Physical Properties And Tissue Compatibility Of Small-Diameter Polymer Vascular Graft Carrying Aspirin

Part one:Blood Compatibility of Polyurethane Modified by Silk FibroinObjective:To study the blood compatibility of PU modified by SF with different ratio.Methods:Blend films of SF powder and medical polyurethane(PU) were produced with different ratio.The influence on blood compatibility of PU modified by different ratio of SF was investigated by using hemolysis test,clotting time(CT),recalcification time (RT),PT,APTT.The blood compatibility of the blend films was compared with that of e-PTFE and rubber membrane.Results:The blood compatibility of rubber membrane was the worst,and that of e-PTFE and PU was better.Rational ratio of SF could further improve the anticoagulate potential of PU.Conclusion:At the optimal ratio of SF,the SF-PU mixture has the best blood compatibility.Part two:The Physical Properties of Polyurethane Modified by Silk Fibroin Carrying AspirinObjective:To investigate the major physical properties of PU modified with 50%SF after addition of aspirin.Methods:The wet method was used to prepare 3 different SF-PU(5:5) films carrying aspirin with doses of 0%,5%,10%respectively,and the SF-PU films carrying aspirin were investigated by using SEM,stretching test and IR spectrum. Results:The films prepared by wet method achieved better appearance,smoothness, stretching stress and initial modulus.Infrared test did not detect any new functional group. In terms of mechanical properties,except for the extension at break which was decreased with the increase of aspirin dose,the curve of the initial modulus,the breaking work and the breaking strength showed a "U" shape--decreases at first and increases afterwards.Conclusion:5%dose of aspirin can be mixed with SF-PU(5:5) films to prepare the biomaterial with better mechanical properties.Part three:The Tissue Compatibility of Polyurethane Modified by Silk Fibroin Carrying AspirinObjective:To investigate the tissue compatibility of PU modified by 50%SF after addition of aspirin.Methods:SF and PU were mixed with a ratio of 5 to 5 to prepare SF-PU(5:5) blend films and subsequently aspirin with doses of 0%,5%and 10%was added respectively.By using rat acute toxicity test,test of local reaction in muscle,tissue section staining, WBC and PLT count,and the TEM,the influence of different doses of aspirin on the tissue compatibility of SF-PU(5:5) was studied.Results:The blend film of SF-PU(5:5) had the better tissue compatibility than traditional e-PTFE.The effects of antiinflammation and antiplatelet aggregation of SF-PU (5:5) were improved after addition of different doses of aspirin,especially with the dose of 5%.But 10%aspirin exerted some side-effect.Conclusion:5%dose of aspirin can be mixed with SF-PU(5:5) films to prepare the biomaterial with better tissue compatibility than the traditional e-PTFE.