| Cardiovascular disease is a disease with high morbidity and high mortality,which is a serious threat to human health.Currently,in the treatment of cardiovascular diseases,biomedical devices such as artificial blood vessels,artificial heart valves,and cardiovascular stents have been widely used.However,as a cardiovascular implant material for the treatment of coronary heart disease,the biocompatibility of materials still has serious problems.Therefore,bio-modification and surface functional modification of existing biomaterials are needed to improve the materials.Biocompatibility is essential.This paper constructs a polylysine(PLL)polyamidoamine-PAMAM mediated layer on the surface of titanium,and further mediates the formation of plasma albumin(BSA)and fibrinogen(Fg)on the surface of the material.Protein membranes to achieve bio-modification of materials.In this study,PLL was introduced into the surface of titanium material by thermal alkali activation and electrostatic adsorption,and then PAMAM terminal carboxyl group was activated by EDC/NHS carboxyl activator,and PAMAM and PLL were formed into a mediated layer by covalent immobilization.FTIR,Alcian blue staining,toluidine blue carboxyl quantification and acid orange amino quantification showed that PLL and PAMAM were successfully introduced and evenly distributed on the surface of the material;the results of the mediated layer stability test indicated that the covalently immobilized PLL/PAMAM mediated The layer has good bonding stability to the substrate.The results of UV-Vis spectrophotometer experiments show that PAMAM changes the microenvironment of amino acid residues in BSA and Fg,which changes the conformation of the protein.Fluorescence spectroscopy results show that BSA can spontaneously bind to PAMAM through hydrogen bonding and hydrophobic interaction,Fg It can spontaneously pass hydrogen bond,van der Waals force and PAMAM;the results of circular dichroism spectroscopy show that as the PAMAM concentration increases from 0μM to 50μM,theα-helix content in BSA conformation gradually decreases from 64.9%to 42.5%,α-helical conformation Partial conversion toβ-sheet and random coil,and PAMAM does not destroy the renaturation of BSA.Under simulated plasma environment conditions,the adsorption of protein on the surface of the mediator layer reduces the roughness of the surface of the material;the results of MicroBCA protein quantitative and water contact angle experiments show that the adsorption amount of BSA and Bg in competitive adsorption process is greater than Fg;The results of ATR-FTIR experiments showed that the conformation of protein adsorbed on the surface of the sample was affected by the concentration of PAMAM.The increase of PAMAM concentration led to the unfolding of BSA and the destruction of Fg conformation.The evaluation of platelet adhesion behavior in vitro showed that the immobilization of PAMAM on titanium surface did not lead to The increase in the number of platelet adhesions and activation,the number of adherent and activated platelets decreased significantly after the material adsorbed BSA;The results of semi-in vivo animal experiments showed that under the whole blood environment,the surface of the mediated layer formed by PAMAM concentration of 0.5 and 1 mg/ml had good blood compatibility,and the blood cell type adsorbed on the surface of the material might be white blood cells in peripheral blood,and In the competitive adsorption process of plasma proteins such as BSA,Fg and globulin,the adsorption of BSA plays a major role.In summary,based on the successful construction of PLL/PAMAM mediator layer,fluorescence spectroscopy experiments show that BSA and Fg can spontaneously bind to PAMAM,and the surface of the material after BSA adsorption has good anticoagulant effect.This study provides important data support for the construction of cardiovascular materials on the microenvironment. |
