Aggregation-induced emission (AIE) active NIR probe of insulin amyloid fibrils

In order to study the mechanism of rapid detection of amyloid fibrils and the kinetic and structural properties of the amyloid fibrillation process for early monitoring of Alzheimer' disease (AD), this paper designed an amphiphilic AIE fluorescent probe (E)-1-butyl-4-(4-(diphenylamino)styryl)pyridin-1-ium bromide (BSTI). The BSTI exhibits high binding affinity, high on-off ratio, high photostability and good two-photon excitation fluorescence properties, as well as appropriate molecular weight and the potential to cross the blood-brain barrier. When combined with bovine insulin amyloid fibrils, it exhibits strong NIR emission with an on/off ratio > 100. In addition, BSTI-based two-photon fluorescence imaging of amyloid fibrils also exhibited a high signal-to-noise ratio. Which make BSTI an ideal probe for detecting amyloid fibrils in vivo and early monitoring of AD.