Gold Nanoparticle−Assisted Fluorescence Recovery as a Sensitive Platform for Monitoring α-Synuclein Aggregation

Abstract Protein−protein interactions (PPIs) are essential to numerous biological processes and are implicated in the progression of various diseases, including neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s disease (PD). The aggregation of α-synuclein (α-syn) into toxic oligomers, followed by amyloid fibril formation, plays a central role in PD pathology. In this study, we introduce a gold nanoparticle (AuNP)−assisted platform for monitoring α-syn aggregation at nanomolar concentrations, enabling evaluation of the inhibitory effects of small molecules. Fluorescently labeled α-syn proteins were adsorbed onto AuNPs, resulting in fluorescence quenching. Upon AuNP aggregation, driven by interactions of adsorbed α-syn, fluorescence recovery was observed. Electric field simulations revealed the formation of hot spots influenced by the number, spacing, and arrangement of aggregated AuNPs. The formation of the hot spots accounts for the fluorescence recovery of quenched, labeled α-syn. This platform may provide a robust and sensitive approach for the development and characterization of PPI inhibitors.