Intracellular and in Vivo Oxygen Sensing Using Phosphorescent Ir(III) Complexes with a Modified Acetylacetonato Ligand
Intracellular and in Vivo Oxygen Sensing Using Phosphorescent Ir(III) Complexes with a Modified Acetylacetonato Ligand
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DOI：
10.1021/ac5040067
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发表时间：
2015-03-03
影响因子：
7.4
通讯作者：
Tobita, Seiji
中科院分区：
文献类型：
--
作者：
Yoshihara, Toshitada;Hosaka, Masahiro;Tobita, Seiji
基于铱（III）配合物BTP， （BTP）(2)Ir(acac) （BTP =苯并噻吩吡啶，acac =乙酰丙酮）的小发光分子探针已被开发用于检测细胞内和体内的O2。这些化合物是BTPSA（含有一个阴离子羧基）、BTPNH2（含有一个阳离子氨基）和BTPDM1（含有一个阳离子二甲氨基）；所有取代基都并入BTP的辅助乙酰丙酮配体中。与BTP相比，引入阳离子二甲胺组导致HeLa细胞对BTPDM1的细胞摄取效率提高了近20倍。活细胞内化的BTPDM1的磷光强度提供了在培养的单层细胞上放置盖层所产生的O-2梯度的视觉表示。通过测定BTPDM1的磷光寿命，可以评估盖盖边缘内外的细胞内O-2水平（pO(2)）。此外，给荷瘤小鼠静脉注射25 nmol BTPDM1，可以通过BTPDM1的磷光显示肿瘤区域。肿瘤区BTPDM1磷光的寿命远长于肿瘤外区，表明肿瘤缺氧(肿瘤pO（2) = 6.1 mmHg，肿瘤外表皮组织pO(2) = 50 mmHg）。组织分布研究表明，BTPDM1在小鼠体内注射2 h后，在肝脏和肾脏中分布最高，24 h后，BTPDM1随粪便排出。这些结果表明，BTPDM1可以作为一个小分子探针，用于测量培养细胞和特定组织和器官的细胞内O-2水平。
Small luminescent molecular probes based on the iridium(III) complex BTP, (btp)(2)Ir(acac) (btp = benzothienylpyridine, acac = acetylacetone) have been developed for sensing intracellular and in vivo O2. These compounds are BTPSA (containing an anionic carboxyl group), BTPNH2 (containing a cationic amino group), and BTPDM1 (containing a cationic dimethylamino group); all substituents are incorporated into the ancillary acetylacetonato ligand of BTP. Introduction of the cationic dimethylamino group resulted in an almost 20-fold increase in cellular uptake efficiency of BTPDM1 by HeLa cells compared with BTP. The phosphorescence intensity of BTPDM1 internalized in living cells provided a visual representation of the O-2 gradient produced by placing a coverslip over cultured monolayer cells. The intracellular O-2 levels (pO(2)) inside and outside the edge of the coverslip could be evaluated by measuring the phosphorescence lifetime of BTPDM1. Furthermore, intravenous administration of 25 nmol BTPDM1 to tumor-bearing mice allowed the tumor region to be visualized by BTPDM1 phosphorescence. The lifetime of BTPDM1 phosphorescence from tumor regions was much longer than that from extratumor regions, thereby demonstrating tumor hypoxia (pO(2) = 6.1 mmHg for tumor and 50 mmHg for extratumor epidermal tissue). Tissue distribution studies showed that 2 h after injection of BTPDM1 into a mouse, the highest distribution was in liver and kidney, while after 24 h, BTPDM1 was excreted in the feces. These results demonstrate that BTPDM1 can be used as a small molecular probe for measuring intracellular O-2 levels in both cultured cells and specific tissues and organs.