Few-wall carbon nanotubes covalently functionalized by ferrocene groups for bioelectrochemical devices.
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Few-wall carbon nanotubes covalently functionalized by ferrocene groups for bioelectrochemical devices. Naoual Allali1, 2,5 , Veronika Urbanova1, Victor Mamane2, Jeremy Waldbock1, Mathieu Etienne1, Martine Mallet1, Xavier Devaux3, Brigitte Vigolo4, Yves Fort2, Alain Walcarius1, Maxime Noël5, Alexander V. Soldatov5, Edward McRae4, Manuel Dossot1 1. Laboratoire de Chimie Physique et Microbiologie pour l’Environnement, UMR 7564 CNRSLorraine University, F-54602 Villers-les-Nancy, France. 2. Laboratoire de Structure et Réactivité des Systèmes Moléculaires Complexes, UMR 7565 CNRS-Lorraine University, F-54506 Vandoeuvre-les-Nancy, France. 3. Département P2M, Institut Jean Lamour, UMR 7198 CNRS-Lorraine University, Ecole des Mines, F-54042 Nancy, France. 4. Département CP2S, Institut Jean Lamour UMR 7198 CNRS-Lorraine University, F-54506 Vandoeuvre-les-Nancy, France. 5. Department of Engineering Sciences and Mathematics, Lulea Technical University, SE-97187 Lulea, Sweden. ABSTRACT The present work reports the covalent functionalization of few-wall CNTs (FWCNTs) by ferrocene derivatives to i) improve their dispersion efficiency in water and ii) to graft electroactive chemical groups on their side-walls in order to promote electron transfer to biomolecules. The functionalized CNTs (f-CNTs) are used to modify a glassy carbon electrode and this modified electrode is used for oxidizing the cofactor NADH (dihydronicotinamide adenine dinucleotide). INTRODUCTION Carbon nanotubes (CNTs) are of strong interest for electrochemical applications due to their electronic properties, their high aspect ratio (length/diameter) and their high surface area [1,2]. They have been used in electrochemical devices for bioanalytical applications. In this case, CNTs can be bonded covalently or not to an electron shuttle (also called a mediator) that will be used to react with the electrocatalytic center of a redox protein or to detect electrochemically the NADH cofactor. In this latter case, functionalized CNTs allow reducing overpotentials at the electrodes and can therefore avoid degradation of biomolecules (biofouling) and loss of sensor sensitivity [3-6]. CNTs are also thought to enhance electron transfer efficiency through catalytic effects [1,3,4]. This catalytic effect is still not fully understood and may also involve residual catalytic particles or other carbonaceous species that may be present in the sample [7]. However, it is clear that modifying electrodes with functionalized CNTs, either covalently or non-covalently, strongly increases the sensitivity of the electrochemical devices [36]. Multi-walled CNTs (MWCNTs) are often used in the literature due to their lower cost compared to single-wall CNTs [1,2]. However, for MWCNTs the inner tubes may play no role in the electron transfer processes, and single-wall or few-wall (2-4 walls) CNTs (FWCNT) may be a better choice for fundamental studies. The covalent attachment of electroactive groups (electron shuttles) on the side-wall of FWCNTs is a good strategy to avoid any diffusion of the
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