A novel hepatocyte-targeting ratiometric fluorescent probe for imaging hydrogen peroxide in zebrafish

Hydrogen peroxide (H 2 O 2 ), as one of important reactive oxygen species (ROS), can be endogenously produced in the liver, and used as a biomarker for predicting drug-induced liver injury (DILI). So, it is important to construct an efficient method for monitoring H 2 O 2 in the liver to assess DILI. Herein, a hepatocyte-targeted fluorescent probe (GCP) for ratiometric detection of H 2 O 2 is developed. GCP consists of two main parts: coumarin-pyran-based fluorophore and galactose-based hepatocyte-targetable group. The probe itself shows near-infrared (NIR) emission owing to its extended π-conjugation. Meanwhile, a large emission shift from 706 to 482 nm (224 nm) is observed after the reaction with H 2 O 2 . Taking advantage of the spectroscopic property, GCP exhibits high sensitivity toward H 2 O 2 with 19-fold fluorescence ratio enhancement and is highly selective over other ROS. Moreover, the probe possesses a good hepatocyte-targeting ability and is applied for ratiometric monitoring endogenous H 2 O 2 in HepG2 cells. Furthermore, the probe can trace H 2 O 2 level during DILI in HepG2 cells. Most importantly, GCP can locate in the liver of zebrafish and detect H 2 O 2 level in the liver during DILI, which will be a potentially useful tool to assess DILI.