Shadow Electrochemiluminescence Microscopy of Single Mitochondria

Mitochondria are the subcellular bioenergetic organelles. The analysis of their morphology and topology is essential to provide useful information on activity metabolism. Herein, we report a label-free shadow electrochemiluminescence (ECL) microscopy based spatial confinement ECL-emitting reactive layer image single living mitochondria deposited electrode surface. ECL mechanism freely-diffusing [Ru(bpy)3]2+ dye with sacrificial tri-n-propylamine coreactant restrains light-emitting region micrometric thickness allowing visualize individual remarkable sharp negative optical contrast. imaging approach named “shadow ECL” (SECL) reflects imprint local diffusional hindrance reagents by each mitochondrion. statistical colocalization spots functional revealed classical fluorescent biomarkers, MitoTracker Deep Red endogenous intramitochondrial NADH, validates reported methodology. versatility extreme sensitivity further demonstrated visualizing mitochondria, which remain hardly detectable usual biomarkers. Finally, alleviating problems photobleaching phototoxicity associated conventional methods, SECL should find promising applications in structures.