Study Of Surface Modification Of Electrospun Polyurethane For Potential Application As Small-diameter Vascular

With the development of tissue engineering, taking the unique advantage ofelectrospinning technology to fabricate the small-diameter blood vessels with bothappropriate mechanical properties and biocompatibility has become a research hotspot.In this paper, we fabricated polycarbonate urethane (PCU)3D vessel scaffolds byelectrospinning technology, then modified the scaffolds surface by polymeric graftingmodification approaches to improve its hemocompatibility for potential using assmall-diameter vessels. Firstly, we prepared PCU nanofibrous blood vessel scaffoldsby electrospinning technology. In order to improve the hydrophilicity of the fibrousscaffolds, hydrophilic poly (ethylene glycol) methacrylate (PEGMA) was grafted ontothe fiber surface by surface-initiated atom transfer radical polymerization (SI-ATRP)method. We controlled the length of the grafting segments by designing the addingamount of monomers, and discussed the effect of the length of grafting chains. Inorder to improve the hemocompatibility of PCU scaffold surface, glutaraldehyde wasused to cross-couple gelatin onto the surface. To enlarge the density of grafting chains,PEGMA chains were introduced as the first layer, because the hydroxyl sites of thePEGMA chains can be transfered to active sites for grafting gelatin.,and also the effectof the grafting density of gelatin was discussed.The modified scaffods were characterized by SEM, the hydrophilicity ofscaffolds surface was tested through water contact angle mesasurement, fouriertransform infrared spectrospcopy (FT-IR) and X-ray photoelectron spectroscopy (XPS)were used to characterize the surface chemical composition, the hemocompatibility ofthe scaffolds was studied by platelet adhesion test, hemolysis test and activated partialthromboplastin time test (APTT).The cyto-compatibility of the scaffolds was tested byculturing human umbilical vein endothelial cells (HUVECs) on the surfaces..The structure of the scaffolds was maintained very well during the process ofmodification. The hydrophilicity and hemocompatibility of PCU scaffolds wereimproved by the modification. The modified surface showed effective resistance ofplatelet adhesion compared with the unmodified surface. Hemolysis test showed thatthe grafting chains reduced blood coagulation, and the APTT of the modified surfacewas much longer. Furthermore, the modified surface showed high tendency to introduce cell adhesion, growth and proliferation. The cells reached out pseudopodiaalong the fibrous direction and formed a continuous monolayer. These resultsindicated that the modification electrospun nanofibrous scaffolds may be used asartificial blood vessels.