Simultaneous\nDetection of Hydrogen Sulfide and Peroxynitrite\nDysregulation with a Sequentially Activated Fluorescent Probe in Ulcerative\nColitis Disease

Ulcerative colitis (UC), often referred to as “green\ncancer”,\nis a chronic inflammatory bowel disease with an unclear etiology,\nclosely associated with the imbalance of hydrogen sulfide (H<sub>2</sub>S) and peroxynitrite (ONOO<sup>–</sup>). H<sub>2</sub>S exhibits\nanti-inflammatory effects at physiological levels, but excessive concentrations\ncan compromise the intestinal barrier, while ONOO<sup>–</sup> aggravates inflammation. To facilitate the molecular-level monitoring\nof these compounds in UC, we developed a novel fluorescent probe, <b>BCH</b>, capable of simultaneously detecting H<sub>2</sub>S and\nONOO<sup>–</sup> via distinct fluorescent channels in a cascade\nmode. <b>BCH</b> features rapid response times (H<sub>2</sub>S: 6 min; ONOO<sup>–</sup>: 5 min) with well-separated emission\npeaks (120 nm), minimizing spectral overlap. The probe demonstrates\nhigh selectivity and good detection linearity for H<sub>2</sub>S (0–500\nμM) and ONOO<sup>–</sup> (0–100 μM), with\ndetection limits of 1.6 μM for H<sub>2</sub>S and 0.05 μM\nfor ONOO<sup>–</sup>. <b>BCH</b> has been successfully\napplied for imaging H<sub>2</sub>S and ONOO<sup>–</sup> in\nliving cells and zebrafish, enabling the sensitive detection of their\nfluctuations in a UC mouse model. These findings indicate that <b>BCH</b> is highly promising for studying the roles of H<sub>2</sub>S and ONOO<sup>–</sup> in UC and assessing their biological\nfunctions.