Quentin Avenas soutient sa thèse le 20/12/2018 à 14:00.
Lieu : INSA de Lyon, Villeurbanne, campus de la Doua, amphithéâtre AE2 du bâtiment Gustave Ferrié.
Title : Integrating an electrokinetic actuation method on a plasmonic biosensor
Jury :
- Rapporteurs : Dr. Anne-Marie HAGHIRI (DR CNRS, C2N); Pr. Frédéric SARRY (Univ. de Lorraine).
- Encadrement : Pr. Abdelkader SOUIFI (INSA Lyon, INL), Pr. Michael CANVA et Pr. Paul CHARETTE (Univ. de Sherbrooke), Dr. Marie FRENEA ROBIN (MCF UCB Lyon 1, Ampère)
- Invités : Pr. Maxime DARNON (Sherbrooke, UMI-LN2) et Dr. David PEYRADE (DR CNRS, LTM)
Abstract :
This thesis focuses on the development of an integrated plasmonic sensor capable to perform mass transport on targeted objects. The goal is to overcome the diffusion limit by trapping particules directly on the sensing surface. The adopted strategy was to structure the gold layer used for plasmonic detection in order to use the sofabricated structures to set the fluid and the molecules in motion by applying electric fields in the fluid. The mass transfer is realized through dielectrophoresis and electroosmosis, those two electrokinetic effects being operated by electrodes acting as sensor and actuator at the same time.
An exhaustive state of the art as well as multiphysical simulations allowed us for designing a prototype for an integrated sensor consisting in gold interdigitated electrodes enabling plasmoninc sensing. The proposed device was obtained through microfabrication in clean room facilities and was characterized before the study of its performances.
A first sequence of tests on a model system – polystyrene microbeads in water – brought the proof of concept we needed to validate the correct operation of the sensor, which is indeed capable of quickly trapping targeted objects on its surface and detecting them. The mass transfer mechanisms were explained and we showed the enhancement of the limit of detection by a factor greater than 100.
In a second phase, performances of the sensor applied to biological objects were evaluated. It can effectively trap yeasts and proteins but no enhancement has been observed while detecting DNA hybridization events. Causes for this result were discussed and understood and two different solutions were explored: the adaptation of the operating frequency and the optimization of the electrodes geometry. Thus, this study highlighted the problematic of operating electrokinetic effects in biological media and suggested relevant leads towards its resolution.
Key Words :
Biosensor ; Surface plasmon resonance (SPR) ; Dielectrophoresis (DEP) ; Electroosmosis (ACEO) ; Limit of detection : Mass transfer : Interdigitated electrodes : Deoxyribonucleic acid (DNA)
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