Fig. 3

NVU on-a-chip expresses relevant BBB transporters and exhibits P-gp functionality. a RNA was isolated from 2D HBMEC cultures or HBMECs cultured in the NVU on-a-chip model. Graph shows mean Cq values for transporters GLUT-1, P-gp, BCRP1, MPR1, and TfR compared to housekeeping gene actin beta (ACTB). Each sample was measured in triplicate, with individual data points representing technical replicates of one biological replicate sample. b Expression of GLUT-1, P-gp, BCRP1, MRP1, and TfR in HBMECs cultured in the NVU on-a-chip model expressed as fold change compared to 2D cultured HBMECs. c Calcein-AM, a substrate of efflux transporter P-gp, was perfused through the lumen of the endothelial vessel and was taken up by the cells and converted to fluorescent calcein. P-gp’s ability to efflux calcein out of the cell was inhibited using cyclosporin-A or zosuquidar, resulting in an increase in intracellular fluorescence. n = 5–19 chips. Graphs show mean ± standard deviation. Statistical analysis was performed using one-way ANOVA; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001