Gd@C82(OH)16的合成及其核磁共振成像

采用电弧放电法合成和HPLC 2步分离法,得到了纯度为95％以上的Gd@C82。以四丁基氢氧化铵(TBAH)为催化剂,用NaOH溶液对Gd@C82进行羟基衍生化,并利用同步辐射XPS分析其C(12)确定Gd@C82羟基化产物的羟基数,得到水溶性的Gd@C82(OH)16。对Gd@C82(OH)16进行了体外弛豫率及体内的核磁共振成像研究。结果表明,与(NMG)2-Gd-DTPA相比,在相同Gd浓度下,Gd@C82(OH)16的质子弛豫率R1提高约3倍,R2提高约7倍。体内核磁成像结果也显示,Gd@C82(OH)16提高了核磁成像对比的效果,其信号在2 h内维持稳定。说明Gd@C82(OH)16在作为磁共振增强剂方面具有较大的潜力。

Synthesis and Usage of Gd @ C82 (OH) 16 as MRI Contrast Agent

Metallofullerene Gd@ C82 was synthesized via electric arc method and separated by two-step HPLC with 95% purity, and its derivative Gd@ C82 (OH)x was synthesized by the reaction of Gd@ C82 with NaOH catalyzed by tetrabutylammonium hydroxide(TBAH). The hydroxyl number of Gd@ C82 (OH)x was determined by XPS on its C1s spectrum and the compound was assigned as Gd@ C82(OH)16. The proton relaxivity and MRI photographs of Gd@ C82 (OH) 16 were evaluated in vitro and in vivo on a Bruker 4. 7T/30 cm Biospec magnetic resonance imaging scanner. Results show that Gd@C82(OH)16 has a high proton relaxivity in vitro, even higher than that of (NMG)2-Gd-DTPA, which is the most popularly used MRI contrast agent clinically. Compared to that of (NMG)2-Gd-DTPA, relaxitivity R1 of Gd@C82(OH)16 increased 3 times, relaxitivity R2 increased 7 times. In vivo experiments found Gd@ C82(OH)16 helped to generate high quality MRI photographs. The bio-distribution results indicate that Gd @ C82 (OH)16 tends to be entrapped in the liver and kidney and remained in these organs for about 2 hours. These results indicate that the metallofullerene derivative Gd@ C82 (OH) 16 might be the potential candidate as a new MRI contrast agent.