Dual-functional AIE fluorescent probes for imaging β-amyloid plaques and lipid droplets

Alzheimer's disease (AD) is a chronic neurodegenerative disease. Better imaging and early diagnosis of biomarkers of AD is extremely important for therapeutic interventions. The amyloid cascade hypothesis and its revised version identify insoluble β-amyloid deposition as a good diagnostic biomarker for AD. Moreover, lipid droplets may also act as an auxiliary biomarker related to AD pathology based on recent studies. Herein, two quinoline-based AIE probes were designed and synthesized for the imaging of Aβ plaques and lipid droplets. The probes exhibited remarkable turn-on fluorescence enhancements with the Aβ aggregates. The lipid droplets-targeting probe FB exhibited high selectivity and binding affinity towards the Aβ aggregates with a detection limit as low as 26.9 nM. Furthermore, FB was capable of readily imaging Aβ plaques and lipid droplets at the cellular level and in brain sections of transgenic AD mice. The probe FB can serve as a promising tool for developing early diagnosis and innovative therapeutics of AD.