磁共振分子成像脂质体探针的制备与表征

Preparation of a Magnetic Resonance Liposomal Contrast Agent for Molecular Imaging and Its Characteristics

目的：制备一种磁共振分子成像探针．钆结合空间稳定脂质体（Gd—SLs），并评价其物理属性。方法：利用挤出法制备空间稳定脂质体，表征脂质体粒径、稳定性、钆含量、弛豫率以及体9bMR成像特点。结果：所制备之钆结合空间稳定脂质体经高压均质仪过膜后粒径控制于117．4±31．8nm；脂质体Gd载药率达87％-100％；常温下（26℃）Gd—SLs磁共振弛豫率为Gd-DTPA的1．16倍，37℃为1．25倍；体9bMR成像显示Gd—SLs与Gd—DTPA两对比剂磁共振T1力口权成像作用接近。结论：顺磁性空间稳定脂质体能有效提高磁共振分子探针体内成像信号，制备方法简单，实验操作可控性好，在一定温度范围内性质稳定，具有较高的磁共振弛豫作用，是理想的磁共振分子影像学对比剂载体。

Purpose： The aim of this study was to develop paramagnetic sterical stabilized liposomes for magnetic resonance molecular imaging and evaluate their physical characteristics. Methods： The sterical stabilized liposomes were prepared by extrusion method. The size, stability, Gd containing, magnetic resonance relaxivity of the liposomes was characterized in vitro. Results： The size of Gd-SLs was 117.4± 31.8nm after homogenized. The incorporation efficiency of Gd-DTPA-BSA was 87%-100%. At 26℃ （room temperature）, the r1 relaxivity of Gd-SLs was 1.16 times that of the solution with free Gd-DTPA and 1.25 times at 37℃. MR T1 imaging of Gd-SLs in vitro presented similar enhancement effect to that of Gd-DTPA. Conclusion： It is easy to prepare the paramagnetic sterical stabilized liposomes which present high relaxivity to improve the MR contrast signal. The liposomes are thermo-sensitive but stable at common temperature. It may potential be served as an ideally useful contrast agent for MR molecular imaging.