17 results on '"Estelle Lebègue"'
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2. Single Electrochemical Impacts of Shewanella oneidensis MR‐1 Bacteria for Living Cells Adsorption onto a Polarized Ultramicroelectrode Surface
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Dr. Hassiba Smida, François‐Xavier Lefèvre, Dr. Christine Thobie‐Gautier, Dr. Mohammed Boujtita, Dr. Catarina M. Paquete, and Dr. Estelle Lebègue
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Industrial electrochemistry ,TP250-261 ,Chemistry ,QD1-999 - Abstract
Abstract Invited for this issue's Front Cover is the Electrochemistry group of the CEISAM Laboratory at Nantes University (France). The cover picture illustrates the electrostatic attraction of the negatively‐charged electroactive Shewanella oneidensis bacterium onto the positively‐charged ultramicroelectrode surface polarized at the oxidation potential of ferrocyanide. Read the full text of the Research Article at 10.1002/celc.202200906.
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- 2023
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3. Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli
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Estelle Lebègue, T Cordeiro, Frédéric Barrière, Inês B. Trindade, G Hernandez, Mario Piccioli, Ricardo O. Louro, Universidade Nova de Lisboa = NOVA University Lisbon (NOVA), Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Firenze = University of Florence (UniFI), 810856, H2020 Spreading Excellence and Widening Participation, CA15133, European Cooperation in Science and Technology, 40814ZE, Campus France, PD/BD/135187/2017, FCT– Fundação para a Ciência e a Tecnologia, I.P., Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), and Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI)
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0301 basic medicine ,Models, Molecular ,Siderophore ,Subfamily ,FMN Reductase ,Stereochemistry ,Redox-Bohr effect ,Reductase ,Ferric-siderophore reductase ,Biochemistry ,2Fe–2S protein ,Inorganic Chemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Protein Domains ,medicine ,Escherichia coli ,[CHIM]Chemical Sciences ,Cysteine ,Ferredoxin ,Ferrichrome ,Original Paper ,030102 biochemistry & molecular biology ,Chemistry ,Nuclear magnetic resonance spectroscopy ,Iron uptake ,Small molecule ,030104 developmental biology ,Ferric ,Oxidation-Reduction ,medicine.drug - Abstract
Graphic abstract Iron is a fundamental element for virtually all forms of life. Despite its abundance, its bioavailability is limited, and thus, microbes developed siderophores, small molecules, which are synthesized inside the cell and then released outside for iron scavenging. Once inside the cell, iron removal does not occur spontaneously, instead this process is mediated by siderophore-interacting proteins (SIP) and/or by ferric-siderophore reductases (FSR). In the past two decades, representatives of the SIP subfamily have been structurally and biochemically characterized; however, the same was not achieved for the FSR subfamily. Here, we initiate the structural and functional characterization of FhuF, the first and only FSR ever isolated. FhuF is a globular monomeric protein mainly composed by α-helices sheltering internal cavities in a fold resembling the “palm” domain found in siderophore biosynthetic enzymes. Paramagnetic NMR spectroscopy revealed that the core of the cluster has electronic properties in line with those of previously characterized 2Fe–2S ferredoxins and differences appear to be confined to the coordination of Fe(III) in the reduced protein. In particular, the two cysteines coordinating this iron appear to have substantially different bond strengths. In similarity with the proteins from the SIP subfamily, FhuF binds both the iron-loaded and the apo forms of ferrichrome in the micromolar range and cyclic voltammetry reveals the presence of redox-Bohr effect, which broadens the range of ferric-siderophore substrates that can be thermodynamically accessible for reduction. This study suggests that despite the structural differences between FSR and SIP proteins, mechanistic similarities exist between the two classes of proteins. Supplementary Information The online version contains supplementary material available at 10.1007/s00775-021-01854-y.
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- 2021
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4. Responsive Polydiacetylene Vesicles for Biosensing Microorganisms
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Estelle Lebègue, Carole Farre, Catherine Jose, Joelle Saulnier, Florence Lagarde, Yves Chevalier, Carole Chaix, and Nicole Jaffrezic-Renault
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vesicles ,polydiacetylene ,biosensing ,bacteria ,toxins ,virus ,peptides ,Chemical technology ,TP1-1185 - Abstract
Polydiacetylene (PDA) inserted in films or in vesicles has received increasing attention due to its property to undergo a blue-to-red colorimetric transition along with a change from non-fluorescent to fluorescent upon application of various stimuli. In this review paper, the principle for the detection of various microorganisms (bacteria, directly detected or detected through the emitted toxins or through their DNA, and viruses) and of antibacterial and antiviral peptides based on these responsive PDA vesicles are detailed. The analytical performances obtained, when vesicles are in suspension or immobilized, are given and compared to those of the responsive vesicles mainly based on the vesicle encapsulation method. Many future challenges are then discussed.
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- 2018
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5. Communication-Electrochemical Single Nano-Impacts of Electroactive Shewanella Oneidensis Bacteria onto Carbon Ultramicroelectrode
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Nazua L. Costa, Frédéric Barrière, Ricardo O. Louro, Estelle Lebègue, Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Universidade Nova de Lisboa = NOVA University Lisbon (NOVA), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), France-Portugal PHC PESSOA program [40814ZE], Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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[SDV.BIO]Life Sciences [q-bio]/Biotechnology ,020209 energy ,Potassium ,Inorganic chemistry ,Shewanella Oneidensis ,chemistry.chemical_element ,Ultramicroelectrode ,02 engineering and technology ,Electroactive Bacteria ,Electrochemistry ,Redox ,chemistry.chemical_compound ,Redox Probe ,Potassium phosphate ,0202 electrical engineering, electronic engineering, information engineering ,Materials Chemistry ,[CHIM]Chemical Sciences ,Electrochemical Single Nano-impacts ,Shewanella oneidensis ,Aqueous solution ,Carbon Ultramicroelectrode ,biology ,[SDE.IE]Environmental Sciences/Environmental Engineering ,Renewable Energy, Sustainability and the Environment ,Chemistry ,Condensed Matter Physics ,biology.organism_classification ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Chronoamperometry Measurements ,Ferricyanide ,[CHIM.OTHE]Chemical Sciences/Other - Abstract
International audience; Electrochemical single nano-impacts of electroactiveShewanella oneidensisbacteria at a 7 mu m diameter carbon fibre ultramicroelectrode in an aqueous potassium phosphate buffer (pH = 7.2) solution containing a redox active probe (potassium ferro- or ferricyanide) is reported. We present chronoamperometric measurements recorded at the ultramicroelectrode polarized at the potential of the steady-state current of the redox probe in solution (oxidation for K4Fe(CN)(6)or reduction for K3Fe(CN)(6)) in the presence of bacteria. The shape of current transients associated to single bacteria nano-impacts is compared and discussed as a function of the redox probe in solution and of the ultramicroelectrode applied potential.
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- 2020
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6. Biomimetic vesicles for electrochemical sensing
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Carole Chaix, Carole Farre, Yves Chevalier, Catherine Jose, Estelle Lebègue, Florence Lagarde, Nicole Jaffrezic-Renault, Joëlle Saulnier, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes-Centre National de la Recherche Scientifique (CNRS), Interfaces & biosensors - Interfaces & biocapteurs, Institut des Sciences Analytiques (ISA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), SIMS - Surfaces-(bio)Interfaces - Micro & Nano Systèmes (2011-2014), Laboratoire d'automatique et de génie des procédés (LAGEP), Université de Lyon-Université de Lyon-École Supérieure Chimie Physique Électronique de Lyon-Centre National de la Recherche Scientifique (CNRS), Sciences Analytiques (SA), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Laboratoire d'automatique, de génie des procédés et de génie pharmaceutique (LAGEPP), EC, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,Vesicle ,010401 analytical chemistry ,Nanotechnology ,02 engineering and technology ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Key issues ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Membrane ,[CHIM.POLY]Chemical Sciences/Polymers ,[SDV.SP.PG]Life Sciences [q-bio]/Pharmaceutical sciences/Galenic pharmacology ,Microfluidic chip ,Electrochemistry ,Electrochemical biosensor ,0210 nano-technology ,Biosensor ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience; Biomimetic vesicles, mainly composed of self-assembled bilayers of phospholipids, have attracted great attention for applications in the biosensor field over a number of decades, as a means to amplify the signal through encapsulated signal probes. In this review paper the most important developments in biomimetic vesicles for electrochemical biosensing within the last 2 years are presented, with a focus on the format of bioassays, their inclusion in microfluidic chip devices and their use in mimicking cell membranes. Key issues and the remaining challenges for future commercialization are analyzed.
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- 2018
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7. Electrochemical Detection of pH-Responsive Grafted Catechol and Immobilized Cytochrome c onto Lipid Deposit-Modified Glassy Carbon Surface
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Ricardo O. Louro, Frédéric Barrière, Estelle Lebègue, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Universidade Nova de Lisboa = NOVA University Lisbon (NOVA), 745689, H2020 Marie Skłodowska-Curie Actions, 40814ZE, Ministère de l'Education Nationale, de l'Enseignement Superieur et de la Recherche, 40814ZE, Minist?re de l?Europe et des Affaires ?trang?res, 40814ZE, FCT - Funda??o para a Ci?ncia e a Tecnologia, Bioresources 4 Sustainability (GREEN-IT), Molecular, Structural and Cellular Microbiology (MOSTMICRO), Instituto de Tecnologia Química e Biológica António Xavier (ITQB), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
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Chemistry(all) ,General Chemical Engineering ,02 engineering and technology ,Glassy carbon ,Electrochemistry ,01 natural sciences ,Redox ,Article ,chemistry.chemical_compound ,[CHIM]Chemical Sciences ,Catechol ,biology ,010405 organic chemistry ,Chemistry ,Cytochrome c ,General Chemistry ,021001 nanoscience & nanotechnology ,Grafting ,0104 chemical sciences ,Covalent bond ,biology.protein ,Chemical Engineering(all) ,lipids (amino acids, peptides, and proteins) ,Cyclic voltammetry ,0210 nano-technology ,Nuclear chemistry - Abstract
International audience; The electrochemical systems of both grafted catechol as a pH-responsive electrophore and immobilized cytochrome c as a model redox protein are detected by cyclic voltammetry at an optimized lipid deposit-modified glassy carbon electrode. The catechol covalent grafting is successfully performed by the one-pot/three-step electrochemical reduction of 3,4-dihydroxybenzenediazonium salts generated in situ from 4-nitrocatechol. The resulting glassy carbon electrode electrochemically modified by grafted catechol species is evaluated as an efficient electrochemical pH sensor. The optimized molar ratio for the lipid deposit, promoting cytochrome c electrochemical activity in solution onto glassy carbon electrode, is reached for the lipid mixture composed of 75% 1,2-dioleoyl-sn-glycero-3-phosphocholine and 25% cardiolipin. Cytochrome c immobilization into the optimized supported lipid deposit is efficiently achieved by cyclic voltammetry (10 cycles) recorded at the modified glassy carbon electrode in a cytochrome c solution. The pH-dependent redox response of the grafted catechol and that of the immobilized cytochrome c are finally detected at the same lipid-modified glassy carbon electrode without alteration of their structure and electrochemical properties in the pH range 5-9. © 2018 American Chemical Society.
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- 2018
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8. An optimal surface concentration of pure cardiolipin deposited onto glassy carbon electrode promoting the direct electron transfer of cytochrome-c
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Thomas Flinois, Corinne Lagrost, Frédéric Barrière, Estelle Lebègue, Hassiba Smida, Véronique Vié, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), 15-CE05-0003, ANR, Agence Nationale de la Recherche, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and ANR-15-CE05-0003,bioWATTS,membranes biomimétiques qui produire de l'énergie biologiquement inspiré(2015)
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Cyclic voltammetry ,Supported lipid deposit ,General Chemical Engineering ,02 engineering and technology ,Glassy carbon ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Redox ,Analytical Chemistry ,chemistry.chemical_compound ,Atomic force microscopy ,Monolayer ,[CHIM]Chemical Sciences ,[PHYS]Physics [physics] ,Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Dielectric spectroscopy ,Chemical engineering ,Electrode ,Cardiolipin ,lipids (amino acids, peptides, and proteins) ,Cytochrome-c ,Ferrocyanide ,0210 nano-technology ,Electrochemical impedance spectroscopy - Abstract
International audience; Pure cardiolipin deposit onto electrodes is optimized and shown to yield an efficient supported lipid film for promoting cytochrome-c immobilization and electroactivity. Cyclic voltammetry and electrochemical impedance spectroscopy measurements in an aqueous electrolyte with potassium ferri- and ferrocyanide as a redox probe evidence that an optimized pure cardiolipin film is reached for a 7 μg cm− 2 deposit onto glassy carbon electrode. At this optimized surface concentration the pure cardiolipin deposit yields the most compact and less permeable supported lipid film on electrode surface. The thickness and the organization of the pure cardiolipin films were analyzed by atomic force microscopy (AFM) measurements. AFM imaging in aqueous buffer shows that the lipid deposit onto the surface forms a thick deposit of approximately 30 ± 10 nm of height with 4 nm average roughness and includes defects. Cytochrome-c electroactivity was studied with the redox protein either in solution or immobilized onto the modified electrode. First, the optimized amount of pure cardiolipin was deposited onto glassy carbon electrodes to study the stable and electrochemically quasi-reversible redox system of cytochrome-c in solution. Then, the potential cycling of a pure cardiolipin-modified glassy carbon electrode in a cytochrome-c solution led to the immobilization of the protein in its native state keeping intact its electrochemical properties, and with a surface coverage of 8 pmol cm− 2 corresponding to 50% of a monolayer.
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- 2018
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9. Preparation of a tetrahydroxyphenazine-modified carbon as cathode material for supercapacitor in aqueous acid electrolyte
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Charles Cougnon, Stéphanie Legoupy, Estelle Lebègue, MOLTECH-Anjou, Université d'Angers (UA)-Centre National de la Recherche Scientifique (CNRS), Institut des Matériaux Jean Rouxel (IMN), Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS), MOLTECH-ANJOU (MOLTECH-ANJOU), Université d'Angers (UA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), and Université de Nantes (UN)-Université de Nantes (UN)
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Materials science ,Rhodizonic acid ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,lcsh:Chemistry ,chemistry.chemical_compound ,Electrochemistry ,medicine ,Specific energy ,[CHIM]Chemical Sciences ,ComputingMilieux_MISCELLANEOUS ,Supercapacitor ,Aqueous solution ,021001 nanoscience & nanotechnology ,Condensation reaction ,0104 chemical sciences ,chemistry ,lcsh:Industrial electrochemistry ,lcsh:QD1-999 ,Oxocarbon ,0210 nano-technology ,Carbon ,Activated carbon ,medicine.drug ,lcsh:TP250-261 - Abstract
A procedure for the grafting of oxocarbon compounds is proposed by condensation reaction with a benzenediamine to obtain an attached-phenazine moieties. A technical proof of concept is given by the covalent capture of rhodizonic acid on the Norit activated carbon and potentiality for supercapacitors is evidenced. The composite material obtained was tested as positive electrode for aqueous supercapacitors in 1 M H2SO4. The redox activity covering a wide range of potential gives an unprecedented increase in specific charge of 350% and a specific energy at the discharge 3.4 times higher than the unmodified carbon. Keywords: Supercapacitor, Activated carbon, Diazonium salt, Oxocarbons, Grafting
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- 2016
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10. Direct introduction of redox centers at activated carbon substrate based on acid-substituent-assisted diazotization
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Estelle Lebègue, Joël Gaubicher, Olivier Crosnier, Thierry Brousse, Charles Cougnon, MOLTECH-Anjou, and Université d'Angers (UA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Carboxylic acid ,Inorganic chemistry ,Substituent ,02 engineering and technology ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Redox ,lcsh:Chemistry ,chemistry.chemical_compound ,Electrochemistry ,medicine ,[CHIM]Chemical Sciences ,chemistry.chemical_classification ,Substrate (chemistry) ,Chemical modification ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,lcsh:Industrial electrochemistry ,lcsh:QD1-999 ,Yield (chemistry) ,Cyclic voltammetry ,0210 nano-technology ,Activated carbon ,medicine.drug ,lcsh:TP250-261 - Abstract
Redox properties have been imparted to activated carbon with a high degree of functionalization by chemical grafting of 2-amino-4,5-dimethoxybenzoic acid in situ diazotized. The diazotization reaction was accomplished in the presence or in the absence of HCl for estimating the positive or negative effect of the carboxylic acid substituent on the grafting yield. Thermal gravimetric analysis, X-ray photoelectron spectroscopy and cyclic voltammetry experiments show that when the carboxylic acid group participates to the diazotization reaction, the grafting yield is improved and becomes even better than when the carboxylic group is not present, increasing the capacitance of pristine carbon electrode from 120 to 200 F/g. Keywords: Activated carbon, Diazonium salt, Catechol, Chemical grafting, Supercapacitor
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- 2012
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11. Electrochemical Detection of Single Phospholipid Vesicle Collisions at a Pt Ultramicroelectrode
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Jeffrey E. Dick, Allen J. Bard, Cari M. Anderson, Lauren J. Webb, Estelle Lebègue, Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
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Chemistry ,Bilayer ,Vesicle ,Inorganic chemistry ,Ultramicroelectrode ,02 engineering and technology ,Surfaces and Interfaces ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Redox ,Amperometry ,0104 chemical sciences ,chemistry.chemical_compound ,Microelectrode ,[CHIM.ANAL]Chemical Sciences/Analytical chemistry ,Electrochemistry ,General Materials Science ,Ferrocyanide ,0210 nano-technology ,Lipid bilayer ,Microelectrodes ,Phospholipids ,Spectroscopy - Abstract
We report the collision behavior of single unilamellar vesicles, composed of a bilayer lipid membrane (BLM), on a platinum (Pt) ultramicroelectrode (UME) by two electrochemical detection methods. In the first method, the blocking of a solution redox reaction, induced by the single vesicle adsorption on the Pt UME, can be observed in the amperometric i-t response as current steps during the electrochemical oxidation of ferrocyanide. In the second technique, the ferrocyanide redox probe is directly encapsulated inside vesicles and can be oxidized during the vesicle collision on the UME if the potential is poised positive enough for ferrocyanide oxidation to occur. In the amperometric i-t response for the latter experiment, a current spike is observed. Here, we report the vesicle blocking (VB) method as a relevant technique for determining the vesicle solution concentration from the collisional frequency and also for observing the vesicle adhesion on the Pt surface. In addition, vesicle reactor (VR) experiments show clear evidence that the lipid bilayer membrane does not collapse or break open at the Pt UME during the vesicle collision. Because the bilayer is too thick for electron tunneling to occur readily, an appropriate concentration of a surfactant, such as Triton X-100 (TX100), was added in the VR solution to induce loosening of the bilayer (transfection conditions), allowing the electrode to oxidize the contents of the vesicle. With this technique, the TX100 effect on the vesicle lipid bilayer permeability can be evaluated through the current spike charge and frequency corresponding to redox vesicle collisions.
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- 2015
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12. Impedance spectroscopy study of a catechol-modified activated carbon electrode as active material in electrochemical capacitor
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G. Pognon, Estelle Lebègue, Charles Cougnon, MOLTECH-Anjou, and Université d'Angers (UA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,Differential capacitance ,Activated carbon ,Analytical chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Diazonium salt ,02 engineering and technology ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,Reference electrode ,Capacitance ,[CHIM]Chemical Sciences ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Electrochemical capacitor ,Grafting ,Renewable Energy, Sustainability and the Environment ,Impedance ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Dielectric spectroscopy ,chemistry ,Electrode ,Cyclic voltammetry ,0210 nano-technology ,Carbon ,Electrode potential - Abstract
International audience; Modified activated carbon (Norit S-50) electrodes with electrochemical double layer (EDL) capacitance and redox capacitance contributions to the electric charge storage were tested in 1M H2SO4 to quantify the benefit and the limitation of the surface redox reactions on the electrochemical performances of the resulting pseudo-capacitive materials. The electrochemical performances of an electrochemically anodized carbon electrode and a catechol-modified carbon electrode, which make use both EDL capacitance of the porous structure of the carbon and redox capacitance, were compared to the performances obtained for the pristine carbon. Nitrogen gas adsorption measurements have been used for studying the impact of the grafting on the BET surface area, pore size distribution, pore volume and average pore diameter.The electrochemical behavior of carbon materials was studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The EIS data were discussed by using a complex capacitance model that allows defining the characteristic time constant, the global capacitance and the frequency at which the maximum charge stored is reached. The EIS measurements were achieved at different dc potential values where a redox activity occurs and the evolution of the capacitance and the capacitive relaxation time with the electrode potential are presented. Realistic galvanostatic charge/discharge measurements performed at different current rates corroborate the results obtained by impedance.
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- 2015
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13. The Role of Surface Hydrogen Atoms in the Electrochemical Reduction of Pyridine and CO 2 in Aqueous Electrolyte
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Julia Agullo, Daniel Bélanger, Mario Morin, Estelle Lebègue, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Département de Chimie [Montréal], Université du Québec à Montréal = University of Québec in Montréal (UQAM), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Hydrogen ,Inorganic chemistry ,chemistry.chemical_element ,Glassy carbon ,Electrochemistry ,Catalysis ,chemistry.chemical_compound ,Adsorption ,chemistry ,Electrode ,Pyridine ,[CHIM]Chemical Sciences ,Pyridinium ,Iridium ,ComputingMilieux_MISCELLANEOUS - Abstract
The present study aims to get more insight into the role of pyridinium ions, surface H atoms and the nature of the electrode surface for the electrochemical reduction of CO2. The electrochemical activity of pyridinium ions in the absence and presence of CO2 is investigated on Ir, Pt, Au and glassy carbon electrodes. Glassy carbon and Au electrodes show irreversible reduction of pyridinium characterized by a cathodic peak potential. In the further presence of CO2, an increase of the current is noticed and the overall reduction process remains irreversible. In contrast, cyclic voltammograms recorded on an Ir electrode in a pyridine solution under nitrogen and CO2 are quasi-reversible and consistent with the participation of H atoms adsorbed onto the electrode surface. Cyclic voltammograms for Ir and Pt electrodes are similar, as expected for metals with a strong affinity for hydrogen. Our results suggest that adsorbed H atoms may play a key role in the electrochemical reduction of CO2.
- Published
- 2014
- Full Text
- View/download PDF
14. Toward fully organic rechargeable charge storage devices based on carbon electrodes grafted with redox molecules
- Author
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Joël Gaubicher, Richard Retoux, Charles Cougnon, Estelle Lebègue, Thierry Brousse, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire de cristallographie et sciences des matériaux (CRISMAT), École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC), MOLTECH-Anjou, Université d'Angers (UA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), and Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,7. Clean energy ,Redox ,Capacitance ,chemistry.chemical_compound ,medicine ,[CHIM]Chemical Sciences ,General Materials Science ,ComputingMilieux_MISCELLANEOUS ,Renewable Energy, Sustainability and the Environment ,[CHIM.ORGA]Chemical Sciences/Organic chemistry ,General Chemistry ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Propylene carbonate ,Electrode ,0210 nano-technology ,Carbon ,Activated carbon ,medicine.drug - Abstract
International audience; Activated carbon powders modified with naphthalimide and 2,2,6,6-tetramethylpiperidine-N-oxyl were assembled into a hybrid electrochemical capacitor containing an organic electrolyte. The fully organic rechargeable system demonstrated an increase in specific capacitance up to 51%, an extended operating voltage of 2.9 V in propylene carbonate, compared to 1.9 V for the unmodified system, and a power 2.5 times higher.
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- 2014
- Full Text
- View/download PDF
15. Chemical functionalization of activated carbon through radical and diradical intermediates
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Thierry Brousse, Charles Cougnon, Estelle Lebègue, Joël Gaubicher, Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN), MOLTECH-Anjou, and Université d'Angers (UA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Benzynes ,Activated carbon ,Reactive intermediate ,chemistry.chemical_element ,02 engineering and technology ,Reaction intermediate ,Capacitors ,Photochemistry ,01 natural sciences ,Redox ,lcsh:Chemistry ,medicine ,Electrochemistry ,Ether cleavage ,Grafting ,010405 organic chemistry ,Diradical ,021001 nanoscience & nanotechnology ,Diazonium salts ,0104 chemical sciences ,lcsh:Industrial electrochemistry ,lcsh:QD1-999 ,chemistry ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Cyclic voltammetry ,0210 nano-technology ,Carbon ,lcsh:TP250-261 ,medicine.drug - Abstract
Small redox molecules were grafted on carbon through radical and diradical procedures. The reactive intermediates were derived from the 3,4-dimethoxybenzenediazonium salt and the 4,5-dimethoxybenzenediazonium-2-carboxylate salt prepared and decomposed in situ, yielding the dimethoxybenzene radical and the analogous diradical benzyne, respectively. In both cases, the activated carbon Norit serves as trapping agent and the dimethoxybenzene–carbon composites obtained were compared by thermal gravimetric analysis, X-ray photoelectron spectroscopy and cyclic voltammetry. After oxidative ether cleavage of dimethoxybenzene molecules attached to the surface, the resultant catechol-modified carbon electrodes served as pseudo-capacitive materials in aqueous electrochemical capacitors. Keywords: Diazonium salts, Benzynes, Electrochemistry, Activated carbon, Capacitors, Grafting
- Published
- 2013
- Full Text
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16. Modification of activated carbons based on diazonium ions in situ produced from aminobenzene organic acid without addition of other acid
- Author
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Thierry Brousse, Charles Cougnon, Lénaïc Madec, Eric Levillain, Estelle Lebègue, Joël Gaubicher, Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire de Génie des Matériaux et Procédés Associés (LGMPA), Ecole Polytechnique de l'Université de Nantes (EPUN), Chimie, Ingénierie Moléculaire et Matériaux d'Angers (CIMMA), Université d'Angers (UA)-Centre National de la Recherche Scientifique (CNRS), Unité de chimie organique moléculaire et macromoléculaire (UCO2M), and Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
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chemistry.chemical_classification ,Substituent ,02 engineering and technology ,General Chemistry ,Sulfonic acid ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Yield (chemistry) ,Materials Chemistry ,medicine ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Organic chemistry ,Amine gas treating ,Triazene ,0210 nano-technology ,Benzene ,Activated carbon ,medicine.drug ,Organic acid - Abstract
International audience; Activated carbon products modified with a benzene sulfonic acid group were prepared based on the spontaneous reduction of diazonium salts in situ generated in water without addition of an external acid. The diazotization reaction assisted by the organic acid substituent, produced at once amine, diazonium and triazene functionalities that maximize the grafting yield by a chemical cooperation effect.
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- 2011
- Full Text
- View/download PDF
17. Electrochemical Detection of Single Phospholipid VesicleCollisions at a Pt Ultramicroelectrode.
- Author
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Estelle Lebègue, Cari M. Anderson, JeffreyE. Dick, Lauren J. Webb, and Allen J. Bard
- Subjects
- *
ELECTROCHEMICAL analysis , *PHOSPHOLIPIDS , *BILAYER lipid membranes , *PLATINUM compounds , *OXIDATION-reduction reaction - Abstract
We report the collision behaviorof single unilamellar vesicles,composed of a bilayer lipid membrane (BLM), on a platinum (Pt) ultramicroelectrode(UME) by two electrochemical detection methods. In the first method,the blocking of a solution redox reaction, induced by the single vesicleadsorption on the Pt UME, can be observed in the amperometric i–tresponse as current steps duringthe electrochemical oxidation of ferrocyanide. In the second technique,the ferrocyanide redox probe is directly encapsulated inside vesiclesand can be oxidized during the vesicle collision on the UME if thepotential is poised positive enough for ferrocyanide oxidation tooccur. In the amperometric i–tresponse for the latter experiment, a current spike is observed.Here, we report the vesicle blocking (VB) method as a relevant techniquefor determining the vesicle solution concentration from the collisionalfrequency and also for observing the vesicle adhesion on the Pt surface.In addition, vesicle reactor (VR) experiments show clear evidencethat the lipid bilayer membrane does not collapse or break open atthe Pt UME during the vesicle collision. Because the bilayer is toothick for electron tunneling to occur readily, an appropriate concentrationof a surfactant, such as Triton X-100 (TX100), was added in the VRsolution to induce loosening of the bilayer (transfection conditions),allowing the electrode to oxidize the contents of the vesicle. Withthis technique, the TX100 effect on the vesicle lipid bilayer permeabilitycan be evaluated through the current spike charge and frequency correspondingto redox vesicle collisions. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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