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.