Chiral effect on Aβ fibrillation from molecular-scale to nanoscale

β-Amyloid (Aβ) peptide fibrillation, one of the characteristic hallmarks of Alzheimer’s disease, is determined by many interfacial physical-chemical factors, e.g., charge, hydrophobicity, etc. Despite extensive research, chiral effect in different-scales on the fibrillation process of Aβ remains unclear. Herein, molecular-scale, sub-nanoscale, and nanoscale chiral-structures were constructed to investigate their chiral effect on the fibrillation of Aβ₄₀ peptides. Chiral structures from molecular-scale to nanoscale were obtained from the different periods of the chemosynthesis process of chiral ZnS quantum-dots (QDs), confirmed by real-time monitoring of circular dichroism spectra. For molecular-scale, both L-penicillamine (L-P) and D-P ligands accelerated the fibrillation of Aβ₄₀, and the speed-up effect of D-P was slightly stronger than L-P. For sub-nanoscale, both two chiral Zn-complexes (L-Zn and D-Zn) induced the agglomeration of Aβ₄₀ without chirality discrimination. For nanoscale, both L-ZnS and D-ZnS QDs inhibited the fibrillation of Aβ₄₀, and the inhibition effect of L-ZnS was notably better than that of D-ZnS. In-situ kinetics experiments of Aβ₄₀ co-incubated with two chiral QDs demonstrated that L-ZnS completely prevents the misfolding of Aβ₄₀ from unfolded to β-sheet, while D-ZnS cannot achieve this. Further site-replacement experiments and simulation results revealed the underlying molecular mechanisms of the different inhibition efficiency of chiral ZnS QDs on Aβ₄₀ fibrillation, which mainly attribute to the stereoselectivity interaction between the chiral ligands of ZnS QDs and electro-positive amino acid residues (R5, K16, and K28) of Aβ₄₀. This work offers a microscopic insight of chiral effect on Aβ fibrillation exerted by structures in different-scales, and provides a guidance in precise regulation of protein fibrillation via manipulating chiral structures in different-scales.