Interactions between gold nanoparticles and amyloid β25-35 peptide.

Amyloid β25-35 (Aβ25-35) peptide is a peculiar peptide for its rapid aggregation properties and high neurotoxicity in Alzheimer's disease. Here, the interactions between gold nanoparticles (GNPs) and Aβ25-35 monomers, oligomers and fibrils are explored under different molar ratio, temperature and pH by ultraviolet-visible and circular dichroism spectra, thioflavin T fluorescence assay and transmission electron microscope. It is concluded that Aβ25-35 can induce the aggregation of GNPs at certain concentration of Aβ25-35 monomer or oligomer. But at higher concentration of Aβ25-35, GNPs aggregates dissociate again. Furthermore, the aggregation rate increases at higher temperature or for lower pH. These results might provide the basis of a simple diagnostic tool for detecting Alzheimer's disease.