For uptake experiments, RAW 264.7 cells were seeded in an Ibidi at a density of 3 × 10 4 cells/ well and incubated at 37° C for 24 h, to allow them to adhere to the slide surface. Incubation of cells with NDs (size 156 nm and 48 nm) was performed for 24 h at 37 °C in a humidified atmosphere with 5% CO2. At the end of the incubation, cells were washed three times with PBS and fixed in 4% PAF at room temperature for fifteen minutes.