Zhang Simin, Zheng Yanmei, Fu Ding-Yi, Li Wen, Wu Yuqing, Li Bao, Wu Lixin
State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, 130012, China.
J Mater Chem B. 2017 Jun 14;5(22):4035-4043. doi: 10.1039/c6tb03263j. Epub 2017 Apr 28.
Two cationic dendrons bearing terminal groups of triethylene glycol monomethyl ether in different generations were used to encapsulate a paramagnetic polyoxometalate cluster K[Gd(β-SiWO)], in which the Gd ion was sandwiched by the coordination of two lacunary [β-SiWO] sub-clusters, through electrostatic interaction. Benefiting from the surface covering of cationic dendrons and ionic complexation, both inorganic polyanionic core and the complexes formed maintained chemical stability in a physiological environment. In addition, the formed charge-neutralized supramolecular complex dendrimers with biocompatible periphery had low cytotoxicity but high relaxivity for in vitro and in vivo magnetic resonance imaging (MRI) in the self-assembled state. Because of the branched structure of organic components on the cluster surface and the disordered packing of complexes in aggregations, a reasonable communication of cluster core with the bulk environment was concluded. Importantly, due to the assembled particle size and molecular weight, the complex dendrimers were a suitable model for liver-specific MRI contrast agents. The results obtained showed that the dendritic supramolecular hybrid complexes represent potential MRI contrast agents in the development of new biomedical materials.
使用两代带有不同端基三甘醇单甲醚的阳离子树枝状分子，通过静电相互作用包封顺磁性多金属氧酸盐簇K[Gd(β-SiWO)]，其中Gd离子通过两个缺位[β-SiWO]子簇的配位作用夹在中间。得益于阳离子树枝状分子的表面覆盖和离子络合作用，无机聚阴离子核心以及形成的络合物在生理环境中均保持化学稳定性。此外，形成的具有生物相容性外围的电荷中和超分子复合树枝状聚合物在自组装状态下对体外和体内磁共振成像（MRI）具有低细胞毒性但高弛豫率。由于簇表面有机成分的分支结构以及聚集体中络合物的无序堆积，得出簇核心与本体环境之间存在合理的相互作用。重要的是，由于组装后的粒径和分子量，复合树枝状聚合物是肝脏特异性MRI造影剂的合适模型。所得结果表明，树枝状超分子杂化复合物在新型生物医学材料的开发中代表了潜在的MRI造影剂。
