Liu Xiangli, Song Bo, Ma Hua, Tang Zhixin, Yuan Jingli
State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China.
J Mater Chem B. 2018 Mar 28;6(12):1844-1851. doi: 10.1039/c8tb00030a. Epub 2018 Mar 13.
A mitochondria targetable ratiometric luminescence probe based on a mixture of Eu and Tb complexes, Mito-NSTTA-Eu/Tb, has been developed for the specific recognition and time-gated luminescence detection of biothiols in aqueous and living samples. This probe was synthesized by conjugating a mitochondria-anchoring motif, triphenylphosphonium, with a biothiol-responsive terpyridine derivative, [4'-(2,4-dinitrobenzenesulfonyloxy)-2,2':6',2''-terpyridine-6,6''-diyl] bis(methylenenitrilo) tetrakis(acetic acid), for coordinating with Eu and Tb ions. When the probe interacts with biothiols, the cleavage of the 2,4-dinitrobenzenesulfonyl moiety leads to a remarkable enhancement of the Tb emission at 540 nm, while the Eu emission at 610 nm is unchanged, which allows Mito-NSTTA-Eu/Tb to be used as a ratiometric probe for the time-gated luminescence detection of biothiols, with the luminescence intensity ratio of I/I as a signal. The triphenylphosphonium group enables the probe molecules to be specifically driven into the mitochondria after cell loading for responding to biothiols therein. Mito-NSTTA-Eu/Tb showed high selectivity and sensitivity for the detection of biothiols under physiological conditions, with detection limits of 0.098 μM for glutathione (GSH) and 0.14 μM for cysteine (Cys). In cell imaging experiments, Mito-NSTTA-Eu/Tb displayed an excellent mitochondria-localization feature, which allowed biothiols in the mitochondria of live cells to be successfully imaged under ratiometric and time-gated luminescence modes. In addition, biothiols in living Daphnia magna were also imaged using Mito-NSTTA-Eu/Tb as a probe. All of the results suggested that Mito-NSTTA-Eu/Tb could serve as a useful tool for monitoring biothiols in vitro and in vivo with high specificity and sensitivity.
基于铕（Eu）和铽（Tb）配合物混合物的可靶向线粒体的比率发光探针Mito-NSTTA-Eu/Tb已被开发出来，用于在水性和活体样品中对生物硫醇进行特异性识别和时间分辨发光检测。该探针是通过将线粒体锚定基序三苯基膦与生物硫醇响应性三联吡啶衍生物[4'-(2,4-二硝基苯磺酰氧基)-2,2':6',2''-三联吡啶-6,6''-二基]双(亚甲基腈基)四乙酸共轭合成的，用于与Eu和Tb离子配位。当探针与生物硫醇相互作用时，2,4-二硝基苯磺酰基部分的裂解导致540 nm处Tb发射显著增强，而610 nm处Eu发射不变，这使得Mito-NSTTA-Eu/Tb能够用作比率探针，用于生物硫醇的时间分辨发光检测，以发光强度比I/I作为信号。三苯基膦基团使探针分子在细胞加载后能够特异性地进入线粒体，以响应其中的生物硫醇。Mito-NSTTA-Eu/Tb在生理条件下对生物硫醇的检测显示出高选择性和灵敏度，对谷胱甘肽（GSH）的检测限为0.098 μM，对半胱氨酸（Cys）的检测限为0.14 μM。在细胞成像实验中，Mito-NSTTA-Eu/Tb表现出优异的线粒体定位特性，使得活细胞线粒体中的生物硫醇能够在比率和时间分辨发光模式下成功成像。此外，还使用Mito-NSTTA-Eu/Tb作为探针，对活体大型溞中的生物硫醇进行了成像。所有结果表明，Mito-NSTTA-Eu/Tb可以作为一种有用的工具，以高特异性和灵敏度在体外和体内监测生物硫醇。
