Human vascular endothelial cell morphology and functional cytokine secretion influenced by different size of HA micro-pattern on titanium substrate

Abstract

Both coverage and morphology of endothelial cells (ECs) on blood contact biomaterials were involved in the antithrombotic and anti-proliferative process. However, most researches have been focused on the ECs amount on the materials surface, but not the morphology. As of now, little is known about the relationship between the ECs morphology and the cytokine secretion, especially those anticoagulant factors on cardiovascular implants. In this study, three sizes of parallel micro-stripes of high molecular weight hyaluronic acid (HMW-HA) were fabricated on the NaOH-treated titanium (TiOH) surface. These micro-patterns of ridges/grooves were used to regulate the distribution, morphology and cytokine secretion of the ECs. The roughness of bare Ti and TiOH was detected by AFM, and the micro-pattern sizes were imaged by SEM. The chemical bonding of HMW-HA to the TiOH surface was demonstrated by FTIR, and the element distribution was examined by EDX. The morphology index of the ECs was analyzed to evaluate the orientation, elongation and spreading of the ECs on the micro-patterned surfaces and the control, while the cell number and cytokine secretion of the ECs were measured by related kits. The characterization of the ECs demonstrated that the bigger L/B index improved NO, PGI2, Fn release and TM, TFPI, E-Selectin expression as well as reducing vWF secretion. The platelet adhesion test and the whole blood clotting time test proved the increasing anticoagulation property of ECs with their elongation increasing. These results suggest that ECs morphology-related function can be regulated by different sizes of micro-patterns.