Immobilization of polyphosphoesters on poly(ether ether ketone) (PEEK) for facilitating mineral coating
Immobilization of polyphosphoesters on poly(ether ether ketone) (PEEK) for facilitating mineral coating
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DOI：
10.1080/09205063.2019.1595305
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发表时间：
2019-07-03
影响因子：
3.6
通讯作者：
Iwasaki, Yasuhiko
中科院分区：
文献类型：
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作者：
Kunomura, Shun;Iwasaki, Yasuhiko
聚醚醚酮（PEEK）是骨科应用中金属的替代材料。然而，PEEK与硬组织的相容性需要改进。为了解决这个问题，本研究提出了一种新的PEEK表面改性技术。以2-羟丙基甲基丙烯酰胺为引发剂，通过环磷酸酯开环聚合得到聚磷酸三酯大分子单体，经脱甲基反应合成聚磷酸二酯大分子单体（PEPMANa）。在不使用任何光引发剂的情况下，通过PEPMANa的光引发和自引发接枝聚合对PEEK进行表面改性。由于固定在PEEK上的聚（PEPMANa）的磷的量随着光照射时间的增加而增加。由于聚（PEPMANa）接枝，PEEK表面变成亲水性的，具有几乎相似的前进和后退接触角，这意味着改性的PEEK表面（PEEK-g-聚（PEPMANa））是均匀的。通过在x1.5模拟体液（1.5SBF）中进行简单静态浸泡以及通过包括在200 mM CaCl 2水溶液中进行额外浸泡步骤的替代过程，对样本进行矿物涂层。和200 mM K2 HPO 4 aq.然后在1.5SBF中静态浸泡。将样本在1.5SBF中简单静态浸泡28天，之后PEEK-g-poly（PEPMANa）表面完全覆盖有类似磷酸八钙（OCP）的球形花椰菜状矿物沉积物。通过X射线衍射（XRD）、能量色散X射线光谱（EDS）和X射线荧光（XRF）分析证实了它们的结构相似性。然而，在裸露的PEEK表面上没有观察到这些矿物沉积物。由于在1.5SBF中静态浸泡样本之前进行了额外的浸泡步骤（交替浸泡），PEEK-g-poly（PEPMANa）上的矿物涂层显著加速，并且仅浸泡一天后表面就完全覆盖有矿物沉积物。两种浸泡过程产生的矿床具有相似的结构。与裸PEEK相比，成骨细胞MC 3 T3-E1在矿物涂层PEEK-g-poly（PEPMANa）上增殖更活跃。因此，聚（PEPMANa）在PEEK表面上的表面固定对于矿物涂层是有效的，并且可用于在PEEK上提供硬组织相容性。
Poly(ether ether ketone) (PEEK) is an alternative material to metals for orthopedic applications. However, the compatibility of PEEK with hard tissues needs to be improved. To address this issue, this study proposes a novel technique for PEEK surface modifications. A polyphosphodiester macromonomer (PEPMANa) was synthesized via the demethylation of polyphosphotriester macromonomer obtained via the ring-opening polymerization of cyclic phosphoesters using 2-hydroxypropyl methacrylamide as the initiator. The surface modification of PEEK was performed via photoinduced and self-initiated graft polymerization of PEPMANa without using any photoinitiators. The amount of phosphorus due to poly(PEPMANa) immobilized on PEEK increased with an increase in the photoirradiation time. The PEEK surface turned hydrophilic due to poly(PEPMANa) grafting, with almost similar advancing and receding contact angles, implying that the modified PEEK surface (PEEK-g-poly(PEPMANa)) was homogeneous. Specimens were mineral coated by simple static soaking in x1.5 simulated body fluid (1.5SBF) and by an alternative process that included additional soaking steps in 200mM CaCl2 aq. and 200mM K2HPO4 aq. before static soaking in 1.5SBF. Specimens were immersed in 1.5SBF for 28days in simple static soaking, after which the PEEK-g-poly(PEPMANa) surface was completely covered with spherical cauliflower-like mineral deposits that resembled octacalcium phosphate (OCP). Their structural similarities were confirmed via X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDS), and X-ray fluorescence (XRF) analyses. However, these mineral deposits were not observed on the bare PEEK surface. Due to the additional soaking steps (alternative soaking) undertaken before the static soaking of the specimens in 1.5SBF, the mineral coating on the PEEK-g-poly(PEPMANa) was dramatically accelerated and the surface was fully covered with mineral deposits in only one day of soaking. The mineral deposits resulting from both the soaking processes had similar structures. Compared with bare PEEK, osteoblastic MC3T3-E1 cells proliferated more actively on mineral-coated PEEK-g-poly(PEPMANa). Thus, the surface immobilization of poly(PEPMANa) on a PEEK surface is effective for mineral coating and may be useful to provide hard-tissue compatibility on PEEK.