Cell penetrating, mitochondria targeting multiply charged DABCO-cyanine dyes

We have prepared new series of lipophilic cyanine dyes equipped with several cationic quaternary ammonium moieties. This was achieved by introducing DABCO within the structures. Furthermore, to investigate the influence of the additional cationic charges to the mitochondrial uptake, DABCO was quaternized with methyl group or alkyl piperidine cation. Spectroscopic and isothermal titration calorimetry studies as well as MTT assay and subcellular localization using confocal laser scanning microscopy revealed the presented dyes combine very low cytotoxicity with efficient cellular uptake and remarkable fluorescent marking of mitochondria