Jiang Bin, Liu Min, Zhang Kunchi, Zu Guangyue, Dong Jingjin, Cao Yi, Zhang Lan, Pei Renjun
Key Laboratory of Nano-Bio Interface, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China.
J Mater Chem B. 2016 May 21;4(19):3324-3330. doi: 10.1039/c6tb00278a. Epub 2016 Apr 26.
PEGylated poly(aspartate-g-OEI) was developed as a magnetic resonance imaging probe. The PEG-PBLA block copolymer was prepared by the ring-opening polymerization of β-benzyl-l-aspartate N-carboxy-anhydride (BLA-NCA) initiated by the terminal primary amino group of mPEG-NH, followed by grafting with oligoethylenimine (OEI, M = 800) and Gd-DTPA. Compared to Gd-DTPA (4.42 mM s), PEG-p(Asp-OEI-DTPA-Gd) exhibited much higher T relaxivity (19.03 mM s), up to 4.3 times higher than Gd-DTPA. No obvious cytotoxicity was observed from the WST assay and H&E analysis, which illustrated that this macromolecular contrast agent (mCA) exhibited excellent biocompatibility. Folic acid (FA) was further labeled onto the mCA to endow the mCA with targeting ability. During in vivo animal studies, the FA labeled MRI probes showed a significant signal intensity enhancement in the tumor during different time intervals and provided a long and efficient window time for MR examination. These results suggest that such mCAs are excellent candidates as magnetic resonance imaging (MRI) probes with high efficiency and safety.
聚乙二醇化聚（天冬氨酸-g-寡聚乙撑亚胺）被开发用作磁共振成像探针。聚乙二醇-聚（β-苄基-L-天冬氨酸）嵌段共聚物是通过mPEG-NH的末端伯氨基引发β-苄基-L-天冬氨酸N-羧基酐（BLA-NCA）的开环聚合反应制备的，随后与寡聚乙撑亚胺（OEI，M = 800）和钆-二乙三胺五乙酸（Gd-DTPA）接枝。与Gd-DTPA（4.42 mM s）相比，聚乙二醇-p（天冬氨酸-OEI-DTPA-Gd）表现出更高的横向弛豫率（19.03 mM s），比Gd-DTPA高4.3倍。从WST检测和苏木精-伊红染色分析中未观察到明显的细胞毒性，这表明这种大分子造影剂（mCA）具有优异的生物相容性。将叶酸（FA）进一步标记到mCA上，使mCA具有靶向能力。在体内动物研究中，FA标记的MRI探针在不同时间间隔内肿瘤部位显示出显著的信号强度增强，并为MR检查提供了长且有效的窗口期。这些结果表明，此类mCA是作为高效且安全的磁共振成像（MRI）探针的优秀候选物。
