A Carbamoyl Oxime-Based Highly Specific Fluorescent Chemodosimeter for Monitoring Labile Fe2+ in Food and Living Organisms.

Iron is an essential element in the composition of living organisms and plays a crucial role in a wide range of biological activities. The human body primarily obtains essential iron through the consumption of food. Therefore, it is vital for the health of human body to maintain iron homeostasis. The reducing character of the cellular microenvironment enables Fe2+ to occupy a dominant position within the cell. Hence, there is an urgent need for a simple and sensitive tool that can detect a large amount of Fe2+ in organisms. In this work, a highly specific fluorescent chemodosimeter NPCO ("NP" represents the naphthalimide fluorophore, and "CO" represents the carbamoyl oxime structure) for the detection of Fe2+ with excellent sensitivity (LOD = 82 nM) was constructed by incorporating a novel carbamoyl oxime structure as the recognition group. NPCO can be effectively employed for the detection of Fe2+ in food samples, living cells, and zebrafish. Furthermore, by using soybean sprouts as a model plant, the application of NPCO was expanded to detect Fe2+ in plants. Therefore, NPCO could be used as an excellent assay tool for detecting Fe2+ in organisms and is expected to be an important aid in exploring the mechanism of iron regulation.

Discovery of a highly selective fluorescent probe for hydrogen peroxide and its biocompatibility evaluation and bioimaging applications in cells and zebrafish.

As one of the most widely distributed reactive oxygen species in vivo, hydrogen peroxide plays divergent and important roles in cell growth, differentiation and aging. When the level of hydrogen peroxide in the body is abnormal, it will lead to genome mutation and induce irreversible oxidative modification of proteins, lipids and polysaccharides, resulting in cell death or even disease. Therefore, it is significant to develop a sensitive and specific probe for real-time detection of hydrogen peroxide in vivo. In this study, the response mechanism between hydrogen peroxide and probe QH was investigated by means of HRMS and the probe showed good optical properties and high selectivity to hydrogen peroxide. Note that the evaluating of probe biocompatibility resulted from cytotoxicity test, behavioral test, hepatotoxicity test, cardiotoxicity test, blood vessel toxicity test, immunotoxicity test and neurotoxicity test using cell and transgenic zebrafish models with more than 20 toxic indices. Furthermore, the detection performance of the probe for hydrogen peroxide was evaluated by multiple biological models and the probe was proved to be much essential for the monitoring of hydrogen peroxide in vivo.

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.