A smart mitochondria-targeting TP-NIR fluorescent probe for the selective and sensitive sensing of H2S in living cells and mice.

Hydrogen sulfide (H₂S) is one of the important gaseous signalling molecules, which plays key roles in various critical biological processes. In this work, we report a novel two-photon near-infrared (TP-NIR) fluorescent probe (MNIR-H₂S) for the sensing of mitochondrial H₂S in living cells, tissues, zebrafish and nude mice. Using a xanthene dye as a TP-excitation (810 nm) NIR-emission (668 nm) fluorophore, a well-known H₂S response moiety with a robust intramolecular charger transfer (ICT) effect can quickly respond to H₂S and effectively quench the fluorescence intensity, and an oxonium cation structure serves as a mitochondria-targeting site. Notably, MNIR-H₂S displays high sensitivity, high selectivity, low cytotoxicity, powerful mitochondrial localization ability, deep tissue penetration, and a very minimal imaging background. Biological imaging results show the biological application of MNIR-H₂S as a robust new tool for use in H₂S imaging in biological systems. [ABSTRACT FROM AUTHOR]