Designing reaction-based fluorescent probes for selective hydrogen sulfide detection.

Hydrogen sulfide (H2S) is a biologically generated, gaseous signaling molecule that mediates a wide range of physiological functions and is misregulated in numerous pathologies ranging from neurodegenerative disease to hypertension to diabetes. Despite swelling interest, a deeper understanding of the biological roles played by H2S has been hindered by a lack of tools for the real-time visualization of its production in living organisms. Recently, reaction-based fluorescent probes have emerged as an ideal approach for selective H2S imaging and are attracting increasing attention with many new innovative designs being introduced. This review will highlight some of the most fruitful reaction-based strategies, including reduction-based, nucleophilic-based, and metal sulfide precipitation-based fluorescent sensors. Strategies to address the key design challenges of sensitivity, selectivity, in vivo compatibility, and quantification will be discussed using examples of recently developed molecular scaffolds for selective H2S detection.