MRI contrast agents based on water-soluble Gd-metallofullere

基于水溶性金属富勒钆的 MRI 造影剂

• 批准号: 12554026
• 负责人: SHINOHARA Hisanori
• 金额: $ 8.77万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12554026/
• 关键词: fullerenols; MRI; Contrast Agents; Gd; Relaxivity; water; 造影剤; フラーレン; 磁気共嗚画像診断; ディスプロシウム

The relaxivities of each Gd-Merenols (pure ; Rl=62 mM-1 sec-1 , R2=69 mM-1 sec-1 , mixture ; Rl=56 rnM-1 sec-1, R2=67 mM-1 sec-1) were much higher than that of a commercial MRI contrast agent, MagnevistR (Rl=3.8 mM-1 sec-1, R2=4.3 mM-1 sec-1).Gd-fullerenols showed high Rl throughout the range of magnetic fields. Further, the peak of Rl appeared nearby 1T. This field strength coincides with the range of common clinical MRI.A Gd3+ ion with 7 unpaired electrons in half filled 4f orbital has been known to exhibit a strong relaxation capability of proton nuclear spin of nearby water molecules. The conventional MRI contrast agents consisting of the Gd3+ -chejate complexes have one direct coordination window to a water molecule that rapidly exchanges with the bulk water molecules surrounding the Gd3+ ion, which leads to an efficient nuclear spin relaxation of solvent water molecules. In contrast, in the Gd-fullerenols, there are no water molecules which can form a direct coordination to the encaged Gd3+ ion. Although the details of the electronic and magnetic properties of the current Gd-fullerenols is not known at present, it is probable that Gd@C82(OH)p has the paramagnetic property due to three electron transfer from Gd to the fullerene cage [ Gd3+@C82(OH)n3-] resulting in seven unpaired electrons in the Gd-4f orbitals inside the C82 cage and one on the cage.

Gd-Merenols的弛豫率（纯的; R1 =62 mM-1 sec-1，R2=69 mM-1 sec-1，混合物; R1 =56 mM-1 sec-1，R2=67 mM-1 sec-1）远高于市售MRI造影剂MagnevistR（R1 =3.8 mM-1 sec-1，R2=4.3 mM-1 sec-1）Xd-富勒烯醇在整个磁场范围内显示高RI。此外，RI的峰值出现在1 T附近。该场强与临床MRI的范围相吻合。在半满4f轨道上具有7个未成对电子的Gd 3+离子显示出对附近水分子质子核自旋的强弛豫能力。由Gd 3 + -chejate络合物组成的常规MRI造影剂具有一个与水分子的直接配位窗口，其与Gd 3+离子周围的大量水分子快速交换，这导致溶剂水分子的有效核自旋弛豫。相比之下，在Gd-富勒烯醇中，没有水分子可以与笼中的Gd 3+离子形成直接配位。虽然目前Gd-富勒烯醇的电子和磁性的细节尚不清楚，但Gd@C82（OH）p可能具有顺磁性，这是由于从Gd到富勒烯笼[Gd 3 +@C82（OH）n3-]的三个电子转移导致在C82笼内的Gd-4f轨道中有七个未配对电子，在笼上有一个。

项目成果

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