A novel near-infrared fluorescent hydrogen sulfide probe for live cell and tissue imaging

Abstract

A dicyanoisophorone-based near-infrared fluorescent probe (NIR-NP) was successfully designed for hydrogen sulfide (H₂S) detection. 7-Nitro-1,2,3-benzoxadiazole (NBD) amine, an electron-withdrawing group, was applied to quench the fluorescence of dicyanoisophorone-based fluorescent dyes and could be removed by H₂S-specific thiolysis of an NBD amine bond, leading to a significant fluorescence turn-on response. The probe could quantitatively detect H₂S with a lower detection limit (0.03 μM) in vitro and in living cells. The probe with a large Stokes shift (186 nm) showed a high selectivity to H₂S in the presence of other biothiols, including glutathione, homocysteine, and cysteine. Moreover, the probe was successfully applied to image endogenous H₂S in different tumor cells and in liver tissues. The excellent properties of the probe and its applications in cell and tissue imaging indicated its potential for further exploration and application of H₂S in the pathophysiology of cancers and even in the diagnosis of H₂S-related diseases.