Study On Surface Anticoagulant And Antibacterial Modification Of Medical Polyurethane Materials Via Ultraviolet Irradiation

As vascular catheter materials,to avoid complications in long-term use,good blood compatibility and antibacterial properties are quite necessary.Catheter related complications can not only increase the cost of treatments,aggravate patients’misery,but even endanger their health.Therefore,it is of great clinical significance to improve the anticoagulant and antibacterial properties of vascular catheter surface by modifying its surface.In this study,heparin and graphene oxide with photosensitive groups were prepared.After that,they were grafted on the surface of commonly used medical polyurethane catheter materials to obtain polyurethane catheters with anticoagulant and antibacterial properties.Several techniques were used in this study to test and analyze their properties.In the study of anticoagulation on the surface of vascular catheters,as a more spatial conformation can make a better anticoagulant effect,three kinds of azide-heparins Hep-2,Hep-6 and Hep-10 were synthesized with the azide groups content of 2.1wt‰,5.8wt‰,8.8wt‰.Through changing the concentrations of Hep-2,Hep-6,Hep-10,three groups of modified polyurethanes（PU-Hep-2,PU-Hep-6,PU-Hep-10）with almost same grafting density were finally obtained.The similar grafting density of these modified polyurethanes,around1.0μg/cm²,were confirmed by Water contact angle,Zeta potential and toluidine blue staining.The coagulation time（including PT,TT,APTT）and adsorption capacity to ATⅢfrom QCM of these three materials were consistent,both of the results showed PU-Hep-2>PU-Hep-6>PU-Hep-10,which indicated that the grafting heparin’s activity were affected by covalent bonds of heparins on polyurethane surface.In the end,APTT calibration curve of raw hepain was used to determine the activity of PU-Hep-2,PU-Hep-6,and PU-Hep-10,their activity was 36.9%,28.8%and 22.9%of primary heparin in turn.In the back part of this paper,we studied the effect of the surface modification of graphene oxide on the anticoagulant and antibackterial properties of polyurethane.First,we synthesized graphene oxide by improved hammer method.Second,azide-graphene oxide（G-N₃）were obtained through introducing the amine groups and the azide groups in turn.In the last,graphene oxide modified polyurethane（GPU）was prepared via UV irradiation.FTIR,Raman spectra,XPS and XRD tests showed GO,G-N₃ and GPU were prepared successfully.Follow-up work proved GPU has good hemocompatibility,no Cytotoxicity and better antibackretial properties.