Electrodeposition of nanostructured SnO2 films for DNA label-free electrochemical detection

Orateur : Min Hai LE (LMGP)

In previous studies, we have demonstrated the feasibility of the use of semiconductive pure or doped-SnO2 films exhibiting 2D dense surfaces for DNA sensors based on the non faradic electrochemical impedance spectroscopy. The aim of the present study is (i) to improve the performances of SnO2 based sensors by using nanostructured surfaces (1 or 3D) in order to develop the specific surface, and (ii) to study the influence of the morphology and topology on the DNA detection signal. Two different kinds of SnO2 nanostructures : nanowires and 3D nanoporous were elaborated by the electrodeposition technique that we have set up and optimized to obtain reproducible films. Compared to the 2D dense SnO2 surfaces, the results have shown a higher sensitivity with an observed limit of detection of 2nM, showing the importance of developed surface. The 1D SnO2 nanowires is more favorable in term of sensitivity. Besides, by using either non complementary DNA targets, or 1base or 2 base mismatch DNA targets, we have shown the selective character of our sensor in both kinds of nanostructured films. This strongly experimental work enabled us to show the importance of the structural and morphological organization of the sensitive matrix on the DNA hybridization detection signal.

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