Fig. 1

Cell uptake dynamics by optical microscopy. a Prussian blue staining and neutral red counterstaining of MCF-7 cells incubated for 24 h with 0.25 mg ml⁻¹ SPION (left) and control cells without nanoparticles (right). Bar 20 μm. b Time-lapse confocal microscopy. Four confocal images of a SPION-incubated MCF-7 cell at 5, 30, 60 and 180 min. Nucleus, blue (DAPI), acidic vesicles, red (LysoTracker Red) and SPION, white (back-scattering light). Bar 10 μm