Fig. 4

Endocytosis and transport mechanism of GCA-NPs in Caco-2 cell monolayers. A 3D images of Caco-2 cells monolayers after incubated for Cou-6@GCA-NPs and Cou-6@NPs for 1 h. Cell nucleus were labeled with DAPI (blue), ASBT were stained with anti-SLC10A2 rabbit polyclonal antibody and labeled with Alexa Fluor® 647 labeled goat anti-rabbit secondary IgG (red). (scale bar: 25 μm, magnification: 630 ×). B Cellular uptake of Cou-6@GCA-NPs in monolayers after treated with GCA-NPs, NPs, GCA-NPs + M-β-CD (β-CD), GCA-NPs + chloroquine (Chloroquine), GCA-NPs + chlorpromazine (Chlorpromazine), GCA-NPs + monensin (Monensin), GCA-NPs + brefeldin A (brefeldin A), GCA-NPs + amiloride (Amirolide), GCA-NPs + TCA (TCA), GCA-NPs + verapamil (Verapamil). C Relative uptake ratio of Cou-6@GCA-NPs in monolayers. D Apparent permeability efficiency (Papp) of Taxol^®, PTX@GCA-NPs and PTX@NPs when penetrated through monolayers after 2 h. E Transwell model. F Transport ratio of Taxol^®, PTX@GCA-NPs and PTX@NPs in predetermined time points (30 min, 60 min, 90 min, 120 min) in the process of penetrating Caco-2 monolayers. G Relative transport ratio of GCA-NPs (control) after 2 h, when pretreated with various inhibitors including M-β-CD, chloroquine, chlorpromazine, monensin, brefeldin A, amiloride, TCA, verapamil. Data is presented as mean ± SEM, n = 3, ***P < 0.001, **P < 0.01, *P < 0.05