Amyloid fibril formation is associated with a wide range of diseases (Chiti & Dobson 2006), though the accumulation and deposition of fibrillar material does not correlate well with disease pathogenesis and it is now widely believed that oligomeric amyloid forms are largely responsible for the cytotoxic effects of amyloid (Glabe 2009). Fibrils have been described as more like crystalline polymer structures than the protein monomers they are derived from (Wetzel et al. 2007). In vitro, fibril formation is usually preceded by the association of monomers into oligomeric structures (Kodali & Wetzel 2007), though this remains to be established in vivo. Amyloid-beta forms spherical structures with around 12 units (Bernstein et al. 2005). Larger structures called protofibrils are also observed, non-spherical filamentous structures lacking a periodic substructure (Goldsbury 2005).