329-38. [PMID: 19167286 DOI: 10.1016/j.bpj.2008.09.046] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 09/15/2008] [Indexed: 11/21/2022] Open
Abstract
Atomic force microscopy (AFM) is an ideal method to study the surface topography of biological membranes. It allows membranes that are adsorbed to flat solid supports to be raster-scanned in physiological solutions with an atomically sharp tip. Therefore, AFM is capable of observing biological molecular machines at work. In addition, the tip can be tethered to the end of a single membrane protein, and forces acting on the tip upon its retraction indicate barriers that occur during the process of protein unfolding. Here we discuss the fundamental limitations of AFM determined by the properties of cantilevers, present aspects of sample preparation, and review results achieved on reconstituted and native biological membranes.
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