| In recent years,vascular diseases have become one of the most important factors affecting human health.Endovascular stent is an important approach of treating vascular diseases such as atherosclerosis.However,inflammation and restenosis may occur at the implant position after stent implantation as a foreign body.Modification of the surface of the scaffold material,such as introducing functional molecules,ions etc,can improve the biocompatibility of the scaffold material.In fact,the surface modification of implant materials has been a research hotspot of this field.Zinc,as one of main essential element of the human body,has an important influence on the biological behavior of human tissues and cells.In order to regulate the biological behavior of vascular cells on the surface of materials,a zinc-loaded dopamine film material was studied in this paper.Since dopamine can undergo self-polymerization,and also contains some functional groups such as carboxyl and phenolic hydroxyl group,metal ions can be introduced into dopamine to form coordination bond.Based on the synergistic effect,zinc ions with some important physiological functions are introduced into the surface of 316L stainless steel(SS)in this thesis.Through the material characterization and biological assessment,the optimized zinc ion concentration and film process procedure were obtained,and the effects of zinc ion concentration and process on vascular cell behavior were also explored.First,a zinc-loaded dopamine film was constructed on the smooth surface of SS by introducing zinc ions using dopamine.After qualitative analysis of the hydrophobicity,morphology and composition of the film,the results show that the zinc ions have successfully combined with the surface of material;by quantitative analysis of the film thickness,total zinc ion quantity and release amount,it is shown that zinc ions can continuously and stably release don the surface of sample.The experiment of hemocompatibility and cytocompatibility evaluation of zinc-loaded dopamine film were done and the result showed that the zinc can promote the adhesion and activation of platelet,and fibrinogen degeneration when zinc ions concentration was below 1.295μg/cm~2.However,the function was opposite when zinc ions concentration was above 1.295μg/cm~2.At the same time,the introduction of zinc ions can also promote the adhesion and proliferation of endothelial cells,smooth muscle cells and stem cells.Through the stimulation of Astragalus and Astragalus oxidase,the results show that zinc ions have protective effects on endothelial cells,which can maintain cell morphology,and have a certain resistance to oxidative damage.Molecular biological evaluation ware also carried out and the QPCR gene results show that gene expression rate of zinc transporter family(Zn T-1),metallothionein(MT)and metal transcription factor(MTF-1)of endothelial cells was higher when zinc ions are stimulated for a longer period of time,and all three kind of gene results show that the sample Z-300 suppressed the gene expression while Z-3000 promoted;and the zinc transporter family(ZIP-1)was reversed.Western Blot protein test results showed that Zn T-1 and MT proteins were expressed less on endothelial cells.Animal experiments show that high concentration of zinc ion(Z-3000)can promote the growth of new tissue and new endothelial layer,and has a certain anti-oxidative damage ability.At the same time,Z-3000 can also maintain the contractile phenotype of smooth muscle cells and exhibit good biocompatibility.In summary,the dopamine film with different concentrations of zinc ions was successfully prepared on the surface of the material through the interaction between dopamine and zinc ions.The film prepared in the work can effectively promote the growth of vascular wall cells and increase the expression rate of genes such as Zn T-1,MT and MTF-1.Also,the property of film is stable and has certain anti-oxidative damage ability.This study has a catalytic effect on the surface modification of cardiovascular biomaterials. |
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