MitoBlue: A Nontoxic and Photostable Blue-Emitting Dye That Selectively Labels Functional Mitochondria

ABSTRACT: We report the discovery of a fluorogenic dye, N1,N3-di(2-aminidonaphthalen-6-yl) propane-1,3-diamine, MitoBlue, which selectively stains functional mitochondria while displaying low toxicity, bright blue emission, and high resistance to photobleaching. Additionally, we show that a biotin-labeled MitoBlue derivative can be used as a handle for the delivery of streptavidin-tagged species to the mitochondria. Fluorescence imaging techniques, allowing the visualizationof molecular events with extraordinary sensitivity and selectivity, have become a fundamental tool in the study of living cells.1−3 The success of these techniques derives in great part from the development of cell-permeable probes that associate with particular cellular structures.4,5 Among them, mitochondria are key organelles that integrate many essential functions in eukaryotic cells.6,7 As expected for such a metabolic focal point, mitochondria have been linked with a number of diseases and have become a major therapeutic target.8,