Surface Modification with Micropatterned Heparin/Poly-L-Lysine Nanoparticles to Direct Platelet and Endothelial Cell Behavior

Thrombus and restenosis after stent implantation continue to be problematic. Surface modification by incorporating functional molecules to improve the biocompatibility of vascular stent has been a hot-topic in recent study. To date, however, researchers have not yet found the right combination of surface physicochemical properties and architecture to meet clinical requirement. To investigate the influence of ordered structure and biofunction on platelets and vascular cells behavior, in this study, we construct three kinds of parallel heparin/poly-l-lysine nanoparticles grooves (25/25 μm, 50/50 μm and 100/100 μm) on dopamine-coated 316L stainless steel surface by using micro-contact printing method. Fourier transform infrared and scanning electron microscopy results demonstrated that the nanoparticles were successfully immobilized to dopamine-coated surface. Water contact angle and biomolecules quantitative characterization results suggested that three patterned groups were of similar hydrophilicity, as well as heparin and amine density. In vitro blood compatibility evaluation result indicated that surface patterned with nanoparticles may selectively prevent platelet adhesion. Besides, the patterned area was found to inhibit endothelial cell adhesion. However, when culture medium contains high concentration of heparin-binding proteins, the endothelial cell growth profile on patterned area was greatly improved.