A Si-rhodamine-based near-infrared fluorescent probe for visualizing endogenous peroxynitrite in living cells,...

Peroxynitrite (ONOO^-) is an extremely powerful biological oxidant and it can react with a wide variety of molecular targets to result in a series of disease states, which has made ONOO^- a central biological pathogenic factor. In order to disclose its various pathological events, a large number of fluorescent ONOO^- probes have been developed in recent years. Nevertheless, some limitations still remain, such as short excitation and emission wavelengths, long fluorescence response times, and cross-interference caused by other reactive oxygen species (ROS). In this work, a new near-infrared (NIR) fluorescent probe, SiRTA, containing an aromatic tertiary amine functional group and a Si-rhodamine fluorophore, was developed for endogenous ONOO^- detection and imaging. The probe exhibits not only a fast, sensitive, and specific fluorescence off-on response toward ONOO^- in chemical systems but also excellent imaging ability for endogenous ONOO^- in living cells. With the probe, the therapeutic effects of phenolic acid antioxidants in EA.hy926 endothelial cells suffering from ischemia-reperfusion injury and the pathogenesis of diabetes and diabetic nephropathy in pancreatic β-cells and diabetic rats have successfully been evaluated. These results indicate that SiRTA is a potentially outstanding imaging tool for studying the physiological and pathological events of ONOO^- and relevant drug therapies.