Figure 4.

Intracellular distribution of nanoparticles. Prussian blue staining micrographs show abundant blue-stained particles in the cytoplasm around red-stained nucleus in cells labeled with ASP-SPIONs (a), while no such blue-stained particles are present in unlabeled cells (b), scale bar: 50 μm. Transmission election microscopy images show that numerous dense iron particles are present in the endosome (inserted magnified view) and cytosol of cells labeled with ASP-SPIONs (c), while no such iron particles are present in unlabeled cells (d), scale bar: 2 μm.