Dynamic proton coupled electron transfer quenching as a sensing modality in fluorescent probes

Area of Science:

• Chemical sensing
• Fluorescence spectroscopy
• Analytical chemistry

Background:

• Modular fluorescent probes with analyte-sensitive photonelectron transfer (PET) moieties are widely used.
• Existing probes often rely on PET mechanisms for analyte detection.

Purpose of the Study:

• To develop a novel modular fluorescence probe utilizing dynamic quenching via proton-coupled electron transfer (PCET).
• To investigate the probe's response mechanism, sensitivity to weak bases, and potential for calibration-free measurements.

Main Methods:

• Design and synthesis of a modular fluorescence probe incorporating a PCET-sensitive moiety.
• Investigation of probe response to various weak bases (acetate, glutamate, phosphate, valine, amines) in solution.
• Utilizing fluorescence lifetime measurements to quantify deprotonation rates.

Main Results:

• The developed probe operates via dynamic quenching through PCET, distinct from traditional PET probes.
• Fluorescence lifetime directly correlates with the deprotonation rate by weak bases.
• The probe demonstrates sensitivity to abundant weak bases and metabolites, enabling calibration-free measurements.

Conclusions:

• The novel modular PCET-based probe design offers a new paradigm for fluorescence sensing.
• Fluorescence lifetime readout provides a calibration-free method for quantifying weak bases.
• These dynamic PCET probes hold promise for studying cellular buffer systems and metabolite pools.