Metal complexes for mitochondrial bioimaging.

Mitochondria are essential organelles in eukaryotic cells, containing various signaling molecules and important enzymes associated with cell growth, death, and proliferation. The visualization of mitochondria and their biochemistry with confocal microscopy, fluorescence (phosphorescence) lifetime microscopy (FLIM, PLIM), and super-resolution microscopy has therefore been of great interest in recent years. In particular, transition metal complexes have emerged as excellent mitochondria-targeting probes, due to their high photostabilities, large Stokes shifts, tunable chemical structures and long luminescence lifetimes. In this review, we focus on platinum, ruthenium and iridium complexes, and their application as detectors of micro-environmental alterations as well as for the imaging of signaling molecules inside mitochondria.