Used primarily as a fluorescent dye to detect amyloid fibrils and aggregates in biological samples. It binds selectively to the cross-beta sheet structure of amyloid, making it a key tool in diagnosing and researching neurodegenerative diseases like Alzheimer's and Parkinson's. Upon binding, its fluorescence intensity increases significantly, allowing visualization under microscopy or quantification using spectrofluorometry. Also employed in high-throughput screening assays to identify compounds that inhibit or promote amyloid formation. Additionally, used in histology for staining tissue sections to reveal amyloid deposits. Its ability to cross the blood-brain barrier in some cases enables in vivo imaging applications in animal models.