Interfaçage d’un capteur inductif pour la biodétection de bactéries pathogènes en milieu aqueux : Comparaison entre les oscillateurs Colpitts et à Trigger de Schmitt

Details

Supervisors

Raskin, Jean-Pierre

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil électricien, à finalité spécialisée

Abstract

enAccess to safe drinking water remains a major challenge in many regions of the world, particularly in rural or low-resource areas. In this context, the development of portable, low-cost biosensors capable of detecting pathogenic bacteria in real time is of great importance. This thesis builds on the principle of the lateral flow assay (LFA), while introducing a significant modification: the integration of an inductive system designed to quantify the pathogens present. The principle relies on magnetic nanoparticles functionalized with antibodies which, once bound to the analyte, alter the value of an inductance. This variation induces a measurable shift in the oscillation frequency of a resonant circuit. An architecture based on a Schmitt trigger oscillator was selected, as it enables a simple and cost-effective implementation using standard off-the-shelf components and a microcontroller, while ensuring good portability. The performance of this oscillator was compared with that of an alternative architecture, the Colpitts oscillator, in order to evaluate their differences in terms of sensitivity, phase noise, and robustness. The work presented includes a review of the state of the art, theoretical modeling, LTSpice simulations, and experimental validation. Finally, the system’s response to nanoparticles was characterized and compared with results from the literature, highlighting the relevance and potential of this type of sensor for bacterial detection in aqueous environments.