The Formation of Amyloid Fibril on Two-Dimensional Surface

Abstract

Several neurodegenerative diseases are accompanied by fibrillar aggregates or amyloids in different parts of the brain. The formation of amyloid fibrils is assisted by the existence of membranes and crowded environment in the brain. However, the detailed mechanism of the way membrane surfaces and other interfaces affect the fibril formation rate is still unclear. In recent work, we have demonstrated a label-free procedure method to study surface effect on fibril growth. In this method, we prepare samples by controlling incubation time and drying process to pause the fibril growth on a hydrophilic surface. Using atomic force microscopy (AFM), the fibril's morphologies and length distribution can be characterized over time. As such, we can study the kinetics of fibril growth on various surfaces. In addition to the kinetic information, we also obtain the dispersion of these surface-mediated fibrils. In the case where fibrils are formed at the interface through a diffusion-limited aggregation process, the dispersion reflects the diffusion coefficient of monomers on surfaces. Overall, the combination of experimental data and the theoretical approach presented here elucidate the importance of surface effects in amyloid formation of short peptides.