186. [4]Helicene-squalene fluorescent nanoassemblies for specific targeting of mitochondria in live-cell imaging
     Andrej Babič, Simon Pascal, Romain Duwald, Dimitri Moreau, Jérôme Lacour, Eric Allémann
     Adv. Funct. Mater. 2017, 27, 1701839

Ester, amide and directly-linked composites of squalene and cationic diaza [4]helicenes 1 were readily prepared. These lipid-dye constructs 2, 3 and 4 gave in aqueous media monodispersed spherical nanoassemblies around 100-130 nm in diameter with excellent stability for several months. Racemic and enantiopure nanoassemblies of compound 2 were fully characterized, including by TEM and cryo-TEM imaging that did not reveal higher order supramolecular structures. Investigations of their (chir)optical properties showed red absorption maxima ca. 600 nm and red fluorescence spanning up to the near-infrared region, with average Stokes shifts of 1350-1550 cm^-1. Live-cell imaging by confocal microscopy revealed rapid internalization on the minute time scale and organelle-specific accumulation. Co-localization with MitoTracker in several cancer cell lines demonstrated a specific staining of mitochondria by the [4]helicene-squalene nanoassemblies. To our knowledge, it is the first report of a sub-cellular targeting by squalene-based nanoassemblies.

DOI : 10.1002/adfm.201701839 

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