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Gatard S.,CNRS Paris Institute of Molecular Chemistry | Blanchard S.,CNRS Paris Institute of Molecular Chemistry | Schollhora B.,CNRS Laboratory of Molecular Electrochemistry | Gouzerh P.,CNRS Paris Institute of Molecular Chemistry | And 3 more authors.
Chemistry - A European Journal | Year: 2010

The electroactive benzothiazole hydrazone AMBTH-H2, a new member of the 2,2'-azino-bis(N-alkylbenzothiazole) family, was synthesised in a five-step procedure and characterised by using X-ray diffraction along with two intermediates and the Nmethylbenzothiazole hydrazone MBTH-H2. Both AMBTH-H2 and MBTH-H2 were coupled to [Mo6O 19]2- in acetonitrile in the presence of dicyclohexylcarbodiimide and dimethylaminopyridine to give two new diazoalkane-hexamolybdates, which were isolated as tetrabutylammonium salts and characterised by using IR, UV/Vis and NMR spectroscopies, cyclic voltammetry and, for one of them, X-ray diffraction. The packing arrangement molecules in crystals of AMBTH-H2, the redox features of the AMBTH-hexamolybdate hybrid together with a good electronic communication between the organic n system and the molybdenum centres make these compounds very promising blocks for the synthesis of conducting molecular materials. © 2010 Wiley-VCH. Verlag GmbH & Co. KGaA, Weinheim.

Chow K.-F.,University of Texas at Austin | Chang B.-Y.,University of Texas at Austin | Zaccheo B.A.,University of Texas at Austin | Mavre F.,CNRS Laboratory of Molecular Electrochemistry | Crooks R.M.,University of Texas at Austin
Journal of the American Chemical Society | Year: 2010

Here we report a new type of sensing platform that is based on electrodissolution of a metallic bipolar electrode (BPE). When the target DNA binds to the capture probe at the cathodic pole of the BPE, it triggers the oxidation and dissolution of Ag metal present at the anodic pole. The loss of Ag is easily detectable with the naked eye or a magnifying glass and provides a permanent record of the electrochemical history of the electrode. More importantly, the decrease in the length of the BPE can be directly correlated to the number of electrons passing through the BPE and hence to the sensing reaction at the cathode. © 2010 American Chemical Society.

Ratel M.,University of Montreal | Provencher-Girard A.,University of Montreal | Zhao S.S.,University of Montreal | Breault-Turcot J.,University of Montreal | And 8 more authors.
Analytical Chemistry | Year: 2013

Ionic liquid self-assembled monolayers (SAM) were designed and applied for binding streptavidin, promoting affinity biosensing and enzyme activity on gold surfaces of sensors. The synthesis of 1-((+)-biotin)pentanamido)propyl)-3-(12- mercaptododecyl)-imidazolium bromide, a biotinylated ionic liquid (IL-biotin), which self-assembles on gold film, afforded streptavidin sensing with surface plasmon resonance (SPR). The IL-biotin-SAM efficiently formed a full streptavidin monolayer. The synthesis of 1-(carboxymethyl)-3-(mercaptododecyl)- imidazoliumbromide, a carboxylated IL (IL-COOH), was used to immobilize anti-IgG to create an affinity biosensor. The IL-COOH demonstrated efficient detection of IgG in the nanomolar concentration range, similar to the alkylthiols SAM and PEG. In addition, the IL-COOH demonstrated low fouling in crude serum, to a level equivalent to PEG. The IL-COOH was further modified with N,N′-bis (carboxymethyl)-l-lysine hydrate to bind copper ions and then, chelate histidine-tagged biomolecules. Human dihydrofolate reductase (hDHFR) was chelated to the modified IL-COOH. By monitoring enzyme activity in situ on the SPR sensor, it was revealed that the IL-COOH SAM improved the activity of hDHFR by 24% in comparison to classical SAM. Thereby, IL-SAM has been synthesized and successfully applied to three important biosensing schemes, demonstrating the advantages of this new class of monolayers. © 2013 American Chemical Society.

Anne A.,CNRS Laboratory of Molecular Electrochemistry | Demaille C.,CNRS Laboratory of Molecular Electrochemistry
Langmuir | Year: 2012

In the present work, exact kinetic equations describing the action of an enzyme in solution on a substrate attached to a surface have been derived in the framework of the Michaelis-Menten mechanism but without resorting to the often-used steady-state approximation. The here-derived kinetic equations are cast in a workable format, allowing us to introduce a simple and universal procedure for the quantitative analysis of enzyme surface kinetics that is valid for any kinetic situation. The results presented here should allow experimentalists studying the kinetics of enzyme action on immobilized substrates to analyze their data in a perfectly rigorous way. © 2012 American Chemical Society.

Schaming D.,CNRS Laboratory of Molecular Electrochemistry | Renault C.,CNRS Laboratory of Molecular Electrochemistry | Tucker R.T.,University of Alberta | Lau-Truong S.,University of Paris Pantheon Sorbonne | And 5 more authors.
Langmuir | Year: 2012

3D nanostructured transparent indium tin oxide (ITO) electrodes prepared by glancing angle deposition (GLAD) were used for the spectroelectrochemical characterization of cytochrome c (Cyt c) and neuroglobin (Nb). These small hemoproteins, involved as electron-transfer partners in the prevention of apoptosis, are oppositely charged at physiological pH and can each be adsorbed within the ITO network under different pH conditions. The resulting modified electrodes were investigated by UV-visible absorption spectroscopy coupled with cyclic voltammetry. By using nondenaturating adsorption conditions, we demonstrate that both proteins are capable of direct electron transfer to the conductive ITO surface, sharing apparent standard potentials similar to those reported in solution. Preservation of the 3D protein structure upon adsorption was confirmed by resonance Raman (rR) spectroscopy. Analysis of the derivative cyclic voltabsorptograms (DCVA) monitored either in the Soret or the Q bands at scan rates up to 1 V s-1 allowed us to investigate direct interfacial electron transfer kinetics. From the DCVA shape and scan rate dependences, we conclude that the interaction of Cyt c with the ITO surface is more specific than Nb, suggesting an oriented adsorption of Cyt c and a random adsorption of Nb on the ITO surface. At the same time, Cyt c appears more sensitive to the experimental adsorption conditions, and complete denaturation of Cyt c may occur as evidenced from cross-correlation of rR spectroscopy and spectroelectrochemistry. © 2012 American Chemical Society.

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