Easy preparation of an MRI contrast agent with high longitudinal relaxivity based on gadolinium ions-loaded graphene oxide†
As far as the longitudinal relaxivity (r1) is concerned, gadolinium ions (Gd3+)-based MRI contrast agents modified by traditional carriers do not appear to be far superior to the clinically used Magnevist. In this study, a type of MRI contrast agent (Gd3+@CGO) possessing a significantly high r1 value was easily prepared using a carboxyl-functionalized graphene oxide (CGO) as a nanocarrier to directly interact with GdCl3·6H2O. With 2.8 wt% of Gd3+ loaded on CGO, the prepared Gd3+@CGO shows good dispersibility in water and possesses r1 of 63.8 mM−1 S−1, which is 14 times higher than that of Magnevist. It is exciting to note that Gd3+ anchored on CGO remains stable at least for one year, probably relying on the electrostatic adsorption and physical encapsulation effect of CGO towards Gd3+.