Figure 3: Uptake of SiO2 NP assessed by confocal imaging. Cells were treated with 15, 60 or 200 nm silica particles at 20 μg/mL for 2 h. Particles are depicted in green (Alexa 488) and nuclei are blue (Hoechst 33342).Uptake was analyzed in THP-1 macrophages, A549, NRK-52E and HaCaT cells.