Long-term, super-resolution imaging of amyloid structures using transient amyloid binding microscopy

摘要

Amyloid fibrils and tangles are signatures of Alzheimer disease, but nanometer-sized aggregation intermediatesare hypothesized to be the structures most toxic to neurons. The structures of these oligomers are too small tobe resolved by conventional light microscopy. We have developed a simple and versatile method, called transientamyloid binding (TAB), to image amyloid structures with nanoscale resolution using amyloidophilic dyes, suchas Thioavin T, without the need for covalent labeling or immunostaining of the amyloid protein. Transientbinding of ThT molecules to amyloid structures over time generates photon bursts that are used to localizesingle uorophores with nanometer precision. Continuous replenishment of uorophores from the surroundingsolution minimizes photobleaching, allowing us to visualize a single amyloid structure for hours to days. Weshow that TAB microscopy can image both the oligomeric and fibrillar stages of amyloid-β aggregation. We alsodemonstrate that TAB microscopy can image the structural remodeling of amyloid fibrils by epi-gallocatechingallate. Finally, we utilize TAB imaging to observe the non-linear growth of amyloid fibrils.