Thesis presented in 2008

Abstract:
The goal of this thesis is to miniaturize immobilization techniques of biological probes to obtain selective addressing of biologically active spots. Especially the nanoscopic size as well as their thickness and their dimensions, are crucial parameters for biosensor application. In this context, we show here for the first time the capacity of addressing oligonucleotide probes by electro-copolymerisation of pyrrole in nanolitre to femtolitre volumes. This evolution must be compatible with the techniques of detection of the biological interactions which are Surface Plasmon Resonance imaging (SPRi) and fluorescence microscopy. First, a needle allowed the realization of chips with about hundred spots confined to the region of interest. Second, the parallel use of ten micro-cantilevers allows electrosynthesis in volumes of the order of the femtolitre giving rise the high density micro arrays: ten thousands of spots on 12mm². The addressing of different DNA sequences as well as their specificity was shown. This shows the features of this technique, in terms of densification and complexification of the chips, in particular for screening applications. Finally, the selective electrochemical functionalization of networks of nanometric electrodes was carried out with the aim of addressing a nano-object spatially. The lateral resolution and the specificity of the oligonucleotides open a promising way for molecular electronics. Indeed, bio-directed positioning and orientation of nano-objects that is modified by oligonucleotides could be done on this electrochemically generated scaffold.

Keywords:
Electropolymerization, Miniaturization, Nano-object

Abstract.