Polypyrrole based DNA hybridization assays: study of label free detection processes versus fluorescence on microchips.
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.
Livache
Thierry
T
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
Maillart
Emmanuel
E
Lassalle
Nathalie
N
Mailley
Pascal
P
Corso
Bruno
B
Guedon
Philippe
P
Roget
André
A
Levy
Yves
Y
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*
D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; D004247:DNA