Department of Physics, School of Engineering, Brown University, Providence, RI 02912, USA.
Acta Biomater. 2011 Mar;7(3):1298-306. doi: 10.1016/j.actbio.2010.10.004. Epub 2010 Oct 21.
Hydroxyapatite (HA) has been widely used in the biomedical community, especially for orthopedic applications (such as reversing osteoporosis). In order to use HA as injectable nanoparticles that can be directed at will to various locations in the body to treat bone defects, HA was coated onto iron oxide nanoparticles in this study. Specifically, magnetite (Fe3O4) nanoparticles were synthesized and coated with HA. The resulting nanoparticles were treated hydrothermally to control the crystalline properties of the coating. Nanoparticles were characterized via transmission electron microscopy (TEM), dynamic light scattering, X-ray diffraction, Ζeta potential and vibrating sample magnetometry. Nanoparticle uptake by osteoblasts was studied using TEM. Osteoblast density was measured after 1, 3 and 5 days in the presence of Fe3O4 nanoparticles alone and HA-coated Fe3O4 magnetic nanoparticles. Long-term osteoblast experiments demonstrated greater alkaline phosphatase activity, total protein synthesis, collagen synthesis and calcium deposition after 7, 14 and 21 days in the presence of greater concentrations (up to 200 μg ml(-1)) of HA-coated iron oxide nanoparticles. In summary, the results of this study showed that HA-coated magnetic iron oxide nanoparticles should be further studied for various orthopedic applications in which such particles could be injected, their location controlled using an external magnetic source and bone growth promoted.
羟基磷灰石（HA）在生物医学领域得到了广泛的应用，特别是在骨科应用（如逆转骨质疏松症）。为了将 HA 用作可注射的纳米颗粒，使其能够随意定向到体内的各个部位以治疗骨缺损，本研究将 HA 涂覆到氧化铁纳米颗粒上。具体来说，合成了磁铁矿（Fe3O4）纳米颗粒并对其进行了 HA 涂层。然后对所得纳米颗粒进行水热处理以控制涂层的结晶性能。通过透射电子显微镜（TEM）、动态光散射、X 射线衍射、Ζeta 电位和振动样品磁强计对纳米颗粒进行了表征。使用 TEM 研究了成骨细胞对纳米颗粒的摄取。单独存在 Fe3O4 纳米颗粒和涂覆有 HA 的 Fe3O4 磁性纳米颗粒时，研究了细胞密度在 1、3 和 5 天的变化。长期成骨细胞实验表明，在存在更高浓度（高达 200μgml(-1)）的涂覆有 HA 的氧化铁纳米颗粒时，7、14 和 21 天后碱性磷酸酶活性、总蛋白合成、胶原合成和钙沉积增加。总之，这项研究的结果表明，HA 涂覆的磁性氧化铁纳米颗粒应该进一步研究用于各种骨科应用，在这些应用中可以注射这些颗粒，通过外部磁场控制其位置并促进骨生长。
