Simultaneous Detection of Hydrogen Sulfide and Peroxynitrite Dysregulation with a Sequentially Activated Fluorescent Probe in Ulcerative Colitis Disease

Ulcerative colitis (UC), often referred to as "green cancer", is a chronic inflammatory bowel disease with an unclear etiology, closely associated with the imbalance of hydrogen sulfide (H2S) and peroxynitrite (ONOO–). H2S exhibits anti-inflammatory effects at physiological levels, but excessive concentrations can compromise the intestinal barrier, while ONOO– aggravates inflammation. To facilitate the molecular-level monitoring of these compounds in UC, we developed a novel fluorescent probe, BCH, capable of simultaneously detecting H2S and ONOO– via distinct fluorescent channels in a cascade mode. BCH features rapid response times (H2S: 6 min; ONOO–: 5 min) with well-separated emission peaks (120 nm), minimizing spectral overlap. The probe demonstrates high selectivity and good detection linearity for H2S (0–500 μM) and ONOO– (0–100 μM), with detection limits of 1.6 μM for H2S and 0.05 μM for ONOO–. BCH has been successfully applied for imaging H2S and ONOO– in living cells and zebrafish, enabling the sensitive detection of their fluctuations in a UC mouse model. These findings indicate that BCH is highly promising for studying the roles of H2S and ONOO– in UC and assessing their biological functions.