Department of Biomedical Science, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi 13488, Republic of Korea.
Department of Biological Science, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
Biomater Sci. 2020 Mar 31;8(7):2018-2030. doi: 10.1039/c9bm01863h.
Poly(l-lactic acid) (PLLA) is a biocompatible and biodegradable polymer that has received much attention as a biomedical material. However, PLLA also produces by-products that acidify the surrounding tissues during in vivo degradation, which induces inflammatory responses. To overcome these problems, magnesium hydroxide nanoparticles (nano-magnesium hydroxide; nMH) were added to the PLLA matrix as a bioactive filler that can suppress inflammatory responses by neutralizing the acidified environment caused by the degradation of PLLA. Despite the advantages of nMH, the strong cohesion of these nanoparticles toward each other makes it difficult to manufacture a polymer matrix containing homogeneous nanoparticles through thermal processing. Here, we prepared two types of surface-modified nMH with oligolactide (ODLLA) utilizing grafting to (GT) and grafting from (GF) strategies to improve the mechanical and biological characteristics of the organic-inorganic hybrid composite. The incorporation of surface-modified nMH not only enhanced mechanical properties, such as Young's modulus, but also improved homogeneity of magnesium hydroxide particles in the PLLA matrix due to the increase in interfacial interaction. Additionally, the PLLA composites with surface-modified nMH exhibited reduced bulk erosion during hydrolytic degradation with lower cytotoxicity and immunogenicity. Hemocompatibility tests on the PLLA composites with nMH showed a higher albumin to fibrinogen ratio (AFR) and a lower influence of platelet activation, when compared with unmodified control samples. Taken all together, the surface-modified nMH could be seen to successfully improve the physical and biological characteristics of polymer composites. We believe this technology has great potential for the development of hybrid nanocomposites for biomedical devices, including cardiovascular implants.
聚（L-丙交酯）（PLLA）是一种生物相容性和可生物降解的聚合物，作为生物医学材料受到了广泛关注。然而，PLLA 在体内降解过程中也会产生副产物，使周围组织酸化，从而引起炎症反应。为了克服这些问题，将纳米氢氧化镁（nano-magnesium hydroxide；nMH）添加到 PLLA 基质中作为生物活性填料，通过中和 PLLA 降解引起的酸化环境来抑制炎症反应。尽管 nMH 具有优势，但这些纳米粒子之间的强烈内聚力使得通过热加工制造含有均匀纳米粒子的聚合物基质变得困难。在这里，我们利用接枝到（GT）和接枝自（GF）策略，用低聚丙交酯（ODLLA）对两种类型的表面改性 nMH 进行了制备，以改善有机-无机杂化复合材料的机械和生物学特性。表面改性 nMH 的掺入不仅增强了机械性能，如杨氏模量，而且由于界面相互作用的增加，提高了氢氧化镁颗粒在 PLLA 基质中的均匀性。此外，表面改性 nMH 的 PLLA 复合材料在水解降解过程中表现出较低的体侵蚀，具有较低的细胞毒性和免疫原性。与未改性对照样品相比，对含有 nMH 的 PLLA 复合材料进行的血液相容性测试显示，白蛋白与纤维蛋白原的比率（AFR）更高，血小板活化的影响更低。综上所述，表面改性 nMH 可以成功改善聚合物复合材料的物理和生物学特性。我们相信这项技术对于开发用于心血管植入物等生物医学设备的混合纳米复合材料具有很大的潜力。
