Dynamics of T cells on endothelial layers aligned by nanostructured surfaces.

In this work, well-aligned endothelial cell (EC) layers were prepared by culturing ECs on surfaces containing nanoscale ridges/grooves fabricated by UV-assisted capillary force lithography. Then, the dynamics of T cells on well-aligned ECs were compared with that on randomly oriented ECs cultured on flat surfaces. With this experimental setting, we demonstrated for the first time that EC alignment is important for the regulation of transendothelial migration (TEM) of T cells, a critical step for leukocyte infiltration; T cells preferentially underwent TEM at the junctions surrounded by more than three ECs only if ECs surrounding those junctions were poorly aligned. As a result, TEM of T cells occurred more quickly and frequently on randomly oriented ECs cultured on flat surfaces than on well-aligned ECs cultured on nanostructured surfaces. This result will suggest a new strategy for the design of synthetic small diameter vascular grafts and extend our current knowledge of leukocyte dynamics on an inflamed endothelium.