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 (HO) 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 HO 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 HO with high sensitivity and specificity. The fluorescence response of AB1 has a good linear relationship with HO 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 HO in living cells. Moreover, owing to the NIR emission of DDAO, the probe was also utilized to image endogenous HO 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 HO-associated diseases in living animals.