Dark Field Microscopic Sensitive Detection of Amyloid Fibrils Using Gold Nanoparticles Modified with Antibody.

Dark field microscopy (DFM) was employed to detect amyloid β (Aβ) fibrils-induced gold nanoparticle (AuNP) aggregation at the single-particle level, with a detection limit of 40 pM fibrils. The sensitivity of this method is higher than that of the current fibril-specific detection method using probe dye, such as thioflavin T, for which sub-μM level of fibrils are necessary. This study further proved the potential application of DFM in the analytical methods based on AuNP aggregation.