A water-soluble two-photon fluorescent probe for rapid and reversible monitoring of redox state

Redox homeostasis is the guarantee for the normal operation of living organisms. Given its importance, moni-toring dynamic changes of redox state will facilitate the study of relevant physiological and pathological pro-cesses. Herein, a two-photon fluorescent probe NA-Se with selenomorpholine as the response site has been developed for reversible detection of redox state. NA-Se exhibits outstanding analytical performance, including a rapid response to ClO- within 8 s, a detection limit as low as 13.3 nM, and at least 10 redox reversible cycles. Furthermore, NA-Se has improved water solubility and extremely low cytotoxicity, making it ideal for bio-imaging. Finally, NA-Se has been successfully applied to monitor the ClO- /GSH redox cycle in living cells and zebrafish. This work may provide an effective tool for studying redox state and related diseases in vivo.