Recent development of fluorescent probes for hydrogen per/polysulfides.

While there is a burgeoning understanding of the overall importance of hydrogen per/polysulfides (H2Sn, n ≥ 2) in human health, their specific biological roles and mechanisms of action remain unclear. To better understand these critical details, fluorescent probes have been developed to monitor these sulfur species in real-time. The identification of H2Sn-specific recognition moieties and compatible fluorescent dyes has become increasingly critical to the development of sensitive and selective fluorescent probes for H2Sn. Probes reported between 2023 and 2026 encompass a broad range of chemical strategies to achieve selectivity in detection and to optimize fluorescence turn-on, with a large focus on leveraging the greater nucleophilicity of H2Sn over hydrogen sulfide and other biothiols. In this short review, we summarize the most recent strategies for H2Sn fluorescent probe design and discuss key considerations for their future development and applications in biological systems.