Fig. 4

Inhibition of cell uptake of Rubipy-SiO₂ NPs by endocytosis inhibitors. CaCo-2 cells were treated with the endocytosis inhibitors for 30 min, then exposed to 30 nm (a) and 80 nm (b) Rubipy-SiO₂ NPs either freshly added to cell medium (grey bars) or pre-incubated in the complete medium for 24 h (black bars). The cellular uptake of NPs was quantified after 3 h exposure by flow cytometry and calculated as a percentage of the cell uptake in absence of the inhibitors, evaluated in parallel. Statistical significance was assessed by a Student’s t test. *p < 0.05, treated cells compared to untreated cells