Dual-quenching NBD-based fluorescent probes for separate detection of H2S and Cys/Hcy in living cells

Abstract

Biothiols are implicated in different physiological and pathological processes, while abnormal levels of biothiols are related to numerous diseases. It is essential to discriminatively detect these molecules and explore their inherent transformation in living biological samples. Herein, dual-reactive and dual-quenching fluorescent probes based on thiolysis of NBD (7-nitro-1,2,3-benzoxadiazole) thioether/ether/amine for separate detection of H₂S and Cys/Hcy were rationally designed. Probe 2 was able to sense H₂S (λ_ex/em = 405/455 nm) and Cys/Hcy (λ_ex/em = 470/550 nm) in the presence of GSH in aqueous buffer. Moreover, the probe not only could be applied for visualization of exogenous H₂S and Cys in living cells but also successfully showcased the potential to verify the biosynthesis of endogenous H₂S from Cys.