*2.9. Cell Uptake Mechanism*

CT26WT cells were seeded into 24 wells at the concentration of 2 <sup>×</sup> <sup>10</sup><sup>5</sup> cells/well and cultured for 24 h. Two inhibitors, chlorpromazine and filipin, were selected to evaluate the bi-HNTs cell uptake mechanism. Chlorpromazine selectively inhibits clathrin-dependent endocytosis and filipin inhibits caveolae-dependent endocytosis. Cells were pre-cultured with CPZ (Sigma Aldrich, St. Louis, MO, USA) (7 μg/mL) or filipin (5 μg/mL) for 2 h. Cells treated without any inhibitor set as the control. bi-HNTs (25 μg/mL) were added to each well and incubated for another 24 h. Fluorescent intensities expressed by cells were measured as above.
