Cell membrane are usually characterized by a cmpositional asymmetry betwen inner and outer leaflet. This asymmerty is not just due do the location of membrane proteins but also to that of lipid molecules. In the case of plasma membrane its outer part is mainly composed by zwitterionic phosphatidylcholine while the inner one by negatively charged phosphatidylserine. The main difficulty in mimic such a structural inhomogeneities is to prevent the spontaneous transmisgration of lipid molecules between the two leaflet of the deposited bilayer. To achieve this we propose to exploit the stabilizing role of electrostatic interaction between negatively charged lipids (PS) and the sapphire substrate which bears a positive charge. The results will help in developing a stable asymmetric deposition to mimic cell membrane.