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Hypochlorite (ClO − ), as a type of reactive oxygen species (ROS), plays a crucial role in the process of oxidative stress and is closely related to many diseases. Thus, developing a method for detecting and imaging of ClO − with high sensitivity and selectivity is of great significance. However, the applications of most luminescent probes are limited to the fact that the excitation and emission wavelengths of them are in the visible light region rather than in the near-infrared (NIR) region. Hence, an NIR iridium(III) complex (Mul-NIRIr) with two-photon excitation is designed for the detecting and imaging of ClO − . In the presence of ClO − , the luminescent intensity and lifetime of Mul-NIRIr are remarkably enhanced. Interestingly, Mul-NIRIr also exhibits excellent electrochemiluminescence (ECL) properties, and the ECL signal is significantly enhanced with the addition of ClO − . What is more, Mul-NIRIr is also suitable for the detection and analysis ClO − by flow cytometry. Therefore, Mul-NIRIr is developed to detect multiple signals and is successfully applied to detect exogenous and endogenous ClO − in living cells with one-photon, two-photon, and phosphorescence lifetime image microscopy (PLIM). In addition, Mul-NIRIr was successfully used for imaging of ClO − in tissues and inflammatory mouse models. All of the above results indicate that Mul-NIRIr is highly effective in detecting ClO − in living systems.

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease with short survival time. However, owing to the unknown etiology and the lack of sensitive and noninvasive methods, the diagnosis of IPF in the early stage is still full of challenges. Since the levels of oxidative stress in mitochondria are relevant to pulmonary fibrosis, we herein present a simultaneous near-infrared (NIR)-Ia window and ratiometic fluorescent probe, rTPONOO-1, with two-photon and mitochondria-targeting abilities to explore the potential biological roles of peroxynitrite (ONOO − ) in different states of lung slices from healthy to lung inflammation and pulmonary fibrosis, and there is a good linear relationship between ratiometric fluorescence changes and the rate of pulmonary fibrosis from hematoxylin and eosin (H&E) and Masson staining. In addition, the therapeutic efficacy of aminoguanidine hemisulfate salt (AG) was also investigated. Thus, rTPONOO-1 has great potential in quickly predicting the progression of pulmonary fibrosis in the early stage and improving effective treatment.

Two new dinuclear Ru(II) polypyridyl complexes containing three and ten methylene chains in their bridging linkers are synthesized and characterized. Their calf thymus DNA-binding and plasmid DNA photocleavage behaviors are comparatively studied with a previously reported, six-methylene-containing analog by absorption and luminescence spectroscopy, steady-state emission quenching by [Fe(CN)6](4-), DNA competitive binding with ethidium bromide, DNA viscosity measurements, DNA thermal denaturation, and agarose gel electrophoresis analyses. Theoretical calculations applying the density functional theory (DFT) method for the three complexes are also performed to understand experimentally observed DNA binding properties. The results show that the two complexes partially intercalate between the base pairs of DNA. Cellular uptake and colocalization studies have demonstrated that the complexes could enter HeLa cells efficiently and localize within lysosomes. The in-vitro antitumor activity against HeLa and MCF-7 tumor cells of the complexes are studied by MTT cytotoxic analysis. A new method, high-content analysis (HCA), is also used to assess cytotoxicity, apoptosis and cell cycle arrest of the three complexes. The results show that the lengths of the alkyl linkers could effectively tune their biological properties and that HCA is suitable for rapidly identifying cytotoxicity and can be substituted for MTT assays to evaluate the cell cytotoxicity of chemotherapeutic agents.

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