Thioflavin S

Thioflavins are dyes used for histology staining and biophysical studies of protein aggregation. They are also used in biophysical studies of the electrophysiology of bacteria. Thioflavins are dyes used for histology staining and biophysical studies of protein aggregation. They are also used in biophysical studies of the electrophysiology of bacteria. Thioflavin T (Basic Yellow 1, CI 49005, or ThT) is a benzothiazole salt obtained by the methylation of dehydrothiotoluidine with methanol in the presence of hydrochloric acid. The dye is widely used to visualize and quantify the presence of misfolded protein aggregates called amyloid, both in vitro and in vivo (e.g., plaques composed of amyloid beta found in the brains of Alzheimer's disease patients). When it binds to beta sheet-rich structures, such as those in amyloid aggregates, the dye displays enhanced fluorescence and a characteristic red shift of its emission spectrum. Additional studies also consider fluorescence changes as result of the interaction with double stranded DNA. This change in fluorescent behavior can be caused by many factors that affect the excited state charge distribution of thioflavin T, including binding to a rigid, highly-ordered nanopocket, and specific chemical interactions between ThT and the nanopocket.