Knowledge about the fibril structure is a prerequisite to the understanding of the forces and biophysical principles stabilising these states as well as for structure- based design methods to interfere with their formation. One method used by our lab for studying amyloid fibrils is cryo electron microscopy, a technique which is specifically of advantage when dealing with species of high molecular weight and symmetry, such as amyloid fibrils. Using this technique have investigated the together with the group of Niko Grigorieff (Brandeis University, U.S.A.) structure of a mature amyloid fibril formed from the Alzheimer's Aβ(1-40) peptide. Other techniqes include Fourier-transform infrared (FTIR), circular dichroism (CD) and fluorescence spectroscopy.