加多(III) 复合物的形成与β-环极素连接体:对潜在的MRI对比剂的XAS研究
Farideh Jalilehvand1, Saba Homayonia2, Ping Zhang2
1Department of Chemistry, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada. faridehj@ucalgary.ca.
概括
宏循环环德素提供更安全的MRI对比剂. 一种新型的加多 (Gd(III)) 复合物与修饰的β-环氧素连接体显示出比临床药物更强的Gd-N结合,表明了改进MRI探针的潜力.
科学领域:
- 协调化学 协调化学
- 生物物理化学 生物物理化学
- 医学成像医学成像
背景情况:
- 基于加多的对比剂 (GBCA) 在磁共振成像 (MRI) 中至关重要.
- 目前正在探索宏循环环素 (CDs) 作为配体,用于开发更安全,更有效的GBCA.
- 之前的研究合成了一种基于β-环氧素的配体 (β-CD(A)) 能有效化Gd(III).
研究的目的:
- 为了研究Gd的局部协调结构 (III) 在1:1复合物中与水溶液中的β-CD (A) 连接体.
- 为了将Gd(III) 协调环境与临床使用的MRI对比剂Na[Gd(DOTA) ((H2O) ]进行比较.
- 评估新型基于环极素的复合物作为MRI对比剂的潜力.
主要方法:
- 扩展的X射线吸收细结构 (EXAFS) 谱学被用来探测Gd(III) 离子周围的局部结构.
- 最小方形曲线的拟合被用来分析EXAFS光谱.
- 将Gd (III) 综合体的协调环境与Na (Gd (DOTA) (H2O)) 的协调环境进行了比较.
主要成果:
- 在EXAFS分析中发现β-CD(A) 复合体中Gd(III) 的9坐标环境,有5个Gd-O键和4个Gd-N键.
- 发现Gd(III):β-CD(A) 复合体中的平均Gd-N键距离比临床使用的Na[Gd(DOTA) ((H2O) ]复合体要短.
- 这种较短的Gd-N距离表明Gd-N结合更强,对循环烯基基剂的复合物形成更稳定.
结论:
- 修改后的β-cyclopodextrin连接体与Gd(III形成了一个稳定的1:1复合体,呈现出类似于临床药物的9坐标结构.
- 与DOTA连接体相比,Gd(III):β-CD(A) 复合体中更强的Gd-N连接表明了增强的稳定性.
- 这些发现支持了这种新型基于环极素的复合物的潜力,作为一种更安全,更有效的MRI对比剂.
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