Modulation of β-amyloid aggregation by graphene quantum dots

Misfolding and abnormal aggregation of β-amyloid peptide is associated with the onset and progress of Alzheimer's disease (AD). Therefore, modulating β-amyloid aggregation is critical for the treatment of AD. Herein, we studied the regulatory effects and mechanism of graphene quantum dots (GQDs) on 1-42 β-amyloid (Aβ_1-42) aggregation. GQDs displayed significant regulatory effects on the aggregation of Aβ_1-42 peptide as detected by thioflavin T (ThT) assay. Then, the changes of confirmations and structures induced by GQDs on the Aβ_1-42 aggregation were monitored by circular dichroism (CD), dynamic light scattering (DLS) and transmission electron microscope (TEM). The in vitro cytotoxicity experiments further demonstrated the feasibility of GQDs on the regulation of Aβ_1-42 aggregation. Meanwhile, the structural changes of a Aβ_1-42/GQDs mixture in different pH revealed that electrostatic interaction was the major driving force in the co-assembly process of Aβ_1-42 and GQDs. The proposed mechanism of the regulatory effects of GQDs on the Aβ_1-42 aggregation was also deduced reasonably. This work not only demonstrated the potential feasibility of GQDs as therapeutic drug for AD but also clarified the regulatory mechanism of GQDs on the Aβ_1-42 aggregation.