Super-Resolution Imaging of Amyloid Structures over Extended Times Using Transient Binding of Single Thioflavin T Molecules

Oligomeric amyloid structures are crucial therapeutic targets in Alzheimer’s and other amyloid diseases. However, these oligomers are too small to be resolved by standard light microscopy. We have developed a simple and versatile tool to image amyloid structures using Thioflavin T without the need for covalent labeling or immunostaining. Dynamic binding of single dye molecules generates photon bursts that are used for fluorophore localization on a nanometer scale. Thus, photobleaching cannot degrade image quality, allowing for extended observation times. Super-resolution Transient Amyloid Binding (TAB) microscopy promises to directly image native amyloid using standard probes and record amyloid dynamics over minutes to days. We imaged amyloid fibrils from multiple polypeptides, oligomeric, and fibrillar structures formed during different stages of amyloid-β aggregation, as well as the structural remodeling of amyloid-β fibrils by the compound epigallocatechin gallate (EGCG).