Figure 2

Intracellular localization of SPIONs. Cells were incubated concomitantly with both SPIONs (γ-Fe₂O₃-PEI-FITC and γ-Fe₂O₃-PMA-Dy636) at a final concentration of 1 μg/ml [Fe] for time periods of 30 min, 1 h, 2 h, 4 h, 8 h, and 24 h. Cells were then stained with wheat germ agglutinin, for EEA1 and for LAMP-1 to visualize the Plasma Membrane (white), the Endosomes (yellow) and the Lysosomes (red), respectively. Fluorescence images were recorded with a LSM. Additionally, the same experiments were performed with cells incubated with each NP system (see Additional file 1).