A pyrene-based colorimetric and fluorescent pH probe with large stokes shift and its application in bioimaging

A pyrene-based colorimetric and fluorescent pH probe with large Stokes shift (145 nm) was developed. PNY afforded a pKa of 2.98 and responded linearly to minor pH changes within the range of 2.43 and 3.71. In addition, PNY could be used for detecting H+ with high sensitivity and selectivity, showing colorimetric and fluorometric dual-modal responses with short response time. Furthermore, PNY had good photostability, excellent reversibility and cell membrane permeability. Significantly, PNY could image acidic pH in A549 cells and visualized extreme acidity in E. coli cells. Probe showed obvious color changes in the absorption and fluorescence titration. More importantly, Probe can be applied to detect the pH fluctuation in the E.coli cells. [Display omitted] •A pyrene-based colorimetric and fluorescent pH probe with large Stokes shift (145 nm) was facilely synthesized.•Probe responded to acidic pH with high selectivity and sensitivity.•Probe was applied to image pH in A549 cells and E. coli cells successfully.