08 Avril – Thesis defense - Justine Guedey

10 h Amphi Jean-Paul Dom - laboratory IMS (building A31)

Contribution to the study of an intracorporeal wireless network.

Constant medical monitoring can significantly reduce the risk of sudden death (cardiovascular diseases, stroke, etc.). A minute-by-minute collection of a limited number of biological signals is enough to correlate predictive models that permit to anticipate critical health conditions. We can enumerate the heart rate, blood pressure, glucose concentration, oxygen level in the blood, temperature, etc. These data must be measured, converted and transmitted transparently and inexpensively in terms of space and body invasion. It is proposed to study communicating objects at the interfaces between electronics and biology. We will call it Internet of Human (IoH). The answer to this problematic is to place a network of implantable sensors. These sensors transform a vital data through a micro / nanomechanical system (MEMS / NEMS) to signals that must be transmitted through and outside of the human body. The transmission of the sensors' informations in the human body is the main subject of this study. This transmission is special because the body is an heterogeneous and living environment. High frequency electromagnetic waves are not necessarily well adapted to the human body, since the latter is composed of 60-70% water. Water is not compatible with high frequencies or the propagation of electromagnetic waves. Innovation in intracorporeal communication, thus consists in taking advantage of the human body in an unconventional way. Research was carried out in the framework of the European ULTRASponder project from 2008 to 2012, aiming to use ultrasound to load sensors embedded in the human body. The results of these investigations are available online at http://www.ultrasponder.org/. This work is a good bibliographical base to illustrate the problematic of this subject. The aim of the thesis is the demonstration and characterization of an ultrasonic link in a living biological environment. Ultrasonic propagation is well adapted. It echoes submarine communication in an aquatic environment. It is low frequency, non-radiating, and secure (restricted to the human body alone without external propagation). Ultrasonic propagation has an attenuation 2 times less than radiofrequency propagation in the human body. We wish to accurately characterize the method and the pairing of ultrasonic propagation in a biological environment. For this purpose, we plan to develop a COTS demonstrator for a three-dimensional mapping of an ultrasonic communication between 0 and 10 MHz with a modulated signal in a biological sample (inert then under fluids). We will define the following specifications : power consumption, data rate (bandwidth, type of modulation), ease of electromechanical interfacing (reliability of the sensor and the transmission). The central focus of this thesis is to bring together knowledge of very different worlds to get the specification of this system and the development of a demonstration prototype (non-integrated or integrated).

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