NIR fluorescence probe based on phenazine with large Stokes shift for detecting and imaging of endogenous H2O2 in RAW 264.7 cells
Hydrogen peroxide (H2O2), one of the reactive oxygen species (ROS), plays vital roles in diverse physiological processes. In order to improve the ratio of signal to noise, a new near-infrared region (NIR) fluorophore (PCN) based on reduced phenazine was developed. PCN can be further designed as a “trun on” fluorescence probe (PCN-BP) for the detection of H2O2 by introducing p-boratebenzyl. After the addition of H2O2, p-boratebenzyl of PCN-BP was oxided to p- hydroxy benzyl then self-departed forming PCN, displayed a 24-fold NIR emission at 680 nm with a large Stokes shift (more than 200 nm). The probe presented an excellent linear relation with concentration of H2O2 as well as a good selectivity to various ions, ROS and biothiols, which could be utilized as colorimetric and fluorescence turn-on probe. More importantly, the probe were also employed for exogenous and endogenous H2O2 imaging in RAW 264.7 cells.