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

Abstract

The superoxide anion (O₂˙⁻), with strong oxidizability and nucleophilicity, is the primary reactive oxygen species in living systems, and the overformation of O₂˙⁻ is associated with many physiological and pathological diseases. Therefore, highly sensitive and selective O₂˙⁻ detection is necessary for exploring its roles in disease situations. In this work, we presented a smart ER-targeted two-photon excitation fluorescent O₂˙⁻ probe, named TPER-O₂˙⁻, based on the caged–decaged method of characteristic hydroxyl groups on fluorophores. The TPER-O₂˙⁻ probe, with good sensitivity (detection limit: 0.33 μM) and excellent selectivity for O₂˙⁻, was applied for the detection of endogenous endoplasmic reticulum O₂˙⁻ in HepG2 cells. Furthermore, it was also successfully applied to image the endoplasmic reticulum O₂˙⁻ level fluctuation in an APAP-stimulated liver injury model. The TPER-O₂˙⁻ probe has been demonstrated to be a potential tool to unmask the role of O₂˙⁻ for endoplasmic reticulum stress-relevant clinical diseases.