Selective Cadmium Fluorescence Probe Based on Bis-heterocyclic Molecule and its Imaging in Cells
作者:Masayori Hagimori、Yasushi Karimine、Naoko Mizuyama、Fumiko Hara、Takeshi Fujino、Hideo Saji、Takahiro Mukai
DOI:10.1007/s10895-021-02748-7
日期:2021.7
Fluorescence probes that selectively image cadmium are useful for detecting and tracking the amount of Cd2+ in cells and tissues. In this study, we designed and synthesized a novel Cd2+ fluorescence probe based on the pyridine-pyrimidine structure, 4-(methylsulfanyl)-6-(pyridin-2-yl)pyrimidin-2-amine (3), as a low-molecular-weight fluorescence probe for Cd2+. Compound 3 could successfully discriminate between Cd2+ and Zn2+ and exhibited a highly selective turn-on response toward Cd2+ over biologically related metal ions. The dissociation constant (Kd) and the limit of detection (LOD) of 5.4 × 10− 6 mol L− 1 and 4.4 × 10− 7 mol L− 1, respectively, were calculated using fluorescence titration experiments. Studies with closely related analogs showed that the bis-heterocyclic moiety of 3 acted as both a coordination site for Cd2+ and a fluorophore. Further, the methylsulfanyl group of compound 3 is essential for achieving selective and sensitive Cd2+ detection. Fluorescence microscopy studies using living cells revealed that the cell membrane permeability of compound 3 is sufficient to detect intracellular Cd2+. These results indicate that novel bis-heterocyclic molecule 3 has considerable potential as a fluorescence probe for Cd2+ in biological applications.
能选择性成像镉的荧光探针可用于检测和跟踪细胞和组织中的 Cd2+ 含量。在这项研究中,我们设计并合成了一种基于吡啶-嘧啶结构的新型 Cd2+ 荧光探针--4-(甲硫基)-6-(吡啶-2-基)嘧啶-2-胺(3),作为 Cd2+ 的低分子量荧光探针。化合物 3 能成功区分 Cd2+ 和 Zn2+,并对 Cd2+ 而非生物相关金属离子表现出高度选择性的开启响应。利用荧光滴定实验计算出的解离常数(Kd)和检测限(LOD)分别为 5.4 × 10- 6 mol L- 1 和 4.4 × 10- 7 mol L- 1。对密切相关的类似物进行的研究表明,3 的双杂环分子既是 Cd2+ 的配位位点,又是荧光体。此外,化合物 3 的甲硫基对于实现选择性和灵敏的 Cd2+ 检测至关重要。利用活细胞进行的荧光显微镜研究表明,化合物 3 的细胞膜渗透性足以检测细胞内的 Cd2+。这些结果表明,新型双杂环分子 3 在生物应用中作为 Cd2+ 的荧光探针具有相当大的潜力。