Figure 6.
Contact mechanics between beads and microplate surface can explain the kinetics of amyloid nucleation and propagation. (A) Schematic showing the components of contact forces between the bead and microplate well. Two of twelve beads (i.e., polypropylene and HDPE) did not sink in the solution and contacted only the side of well. Parameters Fg, Fb, Fcent, r, L, r′, and L′, described in the main text, are depicted with arbitrary scales and visually exaggerated for clarity. (B and C) Correlation plots of total contact pressure (pt) versus lag time and propagation rate, respectively, of D90A apo-SOD1 aggregation. The blue dashed line in (B) indicates the best fit to the linear portion of the plot. We note that a transparent microplate (with a concave bottom) was used to demonstrate buoyancy in (A). Actual experiments were carried out in black polystyrene microplates with flat bottoms (cylindrical wells).