Ratiometric Two-Photon Fluorescent Probes for Mitochondrial Hydrogen Sulfide in Living Cells

摘要

Hydrogen sulfide (H_2S) is an important signaling molecule with diverse biological roles. Various fluorescent probes for H_2S with biological application have been developed. However, two-photon ratiometric imaging of mitochondrial H_2S is scarce. In this paper, we report two ratiometric two-photon probes, AcHS-1 and AcHS-2, which employ 4-amino-1,8-naphthalimide as the fluorophore and 4- azidobenzyl carbamate as the H_2S response site. These probes exhibit high selectivity toward H_2S over biothiols and other reactive species, low detection limits of 50-85 nM, low cytotoxicity, and high stability under physiological conditions. Furthermore, through cell imaging with one-photon and two-photon microscopy, MCF-7 cells incubated with two probes show a marked change in emission color from blue to green in response to H_2S. Cell images costraining with a mitochondrial dye reveal that AcHS-2 is a mitochondria-specific two-photon probe for H_2S. These results show that AcHS-2 may find useful applications in biological research such as tracking mitochondrial H_2S in living biological specimens.