Tracking the super resolved structure of mitochondria using red emissive carbon nanodots as a fluorescent biomarker

Herein, we report new red emissive highly photostable and water-soluble carbon nanodots (TPP CNDs) to visualize mitochondrial dynamics using super-resolution radial fluctuations (SRRF) microscopy. The TPP CNDs were synthesized in a one-step method, using 3-(carboxypropyl)triphenylphosphonium bromide (TPP) and o-phenylenediamine (OPDA) as precursors. The obtained crystal structure, NMR, and mass data suggested the presence of [3-(1H-benzimidazol-2-yl)propyl](triphenyl)phosphonium bromide (C₂₈H₂₆N₂P⁺Br^-) as a molecular fluorophore (MF) on the surface of the TPP CNDs. The TPP CNDs showed better photostability than the commercially available MitoTracker™ Green and were highly capable for long-term imaging of mitochondrial fission during hyperglycemic conditions and structural changes upon an antidiabetic drug treatment, without altering their fluorescence nature.