光诱导RNAi系统的构建及优化

A New Type of Magnetic Resonance Imaging Contrast Agents with High Hydration Numbers

合成了一类具有高水合常数（q）的钆类造影剂，该类配合物由金属钆与含有2个氮氧化基团和4个羧酸基团的有机配体组成，具有高水合常数的特点。通过核磁氢谱、碳谱以及高分辨质谱对配体及配合物的结构进行了表征。通过荧光寿命分析检测配合物的q值在3左右。该类配合物的纵向弛豫率（n）为8．5～10．1（mM）^-1·s^-1，约为商用造影荆二乙三胺五乙酸合钆（Gd-DTPA）的3倍。细胞实验证实该类造影剂具有很低的细胞毒性，这在临床应用中是非常关键的。该类配合物具有合成简便、弛豫率高以及毒性低等特点，为刺备更低成本、更高性能的造影剂打下基础。

A series of Gd （Ⅲ） complexes were synthesized and evaluated as potential magnetic resonance imaging （MRI） contrast agents. The ligands of these complexes are featured with two hyphenated amine-N-oxide and four earboxyl groups, providing the complexes with high hydration numbers （q, the number of inner-sphere water molecules）. The structures of the ligands and complexes were characterized with 1H-NMR,13C-NMR and ESI-MS. Preliminary results on 1.5T MRI measurement of the complexes showed high rl values （longitudinal relaxivity） of 8.5--10.1 （mM）-1 · s-1. The q value of the complexes was determined as up to 3 with fluorescence lifetime analysis with their Eu（ Ⅲ ） analogues. Cell tests revealed low cytotoxicity of the complexes,which is essential for c simplicity,the high relaxivity and the low toxicity of the complexes linical applications. The structural provide a new solution for the development of highly efficient MRI contrast agents.