Preparation of Novel Biocompatible polymeric Additives and Modification of Biomedical Materials Using the Additives

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To improve the blood compatibility of a segmented polyurethane (SPU), 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer was blended in the SPU.The blended membranes composed of SPU and MPC polymers were prepared by a solvent evaporation method. Surface analysis of the SPU membrane blended with the MPC polymer (SPU/MPC polymer) revealed that the MPC polymer was concentrated at the surface of the SPU membrane which contacted the substrate compared with that which contacted air during the membrane formation period. The size of the domains of the MPC polymer became smaller but the number of the domains increased. The amount of the MPC polymer mexed with SPU affected the dispersion state. The mechanical properties of the SPU membrane, as determined by tensile stress-strain measurements, changed very little even after addition of the MPC polymers. Plasma proteins adsorbed on the SPU/MPC polymer membrane surface after contact with human plasma were detected by gold-colloid labeled immunoassay. Both albumin and fibrinogen were observed on the SPU membrane ; however, the amount of these proteins was reduced on the SPU/MPC polymer membrane. It was concluded that the blood compatibility of the SPU was effectively improved by the blending of the MPC polymer. The addition of MPC polymer in the SPU membrane dramatically reduced cell adhesion. It is concluded that the blending of the MPC polymer in the SPU membrane is an effective method to impart nonthrombogenicity. By using of this SPU/MPC polymer blend, small-diameter vascular prosthesis was prepared. The prosthesis indicated excellent performance compared with normal or original prosthesis, that is, during more than 8 months the SPU/MPC polymer blend prosthesis did not osculate even when the prosthesis was implanted into rabbit vain.