Figure 3. Intracellular iron levels by MRI phantoms after SPIO and IgG-SPIO monocyte uptake.

Internalization kinetics of IgG-SPIO and SPIO at iron concentrations of 0.5 mg/ml were determined in human monocytes incubated at 37°C. (A) Estimation of the iron loading by ferrozine assay (top) and by measurement of the relaxation (R2) of iron-labeled monocytes (bottom).