Endosomal Escape of Gd-Agents Activated by External Photochemical Stimulus

Eliana Gianolio¹, Francesca Arena¹, Anders Hogset², Silvio Aime¹

The novel Photochemical internalisation (PCI) technology, that promotes the release of endocytosed molecules into cells cytosol, has been succesfully adapted to MRI applications in order to improve the efficiency of Gd-containing probes internalized by cells through pinocytotic mechanism. The release of endocytosed paramagnetic probes into the cytosol removes the relaxivity quenching produced by the entrapment of high concentrations of Gd-complexes into endosomes thus traducing in a great enhancement in signal intensity if compared with the case of endosomes compartimentalized agents.