Hydroxyethyl-Modified Cycloheptatriene-BODIPY Derivatives as Specific Tau Imaging Probes.

Near-infrared fluorescence (NIRF) imaging as an exquisite sensitive, high spatial-resolution, and real-time tool plays an important role in visualizing pathologies in the brain. In this study, we designed and synthesized a series of NIR probes of hydroxyethyl cycloheptatriene-BODIPY derivatives that have demonstrated strong binding specificity to native neurofibrillary tangles (NFTs) in Alzheimer's disease (AD) brain sections. The improved hydrophilicity of and resulted in faster clearance rates from healthy brains (4.2 and 10.9, respectively) compared to previously reported compounds. Furthermore, , which features a fluorinated modification, exhibited a high binding affinity to Tau aggregates ( = 11.8 nM) and held promise for future PET studies.