Preparation And Evaluation Of Dextran Sulfate Modified Electrospun Chitosan/PLCL Vascular Scaffold

In recent years,health of human has been threatened by a high incidence of cardiovascular diseases.patients with vascular diseases are treated by repairing and regenerating by vascular tissue.However,therapeutic methods are constrained by factors such as high cost of treatment.so artificial vascular grafts have become a new method to solve this problem.Nowadays,large-diameter artificial vascular grafts have been successfully applied,but there are still defects such as thrombosis and low patency in the application of small-diameter artificial vascular grafts.Therefore,the biomechanical properties and biocompatibility compatibility of small-diameter artificial vascular grafts need to be improved so that small-diameter artificial vascular grafts can be better applied.In this dissertation,a functional nanofiber tube scaffold with PLCL/SF shell and heparin as core layer was prepared by using coaxial electrospinning,which is used as the inner layer of the double-layer tube scaffold.PLCL/SF was prepared by conjugated electrospinning,which is used as the outer layer of double-layer tube scaffold.The double-layer tube scaffold combines the advantages of natural materials and synthetic materials,and the nanofibers of the shell-core structure can release heparin slowly,which can achieve long-term anticoagulant effects.And the mechanical properties,biocompatibility and other characteristics of the double-layer tube scaffold are investigated.The details are as follows:(1)Preparation of PLCL,PLCL/SF,PLCL/SF/Hep,PLCL/Hep Nanofiber Membrane,PLCL/SF Nanofilament Membrane and Single Electrospinning PLCL/SF,Single Conjugate PLCL/SF by Electrospinning Mechanical properties of single electrospinning PLCL,single conjugated PLCL,and double-layered PLCL/SF/Hep+PLCL/SF tube scaffold.The outer layer of double-layer PLCL/SF/Hep+ PLCL/SF tube scaffold is oriented around the axis.The nano-yarns have a large pore with a loose structure,so as to solve the problems that the diameter of the scaffolds prepared by ordinary electrospinning,which is small and hinders the penetration of cells into the scaffolds,and it is bad to regenerate three-dimensional tissues.The inner layer is a dense layer,and the nanofiber is a shell-core structure,which achieves the effect of slow-release heparin,and it can prevent burst release and play a role in anticoagulation for a long time.In addition,the PLCL/SF/Hep+PLCL/SF double-layer tube scaffold can simulate the composition and structure of the extracellular matrix of natural stents well.The PLCL/SF/Hep+PLCL/SF double layer tube scaffold has excellent hydrophilicity,which will facilitate cell adhesion,proliferation and migration.And the mechanical properties of the PLCL/SF/Hep+PLCL/SF double-layer tube scaffold are very good,which are similar to natural vascular scaffold.(2)In the blood compatibility test,The plasma recalcification test indicated that the double-layer PLCL/SF/Hep+PLCL/SF tube scaffold didn’t cause acute coagulation due to material.The platelet adhesion of the double-layer PLCL/SF/Hep+PLCL/SF tube scaffold was significantly more effective than that of the control group.In addition,HUVECs and HSMCs showed good adhesion,spreading and proliferation on the scaffold.HUVECs can form a cell layer in the scaffold,which is of great significance to achieve complete natural vascular scaffold.At the same time,the proliferation of HSMCs can promote angiogenesis and provide blood vessels with the elasticity required for contraction and relaxation.In addition,in the subcutaneous embedding experiment,the double-layer PLCL/SF/Hep+PLCL/SF tube scaffold facilitated cell ingrowth.(3)Through various tests,the inner layer of the PLCL/SF/Hep+PLCL/SF double-layer tube scaffold is helpful for endothelialization of the inner layer to achieve anticoagulant effect,and the outer layer of the the PLCL/SF/Hep+PLCL/SF double-layer tube scaffold was loose and aligned around the axis.Yarn is conducive to the proliferation and growth of smooth muscle cells,so that the mechanical properties of the tube scaffold should match the mechanical properties of natural tube scaffold match.In summary,the PLCL/SF/Hep+PLCL/SF double-layer tube scaffold had good application prospects in vascular stents...