Utilizing a fluorescent probe for the in vivo visualization of H2S activity under gastric conditions caused by Helicobacter pylori

Helicobacter pylori ( H. pylori ) is a gram-negative, spiral-shaped, microaerophilic bacterium that specifically colonizes the human gastric mucosa. Distinguished as the sole microorganism capable of surviving the harsh acidic environment of the stomach, this unique adaptation underpins its pivotal role in the onset and progression of gastric diseases. Consequently, H. pylori is recognized as the primary etiological agent of chronic gastritis, a condition that presents significant global health challenges. This work reports the development of a newly engineered hemicyanine-based molecular probe, designated HD-WY , for the real-time and highly sensitive quantification of hydrogen sulfide (H 2 S), a key gaseous signaling molecule involved in gastritis and associated disease mechanisms. The HD-WY probe functions via an H 2 S-specific activation mechanism, which induces a marked enhancement in both optical absorption and fluorescence intensity. Exhibiting a linear response to H 2 S concentrations, the probe achieves a low detection limit of 160 nM. In cellular assays, the probe effectively monitored real-time variations in endogenous H 2 S levels, with approximately 17-fold fluorescence increase from the 2.5 μM HD-WY group to the 10.0 μM group and approximately 3-fold fluorescence from the 0 min group to the 60 min group, validating its utility for the early detection and continuous observation of gastritic conditions. A notable finding was the probe's capacity to differentiate between healthy controls and gastritis patients, demonstrating a marked increase (approximately 50-fold) in fluorescence output within patient-derived samples, thereby highlighting its diagnostic potential. Complementary histopathological evaluation using hematoxylin and eosin (H&E) staining further verified distinct morphological changes in gastric tissues from gastritis subjects relative to healthy counterparts. The demonstrated high specificity, robust stability, and excellent biocompatibility of the HD-WY probe under physiological settings underscore its promising utility in clinical diagnostic procedures and biomedical research, furnishing a dependable tool for non-invasive disease monitoring and facilitating timely therapeutic strategies.