Flow-cytometry analysis of extracellular markers and tube formation assay after incubation with uSPIONs (a) Flow-cytometry analysis of extracellular markers of HUVECs, HSVECs and ECs-HU after 24 and 48 h of incubation with uSPIONs. CTRL corresponds to cell population that was not incubated with uSPIONs. (n = 3 ± SEM). Statistical evaluation (t-test) showed no significant change in expression of endothelial markers between cell lines (p > 0.05). (b) Tube formation assay following 24 and 48 h of incubation with 10 µg/mL of uSPIONs and control (cells without incubation with uSPIONs). Abbreviations: HUVECs, human umbilical vein endothelial cells; HSVECs, human saphenous vein endothelial cells; ECs-HUs, endothelial cells differentiated from hiPSCs-HU; ECs-HS, endothelial cells differentiated from hiPSCs-HS; ECs-HF, endothelial cells differentiated from hiPSCs-HF.