Platelet compatible blood filtration fabrics using a phosphorylcholine polymer having high surface mobility

To obtain a novel polymer for coating on blood filtration devices, which can reduce platelet adhesion and activation when the polymer is in contact with blood under a dry condition, a phosphorylcholine polymer with high mobility of the polymer side chain was designed. The polymer possesses 2-methacryloyloxyethoxyethyl phosphorylcholine unit (PMEO2B) having a diethylene oxide chain between the phosphorylcholine group and the backbone. The surface density of the phosphorylcholine groups and their orientation under aqueous conditions were analyzed with an X-ray photoelectron spectroscope. On the PMEO2B surface, the surface density of phosphorylcholine groups was much higher than that of the theoretical value even when the surface was in air atmosphere. The period for equilibrating the surface of PMEO2B by hydration was shorter than that of the 2-methacryloyloxyethyl phosphorylcholine polymer (PMB). The mobility of the polymer chain with hydration was remarkably improved with the addition of a diethylene oxide chain as a bridging unit. The platelet activation and adhesion were evaluated using a non-woven fabric made from poly(ethylene terephthalate) fibers and that coated with these phosphorylcholine polymers. Even when the platelets were passed through the PMEO2B-coated fabric without prehydration, the activity of the platelets eluted was similar to that of native platelets. Moreover, adherent cells were not observed on the fabric. On the other hand, the platelets adhered to the PET fabric and to that coated with PMB. Based on these results, we concluded that the higher mobility of the polymer chain is very important to reduce interactions with platelets.