Glass Beads Increase the Formation Kinetics of Beta-Lactoglobulin Amyloid Fibrils

In this study beta-lactoglobulin solutions were processed with glass beads in an orbital shaker at high temper-atures and low pH value to identify the effect of mechanical stressing and surfaces on amyloid aggregation ki-netics. The information will provide a better understanding on how specific mechanical factors provide a nucleation supporting effect on the assembling of building blocks for a more efficient production of functional amyloid aggregates. Because aggregate morphologies vary at pH 2 (semiflexible) or pH 3.5 (worm-like), ex-amination at both pH values gives information about their specific formation and stability characteristics. Different diameters of glass beads (20-1000 mu m), and different shaking frequencies (0 -280 min-1) were used to vary mechanical stress energy, which was quantified by CFD-DEM simulations. To investigate surface effects, the hydrophobicity and surface roughness of glass beads was altered by modification with stearic acid. Amyloid aggregates and bead surfaces were analysed by ThT-assay, AFM and ATR-FTIR.Hydrophobic beads with high surface roughness affected the aggregation negatively. The use of non -hydrophobic beads increased the formation kinetics of fibrils but not of worm-like aggregates, although, both morphologies had a reduced mean length.