Efficient Labeling of Multiple Cell Lines with a New SPIO Agent for Cell Tracking by MRI

Catherine Ramsay¹, Christiane Mallett¹, Paula Foster¹

The purpose of this study was to test a new commercially available SPIO which has a colloidal size of 50 nm, a zeta potential of +31 mV and which is cross-linked with a rhodamine B label. Here we show that a variety of cell lines (lymphocytes, cancer and stem cells) can be labeled with this agent (MoldayION Rhodamine B, BioPal Inc), by simple co-incubation, without the use of transfection agents, at a level that permits their detection by MRI and without affecting cell viability. This is illustrated using iron staining of cells, fluorescence microscopy, electron microscopy and cellular MRI.