Controlling Amyloid Assembly Dynamics Using Spin Interfaces.

Protein aggregation into amyloid fibrils is central to numerous diseases, yet the role of electron spin interactions during nucleation and self-assembly remains unexplored. We investigated amyloid formation of A-β(1-42) polypeptide, implicated in Alzheimer's disease, and its smaller recognition motifs on ferromagnetic substrates. We observed a strong dependence of fibril formation dynamics on the substrate's magnetization orientation using electron and fluorescence microscopy. Specifically, one magnetization orientation yielded approximately twice as many and significantly longer (up to 20-fold) fibrils compared with the opposite orientation, a preference that flipped with the opposite monomer chirality. Furthermore, ATR-FTIR detected structural variations in the fibril structure, depending on the substrate magnetization. These findings suggest that transient spin polarization of the monomers during self-assembly, potentially driven by the Chiral-Induced Spin Selectivity (CISS) effect, plays a critical role in amyloid assembly dynamics. The consistency of these effects across different molecule length scales suggests a fundamental spin-based influence on biomolecular aggregation. This insight may have implications for therapeutic strategies, including the use of spin-polarized magnetic nanoparticles to selectively modulate amyloid formation in neurodegenerative diseases and the integration of spin-selective interfaces in dialysis systems to mitigate dialysis-related amyloidosis.