Permeability measured using the microfluidic system lacking or containing BECs and LECs.

No cells (x), BEC monolayer (yellow triangles), BEC-LEC coculture (blue diamonds), and BEC-BEC coculture (pink squares). The values are presented as means ± SD. The fluorescent tracers used were (a) TRITC-dextran and (b) Lucifer Yellow. The statistical significance of the differences between the values obtained at 60 min was evaluated using t tests: (a) P < 0.005, between No cells and BEC monolayer; P < 0.001, between BEC monolayer and BEC-LEC coculture; and P < 0.32, between BEC-LEC coculture and BEC-BEC coculture. (b) P < 0.001, between No cells and BEC monolayer; P < 0.001, between BEC monolayer and BEC-LEC coculture; and P < 0.45, between BEC-LEC coculture and BEC-BEC coculture. Each data point was obtained from three devices (n = 3).