Fig. 6: The relationship between the structural properties of sonicated PFFs and their seeding activities.

The seeding activity of sonicated α-syn fibrils is determined by the number of fibril ends with the preserved β-sheet structure. A suitable sonication duration up to 30 min increases seeding activity by augmenting the number of fibril ends with abundant intact β-sheet structure. However, prolonged sonication leads to release of monomers with disrupted β-sheet structure from PFFs, resulting in reduced seeding activity. A spider chart was used to compare S5, S30, S60, and unsonicated PFFs across five axes: seeding activity, number of fibril ends, β-sheet structure, number of fibril ends with intact β-sheet, and oligomers fraction.