A near-infrared ratiometric/turn-on fluorescent probe for in vivo imaging of hydrogen peroxide in a murine model of acute inflammation.

Much attention has been paid to develop optical probes for noninvasive, quantitative, in vivo monitoring of hydrogen peroxide (H2O2) due to its important roles in the initiation and development of numerous diseases. Motivated to meet this need, we herein report the synthesis of a near-infrared (NIR) fluorescent probe (AB1) for H2O2 by modulating intramolecular charge transfer (ICT) process of the dye 9H-1,3-Dichloro-7-hydroxy-9,9-dimethylacridine-2-one (DDAO). The probe AB1 exhibits both a large NIR fluorescence turn-on and a ratiometric response to H2O2 with high sensitivity and specificity. The fluorescence response of AB1 has a good linear relationship with H2O2 over a wide concentration range from 1 µM to 100 µM, thus affording a detection limit of 0.42 µM. Confocal microscopic experiments demonstrated that AB1 could ratiometrically detect exogenous and endogenous H2O2 in living cells. Moreover, owing to the NIR emission of DDAO, the probe was also utilized to image endogenous H2O2 from the peritoneal cavity in a mouse model of lipopolysaccharide-induced acute inflammation, based on the fluorescence turn-on mode. This new probe shows great potential as a reliable chemical tool to study the development and progression of H2O2-associated diseases in living animals.