Indole-based PH Probe With Ratiometric Fluorescence Behavior For Intracellular Imaging

3-[3-(4-Fluorophenyl)-1-(1-methylethyl)-1H-indol-2-yl]-(E)-2-propenal(FMIP) was used as a ratiometric fluorescent pH probe with favorable optical properties. The probe has excellent cell membrane permeability and is applied successfully to monitor pH in living cells.