Ishihara K, Fujita H, Yoneyama T, Iwasaki Y
Department of Materials Science, Graduate School of Engineering, The University of Tokyo, Japan.
J Biomater Sci Polym Ed. 2000;11(11):1183-95. doi: 10.1163/156856200744264.
To evaluate the antithrombogenicity of a new polymeric biomaterial in vivo, a polymer alloy tube composed of poly2-methacryloyloxyethyl phosphorylcholine(MPC)-co-2-ethylhexyl methacrylate polymer and a segmented polyurethane (SPU) was prepared by a solvent evaporation method on a Teflon rod from a homogeneous solution containing both the PMHE and SPU. The composition of the PMEH vs the SPU was 10 wt%. The inner and outer surfaces of the polymer alloy tubing were characterized by X-ray electron spectroscopic (XPS) measurements. The MPC units were located on the inner surface of the polymer alloy tubing rather than the outer surface. After immersion in aqueous media, a higher concentration of the MPC units was observed on both surfaces. Selective staining of the MPC units with osmium tetraoxide was carried out to observe the morphology of the PMEH domain on the surface of the polymer alloy. There were large-sized PMEH domains on the inner surface of the tubing but small-sized domains were found on the outer surface. This result was in good agreement with the XPS results. Blood compatibility of the polymer alloy was evaluated by observation of fibrinogen adsorption and platelet adhesion from human plasma. A lot of fibrinogen was adsorbed and many platelets adhered to the inner surface of the original SPU tubing. On the other hand, the PHEH/SPU polymer alloy tubing suppressed these adsorptions and adhesions. When the PMEH/SPU polymer alloy tubing was implanted into a rabbit's artery, thrombus could not be observed even after a 7-day implantation but the original SPU tubing was almost totally occluded only after a 90-min implantation due to serious thrombus deposition on the surface. These results clearly indicated that the PMEH in the SPU matrix acted as an antithrombus reagent by suppression of protein adsorption and platelet adhesion and activation. Particularly, the MPC units played a significant role in this function.
为了在体内评估一种新型高分子生物材料的抗血栓形成性，通过溶剂蒸发法在聚四氟乙烯棒上，由包含聚2-甲基丙烯酰氧基乙基磷酰胆碱(MPC)-co-2-乙基己基甲基丙烯酸酯聚合物和嵌段聚氨酯(SPU)的均相溶液制备了一种由PMEH聚合物和SPU组成的聚合物合金管。PMEH与SPU的组成为10 wt%。通过X射线电子能谱(XPS)测量对聚合物合金管的内表面和外表面进行了表征。MPC单元位于聚合物合金管的内表面而非外表面。浸入水性介质后，在两个表面上均观察到较高浓度的MPC单元。用四氧化锇对MPC单元进行选择性染色，以观察聚合物合金表面PMEH区域的形态。在管的内表面有大尺寸的PMEH区域，但在外表面发现的是小尺寸区域。该结果与XPS结果非常吻合。通过观察人血浆中纤维蛋白原的吸附和血小板的黏附来评估聚合物合金的血液相容性。大量纤维蛋白原被吸附，许多血小板黏附在原始SPU管的内表面。另一方面，PHEH/SPU聚合物合金管抑制了这些吸附和黏附。当将PMEH/SPU聚合物合金管植入兔动脉时，即使在植入7天后也未观察到血栓，但由于表面严重的血栓沉积，原始SPU管仅在植入90分钟后几乎完全堵塞。这些结果清楚地表明，SPU基质中的PMEH通过抑制蛋白质吸附以及血小板黏附与活化而起到抗血栓试剂的作用。特别是，MPC单元在该功能中发挥了重要作用。
