Cyanine dye-embedded fluorescent film for ratiometric pH measurement.

The precise monitoring of pH is critical in various applications, particularly in biology-related areas. In this work, we report the synthesis and characterization of a novel cyanine-based fluorescent pH sensor with a pK around 6. This pH-sensitive dye features a cyanine chromophore coupled to a piperazine moiety, which modulates the protonation equilibrium and thus the optical response.