Preparation And Properties Of L-tyrosine Derivative/PVA/PEG Composite Membranes For Vascular Scaffold

Cardiovascular disease shows high incidence and mortality.Neither drug treatment nor surgery can effectively treat cardiovascular disease.Xenotransplantation and autotransplantation are also limited owing to source and immunogenicity.Therefore,tissue engineering and regenerative medicine are regarded as the most promising methods to solve cardiovascular diseases.Vascular tissue engineering scaffolds display many advantages in cardiovascular treatment.In vitro culture and transplantation of large-diameter(inner diameter>6mm)blood vessels have achieved better clinical evaluation,while the small-diameter(inner diameter<6mm)vascular tissue engineering scaffolds still have the problems of low long-term patency rate and easy restenosis.In view of the current problems of small-diameter vascular tissue engineering scaffolds,the L-tyrosine derivative/polyvinyl alcohol/polyethylene glycol(TEA/PVA/PEG)composite membranes were designed and fabricated.Meanwhile,the effect of PEG molecular weight on material properties was initially explored,and then the composite membrane with the optimal PEG molecular weight was selected.Finally,we further explore the effect of TEA content on material properties.At the same time,hemocompatibility and cell compatibility were investigated on materials with different TEA contents.The purpose is to explore the application prospect of the optimal ratio of TEA/PVA/PEG composite materials in the field of vascular tissue engineering.In this experiment,the structure and properties of the material were characterized by Fourier transform infrared spectroscopy(FT-IR),energy spectrum analysis(EDS),scanning electron microscope(SEM),X-ray diffractometer(XRD),contact angle measuring instrument,thermal analysis instrument and universal material testing machine.The specific work is as follows:(1)The composite membranes developed by PVA,TEA and PEG through intermolecular force were fabricated using the solution blending method.The properties and microstructure of TEA/PVA/PEG composite membranes with different molecular weights PEG were comparatively observed.The results show that TEA/PVA/PEG4000 possess favorable mechanical properties,hydrophilicity,water absorption and degradation rate.EDS displayed that TEA was distributed on the surface of materials in a large amount.TEA possessing positive charge,this will promote the proliferation and adhesion of endothelial cells,endothelize the surface of the material,and increase the anticoagulant properties of the material.(2)The TEA/PVA/PEG4000 composite system with the optimal PEG molecular weight was selected.The effect of TEA content on the microstructure and performance of the composite membrane was studied by changing the content of TEA in the system.The results showed that the contact angle of the materials decreased from 49.91° ± 2.31° to 33.41° ± 1.79° as the ratio of PEG4000 to TEA increased from1:0.5 to 1:2.EDS and SEM images results displayed that the content of TEA distributed on the surface of the material increased,which improved the structure regularity of materials.The water absorption and mechanical properties have been improved with increasing the TEA content.(3)The TEA/PVA/PEG4000 composite system with different TEA content was employed to characterize the cell compatibility and anticoagulant properties.The results showed that the increase of TEA content promoted the proliferation and adhesion of endothelial cells.The adhesion and activation of platelets was inhibited,indicating its high cell adhesion and low platelet adsorption.