Dual-Emissive Nanohybrid for Ratiometric Luminescence and Lifetime Imaging of Intracellular Hydrogen Sulfide

We design a nanohybrid for the detection of hydrogen sulfide (H₂S) based on mesoporous silica nanoparticles (MSNs). A phosphorescent iridium­(III) complex and a specific H₂S-sensitive merocyanine derivative are embedded into the nanohybrid. It exhibits a unique dual emission that is ascribed to the iridium­(III) complex and the merocyanine derivative, respectively. Upon addition of sodium hydrogen sulfide (NaHS), the emission from the merocyanine derivative is quenched, while the emission from the iridium­(III) complex is almost unchanged, which enables the ratiometric detection of H₂S. Additionally, the nanohybrid has a long luminescence lifetime and displays a significant change in luminescence lifetime in response to H₂S. Intracellular detection of H₂S is performed via ratiometric imaging and photoluminescence lifetime imaging microscopy. Compared with the intensity-based method, the lifetime-based detection is independent of the probe concentration and can efficiently distinguish the signals of the probe from the autofluorescence in complex biological samples