Research For The Establishment Of Anticoagulation/Endothelialization Inducing Multi-Biofunctional Microenvironment On Ti Surface With REDV Peptide-Heparin-VEGF

Cardiovascular disease especially coronary heart disease serious damage to human health.Currently,the most effective treatment to coronary heart disease is to implant stent in the lesion region.However,due to the intimal injury,late thrombosis and restenosis will follow.The best way to solve the problem would be the rapid endothelium of the stent.With the biotin-avidin system,this study would establish anticoagulation/induced endothelial multi-function microenvironment to realize the rapid endothelium on material surface.The system would introduce the anticoagulant molecule named biotinylated heparin(B-Hep),the specific adhesion molecule named polypeptide GREDVY(B-GREDVY)and the vascular endothelial growth factor(VEGF).Firstly,the negatively charged hydroxyl was introduced onto the Ti surface by alkali activation Then the avidin middle layer was fixed by electrostatic incorporation,and B-Hep and B-GREDVY were binded by the specific binding effect of biotin-avidin system(BAS).At least,VEGF was binded by the natural combination of heparin.AFM,WCA,XPS,Alcian Blue and MicroBCA results indicated that the alkali activate and the binding of avidin and B-Hep were successful.FITC fluorescent staining results indicated that peptide B-GREDVY was successfully fixed.B-Hep releasing result revealed that B-Hep released slightly and steadily,the microevironment was stable.VEGF releasing showed that the releasing of VEGF was also steadily.The total release amount after 21d was 0.89±0.54ng.Hemocompatibility evaluation results showed that the binding activity between B-Hep and ATIII was quite well.The B-Hep/B-GREDVY blending fixed sample surfaces showed good characteristics including anti-platelet adhesion,aggregation and activation.Simultaneously,this microenvironment could inhibite the adhesion and activation of fibrinogen(Fg),extend APTT to 10s,and inhibit the coagulation of whole blood.Cell compatibility evaluation results showed that the sample HR200 possessed optimal compatibility with ECs and EPCs and inhibited the growth of SMCs.This microenvironment would complete chemotaxis of EPCs and induced the migration and growth of ECs after introducing VEGF onto the HR200 sample surfaces.Mechanism study indicated that,the introduction,proportion and existence form of different biomolecule could effectively improve the compatibility of substrate,exert biofunctions and finally achieve the desired effect of microenvironment.Above all,this study successful completed the construction of multi-fuctional microenvironment for anticoagulation and induction of endothelial.This work provided a new way to realize rapid endothelialization.