Real-time and in situ visualizing the details of mitochondrial fragmentation with a leakage-free fluorescent probe in living cells

Mitochondrial fragmentation is a crucial physiologic process that is closely associated with energy production, metabolism, and apoptosis. However, the details of morphological changes are rarely reported. To visualize them, a leakage-free fluorescent probe composed of an indole-pyridinium and a C8-alkyl chain, IP-8, was constructed. IP-8 could firmly immobilize in mitochondria by strong hydrophobic interaction between the C8-alkyl chain and phospholipid bilayer of the mitochondrial inner membrane, thus realizing the long-term staining without leakage regardless of mitochondrial membrane potential (MMP) changes. Importantly, using IP-8, three details during mitochondrial fragmentation process, from granule to donut, eventually formed cluster, were successfully visualized real-time and in situ. Therefore, IP-8 was suggested as a useful tool for visualizing and tracking of mitochondrial morphology changes.