Block copolymer vesicles containing paramagnetic lanthanide complexes: a novel class of T-1- and CEST MRI contrast agents

Block copolymer vesicles containing paramagnetic lanthanide complexes represent a versatile class of MRI contrast agents. By exploiting the water flux across the membrane, these nanovesicles can be employed as T-1- and CEST MRI contrast agents. The incorporation of paramagnetic amphiphilic lipids (Gd-1 for T-1 MRI CAs agents and Tm-2 for CEST MRI CAs) into the polymeric bilayer markedly improves the properties of the MRI contrast agents with respect to the longitudinal relaxivity (22 mM(-1) s(-1) at 20 MHz) and the chemical shift of the intrapolymersomal water protons.