Institute of Chemistry, St. Petersburg State University, Universitetskaya Embankment 7-9, 199034 St. Petersburg, Russia.
Institute of Experimental Oncology and Biomedical Technologies, Privolzhskiy Research Medical University, Minin and Pozharsky Sq. 10/1, 603005 Nizhny Novgorod, Russia.
Biosensors (Basel). 2023 Jun 26;13(7):680. doi: 10.3390/bios13070680.
In this work, we obtained three new phosphorescent iridium complexes (-) of general stoichiometry [Ir(N^C)(N^N)]Cl decorated with oligo(ethylene glycol) fragments to make them water-soluble and biocompatible, as well as to protect them from aggregation with biomolecules such as albumin. The major photophysical characteristics of these phosphorescent complexes are determined by the nature of two cyclometallating ligands (N^C) based on 2-pyridine-benzothiophene, since quantum chemical calculations revealed that the electronic transitions responsible for the excitation and emission are localized mainly at these fragments. However, the use of various diimine ligands (N^N) proved to affect the quantum yield of phosphorescence and allowed for changing the complexes' sensitivity to oxygen, due to the variations in the steric accessibility of the chromophore center for O molecules. It was also found that the N^N ligands made it possible to tune the biocompatibility of the resulting compounds. The wavelengths of the - emission maxima fell in the range of 630-650 nm, the quantum yields reached 17% () in a deaerated solution, and sensitivity to molecular oxygen, estimated as the ratio of emission lifetime in deaerated and aerated water solutions, displayed the highest value, 8.2, for . The obtained complexes featured low toxicity, good water solubility and the absence of a significant effect of biological environment components on the parameters of their emission. Of the studied compounds, and were chosen for in vitro and in vivo biological experiments to estimate oxygen concentration in cell lines and tumors. These sensors have demonstrated their effectiveness for mapping the distribution of oxygen and for monitoring hypoxia in the biological objects studied.
在这项工作中，我们获得了三个新的磷光铱配合物（-），其化学计量比为[Ir（N^C）（N^N）]Cl，用聚乙二醇片段修饰，使其水溶性和生物相容性，并防止其与白蛋白等生物分子聚集。这些磷光配合物的主要光物理特性取决于两种基于 2-吡啶-苯并噻吩的环金属化配体（N^C）的性质，因为量子化学计算表明，激发和发射的电子跃迁主要定域在这些片段上。然而，使用各种二亚胺配体（N^N）被证明会影响磷光量子产率，并允许通过改变发色团中心对 O 分子的空间位阻来改变配合物对氧气的敏感性。还发现，N^N 配体可以调节所得化合物的生物相容性。-发射最大值的波长范围在 630-650nm 之间，在无氧溶液中的量子产率达到 17%（），对分子氧的敏感性，以无氧和有氧水溶液中发射寿命的比值来估计，对于 ，显示出最高值 8.2。所得配合物具有低毒性、良好的水溶性和生物环境成分对其发射参数无显著影响。在体外和体内生物学实验中，选择了和来估计细胞系和肿瘤中的氧浓度。这些传感器已证明其在生物对象中氧分布的映射和缺氧监测方面的有效性。
