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Détection de l'hybridation de l'ADN sur réseaux de transistors à effet de champ avec fixation polylysine

Abstract : A new approach aiming at detecting electronically and in a differential mode DNA hybridization using polylysine fixation of the probes, has been developed. The measurements were performed with integrated arrays of EOSFET structures covered with an electrolyte. This type of semiconductor structures is operating with a reference electrode and is characterized by electrolyte-oxide-semiconductor (EOS) interfaces. The electronic detection of two charged biopolymers, polylysine and DNA, has been investigated. Local spotting of these biomolecules solutions onto the array, induces sizeable variations in the DC current-voltage characteristics of the transistors exposed to the molecular charges. The variation of the DC characteristics due to the adsorption of polylysine or DNA showed opposite effects and can be correlated to a contribution of positive charges for polylysine and negative charges for DNA. For oligonucleotides surface densities lower than 1000-10000 molecules per µm², the electronic signal detected increases linearly, with a variation of 10 mV for 1000-10000 molecules spotted per µm². Above this limit, a saturation of the electronic signal appears. A modeling of the interface charge screening by the electrolyte may account for the reductions in the electronic signals observed when the electrolyte salt molarity is gradually increased. A hybridization protocol without blocking step, aiming at limiting non specific adsorption of target, showed a differential electronic signal of 5 mV, measured with a KCl electrolyte at 20 mM, and of 15 mV at [KCl]=0.01 mM. The sensitivity of this hybridization system (100-1000 double stranded DNA molecules per µm²) is closed to the fluorescence detection sensitivity (0.5-80 double stranded DNA molecules per µm²).
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https://tel.archives-ouvertes.fr/tel-00110298
Contributor : Philippe Thomen <>
Submitted on : Friday, October 27, 2006 - 12:23:48 PM
Last modification on : Thursday, December 10, 2020 - 12:38:59 PM
Long-term archiving on: : Thursday, September 20, 2012 - 1:57:11 PM

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  • HAL Id : tel-00110298, version 1

Citation

Cédric Gentil. Détection de l'hybridation de l'ADN sur réseaux de transistors à effet de champ avec fixation polylysine. Biophysique [physics.bio-ph]. Université Pierre et Marie Curie - Paris VI, 2005. Français. ⟨tel-00110298⟩

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