(a). Expression of cell adhesion proteins in endothelial cells on day 7, normalized to day 1. Mouse specific primers were used to measure gene expression levels of claudin-5, ZO-1, and CD31 using RT-PCR. * p < 0.05. (b). Immunostaining of cell-cell junction proteins on day 14. Blue = nuclei. Red = human nuclear antigen. Green = claudin-5, ZO-1, or CD31. White dashed line = microchannel edge. Scale bar =100 μm. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)