The Fabrication Of Bilayer Vascular Grafts

Cardiovascular disease is a serious one of the diseases that affect human health.Patients with more serious vascular need replacement.The artificial large-diameter aortic vascular has achieved good effect,and has been successfully applied to clinic.Buttissue-engineered blood vessels were easily lead to blood clots and intimal hyperplasia for small diameter vascular lesions,and to use in clinicaldifficultly.Throughtissue engineering scaffolds were used by the electrospinning technique,with a high ratio surface area and porosity,connected network spaceinternally,conducive to cell adhesion and penetration,and the choice of materials to adjust the mechanical properties of grafts,so,it’s very suitable to constructethe small diameter artificial blood vessels.This paper has poly-caprolactone(PCL)and gelatin(GT)as the skeleton with good biocompatibility and good mechanical properties,and they blended water soluble materials polyoxyethylene(PEG)by co-electrospinning technology.lt build into a novel biodegradable double small vascular scaffoldwith good mechanics performance of rapid vascular endothelials.The following research achievements and progress has been made:1:Making the bilayer vascular scaffold by co-electrospinning with PCL/GT successfully.The bilayer vascular scalffold was constrituted of the density longitudinal alignedfibers inlayer and high porosity external layer.We collected the aligned fibers membrane by the home-made collector,then PCL/GT and PEG fibers formed the external layer with wapping outside the aligned fibers membrane by co-electrospining.We made the bilayer vascular scaffold immerse the PBS at 37℃ to remove the PEG fibers and forming the high porosity external layer.Final,the bilayer vascular scaffold was preparative include the density longitudinal alignedfibers inlayer and high porosity external layer.2:Conduct a comprehensive evaluation about mechanical properties and biocompatibility of artificial vascular scaffold.After the artificial vascular scaffold immerse the PBS,we made the tensile stress and strain experiment and mechanical performance parameters meet the requirements.We detected the blood compatibility of artificial vascular scaffold after heparinization.We cultured cells on the inlayer of the bilayer vascular scaffold,then detecting the cells vitality,extracting DNA to evaluate.We observed the cell proliferation,shape and distributioncultured on the inlayer of the bilayer vascular scaffold by SEM,then discuss the shape of cells by DAPI and H&E staining.3:Proving that histocompatibility and cells infiltration abilityof artificial vascular scaffold according to observe the morphology and the organization of subcutaneous implantation in rats.It illustractes that the vascular scaffolds have good biological morphology stability and biological compatibility after the four weeks,eight weeks and sixteen weeks in the subcutaneous of rat.The vascular scaffolds were cut into 7μm sections by freezing microtome and subjected to H&E and DAPI staining.The cells were distributed through the whole scaffoldsand a better endothelialization could be achieved.The bilayer vascular scaffolds were more favorable for cell migration and infiltration in vivo.Comprehensive the above experiments,the small double artificial vascular scaffold has good mechanical properties and biocompatibility.And the vascular scaffold can promote cell proliferation and vascularization quickly,meet the requirements of application in vivo,will have widely applied in clinical vascular transplantation.