Preparation And Functional Study Of HA/PEI Nanoparticle Composite Coating On Mg-Zn-Y-Nd Alloy Surface For Biodegradable Vascular Stent

Biodegradable magnesium alloy as a new generation of vascular stent material has attracted much attention.However,the problems of excessive degradability and lack of corresponding biological functions of magnesium alloys still need to be solved urgently.In order to solve the problems of magnesium alloy,HA/PEI nanoparticles were fixed on the surface of Mg-Zn-Y-Nd alloy after fluorination and dopamine deposition.The degradation and biological function of Mg-Zn-Y-Nd alloy were improved by preparing Mg F₂-PDA-HA/PEI nanoparticles composite coating.The main contents of this research are as follows:In this research,the average particle size,particle dispersion index?PDI?and zeta potential of HA/PEI nanoparticles were measured by dynamic light scattering?DLS?and screened.Finally,five kinds of HA/PEI nanoparticles with HA molecular weight of 4 k Da,HA concentration of 0.5,1.0,1.5,2.0,2.5 mg/m L,PEI molecular weight of10 k Da and PEI concentration of 0.5 mg/m L were selected for coating preparation,and the morphology of the five nanoparticles in solution was observed by transmission electron microscopy?TEM?.The samples of Mg-Zn-Y-Nd alloy treated by fluorination were labeled HF,the samples of dopamine deposition after fluorination were labeled HP,the samples of HA/PEI nanoparticles fixed on HP were labeled NP,and the samples of five kinds of HA concentrations were labeled NP0.5,NP1.0,NP1.5,NP2.0 and NP2.5 respectively.The samples were characterized by a series of material characterization methods such as scanning electron microscope?SEM?,Fourier transform infrared spectrometer?FTIR?,X-ray photoelectron spectroscopy?XPS?,water contact angle meter and three-dimensional topography meter.The results showed that HA/PEI nanoparticles were successfully fixed on the surface of HP,and NP had good wettability.The results of electrochemical test and immersion tests showed that the degradation resistance of NP group was better than that of Mg-Zn-Y-Nd alloy,and NP1.5 and NP2.5 were the best.The results of hemolysis rate test,platelet adhesion and activation tests,fibrinogen adhesion and denaturation tests showed that NP group effectively inhibited platelet adhesion and activation,significantly improved the blood compatibility of the samples,and NP2.5 showed best.The results of endothelial cell static culture experiment,smooth muscle cell static culture experiment and macrophage static culture experiment showed that NP group could promote the proliferation of endothelial cells and the release of functional factor?nitric oxide?,inhibit the proliferation of pathological smooth muscle cells and inhibit the adhesion of macrophages,which had the effects of promoting endothelium,anti-proliferation and anti-inflammatory,significantly improving the cell phase of the samples,and both NP1.5 and NP2.5 were the best.In conclusion,HA/PEI nanocomposite coating could achieve the effects of anti-degradation,anti-coagulation,anti-proliferation,anti-inflammatory and endothelium promoting,significantly improved the related properties of Mg-Zn-Y-Nd alloy,and NP1.5 and NP2.5 were selected to have the best comprehensive properties.