AMYLOID-b-PEPTIDE SELF ASSEMBLY KINETICS BY AFM AND MALDI-TOF MASS SPECTROMETRY

Following our previous in vitro circular dichroism and fluorometric studies on the role of chaperone protein (acetylcholinesterase) in amyloid- peptide (A) aggregation1, and on A direct self assembly2, AFM and MALDI-ToF mass spectrometry approaches are here presented for the characterization of the dimension and molecular weight of A (1-42) aggregates. The results presented here provide nanometric resolution of the main structures characteristic of the several steps from monomeric A (1-42) to mature fibrils in vitro. Oligomeric globular aggregates of A (1-42) precede the appearance of protofibrils, the first fibrillar species. The most abundant form of A (1-42) fibril exhibits a nodular structure with a ~100-nm periodicity. These studies are in the frame of BISNES european project3, focused on the design, fabrication and operation of biomimetic nanostructured surfaces which precisely control the self-assembly of biomolecules in long-range architectures.