Comparative Study Of Four Kinds Of Biomoleculars Modified Layers On Ti Surface

Coronary heart disease is a major threat to human beings health. One of the therapeutic methods should be coronary percutaneous coronary intervention. However, thrombosis formation and restenosis after artery stent implantation continue to be problematic. Because of desirable anticoagulation ability, endothelial cells are able to maintain coronary microenvironment balance. Thereby, the presence of a confluent endothelium layer on stent surface has become to be the most potential strategy. Numerous effective anticoagulation/induced endothelialization modified coatings on stent materials was used, including LBL, nanoparticles,co-immobilization and so on. However, among the methods, the comparative study was insufficient.In this work, four kinds of anticoagulation/induced endothelialization function modified coatings were chose. The influence of the ways of construction, adhesion proteins and functional factors on the biocompatibility of functional layer were investigated via physicochemical and biocompatibility experiments. Finally, the most potential layer was adopted.Comparative study indicated that construction means based on nanoparticles improved the exposed density and activity of heparin, which helped functional coatings play an excellent anticoagulant. However, it was proved that this functional layer was not an ideal layer with the platelets spreading motivated by dopamine and insufficient cytocompatibility in the subsequent experiment. At the same time, the construction way of biomolecules co-immobilized on negative charged surface could partly protect heparin density on surface and activity, which reduced platelet spreading while prolong activated partial thromboplastin time and accelerated cell proliferation. Hence, the construction way of biomolecules co-immobilized on negative charged surface was considered to be better one in this work.Biocompatibility evaluation in vitro results demonstrated that peptide REDV efficiently captured endothelial cells while inhibited platelet adhesion. However, because of the single function of peptide, this bio-functional coating mildly regulated the spread and proliferation behaviors of endothelial cells. The introduction of laminin into functional coating produced positive amino-rich surface, which maybe inhibitd endothelial cells initial spreading and proliferation. In contrast, fibronectin induced layer could facilitate endothelial cells adhesion, spread and proliferation. Therefore, it was consented that fibronectin was better in this article.The introduction of SDF-1α into functional layer slightly inhibited SMCs proliferation and promoted ECs proliferation and migration. Whereas, VEGF induced layer could maintain the inhibition of smooth muscle cells proliferation. However, it was more effective to promote the proliferation and migration of the endothelial cells. Consequently, VEGF functional factor was more remarkable and meaningfully in this work.In summary, the functional layer that co-immobilized adhesion protein fibronectin and VEGF factor on negative charged surface was the best one, which would provide a theoretical basis to further improvement and optimization.