| As one of the most cardiovascular disease,coronary heart disease is seriously threat to human health.The most effective way is to implant stents in the damaged parts,which can open the blocked blood vessels.However,the restenosis and thrombosis form easily because of the hurt vessel wall during stents implantation.In order to slove this problem,biological functional building is the best choice,which can form endothelial layer quickly.The research has also been a hotspot in the field.In this study,poly-dopamine(DM)coating was deposited on the stainless steel(SS)surface,then grafting heparin-PLL nanoparticles loaded vascular endothelial growth factor(VEGF),to obtain a micro-environment with better anticoagulation and endothelialization.Then compared with the stromal cell derived factor(SDF-1α),exploring the different influence to blood and cells of two kinds of factors in heparin-PLL nanoparticles.DM can adhere to SS surface by auto polymerization and form a variety of active groups such as amino,phenolic hydroxyl and quinonyl.Heparin not only can interact with PLL via electrostatic bonding form nanoparticles,but also directionally link to VEGF and SDF-1α.The quinonyl of DM coating can bond with amino of PLL by Michael reaction and Schiff base reaction to graft the heparin-PLL nanoparticles.To evaluate the nanoparticles whether grafted successfully through water contact angle,amino quantitative,heparin quantitative and so on.The nanoparticles were distributed evenly on the surface through Alcian Blue.And the nanoparticles can release stably by heparin release results.The results of blood and cell compatibility evaluation in vitro showed that the samples with nanoparticles had better effect on inhibiting platelet adhesion and activation,at the same time promoting ECs proliferation and migration.According to the comprehensive contrast analysis,the heparin-PLL nanoparticles loaded VEGF concentration of 350ng/mL had good properties in anticoagulation and endothelialization.In optimal concentration,blood compatibility evaluation in vitro suggests that both NPV350 and NPS350 had better properties in platelet adhesion and activation compared with SS and DM.But VEGF had better effect than SDF-1α.At the same time,both NPV350 and PNS350 had continuous anticoagulation via dynamic simulation experiment in vitro.In optimal concentration,cell compatibility evaluation showed that NPV350 and NPS350 not only promoting ECs adhesion and proliferation,but also promote ECs proliferation persistently.From the EPCs evaluation suggests that SDF-1α had a better function in promoting EPCs adhesion,proliferation,chemotaxis and capture compared with VEGF.The two nanoparticles could inhabit SMCs proliferation,but NPS350 had a good effect on inhibiting SMCs hyperplasia with a long time.For the anti-inflammatory,VEGF and SDF-1α had an equal ability.In conclusion,the two factors of VEGF and SDF-1α had similar ability of promoting endothelialization and anti-inflammatory.VEGF had a better function in inhibiting SMCs hyperplasia,while SDF-1α had a better ability to promote ECs migrating and influence EPCs’ behaviour. |
