PhD of Mr Louis FRADETAL

Biosensors are designed to detect small quantities of biomolecules in order to improve the accuracy and earliness of medical diagnosis. Among them, nanowire transistors are promising devices, as they allow the electrical detection of biomolecules without labeling with high sensitivity and a short response time. Currently, most of these devices use silicon nanowires, which are limited by a low chemical resistance, which leads to signal variations in the presence of biological solutions. To overcome these limitations, silicon carbide (SiC) is a promising material already used in the biomedical field for the coating of prosthesis or bone screws. In addition to its semiconducting properties, this material is biocompatible and shows a high resistance to chemical corrosion. Therefore, it opens the way for in vivo integration of sensors.
The goal of this thesis is to develop SiC biosensors at the nanoscale to detect DNA molecules. The first step is the fabrication of SiC nanowire-based back gate transistors. A novel process combining functionalization and lithography leading to the covalent grafting of DNA probe molecules has been developed. Finally, the sensor response was measured between each step of the functionalization process. The variations of the signal during the steps of grafting of DNA probes molecules and hybridization of target DNA molecules demonstrate the ability of these devices to detect DNA molecules. Additional steps have also shown the stability, selectivity and reversibility of the device

Keywords : Silicon Carbide, Nanowire FET, Biosensor, DNA detection, Nanowire

Jury members :
Blanquet Elisabeth    Dr    SIMAP, Grenoble (France) : President
Godignon Phillippe    Professeur étranger    CNM , Barcelona (Espagne): Rapporteur
Attolini Giovani    Professeur étranger    IMEM, Pama (Italie) : Examiner
Aguir Khalifa    PR    IM2NP, Marseille (France) : Rapporteur
Bano Edwige    PR    IMEP-LAHC, Grenoble INP Minatec,(France) :Supervisor
Stambouli Valérie    CR    LMGP, Grenoble INP Minatec,  (France) :  Co-supervisor