Chang Wei-Jen, Pan Yu-Hwa, Tzeng Jy-Jiunn, Wu Ting-Lin, Fong Tsorng-Harn, Feng Sheng-Wei, Huang Haw-Ming
School of Dentistry, Taipei Medical University, Taipei, Taiwan.
Department of General Dentistry, Chang Gung Memorial Hospital, Taipei, Taiwan; Chang Gung University, Taoyuan, Taiwan.
PLoS One. 2015 Oct 14;10(10):e0140354. doi: 10.1371/journal.pone.0140354. eCollection 2015.
Nanosized iron oxide particles exhibit osteogenic and radiopaque properties. Thus, iron oxide (Fe3O4) nanoparticles were incorporated into a biodegradable polymer (poly-L-lactic acid, PLLA) to fabricate a composite bone screw. This multifunctional, 3D printable bone screw was detectable on X-ray examination. In this study, mechanical tests including three-point bending and ultimate tensile strength were conducted to evaluate the optimal ratio of iron oxide nanoparticles in the PLLA composite. Both injection molding and 3D printing techniques were used to fabricate the PLLA bone screws with and without the iron oxide nanoparticles. The fabricated screws were implanted into the femoral condyles of New Zealand White rabbits. Bone blocks containing the PLLA screws were resected 2 and 4 weeks after surgery. Histologic examination of the surrounding bone and the radiopacity of the iron-oxide-containing PLLA screws were evaluated. Our results indicated that addition of iron oxide nanoparticles at 30% significantly decreased the ultimate tensile stress properties of the PLLA screws. The screws with 20% iron oxide exhibited strong radiopacity compared to the screws fabricated without the iron oxide nanoparticles. Four weeks after surgery, the average bone volume of the iron oxide PLLA composite screws was significantly greater than that of PLLA screws without iron oxide. These findings suggested that biodegradable and X-ray detectable PLLA bone screws can be produced by incorporation of 20% iron oxide nanoparticles. Furthermore, these screws had significantly greater osteogenic capability than the PLLA screws without iron oxide.
纳米级氧化铁颗粒具有成骨和不透射线的特性。因此，将氧化铁（Fe3O4）纳米颗粒掺入可生物降解聚合物（聚-L-乳酸，PLLA）中以制造复合骨螺钉。这种多功能的3D可打印骨螺钉在X射线检查中可被检测到。在本研究中，进行了包括三点弯曲和极限拉伸强度在内的力学测试，以评估PLLA复合材料中氧化铁纳米颗粒的最佳比例。使用注塑成型和3D打印技术来制造含和不含氧化铁纳米颗粒的PLLA骨螺钉。将制造的螺钉植入新西兰白兔的股骨髁中。术后2周和4周切除含有PLLA螺钉的骨块。评估周围骨的组织学检查和含氧化铁的PLLA螺钉的不透射线性。我们的结果表明，添加30%的氧化铁纳米颗粒会显著降低PLLA螺钉的极限拉伸应力性能。与未添加氧化铁纳米颗粒制造的螺钉相比，含有20%氧化铁的螺钉表现出较强的不透射线性。术后4周，氧化铁PLLA复合螺钉的平均骨体积显著大于不含氧化铁的PLLA螺钉。这些发现表明，通过掺入20%的氧化铁纳米颗粒可以生产出可生物降解且能在X射线下检测到的PLLA骨螺钉。此外，这些螺钉的成骨能力明显强于不含氧化铁的PLLA螺钉。
