A quinolinium-based dual-functional NIR fluorescent probe for the imaging of Aβ aggregation and mitochondrial pH

Mitochondria are the most important energy supply centers in the cell, the changes in function and structure are implicated in many diseases. Among them, Aβ peptide, one of the targets of Alzheimer's disease, is closely related to mitochondrial autophagy, during the process of mitochondrial autophagy, the mitochondrial matrix will undergo acidification and the pH will be obviously reduced. Herein, a quinolinium-based NIR fluorescent probe QM12 was rationally designed and synthesized for the simultaneous imaging of Aβ aggregates and mitochondrial pH with different emission readout. The probe QM12 exhibited excellent selective toward Aβ aggregates, and can also trace the real-time changes of mitochondrial pH, which could serve as a promising tool for the pathological study of Alzheimer's disease, especially the cross talk between different biomarkers of Alzheimer's disease.