Directing vascular cell selectivity and hemocompatibility on patterned platforms featuring variable topographic geometry and size.

Abstract

It is great challenge to generate multifunctionality of vascular grafts and stents to enable vascular cell selectivity and improve hemocompatibility. Micro/nanopatterning of vascular implant surfaces for such multifunctionality is a direction to be explored. We developed a novel patterned platform featuring two typical geometries (groove and pillar) and six pattern sizes (0.5-50 μm) in a single substrate to evaluate the response of vascular cells and platelets. Our results indicate that targeted multifunctionality can be indeed instructed by rationally designed surface topography. The pillars nonselectively inhibited the growth of endothelial and smooth muscle cells. By contrast, the grooves displayed selective effects: in a size-dependent manner, the grooves enhanced endothelialization but inhibited the growth of smooth muscle cells. Moreover, our studies suggest that topographic cues can affect response of vascular cells by regulating focal adhesion and stress fiber development, which define cytoskeleton organization and cell shape. Notably, both the grooves and the pillars at 1 μm size drastically reduced platelet adhesion and activation. Taken together, these findings suggest that the topographic pattern featuring 1 μm grooves may be the optimal design of surface multifunctionality that favors vascular cell selectivity and improves hemocompatibility.