Suivi rhéologique du processus d'agrégation de la protéine tau
Résumé
Alzheimer's disease is one of thirty pathology called conformational disease that are characterized by errors folding and assembly of protein. In Alzheimer's disease, tau protein and amyloid beta peptide are responsible of the neuronal degeneration. Understanding these mechanisms and diagnosis are closely linked to the availability of an efficient analytical concept for monitoring ex vivo self-assembly of proteins.
To understand the aggregation's mechanism, a microsystem is developed for the detection of protein tau based on the micro-rheological followed by high frequency ultrasonic waves. The sensor used is a TSM (Thickness Shear Mode) resonator operating in shear mode at a fundamental frequency of 5MHz. In contact with the fluid to be characterized, the sensor generate shear waves, which are measured in reflection through instrumentation developed in the laboratory.
From the measurement of the complex impedance of quartz with a network analyzer, the extraction of G' (elastic modulus) and G'' (viscous modulus) is possible.
Initial results indicate that our sensor can quantify, by viscosity, concentration variations of a peptide sequence of tau protein, and can differentiate, by plasticity, the conformational state.