Imaging of endoplasmic reticulum superoxide anion fluctuation in a liver injury model by a selective two-photon fluorescent probe

The superoxide anion (O-2(center dot-)), with strong oxidizability and nucleophilicity, is the primary reactive oxygen species in living systems, and the overformation of O-2(center dot-) is associated with many physiological and pathological diseases. Therefore, highly sensitive and selective O-2(center dot-) detection is necessary for exploring its roles in disease situations. In this work, we presented a smart ER-targeted two-photon excitation fluorescent O-2(center dot-) probe, named TPER-O-2(center dot-), based on the caged-decaged method of characteristic hydroxyl groups on fluorophores. The TPER-O-2(center dot-) probe, with good sensitivity (detection limit: 0.33 mu M) and excellent selectivity for O-2(center dot-), was applied for the detection of endogenous endoplasmic reticulum O-2(center dot-) in HepG2 cells. Furthermore, it was also successfully applied to image the endoplasmic reticulum O-2(center dot-) level fluctuation in an APAP-stimulated liver injury model. The TPER-O-2(center dot-) probe has been demonstrated to be a potential tool to unmask the role of O-2(center dot-) for endoplasmic reticulum stress-relevant clinical diseases.