Mapping hydrogen sulfide in rats with a novel azo-based fluorescent probe

Area of Science:

• Chemical Biology
• Analytical Chemistry
• Biomedical Sensing

Background:

• Sulfide is a crucial signaling molecule in biological systems.
• Accurate quantification of endogenous sulfides is essential for understanding physiological and pathological processes.
• Existing methods for sulfide detection often lack sensitivity, selectivity, or biocompatibility.

Purpose of the Study:

• To develop a novel reaction-based fluorescent sensor, azo3, for sensitive and selective quantification of endogenous sulfides.
• To investigate the performance of azo3 in biological samples, including rat plasma and various tissues.
• To explore the design principles for future reaction-based fluorescent probes.

Main Methods:

• Development of azo3 based on azo-sulfide chemistry, utilizing a locked rhodol fluorophore.
• Characterization of azo3's fluorescent response, sensitivity, selectivity, and detection limit.
• Application of azo3 for quantifying endogenous sulfides in rat plasma and tissues (heart, brain, liver, spleen, lung, kidney).
• Assessment of the sensor's stability under UV irradiation.

Main Results:

• Azo3 demonstrated a significant "switch-on" fluorescent response (148-fold increase).
• The sensor exhibited high sensitivity with a low detection limit (500 nM) and excellent selectivity (22-fold over other bio-thiols).
• Azo3 successfully quantified endogenous sulfides in various rat tissues and plasma, unaffected by UV light.
• The study provided insights into electron effects influencing probe sensitivity.

Conclusions:

• Azo3 is a highly sensitive, selective, and UV-resistant fluorescent probe for endogenous sulfide quantification in biological systems.
• The developed sensor serves as a valuable tool for analyzing sulfides in complex biological matrices.
• The findings contribute to the rational design of future reaction-based fluorescent probes.