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

Hydrogen peroxide (HO), 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 HO in the body. Mitochondria are the main organelles producing HO in the human body, and monitoring the level of HO in mitochondria can help to deepen the understanding of the detailed functions of HO in physiological activities. However, due to the highly dynamic nature of the cells, real-time quantitative monitoring of HO levels in mitochondria remains an ongoing challenge. Herein, a novel highly immobilized mitochondria-targeting fluorescent probe (QHCl) for detection of HO was reasonably constructed based on quinolinium dye containing benzyl chloride moiety. Spectral experimental results demonstrated QHCl possessed outstanding selectivity toward HO (λ = 380/513 nm). In addition, QHCl can quantitatively detect HO 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 HO in the mitochondria of living cells and zebrafish by its unique mitochondrial immobilization.