Supramolecular aggregates of amphiphilic gadolinium complexes as blood pool MRI/MRA contrast agents:: Physicochemical characterization
Supramolecular aggregates of amphiphilic gadolinium complexes as blood pool MRI/MRA contrast agents:: Physicochemical characterization
复制标题
DOI：
10.1021/la053500k
复制
发表时间：
2006-07-18
期刊：
影响因子：
3.9
通讯作者：
Paduano, Luigi
中科院分区：
文献类型：
--
作者：
Vaccaro, Mauro;Accardo, Antonella;Paduano, Luigi
在本文中，我们介绍了一种新的潜在的血池造影剂的开发，该造影剂基于含有两亲性超分子聚集体的钆配合物，可用于磁共振成像（MRA/MRI）。合成了一种新型的两亲性一元聚合物，其包含DTPAGlu螯合剂共价结合在两个C18烷基链上。DTPAGlu是一种众所周知的多种离子螯合剂，如MRA/MRI中用作造影剂的顺磁性金属离子Gd3+。采用动态光散射、小角中子散射和低温透射电镜技术，对该表面活性剂作为游离碱和钆配合物的广泛聚集行为进行了研究和比较。在这两种情况下，接近中性的pH值，主要的聚集体是胶束。表面活性剂头群的高负电荷引起了强的头群斥力，促进了大而高曲率聚集体的形成。通过降低pH值和不太明显地增加离子强度，我们观察到由减少的静电斥力驱动的胶束到囊泡的转变。在不同聚集状态之间的直接切换在ph反应性MRA/MRI造影剂的开发中特别有用。
In this paper, we present the development of a new potential blood pool contrast agent for magnetic resonance imaging applications (MRA/MRI) based on gadolinium complexes containing amphiphilic supramolecular aggregates. A novel amphiphilic unimer, containing the DTPAGlu chelating agent covalently bound to two C18 alkylic chains, has been synthesized. DTPAGlu is a well-known chelating agent for a wide number of ions such as the paramagnetic metal ion Gd3+ used as contrast agent in MRA/MRI. The wide aggregation behavior of this surfactant, as free base or as gadolinium complex, has been studied and compared by means of dynamic light scattering, small-angle neutron scattering and cryogenic transmission electron microscopy techniques. Near neutral pH in both cases, the dominant aggregates are micelles. The high negative actual charge of the surfactant headgroup causes a strong headgroups repulsion, promoting the formation of large and high curvature aggregates. By decreasing pH and less markedly increasing the ionic strength, we observe a micelle-to-vesicle transition driven by a decreased electrostatic repulsion. A straightforward switch between different aggregation states can be particularly useful in the development of pH-responsive MRA/MRI contrast agents.