Development of highly selective novel fluorescence turn-on probe based on carbon dots for sensing peroxynitrite (ONOO−) in vitro and in vivo

Peroxynitrite (ONOO − ), a highly reactive nitrogen and oxygen species (RNS/ROS), has been associated with a numerous of pathophysiological diseases, including inflammation, cancer, neurodegenerative, and cardiovascular diseases. There are great demands to develop strategies that can detect ONOO − in biological systems. Herein, we developed a novel fluorescent probe based on carbon dots (CDs) for a very sensitive and selective detection and imaging of endogenous and exogenous ONOO − in cells and animal models. Green light-emitting (527 nm) CDs with high quantum yield (QY) was synthesized by hydrothermal method using resorcinol as carbon source. After the phenolic hydroxyl groups of the CDs are combined with the recognition group of ONOO − via covalent ether bond, the fluorescence is quenched and forming the fluorescent probe. Upon the addition of ONOO − to the probe, the ether bond has broken and the CDs fluorescence has recovered. This response has been detailed investigated, including response time, pH values, selectivity and sensitivity, and linearity range, which confirmed the satisfactory detection ability for ONOO − . The probe shows low cytotoxicity and was successfully applied for imaging of ONOO − exogenously and endogenously in cells and in live models of zebrafish and mice.