Figure 5.

Different means to evaluate the BBB integrity. (A) TEER measurement in a BOC device, where copper electrode wiring is connected to the voltohmmeter via an electrode adapter [4]. (B) Immunofluorescence micrographs of the human brain endothelium cultured on-chip for 3 days, showing high expression levels of ZO-1, claudin-5, PECAM-1, GLUT-1, and P-glycoprotein (bar, 20 µm) [65]. (C) Electron micrograph of human brain microvascular endothelium after 3 days of culture in the BBB chip. The presence of well-formed tight junctions (top, pointed by arrows) and adherent junctions (bottom, indicated by arrows) are highlighted [65]. (D) Confocal fluorescence imaging of VE-cadherin for a portion of the endothelium after US exposure with the presence of MBs [21]. (E-i) Permeability of Texas Red dextran (40 kDa) from the vascular channel to the tissue compartment in the cell-free BOC after 5 min, 15 min, 30 min, 60 min. and 120 min from the start of flow in the vascular channel. (E-ii) Quantification of the normalized intensity of the dextran in the tissue compartment as shown in (E-i). The intensity increased linearly with time [74].