A versatile fluorescent probe for simultaneously detecting viscosity, polarity and nitroreductases and its application in bioimaging

Pathophysiological micro-environments such as viscosity, polarity and hypoxia are tightly correlated with regulating diffusion, transportation, and intermolecular interactions in living cells. However, the interplay and crosstalk among these key factors have not been clearly explored yet due to the lack of practical tools. In this work, based on logic-gate, we developed a versatile fluorescent probe (VPHPP) for simultaneously detecting viscosity, polarity and Nitroreductases (NTRs) in living cells. This probe was able to distinguish cancer cells from normal cells with signals in blue channel (λem = 540 nm) for NTRs and red channel (λem > 747 nm) for viscosity/polarity, which seemed more accurate (or more information at least) to define the cell types than testing only one factor. Meanwhile, the dynamic changes of viscosity, polarity and NTRs were simultaneously observed under hypoxic conditions in living cells for the first time. Furthermore, the detection system could image the simultaneous down-regulation of NTRs and the elevation of viscosity level (decreasing polarity degree) induced by dicoumarin in living cells under a confocal microscopy. Last but not least, VPHPP could achieve the imaging in tumor-bearing mouse model. In brief, VPHPP could be used as a promising visualizing agent in image-guided surgery.