Jonathan CASTELLI soutiendra sa thèse intitulée "Design and validation of innovative integrated circuits and embedded systems for neurostimulation applications" mercredi 6 décembre à 10h30, dans l'amphi J.P. Dom du Laboratoire IMS.
Bioelectronics is a cross-disciplinary field that studies interconnections and interactions between biological entities (cells, tissues, organs) and electronic systems, using the adequate transducer. For excitable cells or tissues (neurons, muscles, . . . ), the transducer takes the form of a simple electrode, as these tissues produce a spontaneous electrical activity or, in the opposite way, may be excited by an external electrical signal. This bi-directional communication gives rise to two experimental schemes: acquisition and stimulation. Acquisition consists in recording, processing and analyzing bio-signals whereas stimulation consists in applying the adequate electrical current to living tissues in order to trigger a reaction. This thesis focuses on the latter: two generations of stimulation systems have been developed, both being centered on an Application Specific Integrated Circuit, and adapted to different application contexts.
First, the scientific framework was given by the CENAVEX project, focusing on Functional Electrical Stimulation to rehabilitate the respiratory function, following a Spinal Cord Injury. Then, the design objectives were extended to cover new application needs: in situ electrical impedance monitoring and exploration of original stimulation waveforms. The first one could be a solution to follow the tissue reaction after electrode implantation, hence contributing to long-term biocompatibility of implants; the second one proposes to go further the conventional constant biphasic pulse and explore new waveforms that could be most efficient in terms of energy consumption, for a given physiological effect. The work presented in this manuscript is a contribution to the design, fabrication and test of innovative stimulation devices. It leaded to the development of two integrated circuits and two stimulation devices permitting multichannel stimulation. Both electrical characterizations and biological validations, from in vitro feasibility to in vivo experiments, have been conducted and are described in this manuscript.