Bioimaging of Glutathione with a Two-Photon Fluorescent Probe and Its Potential Application for Surgery-Guide in Laryngeal Cancer.

As the most abundant non-protein biothiol in living cells, glutathione (GSH) prevents cellular components from oxidative damage and maintains the intracellular redox homeostasis. For further exploring whether GSH can be employed as a bio-indicator to discriminate tumor lesion at cellular level, the highly selective detection and accurate quantification of GSH under pathological con-ditions are critical. Herein, we design a coumarin derivative-based two-photon fluorescent probe Cou-Br for the detection of GSH in living cells, in mice models, and in clinical specimens. The prepared probe is capable of sensitively and selectively detecting GSH in complex biological systems. Cou-Br displays a good linear relationship in response to GSH and a low limit of detection. With the fluorescence signal positively associated with intracellular GSH levels, the probe enables real-time imaging of GSH in various cell lines. Under the condition of CS2 stimulation, Cou-Br can rapidly respond to the fluctuation of intracellular GSH induced by oxidative damage. Furthermore, the in situ and in vivo bioimaging performances of Cou-Br are demonstrated both in vitro and in vivo. Typically, relying on the different cellular concentrations of GSH, the probe is successfully employed to identify the human laryngeal cancer lesion with outstanding capabilities of deep tissue imaging and tumor margin recognition. We assume that the abnormal expression level of GSH may be utilized as a potential bio-indicator to discriminate tumor tissues from the surrounding disease-free tissues. To conclude, the proposed probe Cou-Br may potentially serve as a powerful chemical tool for the surgical navigation of cancer in clinic.