Hypotonic Swelling: A Soft Route for ex vivo Cellular Labeling with Paramagnetic Complexes

Enza Di Gregorio¹, Giuseppe Ferrauto¹, Eliana Gianolio¹, Daniela Delli Castelli¹, Silvio Aime¹

Different strategies to label cells with paramagnetic MRI contrast agents have been exploited in the last years like pinocytosis, electroporation, receptor/transporter mediated endocytosis, external labeling. Herein we show that hypotonic swelling of cells is a new efficient route to label cells with paramagnetic Gd-complexes. In fact, the cytoplasmatic uptake shifts to much higher loadings the quenching effect on the relaxivity observed when the paramagnetic Gd-complexes are compartmentalized into endosomal vesicles.