To deal with the problematic of Central Nervous System dysfunction and associated pathologies that can be traumatic (eg, accidents, vascular lesions), psychological (eg, autism, depression, anorexia, bipolar disorder), neurodegenerative (eg Parkinson's, Alzheimer's, Huntington's) or tumor-related (eg glioblastoma, medulloblastoma neuromas), the development of brain implants is crucial to better decipher neuronal information and intervene very thinly on neural networks using microstimulation. This project aim was to address two major challenges: to achieve the realization of a highly mechanically stable implant, allowing long term connection between neurons and microelectrodes and to provide neural implants with a high temporal and spatial resolution. To do so, the present project aim was to develop implants with structural and mechanical properties that resemble those of the natural brain environment. According to the literature, using electrodes and electric leads with a size of a few microns allows for a better neural tissue reconstruction around the implant. Also, the mechanical mismatch between the usually stiff implant material and the soft brain tissue affects the adhesion between tissue cells and electrodes. Here the objective was to implant a highly flexible free-floating microelectrode array in the brain tissue, through methods using micro-nanotechnology steps as well as a combination of polymers. Moreover, the literature and preliminary studies indicate that some surface chemistries and nanotopographies can promote neurite outgrowth while limiting glial cell proliferation. Implants nanostructuration was to be studied so as to help the neural tissue growth and to provide implants with a highly adhesive property, which will ensure its stable contact with the brain neural tissue over time. Implants with different microelectrode configurations (size and shape of wires) were to be tested in vitro and in vivo for their biocompatibility and their ability to record and stimulate neurons with high stability. This project final aim was to produce high-performance generic implants that can be used for various fundamental studies and applications, including neural prostheses and brain machine interfaces
