A red emitting two-photon fluorescent probe for dynamic imaging of redox balance meditated by a superoxide anion and GSH in living cells and tissues

Cellular self-regulation of reactive oxygen species (ROS) stress via antioxidant repair plays an important role in maintaining the redox balance. The redox balance between reducing and oxidizing species within cells is significant in the regulation of a signal pathway and is achieved by a series of elaborate mechanisms. In this work, we employed our previously reported D-π-A-structured naphthalene-BODIPY TBET platform to design an efficient two-photon fluorescent probe for dynamic monitoring of superoxide anion oxidative stress and the GSH reducing repair process. The probe displayed high energy transfer efficiency (91.4%), large pseudo-Stokes shifts upon one-photon excitation, and red fluorescence emission (λ_em = 596 nm), which is highly desirable for bioimaging applications. The probe exhibits reversibility, rapid response, good photostability, high selectivity and sensitivity for the superoxide anion and GSH. More importantly, the probe was successfully applied for visualizing the redox changes in living cells and tissues.