Influence of nanopatterns on endothelial cell adhesion: Enhanced cell retention under shear stress

In this study, nanopatterned crosslinked films of collagen Type I were seeded with human microvascular endothelial cells and tested for their suitability for vascular tissue engineering. Since the films will be rolled into tubes with concentric layers of collagen, nutrient transfer through the collagen films is quite crucial. Molecular diffusivity through the collagen films, cell viability, cell proliferation and cell retention following shear stress were studied. Cells were seeded onto linearly nanogrooved films (groove widths of 332.5, 500 and 650nm), with the grooves aligned in the direction of flow. The nanopatterns did not affect cell proliferation or initial cell alignment; however, they significantly affected cell retention under fluid flow. While cell retention on unpatterned films was 35+/-10%, it was 75+/-4% on 332.5nm patterned films and even higher, 91+/-5%, on 650nm patterned films. The films were found to have diffusion coefficients of ca. 10(-6)cm(2)s(-1) for O(2) and 4-acetaminophenol, which is comparable to that observed in natural tissues. This constitutes another positive asset of these films for consideration as a scaffold material for vascular tissue engineering.