Mangala Srinivas1, Houshang Amiri2, Fernando Bonetto3, Javier L. Cruz4, Eric van Dinther2, Jeanette Pots2, Arend Heerschap5, Carl Figdor1, Jolanda de Vries1
1Tumor Immunology, RUNMC, Nijmegen, Gelderland, Netherlands; 2Tumor Immunology, RUNMC, Netherlands; 3INTEC-CONICET, Argentina; 4Molecular Imaging, UMC Leiden, Leiden, Netherlands; 5Radiology, RUNMC, Nijmegen, Gelderland, Netherlands
Gadolinium has previously been used to enhance the relaxativity of perfluorocarbons for more efficient 19F MRI. However, the poor interaction between hydrophilic Gd chelates and hydrophobic perfluorocarbons is problematic. We overcome this issue using polymeric nanoparticles encapsulating both Gd chelates and perfluorocarbon, thereby forcing close interaction. These particles are synthesized using clinically-approved components, and are stable for at least 6 months. We demonstrate frequency and concentration dependence of the 19F longitudinal relaxation time. Finally, we show that labeling has minimal effect on cell function and viability when used to label primary human dendritic cells, as currently used in cancer vaccines.