[en] The presented work deals with fundamental research to develop an all-organic sensor device capable of detecting changes of the electrical potential, e.g. neural activity, in a biologically relevant environment. In this approach the active area of the sensor is built from organic materials only. The effective interface between the sensor and the cells is an artificial cell membrane decorated with a synthetic binding unit, which has been constructed adopting the methods found in nature. The sensor itself is an organic thin film transistor (OTFT), obtaining its sensitivity from the properties of the organic semiconductor and from having an active layer with a thickness of only 50 nm. The fabricated multilayer systems were characterized with X-ray and neutron diffraction using giant equipment (synchrotron, reactor). A major focus of the presented thesis lies on discovering and manipulating the structure of the involved materials on the molecular scale. At first, an overview on aggregation mechanism and molecular interaction with surfaces depending on the shape of the molecules is given. The experimental part deals with the growth of the organic semiconductor, pentacene (C₂₂H₁₄) on various surfaces. By chemically modifying diamond surfaces, controlled pentacene film growth in a standing or lying configuration was achieved. Furthermore, the encapsulation with an alkane, tetratetracontane (TTC, C₄₄H₉₀), which has been achieved using vacuum deposition. Applying the correct process parameters, the electronically best suited ''thin film phase'' of pentacene could be conserved. Coating of the pentacene film with a TTC layer was possible in a way that a transducer device showed stable operation in ionic aqueous environment, which is the essential step towards sensor technology. On the other hand we succeeded in constructing a versatile functional coating, providing a surface which cells accept as their ''natural'' environment. On the basis of a supported lipid bilayer, a synthetic peptide conjugate is bound to the surface with the help of biotin linking via a streptavidin interlayer. This conjugate contains multiples of the RGD sequence (amino acid sequence responsible for binding of proteins to their receptors on the cell surface). The structure of the coating has been determined with a resolution of 9 Aa with X-ray and neutron scattering. It has been found to form a layered stacking with a 36 Aa lipid bilayer, above a highly hydrated interlayer (26 Aa) followed by a 38 Aa streptavidin layer and a 30 Aa film of lying binding units on top. Neural stem cells have been grown on the coated surface. They have been found to attach rapidly and spread on the surface. The compatibility of the coating with the encapsulated transducer device has been demonstrated by confirming lipid layer formation. In the near future the capabilities of this system to measure changes of the electrical potential will be further explored by detecting reference signals induced with a platinum and a Ag/AgCl counter electrode. Due to the large variety of surfaces that can be coated by lipid layers, this membrane based method to bind cells is of general interest, also for tissue engineering or coating implants. (orig.)