Study Of Phosphorylcholine Modified Polycarbonate Urethane For Resisting Platelet Adhesion

In order to improve the resistance of platelet adhesion on polycarbonate urethane(PCU) surface, we designed three different methods for PCU surface modification, thecompound containing phosphorylcholine (PC) group was grafted onto the PCUsurface.Firstly, we used the amino groups in the molecule of tris (2-aminoethyl) amine(TAEA) to react with the-NCO functional groups in order to introduce amino groupsonto PCU surface. The number of the surface amino groups was amplified due toTAEA.Subsequently,2-methacryloyloxyethyl phosphorylcholine (MPC) was graftedonto PCU surface via the Michael addition reaction between amino group and doublebond of MPC. And the grafting content of PC groups on PCU surface was increased.Secondly, we used glyceryl phosphorylcholine (GPC) instead of MPC, which wasmore economical and had been commercialized. PCU was treated by low-temperatureallylamine plasma in order to introduce the amino groups on PCU surface. Then, GPCwas oxidized into phosphorylcholine glyceryl aldehyde (PCGA). We used thereductive amination reaction between the amino group and the aldehyde group ofPCGA to graft PC functional groups onto PCU surface.Thirdly, polyethylene glycol methacrylate (PEGMA), which is a kind ofhydrophilic monomer, was grafted onto PCU surface via UV initiatedphotopolymerization, then PCGA molecules was grafted on the amino terminalgroups of PEGMA to form a composite structure. The synergistic effect of PEG andPC groups improved the resistance of platelet adhesion on PCU surface.The results of Fourier transform infrared spectroscopy (FTIR) and X-rayphotoelectron spectroscopy (XPS) shows that the PC groups were successfully graftedonto the PCU surface. The low water contact angle of modified PCU means that thehydrophilic PC functional groups improved the surface hydrophilicity significantly. Inaddition, platelet adhesion was evaluated by scanning electron microscopy (SEM)observation. Fewer platelets adhered to the modified PCU surface than to the blankPCU surface. Meanwhile, the adhered platelets kept a round shape, which mightindicate that the platelets had not been activated. The results shows that the PC functional groups modified PCU material could improve the resistance of plateletadhesion significantly.