A NIR fluorescent probe based on phenazine with a large Stokes shift for the detection and imaging of endogenous H2O2in RAW 264.7 cells

Hydrogen peroxide (H2O2), one of the reactive oxygen species (ROS), plays vital roles in diverse physiological processes. Thus, herein, to improve the signal-to-noise ratio, a new near-infrared region (NIR) fluorophore (PCN) based on reduced phenazine was developed.PCNwas further designed as a "turn on" fluorescent probe (PCN-BP) for the detection of H(2)O(2)by introducingp-boratebenzyl. After H(2)O(2)was added, thep-boratebenzyl group inPCN-BPwas oxidized top-hydroxy benzyl; it then self-departed, formingPCN, which displayed 24-fold NIR emission at 680 nm with a large Stokes shift (more than 200 nm). This probe presented an excellent linear relation with the concentration of H(2)O(2)and good selectivity to various ions, ROS and biothiols; thus, it can be utilized as a colorimetric and fluorescence turn-on probe. More importantly, the probe was also employed for the exogenous and endogenous imaging of H(2)O(2)in RAW 264.7 cells.