Monitoring the Fluctuation of Hydrogen Peroxide in Diabetes and Its Complications with a Novel Near-Infrared Fluorescent Probe.

Diabetes is one of the metabolic diseases marked by hyperglycemia and is often accompanied by the occurrence of some complications. As a biomarker of oxidative stress, hydrogen peroxide (HO) has close association with the occurrence and development of diabetes and its complications. Unfortunately, there is no fluorescent probe reported for imaging HO in diabetic mice. Here, a novel near-infrared (NIR) fluorescent probe named QX-B was designed and synthesized to detect HO. For the probe, the quinolinium-xanthene dye is used as the fluorophore and borate ester is chosen as the response group. After the addition of HO, a strong NIR fluorescence signal at 772 nm is observed. The probe not only shows high sensitivity with 10-fold enhancement but also displays excellent selectivity to HO over other possible interfering species. In the meantime, the possible response mechanism of QX-B toward HO was proposed and verified by the high-performance liquid chromatography (HPLC) experiment, mass spectra (MS) experiment, and density functional theory (DFT) calculation. Furthermore, based on the low cell cytotoxicity of QX-B, it has been applied in imaging exogenous and endogenous HO in HeLa cells, HCT116 cells, 4T1 cells, and zebrafish successfully. More importantly, inspired by the performance of NIR fluorescence, QX-B has been used in monitoring HO in diabetic mice for the first time. This provides very important information for the diagnosis and treatment of diabetes and its complications.