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Microscopie électrochimique pour l'élaboration et la caractérisation de bio-assemblages sur électrode : application aux biopuces

Abstract : This work deals with : (i) the electrochemical detection of nucleosides on a new carbon
electrode material, Boron Doped Diamond (BDD), and (ii) the use of a recent apparatus,
scanning electrochemical microscopy (SECM) to micropattern surfaces with oligonucleotides
and to detect the hybridization event.
On the one hand, we illustrate the capacity of scanning electrochemical microscopy to
micropattern and characterize surfaces. By direct mode of SECM, using the microelectrode
as a counter electrode, polypyrrole-oligonucleotide spots with micrometric dimensions are
deposited on a gold surface. This patterning method is optimized studying the spots
hybridization by fluorescence microscopy. By the difference in surface conductivity between
gold and polypyrrole-oligonucleotide, SECM can detect the spots on the gold surface using
the feedback mode. Then, the hybridization event is detected using the feedback mode by the
precipitation of an insulating product on the surface generated by the reaction catalysed by
the peroxidase which is coupled by a biological assembly to the complementary
oligonucleotide. Finally, this electrochemical method is coupled to an optical one, Surface
Plasmon Resonance imaging (SPRi), to visualize in real time the patterning step of the gold
surface with oligonucleotide spots or surface oligonucleotide gradients.
On the other hand, the oxidation reactions of both nucleosides, 2'-deoxyguanosine
and 2'-deoxyadenosine, are performed on an oxygenated boron doped diamond electrode.
This points out the interest of this new material thanks to its enlarged potential window in
aqueous media and its little and stable background current. Then, we show the formation of
a continuous film of oxidized products on the BDD surface by a macroscopic study analysing
cyclic voltametries of a redox mediator, and in a microscopic way with the use of scanning
electrochemical microscopy.
Document type :
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https://tel.archives-ouvertes.fr/tel-00011491
Contributor : Elodie Fortin <>
Submitted on : Monday, January 30, 2006 - 12:43:45 PM
Last modification on : Wednesday, November 4, 2020 - 2:23:22 PM
Long-term archiving on: : Saturday, April 3, 2010 - 9:57:46 PM

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  • HAL Id : tel-00011491, version 1

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Elodie Fortin. Microscopie électrochimique pour l'élaboration et la caractérisation de bio-assemblages sur électrode : application aux biopuces. Autre. Université Joseph-Fourier - Grenoble I, 2005. Français. ⟨tel-00011491⟩

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