Cao Yi, Liu Min, Kuang Ye, Zu Guangyue, Xiong Dangsheng, Pei Renjun
School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
J Mater Chem B. 2017 Nov 14;5(42):8408-8416. doi: 10.1039/c7tb01967j. Epub 2017 Oct 23.
Gadolinium-based macromolecular contrast agents (CAs) with favorable biocompatibility, targeting specificity, and high relaxivity properties are desired for magnetic resonance imaging (MRI) of tumors. Herein, a novel triblock polymeric micelle based on poly(glycerol) (PG) and poly(ε-caprolactone) (PCL) was designed as a nanocarrier to fabricate a tumor targeted contrast agent (CA). Through conjugating gadolinium chelates and folic acid (FA) molecules to the PG block, a triblock-micelle contrast agent (T-micelle) formed from self-assembly demonstrated a low critical micelle concentration (CMC) of 6 mg L and a hydrodynamic diameter of about 250 nm. Compared with small-molecule CAs, the T-micelle exhibited a higher longitudinal relaxivity (r) of 14.71 mM s. Moreover, the cellular viability assay revealed negligible cytotoxicity, and estimation of targeting capacity showed significant targeting specificity to tumor cells. In addition, MRI on tumor-bearing mice confirmed that the T-micelle could efficiently accumulate at the tumor region through targeting specificity and provide obvious contrast enhancement. Consequently, the T-micelle is a promising gadolinium-based macromolecular CA for tumor diagnosis.
具有良好生物相容性、靶向特异性和高弛豫率特性的基于钆的大分子造影剂（CAs）是肿瘤磁共振成像（MRI）所需要的。在此，一种基于聚甘油（PG）和聚己内酯（PCL）的新型三嵌段聚合物胶束被设计为纳米载体，以制备肿瘤靶向造影剂（CA）。通过将钆螯合物和叶酸（FA）分子共轭到PG嵌段上，由自组装形成的三嵌段胶束造影剂（T-胶束）表现出6 mg/L的低临界胶束浓度（CMC）和约250 nm的流体动力学直径。与小分子造影剂相比，T-胶束表现出更高的纵向弛豫率（r1），为14.71 mM-1 s-1。此外，细胞活力测定显示细胞毒性可忽略不计，靶向能力评估显示对肿瘤细胞具有显著的靶向特异性。此外，对荷瘤小鼠的MRI证实，T-胶束可通过靶向特异性有效地在肿瘤区域积聚，并提供明显的对比增强。因此，T-胶束是一种有前途的用于肿瘤诊断的基于钆的大分子造影剂。
