Sander Langereis

Dendrimers and magnetic resonance imaging

The multivalent character of dendrimers has positioned these well-defined, highly branched macromolecules at the forefront in the development of new contrast agents for biomedical magnetic resonance imaging (MRI). By modifying the periphery of the dendrimer with gadolinium(III) chelates, the relaxivity of the resulting MRI contrast agent is increased considerably, compared to low molecular weight Gd(III) chelates. The monodisperse character of dendrimers creates a unique opportunity to introduce dendritic MRI contrast agents into clinics. In addition, a prolonged vascular retention time is obtained due to the larger size of the dendritic molecules. By using dendrimers as multivalent scaffolds carrying multiple ligands, the interaction between ligand and marker can be enhanced through multivalent interactions. Current research focuses on the combination of multivalent targeting and enhanced relaxivity. This paper describes the application of dendrimers in biomedical MRI.

A supramolecular approach to multivalent target-specific MRI contrast agents for angiogenesis

The synthesis of a cyclic peptide-Gd(III)DTPA molecule equipped with biotin is presented, yielding a well-defined multivalent MRI contrast agent after its coupling to avidin.

Probing the interaction of the biotin?avidin complex with the relaxivity of biotinylated Gd-DTPAElectronic supplementary information (ESI) available: further results and experimental details. See http://www.rsc.org/suppdata/ob/b4/b402917h/

A biotinylated Gd-DTPA complex is designed to study the biotin-avidin complexation using the longitudinal relaxivity of this new MRI label, which illustrates the use of MRI contrast agents to probe the formation of supramolecular assemblies in water.