Study On Preparation And Properties Of The Regenerated Silk Fibroin Vascular Prosthesis

The vascular prosthesis with small caliber has been the important research project. It is important to solve the mechanical property and blood clotting problem of vascular prostheses with small calibers. In the paper, the regenerated silk fibroin (SF) and an epoxy material (PEG-DE) were cross-linked by freezing and air drying to coat the exterior and interior surface of silk tubular braid which is used as the smooth muscle to construct a novel vascular prosthesis (<6mm)with three layers by bionic techniques. The properties under conditions such as cross-linking ratio (SF:PEG-DE, w/w), SF concentration and freezing temperature were studied sufficiently. The cytotoxicity of vascular prosthesis,fibroblast cells and HUVECs growth on the interior surface of vascular prostheses were also studied.With the increasing of cross-linking ratio from1:0.2to1:1.5, the vascular prosthesis formed better and silk frbroin binding ratio raised. The vascular prosthesis formed best in the cross-linking ratio of1:1, when the silk fibroin molecules crossed sufficiently and the micropore distribution is even. With the stepping up of SF concentrition from3%to6%, vascular prostheses formed better, silk fibroin binding and wall thickness increased, while pore size decreased.The interior surface did not formed well when the SF concentrition is3%. When the freezing temperature descended form-20℃to-80℃, pore size and wall thickness raised. There is no function to silk fibroin binding. The outside diameter and inside diameter is4.4-4.7,3.0-3.2respectively.The wall thickness is less than lmm and the kinking diameter is5.8-6.7mm which showed good kinking property. The axial and radial breaking strength is more than90MPa and1000MPa, respectively. The axial and radial enlongation at break is more than84%,160%, respectively and have good compression elasticity. Results demonstrated that the vascular prosthesis had superior mechanical properties. The hot water dissolution is less than1%.Results by MTT and total counts of DNA analysis stated that vascular prosthesis material had no evident cytotoxicity. L929cells spreaded close and proliferated actively on the blend membranes.Results by the inverted fluorescence microscope (IFM), scanning electron microscope (SEM), laser confocal microscopy (LCM), MTT analysis showed that the adherency and proferation of L929cells could be supported excellently by silk fibroin vascular prostheses and the adherency and proferation of HUVECs also performed upstandingly on the interior surface after further study.