Styryl-Based Compounds as Potential in vivo Imaging Agents for β-Amyloid Plaques

A group of styryl-based neutral compounds has been synthesized in this study for potential use as in vivo imaging agents for β-amyloid plaques. Of 56 candidates, 14 compounds were found to label β-amyloid plaques well on Alzheimer's disease (AD) human brain sections in vitro. The binding affinity to β-amyloid fibrils was then determined by measuring the change in fluorescence intensity. Interestingly, we found that a class of quinaldine-styryl scaffold compounds displays specific binding to β-amyloid fibrils. A representative compound, STB-8, was used in ex vivo and in vivo imaging experiments on an AD transgenic mouse model and demonstrated excellent blood-brain barrier (BBB) permeability and specific staining of the AD β-amyloid plaques.