Recent advances of small-molecule fluorescent probes for detecting biological hydrogen sulfide

H2S is well-known as a colorless, acidic gas, with a notoriously rotten-egg smell. It was recently revealed that H2S is also an endogenous signaling molecule that has important biological functions, however, most of its physiology and pathology remains elusive. Therefore, the enthusiasm for H2S research remains. Fluorescence imaging technology is an important tool for H2S biology research. The development of fluorescence imaging technology has realized the study of H2S in subcellular organelles, facilitated by the development of fluorescent probes. The probes reviewed in this paper were categorized according to their chemical mechanism of sensing and were divided into three groups: H2S reducibility-based probes, H2S nucleophilicity-based probes, and metal sulfide precipitation-based probes. The structure of the probes, their sensing mechanism, and imaging results have been discussed in detail. Moreover, we also introduced some probes for hydrogen polysulfides.