Hemicyanine based fluorimetric and colorimetric pH probe and its application in bioimaging

• The probe displayed excellent water solubility which could detect pH in aqueous solution.
• The probe can be applied in bioimaging in living cells.
• The distinct color changes promoted probe to be used for precise pH paper preparation.

To obtain a better insight into the physiological and pathological functions of pH, probes with supra optical properties in water are still needed urgently. Focused on this situation, we herein reported a hemicyanine based probe for pH detection in aqueous solution. The probe has excellent water-solubility, high selectivity and sensitivity. Also, the structure of the probe from phenol to phenoxide induced a turn-on fluorescent response within a certain pH range of 4.5–10.7 and peaked with 30-fold enhancement, and the pKa value was determined to be 8.5. Simultaneously with the pH increase, a prominent solution color of the system changed from yellow to amaranth. More importantly, the biological experiments demonstrated the applicable of the probe to monitor the pH changes in living cells. This work illustrates that the probe could be practical and ideal pH indicator with good biological significance.

Connected vanilline with benzoindoles moiety, we developed a novel pH probe which featured turn-on fluorescent responses and distinct color changes from yellow to amaranth within the pH range of 4.5–9.7 in aqueous solution. The probe has excellent water-solubility and high selectivity and sensitivity. Also, the probe could be used to monitor pH changes in living cells.Figure optionsDownload as PowerPoint slide