With the development of high magnetic field strength in magnetic resonance imaging (MRI), there is a demand to develop MRI contrast agents to attain high relaxation effects. Compared to typical T₁ agents, the transverse relaxation rate of T₂-based contrast agents increases with increasing magnetic field strength. However, better contrast agents are needed to improve the signal-to-noise issue. Here, a series of T_2ex contrast agents composed of an Au nanoparticle (NP) and a dysprosium complex (AuNP-DyDOTA(amide)_x) were designed. The transverse relaxivity of three molecules bearing different side arm chains were investigated. After screening by NMR signals, the transverse relaxivity of AuNP-DyDOTA(amide)₂ achieved 22.9 mM^–1 s^–1 at 9.4 T, which is higher than dysprosium-based small molecules. The in vivo results demonstrate that the AuNP-DyDOTA(amide)₂ is very efficient for specific accumulation in tumor regions and rapid metabolization was realized, making them promising for ultrahigh field strength imaging and clinical diagnosis in the future.

中文翻译：

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T修饰的金纳米粒子作为磁共振成像的T _2ex造影剂

随着磁共振成像（MRI）中高磁场强度的发展，需要开发MRI造影剂以获得高松弛效果。与典型的T ₁试剂相比，基于T ₂的造影剂的横向弛豫速率随磁场强度的增加而增加。但是，需要更好的造影剂来改善信噪比问题。在此，一连串的Ť _2EX的Au纳米颗粒（NP）和镝复合物（的AuNP-DyDOTA（酰胺）组成的造影剂_X）的设计。研究了带有不同侧臂链的三个分子的横向弛豫性。通过NMR信号筛选后，AuNP-DyDOTA（酰胺）₂在9.4 T时的横向弛豫度达到22.9 mM ^–1 s ^–1，高于基小分子。该体内结果证明的AuNP-DyDOTA（酰胺）₂是用于肿瘤区域和快速代谢特异性蓄积非常高效的实现了，使它们有前途的超高场强成像和临床诊断中的未来。