Fig. 1

NBTXR3 nanoparticles are internalized by different endocytosis pathways. Transmission electronic microscopy (TEM) representative images of NBTXR3 nanoparticles uptake by macropinocytosis and clathrin-mediated endocytosis in CT26.WT (upper panel), HT1080 (middle panel) and 42-MG-BA (lower panel) at 1 h, 3 h and 24 h after addition of 400 µM NBTXR3. The membrane invagination and lamellipodia observed indicate membrane perturbations typical of macropinocytosis. White arrow: membrane ruffles enclosing a small number of NBTXR3 nanoparticles; black arrow: internalized NBTXR3 nanoparticles cluster in early endosomes. Scale bar, 300 nm. Abbreviations: C, Clathrin; CTL, control cells (no NBTXR3); Cyt, cytoplasm; Nuc, nucleus