Recent progress in the development of sensing systems for in vivo detection of biological hydrogen sulfide

H₂S is recognized as the third gasotransmitter after nitric oxide and carbon monoxide that anticipates in various pathophysiological processes. Despite its physiological functions, abnormal expression of H₂S in vivo was found to be related to the emergence and development of many diseases, including cancers. Therefore, monitoring H₂S levels in vivo has great significance in biological systems physiologically and pathologically. Owing to the activity of H₂S in chemistry as reducibility, nucleophilicity and metal coordination, diverse H₂S probes were developed. Among which, probes for in vivo gathered much more preclinical and practical significance that challenged the imaging techniques and material-design systems. In addition, in vivo models for simulating pathological environment to understand the physiological and pathological effects of H₂S have been well established. In this review, we will comprehensively summarize recent progress in the development of sensing systems for in vivo detection of biological hydrogen sulfide. Their designed structures, response mechanisms and in vivo imaging will be discussed in detail. Furthermore, the perspective for the H₂S probes in the following clinical application will be presented as well.