Cellular SPIO Nanoparticle Dosimetry. Measured in vitro target cell doses of SPIO nanoparticles in C10 (A, Left) and BMM (C, right) lung epithelial cells measured by magnetic particle detection. Cell associated SPIO nanoparticles in C10 epithelial cells (B, lower left) and BMM (D, lower right) after a 4 h exposure. Iron oxide particles are stained with prussian blue and cells are stained with nuclear fast red. Magnification, 20×.