Fig. 4
Number-based cellular uptake of NPs in Neuro-2a cells as analyzed by SP-ICP-MS. Depicted are data for TiO2 NPs (a) and Ag NPs (b). The 48Ti and 107Ag isotopes were selected for Ti and Ag detection, respectively. Analysis was conducted using a quadrupole ICP mass spectrometer, operated in spike mode (1 min per run, dwell time of 3 ms per reading). The small TiO2 NPs cannot be detected by SP-ICP-MS because their size was below the limit of detection size (LODsize) of TiO2 (69 nm). #Calculated number of NPs per cell using ICP-MS (mass) data. &Calculated number of NPs per cell using ICP-MS (mass) data based on DLS size. (*) indicates a significant difference between two treatment groups as determined by student’s t-test (p < 0.05)