Shear flow promotes amyloid-β fibrilization

Abstract

The rate of formation of amyloid fibrils in an aqueous solution of amyloid-β (Aβ) is greatly increased when the solution is sheared. When Aβ solution is stirred with a magnetic stirrer bar at 37°C, a rapid increase in thioflavin T fluorescence is observed. Atomic Force Microscopy (AFM) images show the formation of aggregates, the growth of fibrils and the intertwining of the fibrils with time. Circular dichroism (CD) spectroscopy of samples taken after stirring shows a transition from random coil to α-helix to β-sheet secondary structure over 20 h at 37°C. The fluorescence, AFM and CD measurements are all consistent with the formation of amyloid fibrils. Quiescent, non-stirred solutions incu..