Quinolinium-Based Fluorescent Probes for Dynamic pH Monitoring in Aqueous Media at High pH Using Fluorescence...

Area of Science:

• Analytical Chemistry
• Biophysical Chemistry
• Materials Science

Background:

• Spatiotemporal pH imaging is crucial for understanding dynamic electrochemical processes.
• Existing fluorescence lifetime imaging microscopy (FLIM) probes lack responsiveness at high pH values.

Purpose of the Study:

• To develop novel pH probes for FLIM capable of operating at high pH.
• To characterize the performance of these probes for dynamic pH imaging.

Main Methods:

• Development of quinolinium fluorophore-based probes with tunable fluorescence lifetimes.
• Utilizing fluorescence lifetime imaging microscopy (FLIM) for spatiotemporal pH measurements.
• Characterization of probe performance across a wide pH range (5.5-13), including stability and ion interference.

Main Results:

• Successfully developed quinolinium-based probes with fluorescence lifetimes tunable from pH 5.5 to 13.
• Achieved high fluorescence quantum yield, photostability, and water solubility.
• Demonstrated reliable FLIM imaging at rates of 3 images/sec with 4 μm resolution, measuring pH up to 12.
• Probe performance was minimally affected by temperature and common inorganic ions.

Conclusions:

• The developed quinolinium-based probes significantly expand the capabilities of FLIM for high pH imaging.
• These probes enable detailed investigation of dynamic electrochemical processes involving pH changes.
• The high performance and reliability of these probes facilitate advanced studies in chemistry and biology.