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.