Gd3N@C84(OH)x: A New Egg-Shaped Metallofullerene Magnetic Resonance Imaging Contrast Agent

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• 作者：Jianyuan Zhang ; Youqing Ye ; Ying Chen ; Christopher Pregot ; Tinghui Li ; Sharavanan Balasubramaniam ; David B. Hobart ; Yafen Zhang ; Sungsool Wi ; Richey M. Davis ; Louis A. Madsen ; John R. Morris ; Stephen M. LaConte ; Gordon T. Yee ; Harry C. Dorn
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：February 12, 2014
• 年：2014
• 卷：136
• 期：6
• 页码：2630-2636
• 全文大小：492K
• ISSN：1520-5126

文摘

Water-soluble derivatives of gadolinium-containing metallofullerenes have been considered to be excellent candidates for new magnetic resonance imaging (MRI) contrast agents because of their high relaxivity and characteristic encapsulation of the lanthanide ions (Gd³⁺), preventing their release into the bioenvironment. The trimetallic nitride template endohedral metallofullerenes (TNT EMFs) have further advantages of high stability, high relative yield, and encapsulation of three Gd³⁺ ions per molecule as illustrated by the previously reported nearly spherical, Gd₃N@I_h-C₈₀. In this study, we report the preparation and functionalization of a lower-symmetry EMF, Gd₃N@C_s-C₈₄, with a pentalene (fused pentagons) motif and an egg-shaped structure. The Gd₃N@C₈₄ derivative exhibits a higher ¹H MR relaxivity compared to that of the Gd₃N@C₈₀ derivative synthesized the same way, at low (0.47 T), medium (1.4 T), and high (9.4 T) magnetic fields. The Gd₃N@C_s-C₈₄ derivative exhibits a higher hydroxyl content and aggregate size, as confirmed by X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS) experiments, which could be the main reasons for the higher relaxivity.