title: Polypyrrole based DNA hybridization assays: study of label free detection processes versus fluorescence on microchips.
abstract: In this paper, we present different ways to detect DNA hybridization on a solid support. The grafting chemistry is based on the electro-controlled copolymerization of a pyrrole-modified oligonucleotide and pyrrole. This process allows an easy functionalization of conducting materials. Three kind of devices were studied: silicon chips bearing an array of addressable 50 or 4 microm microelectrodes, quartz crystal microbalance (QCM) and a non patterned gold/glass slide bearing 500 microm spots. Each device is compatible with a specific detection process: a classical indirect fluorescence detection for the microchips, a microgravimetric measurement for the QCM and a surface plasmon resonance imaging process (SPRi) for the gold slides. Both QCM and SPRi are a label-free real time detection process whereas the fluorescence methodology gives end-point data but only the fluorescence and the SPRi give multiparametric results. Although the hybridization experiments show that the detection limit for an oligonucleotide is better for the fluorescence (1-10 pM) than that found for SPRi (10 nM) and QCM (250 nM), the information content of real time measurement techniques such as SPRi is of interest for many biological studies.
authors.affiliation: Département de Recherche sur la Matière Condensée, UMR 5819 (CEA, CNRS, Université J. Fourier), CEA-Grenoble, 17 Rue des Martyrs, 38054 Grenoble Cedex 09, France. tlivache@cea.fr
authors.forename: Thierry
authors.initials: T
authors.lastname: Livache
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Maillart
authors.forename: Nathalie
authors.initials: N
authors.lastname: Lassalle
authors.forename: Pascal
authors.initials: P
authors.lastname: Mailley
authors.forename: Bruno
authors.initials: B
authors.lastname: Corso
authors.forename: Philippe
authors.initials: P
authors.lastname: Guedon
authors.forename: André
authors.initials: A
authors.lastname: Roget
authors.forename: Yves
authors.initials: Y
authors.lastname: Levy
mesh_terms: D004247:DNA / Q000032:analysis* / Q000235:genetics; D004563:Electrochemistry; D005453:Fluorescence; D009693:Nucleic Acid Hybridization / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation / Q000379:methods*; D011108:Polymers / Q000032:analysis*; D011758:Pyrroles / Q000032:analysis*
chemical_list: D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; D004247:DNA