Preparation And Hirudin Modification Of Silk Fibroin Tubular Scaffold

The low long-term patency rate of small diameter artificial blood vessels is due tothrombosis and intima hyperplasia. Electrostatic spinning and gel spinning technology hasbeen used for preparation of silk fibroin small diameter artificial blood vessels, but themechanical properties and blood compatibility of silk fibroin artificial small blood vesselsstill need to be improved. Silk fibroin and fiber were used to build a biomimetic tubularscaffold, simulation the natural blood vessels tissue structure of three layers. Weresearched the influence of crosslinking ratio (SF: PEG-DE, w/w), SF concentration andfreezing temperature on the structure and mechanical properties of tubular scaffold. Wealso study on the structure, mechanical property, cell compatibility the anticoagulation ofhirudin modified silk fibroin materials.PEG-DE crosslinked silk fibroin material has good water stability, PEG-DEcrosslinking reaction efficiency is about30%. The internal diameter of tubular scaffoldsbecame smaller with the increasing of silk fibroin concentration and the decreasing offreezing temperature. The internal diameter of tubular scaffolds prepared in differentconditions was about50-300μm. Among all tubular scaffolds prepared in differentconditions, the tubular scaffold prepared in the condition of SF8%,40℃is the best onewith good aperture size and feel good. FTIR and XRD results show that PEG-DE inducedthe silk fibroin molecules from the random coil to β-sheet, compare with the freeze dryingsilk fibroin the crystallinity of PEG-DE crosslinked silk fibroin materials increased. Thesilk fibroin tubular scaffolds (SFTS) have good tensile and elastic recovery properties, theaxial tensile strength of SFTS was about0.53-0.76MPa, elongation was about52.5-73.8%,the radial breaking strength and elongation were about12-21MPa and345-398%,respectively. The elastic recovery rate of SFTS is around90%, suture strength was around20N can meet the clinical needs.We prepared the hirudin modified silk fibroin films and tubular scaffolds. Leaching solution method is used to evaluate the cytotoxicity of hirudin modified silk fibroin tubularscaffolds. MTT results showed that the hirudin modified silk fibroin materials have noobvious cytotoxicity. The SEM、DNA content test and CLSM results showed that thehirudin modified silk fibroin materials can support the adhesion and proliferation of L929and HUVEC cells. HAVSM also an be adhesion and proliferation on hirudin modified silkfibroin, but in the SF: Hir=10000:6materials, HAVSM cellular DNA content is lowerthan other materials, shows that along with the increase of hirudin, caused a degree ofinhibition on the HAVSM cell proliferation. According to the results of activated partialthrombin time (APTT), prothrombin time (PT) and thrombin time (TT), theantithrombogenicity of hirudin modified silk fibroin tubular scaffolds were better thanunmodified silk fibroin materials.