Physical Mechanism of Amyloid-β Peptide Chain Aggregation on Fluidic Lipid Nanotubules

The question of how peptide chain aggregation is influenced by lipid membranes with varying shapes and structures is crucial for a detailed understanding of the neurotoxicity effect of the peptide chains. Not like the more usual spherical liposomes and planar lipid membranes, herein, we use lipid nanotubules as a model of important neuron synapse nanowire structures and devote particular attention to the effect of nanotubule fluidity on amyloid-β peptide (Aβ) chain aggregation. We apply single-molecule tracking (SMT) to elucidate how Aβ chains diffuse and aggregate on lipid nanotubules with different fluidities. The physical mechanism implies that fluidic lipid nanotubules facilitate the super-diffusion of two-dimensional (2D)-mobile precursor Aβ chains and promote their aggregation. This aggregation mechanism is retarded on less fluidic lipid nanotubules where the super-diffusion of 2D-mobile precursor Aβ chains is restricted by "frozen" lipids with less mobility. This work provides a mechanistic explanation for Aβ chain aggregation on fluidic lipid nanotubules.