Supervisors: André Schroder and Carlos Marques
The research presented in this memory deals with biomimetisation of cell membranes, and more precisly with the insertion of two new types of amphiphilic molecules in mimetic membranes. These ones are prepared by different technics like electroformation, sonication, Langmuir-Blodgett deposition, and caracterised by QCM, fluorescence microscopy, reflexion interference contrast micorscopy (RICM) adapted for mica. All these technics are presented in details. In first time, we studied the insertion of an amphiphilic molecule formed by one or two cholesterol anchor(s) attached to a cyclodextrin (TASC or TBdSC) playing the role of a ring, through which an hydrosoluble linear macromolecule (polyethylene glycol PEG) would be free to slide. We observed that the insertion seems possible, but the siding event seems dependant of the concentration of the inserted molecule, and of the tension of the « model » membrane, supposing a better accessibility of the inserted ring by the PEG. In a second time, the insertion of a new synthetic glycolipid in a lipid membrane has been studied. In order to put in evidence his presence, his affinity with a lectin, Concanavalin A, linked to a fluorophore, has been used. By this way, it has been proved that the new glycolipid can be inserted in model lipid membranes, with more or less success.