Mogilireddy Vijetha, Déchamps-Olivier Isabelle, Alric Christophe, Laurent Gautier, Laurent Sophie, Vander Elst Luce, Muller Robert, Bazzi Rana, Roux Stéphane, Tillement Olivier, Chuburu Françoise
Institut de Chimie Moléculaire de Reims, CNRS UMR 7312, UFR des Sciences Exactes et Naturelles, Bâtiment 18, Europol'Agro, BP 1039, 51687, REIMS Cedex 2, France.
Laboratoire de Physico-Chimie des Matériaux Luminescents, UMR CNRS 5620, Université Claude Bernard Lyon 1, 69622, Villeurbanne Cedex, France.
Contrast Media Mol Imaging. 2015 May-Jun;10(3):179-87. doi: 10.1002/cmmi.1616. Epub 2014 Aug 8.
Gold nanoparticles coated by gadolinium (III) chelates (Au@DTDTPA) where DTDTPA is a dithiolated bisamide derivative of diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA), constituted contrast agents for both X-ray computed tomography and magnetic resonance imaging. In an MRI context, highly stable Gd(3+) complexes are needed for in vivo applications. Thus, knowledge of the thermodynamic stability and kinetic inertness of these chelates, when grafted onto gold nanoparticles, is crucial since bisamide DTPA chelates are usually less suited for Gd(3+) coordination than DTPA. Therefore, these parameters were evaluated by means of potentiometric titrations and relaxivity measurements. The results showed that, when the chelates were grafted onto the nanoparticle, not only their thermodynamic stability but also their kinetic inertness were improved. These positive effects were correlated to the chelate packing at the nanoparticle surface that stabilized the corresponding Gd(3+) complexes and greatly enhanced their kinetic inertness.
由钆（III）螯合物包覆的金纳米颗粒（Au@DTDTPA），其中DTDTPA是二乙烯三胺-N,N,N',N'',N''-五乙酸（DTPA）的二硫醇化双酰胺衍生物，构成了用于X射线计算机断层扫描和磁共振成像的造影剂。在磁共振成像的背景下，体内应用需要高度稳定的Gd(3+)配合物。因此，了解这些螯合物接枝到金纳米颗粒上时的热力学稳定性和动力学惰性至关重要，因为双酰胺DTPA螯合物通常比DTPA更不适合与Gd(3+)配位。因此，通过电位滴定和弛豫率测量对这些参数进行了评估。结果表明，当螯合物接枝到纳米颗粒上时，不仅其热力学稳定性得到提高，其动力学惰性也得到改善。这些积极作用与纳米颗粒表面的螯合物堆积有关，这种堆积稳定了相应的Gd(3+)配合物并大大增强了它们的动力学惰性。
