College of Chemistry, Beijing Normal University, Beijing, People's Republic of China.
Nanotechnology. 2011 Jun 17;22(24):245604. doi: 10.1088/0957-4484/22/24/245604. Epub 2011 Apr 21.
The development of new types of high-performance nanoparticulate MR contrast agents with either positive (T(1)) or dual-contrast (both positive and negative, T(1) + T(2)) ability is of great importance. Here we report a facile synthesis of ultrasmall PEGylated iron oxide nanoparticles for dual-contrast T(1)- and T(2)-weighted MRI. The produced superparamagnetic iron oxide nanoparticles (SPIONs) are of high crystallinity and size uniformity with an average diameter of 5.4 nm, and can be individually dispersed in the physiological buffer with high stability. The SPIONs reveal an impressive saturation magnetization of 94 emu g(-1) Fe(3)O(4), the highest r(1) of 19.7 mM(-1) s(-1) and the lowest r(2)/r(1) ratio of 2.0 at 1.5 T reported so far for PEGylated iron oxide nanoparticles. T(1)- and T(2)-weighted MR images showed that the SPIONs could not only improve surrounding water proton signals in the T(1)-weighted image, but induce significant signal reduction in the T(2)-weighted image. The good contrast effect of the SPIONs as T(1) + T(2) dual-contrast agents might be due to its high magnetization, optimal nanoparticle size for T(1) + T(2) dual-contrast agents, high size monodispersity and excellent colloidal stability. In vitro cell experiments showed that the SPIONs have little effect on HeLa cell viability.
开发具有正对比（T1）或双对比（正、负对比，T1 + T2）能力的新型高性能纳米颗粒磁共振对比剂具有重要意义。本研究报告了一种简便的方法，用于合成超小的聚乙二醇化氧化铁纳米颗粒，用于 T1 和 T2 加权磁共振的双对比。所制备的超顺磁氧化铁纳米颗粒（SPIONs）具有高结晶度和尺寸均匀性，平均直径为 5.4nm，可以在生理缓冲液中以高稳定性单独分散。SPIONs 具有令人印象深刻的饱和磁化强度 94 emu g-1 Fe3O4，目前报道的最高 r1 值为 19.7 mM-1 s-1，在 1.5 T 下的 r2/r1 比值最低为 2.0，这是迄今为止报道的聚乙二醇化氧化铁纳米颗粒。T1 和 T2 加权磁共振图像显示，SPIONs 不仅可以提高 T1 加权图像中周围水质子信号，而且可以在 T2 加权图像中引起显著的信号减少。SPIONs 作为 T1 + T2 双对比剂的良好对比效果可能归因于其高磁化强度、适用于 T1 + T2 双对比剂的最佳纳米颗粒尺寸、高尺寸单分散性和优异的胶体稳定性。体外细胞实验表明，SPIONs 对 HeLa 细胞活力几乎没有影响。
