We plan to investigate the interaction between amyloid proteins and model biomembranes deposited on solid surfaces. The model membranes will be single zwitterionic and mixed zwitterionic/anionic phospholipid bilayers deposited from small unilamellar vesicles, and the proteins are amyloid proteins Abeta(M1-40) and alfa-synuclein, which have been associated with Alzheimer¿s and Parkinson¿s diseases. In our recent studies, we have shown that Abeta(M1-40) associate with model membranes and that this influence aggregation kinetics. In the proposed neutron reflectivity studies, we will investigate protein penetration in different model membrane, aiming at understanding the link between membrane association and aggregation. The amyloid protein alfa-synuclein will be studied in parallel as it has been suggested to binds to and translocates across biological membranes.