State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology , Mianyang 621010, China.
Department of Bone and Joint Surgery, Institute of Orthopedic Diseases, The First Affiliated Hospital, Jinan University , Guangzhou 510630, China.
ACS Appl Mater Interfaces. 2017 Dec 27;9(51):44356-44368. doi: 10.1021/acsami.7b16206. Epub 2017 Dec 14.
In the absence of external assistance, autogenous healing of bone fracture is difficult due to impaired regeneration ability under osteoporosis pathological conditions. In this study, a reduced graphene oxide/zinc silicate/calcium silicate (RGO/ZS/CS) conductive biocomposite with an optimal surface electroconductivity of 5625 S/m was prepared by a two-step spin-coating method. The presence of lamellar apatite nanocrystals on the surfaces of the biocomposite suggests that it has good in vitro biomineralization ability. The silicon and zinc released from the biocomposite induced a significant increase in the osteogenesis of mouse bone mesenchymal stem cells (mBMSCs). Furthermore, alkaline phosphatase activities were further promoted when 3 μA direct current was applied to stimulate the mBMSCs that were cultured on the RGO/ZS/CS surface. However, electrical stimulation failed to further upregulate the osteogenesis-related gene expression. Moreover, RGO/ZS/CS extracts were found to suppress the receptor activator of nuclear factor-κB ligand-induced osteoclastic differentiation of mouse leukemic monocyte macrophages (RAW264.7 cells). Although the zinc ions in the RGO/ZS/CS extracts showed an inhibitory role in human umbilical vein endothelial cell (HUVEC) proliferation, dilutions of the RGO/ZS/CS extracts (1/16, 1/32, and 1/64) promoted HUVEC proliferation, and their angiogenesis-related gene expression was also upregulated. On the basis of the results of the in vitro angiogenesis model, more interconnected tubes formed when the above dilutions of RGO/ZS/CS extracts were added to ECMatrix. The new RGO/ZS/CS electroconductive biocomposite has potential to be used for stimulating osteoporotic bone regeneration.
在缺乏外部辅助的情况下，由于骨质疏松病理条件下再生能力受损，骨骨折的自体愈合较为困难。在这项研究中，通过两步旋涂法制备了具有最佳表面电导率为 5625 S/m 的还原氧化石墨烯/硅酸锌/硅酸钙（RGO/ZS/CS）导电生物复合材料。生物复合材料表面存在层状磷灰石纳米晶体表明其具有良好的体外生物矿化能力。生物复合材料中释放的硅和锌诱导了小鼠骨髓间充质干细胞（mBMSCs）的成骨作用显著增加。此外，当施加 3 μA 直流电刺激在 RGO/ZS/CS 表面培养的 mBMSCs 时，碱性磷酸酶活性进一步得到促进。然而，电刺激未能进一步上调成骨相关基因的表达。此外，发现 RGO/ZS/CS 提取物可抑制核因子-κB 配体受体激活诱导的小鼠白血病单核巨噬细胞（RAW264.7 细胞）破骨细胞分化。虽然 RGO/ZS/CS 提取物中的锌离子对人脐静脉内皮细胞（HUVEC）增殖具有抑制作用，但 RGO/ZS/CS 提取物的稀释液（1/16、1/32 和 1/64）促进了 HUVEC 的增殖，其血管生成相关基因的表达也上调了。基于体外血管生成模型的结果，当将上述 RGO/ZS/CS 提取物稀释液添加到 ECMatrix 中时，会形成更多相互连接的管。新型 RGO/ZS/CS 导电生物复合材料具有刺激骨质疏松性骨再生的潜力。
