Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; Division of Science for Joint Reconstruction, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan; Research Department, KYOCERA Medical Corporation, 3-3-31 Miyahara, Yodogawa-ku, Osaka 532-0003, Japan.
Division of Science for Joint Reconstruction, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan; Sensory & Motor System Medicine, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
Biomaterials. 2017 Jan;112:122-132. doi: 10.1016/j.biomaterials.2016.10.021. Epub 2016 Oct 11.
The surface and substrate of a cross-linked polyethylene (CLPE) liner are designed to achieve resistance against oxidative degradation in the construction of hip joint replacements. In this study, we aimed to evaluate the oxidative degradation caused by lipid absorption of a highly hydrophilic nanometer-scaled thickness layer prepared by grafting a poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) layer and a high-dose gamma-ray irradiated CLPE with vitamin E blending (HD-CLPE[VE]). The HD-CLPE(VE) and PMPC-grafted HD-CLPE(VE) exhibited extremely high oxidation resistance regardless of lipid absorption, even though residual-free radical levels were detectable. The water wettability of the PMPC-grafted CLPE and PMPC-grafted HD-CLPE(VE) surfaces was considerably greater than that of untreated surfaces. The hydrated PMPC-grafted layer also exhibited extremely low solubility for squalene. Lipids such as squalene and cholesterol esters diminished the oxidation resistance of CLPE despite the vitamin E improvement. Notably, the PMPC-grafted surface was resistant to lipid absorption and diffusion as well as subsequent lipid-related oxidative degradation, likely because of the presence of the hydrated PMPC-grafted layer. Together, these results provide preliminary evidence that the resistance against lipid absorption and diffusion of a hydrated PMPC-grafted layer might positively affect the extent of resistance to the in vivo oxidation of orthopedic implants.
交联聚乙烯（CLPE）衬里的表面和基底旨在抵抗髋关节置换构建中氧化降解，本研究旨在评估由高度亲水性纳米级厚度层的脂质吸收引起的氧化降解，该厚度层是通过接枝聚（2-甲基丙烯酰氧基乙基磷酸胆碱）（PMPC）层和高剂量γ射线辐照维生素 E 共混的 CLPE（HD-CLPE[VE]）制备的。即使检测到残留自由基水平，HD-CLPE（VE）和接枝 PMPC 的 HD-CLPE（VE）也表现出极高的抗氧化性，无论脂质吸收如何。接枝 CLPE 和接枝 PMPC 的 HD-CLPE（VE）表面的水润湿性明显大于未处理表面。水合 PMPC 接枝层对角鲨烯的溶解度也极低。尽管维生素 E 有所改善，但角鲨烯和胆固醇酯等脂质仍会降低 CLPE 的抗氧化性。值得注意的是，PMPC 接枝表面能够抵抗脂质吸收和扩散以及随后的脂质相关氧化降解，这可能是由于存在水合的 PMPC 接枝层。总之，这些结果初步表明，水合 PMPC 接枝层对脂质吸收和扩散的抵抗力可能会对骨科植入物体内氧化的抵抗力产生积极影响。
