Development of an ¹⁸F-labeled azobenzothiazole tracer for α-synuclein aggregates in the brain

Nuclear imaging of aggregated α-synuclein pathology is an urgent clinical need for Parkinson's disease, yet promising tracers for brain α-synuclein aggregates are still rare. In this work, a class of compact benzothiazole derivatives was synthesized and evaluated for α-synuclein aggregates. Among them, azobenzothiazoles exhibited specific and selective detection of α-synuclein aggregates under physiological conditions. Fluoro-pegylated azobenzothiazole NN-F further demonstrated high-affinity binding to α-synuclein aggregates and efficient ¹⁸F-radiolabeling via nucleophilic displacement of a tosyl precursor. [¹⁸F]NN-F was stable in plasma in vitro and showed efficient brain uptake with little defluorination in vivo.