Improvement of hemocompatibility on a cellulose dialysis membrane with a novel biomedical polymer having a phospholipid polar group.

To improve surface hemocompatibility on cellulose hollow fibers for hemodialysis, newly designed hemocompatible polymers with a phospholipid polar group, 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers, were introduced on the surface through two different methods: direct grafting of MPC on the surface, or coating of a water-soluble cellulose grafted with MPC. The MPC was polymerized using cerium ion as an initiator in the cellulose hollow fibers, and the poly(MPC) chains were grafted directly on the surface. Another modification of the cellulose hollow fibers was attempted by coating them with a water-soluble graft copolymer composed of a poly(MPC) side chain and a cellulose backbone. The coating process from an aqueous solution of the graft copolymer was very convenient, and the graft copolymer on the surface was not detached even after water circulated into the hollow fibers. These cellulose hollow fibers modified with MPC polymers displayed excellent hemocompatibility such as prevention of blood cell adhesion and aggregation after contact with blood without an anticoagulant. The permeability of the hollow fibers did not decrease as a result of these modifications. From these results, it is clearly suggested that introduction of the MPC units was effective for improving the hemocompatibility of the hollow fibers for hemodialysis.