A Novel Near-Infrared Fluorescent Probe for the Detection of Endogenous Peroxynitrite (ONOO-) in Living Cells.

In this study, we present a novel near-infrared (NIR) fluorescent probe Nile-ONO designed for the selective and sensitive detection of ONOO-. The probe Nile-ONO employed Nile red as the fluorophore, with diphenylphosphinate serving as the reaction site. In the presence of ONOO-, the probe Nile-ONO exhibits remarkable fluorescence enhancement at 659 nm, with a response time of less than 20 min and a low detection limit of 0.32 µM. Importantly, MTT assays demonstrate low cytotoxicity in living cells. Furthermore, Nile-ONO has excellent imaging capabilities for endogenous ONOO-. Overall, this work introduces a valuable new method for the rapid detection of ONOO- in biological systems.