Influence of Au nanoparticles on the aggregation of amyloid-β-(25–35) peptides
Abstract
The influence of Au nanoparticles (Au NPs) on the aggregation of amyloid-β-(25–35) peptides (Aβ25–35) is investigated by atomic force microscopy and Thioflavin T fluorescence measurements. It is found that, without Au NPs, the Aβ25–35 peptides aggregate gradually from monomers and oligomers to long fibrils with the incubation time. In contrast, short protofibrils are formed quickly after Au NPs are added to the Aβ25–35 solution, which can be further aggregated to form short fibril bundles or even bundle conjunctions. To reveal the origin of Au NPs on the aggregation of Aβ25–35, electrostatic force microscopy and scanning Kelvin microscopy are employed to investigate the electrical properties of the Aβ25–35 fibrils with and without Au NPs. Due to the significant difference of the electrical properties between the Aβ25–35 fibrils and Au NPs, the locations of Au NPs inside the Aβ25–35 fibril bundles can be revealed and hence a possible influence mechanism of Au NPs on the aggregation of Aβ25–35 is suggested.