A simple mitochondria-immobilized fluorescent probe for the detection of hydrogen peroxide

Hydrogen peroxide (H2O2), as one of reactive oxygen species (ROS) widely present in the human body, is involved in a variety of physiological activities. Many human diseases are associated with abnormal levels of H2O2 in the body. Mitochondria are the main organelles producing H2O2 in the human body, and monitoring the level of H2O2 in mitochondria can help to deepen the understanding of the detailed functions of H2O2 in physiological activities. However, due to the highly dynamic nature of the cells, real-time quantitative monitoring of H2O2 levels in mitochondria remains an ongoing challenge. Herein, a novel highly immobilized mitochondria-targeting fluorescent probe (QHCl) for detection of H2O2 was reasonably constructed based on quinolinium dye containing benzyl chloride moiety. Spectral experimental results demonstrated QHCl possessed outstanding selectivity toward H2O2 (λex/em = 380/513 nm). In addition, QHCl can quantitatively detect H2O2 in the concentration range of 0-20 μM with excellent sensitivity (LOD = 0.58 μM) under the PBS buffer solution (10 mM, pH = 7.4). Finally, bioimaging experiments demonstrated that the probe QHCl was able to be used for accurately detecting both endogenous and exogenous H2O2 in the mitochondria of living cells and zebrafish by its unique mitochondrial immobilization.