Spatially Dependent Fluorescent Probe for Detecting Different Situations of Mitochondrial Membrane Potential Conveniently and Efficiently.

The feedback from mitochondrial membrane potential (MMP) in different situations (normal, decreasing, and vanishing) can reflect different cellular status, which can be applied in biomedical research and diagnosis of the related diseases. Thus, the efficient and convenient detection for MMP in different situations is particularly important, yet the operations of current fluorescent probes are complex. In order to address this concern, we presented herein a spatially dependent fluorescent probe composed of organic cationic salt. The experimental results from normal and immortalized cells showed that it could accumulate in mitochondria selectively when MMP was normal. Also, it would move into the nucleus from mitochondria gradually with the decrease of MMP, and finally it targeted the nucleus exclusively when MMP vanished. According to the cell morphology, there is a straightforward spatial boundary between the nucleus and cytoplasm where mitochondria locate; thus, the three situations of MMP can be point-to-point indicated just by fluorescence images of the probe: that all probes accumulate in mitochondria corresponds to normal MMP; that probes locate both in the mitochondria and nucleus corresponds to decreasing MMP; that probes only target the nucleus corresponds to vanishing MMP. It is worth noting that counterstaining results with S-11348 indicated that the spatially dependent probe could be applied to distinguishing dead from viable cells in the same cell population. Compared with the commercial Cellstain-Double staining kit containing calcein-AM and propidium iodide (PI), this probe can address this concern by itself and shorten the testing time, which brings enormous convenience for relevant researches.