Thioflavin T (ThT) is a fluorescence dye that has first been used for staining amyloid fibrils in histological samples by Vassar and Culling in 1959 (Vassar and Culling, 1959), its application for detecting and quantifying amyloid fibrils in vitro has first been described by Naiki et al.
Formation of amyloid fibrils underlies a wide range of human disorders, including Alzheimer's and prion diseases. The amyloid fibrils can be readily detected thanks to thioflavin T (ThT), a small molecule that gives strong fluorescence upon binding to amyloids. Using the amyloid fibrils of Aβ40 and Aβ42 involved in Alzheimer's disease, and of yeast prion protein Ure2, here we study three aspects of ThT binding to amyloids: quantification of amyloid fibrils using ThT, the optimal ThT concentration for monitoring amyloid formation and the effect of ThT on aggregation kinetics.