An ultra-photostable and leakage-free fluorescent probe for long-term and high-fidelity mitochondria visualization and tracking

Mitochondria are important morphologically diverse organelles, and each characteristic has specific physio-logical significance. Thus, mitochondrial long-term and high-fidelity visualization and tracking are valuable. As a consequence, an ultra-photostable and leakage-free fluorescent probe is desired. Herein, we report a cationic probe DQPI-12 with a long alkyl chain, which can exclusively and firmly target mitochondria independent of mitochondria membrane potential changes. In particular, even after the cells have been fixed and left in place for 12 days, filamentous fluorescence signals from mitochondria could still be observed clearly, indicating DQPI-12 possesses excellent leakage-free performance. At the same time, compared with commercial mitochondria probes and those reported by others, DQPI-12 also displays excellent photostability. Inherent characters of DQPI-12 enable it to long-term and high-fidelity visualize mitochondria within a special microscopic field under continuous or intermittent irradiation of laser. Benefit from these advantages, DQPI-12 is successfully applied to track mitochondrial dynamic processes in living HeLa cells and neurons, and monitor the occurrence of mitophagy real-time, in-situ, and long-term.