Characterization of iron-oxide loaded adult stem cells for magnetic particle imaging in targeted cancer therapy

Recently, magnetic particle imaging (MPI) has been presented as a new method for the measurement of the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIONs). MPI is based on the nonlinear magnetization response of nanoparticles that are subjected to a sinusoidal magnetic field. Spatial resolution and signal to noise ratio of MPI depend on the particle quality. This is particularly important when stem cells shall be tracked with MPI. Stem cell-based treatment is an upcoming technology in targeted cancer-therapy. In this study, we analyzed the particle quality of newly developed dextran-coated SPIONs - with respect to their response in the imaging experiment - using magnetic particle spectrometry. The uptake of dextran-coated SPIONs into rat and human adult stem cells was monitored via transmission electron microscopy. Furthermore, adult stem cells were incubated with FITC-dextran-coated SPIONs and stained for confocal laser scanning microscopy. The dextran- and FITC-dextran coated SPIONs were localized in the cytoplasm of rat and human adult stem cells. MPI promises real-time imaging with high spatial resolution at high sensitivity. Our data support iron oxide loaded adult stem cells as a powerful tool for targeted cancer therapy.