A highly selective near-infrared fluorescent probe for imaging H2Se in living cells and in vivo

Abstract

Hydrogen selenide (H₂Se), a highly reactive Se species, is an important selenium metabolism intermediate involved in many physiological and pathological processes. This compound is of scientific interest with regard to the real-time monitoring of H₂Se in living cells and in vivo to understand the anti-cancer mechanism of selenium. However, monitoring H₂Se in living cells is still challenging due to the lack of straight forward, highly selective and rapid methods. Here, we developed a novel small-molecule fluorescent probe, NIR-H₂Se, for imaging endogenous H₂Se. NIR-H₂Se exhibited high selectivity toward H₂Se over selenocysteine (Sec), H₂S and small molecule thiols and was successfully used to image the H₂Se content in HepG2 cells during Na₂SeO₃-induced apoptosis. Increased H₂Se content and reduced ROS levels were observed under hypoxic conditions compared to normoxic conditions, which indicated that the cell apoptosis induced by Na₂SeO₃ under a hypoxic environment is via a non-oxidative stress mechanism. Thus, this probe should serve as a powerful tool for exploring the physiological function of H₂Se and Se anticancer mechanisms in a variety of physiological and pathological contexts.