Department of Prosthodontics, Oral Bioengineering and Regenerative Medicine Lab, Shanghai Key Laboratory of Stomatology, Ninth People's Hospital Affiliated to Shanghai JiaoTong University, School of Medicine, Shanghai 200011, China,
Shanghai Engineering Research Center of Advanced Dental Technology and Materials, Shanghai 200011, China,
Int J Nanomedicine. 2019 Jan 18;14:733-751. doi: 10.2147/IJN.S187664. eCollection 2019.
Bone tissue engineering has become one of the most effective methods to treat bone defects. Silk fibroin (SF) is a natural protein with no physiological activities, which has features such as good biocompatibility and easy processing and causes minimal inflammatory reactions in the body. Scaffolds prepared by electrospinning SF can be used in bone tissue regeneration and repair. Graphene oxide (GO) is rich in functional groups, has good biocompatibility, and promotes osteogenic differentiation of stem cells, while bone morphogenetic protein-2 (BMP-2) polypeptide has an advantage in promoting osteogenesis induction. In this study, we attempted to graft BMP-2 polypeptide onto GO and then bonded the functionalized GO onto SF electrospun scaffolds through electrostatic interactions. The main purpose of this study was to further improve the biocompatibility of SF electrospun scaffolds, which could promote the osteogenic differentiation of bone marrow mesenchymal stem cells and the repair of bone tissue defects.
The successful synthesis of GO and functionalized GO was confirmed by transmission electron microscope, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Scanning electron microscopy, atomic force microscopy, mechanical test, and degradation experiment confirmed the preparation of SF electrospun scaffolds and the immobilization of GO on the fibers. In vitro experiment was used to verify the biocompatibility of the composite scaffolds, and in vivo experiment was used to prove the repairing ability of the composite scaffolds for bone defects.
We successfully fabricated the composite scaffolds, which enhanced biocompatibility, not only promoting cell adhesion and proliferation but also greatly enhancing in vitro osteogenic differentiation of bone marrow stromal cells using either an osteogenic or non-osteogenic medium. Furthermore, transplantation of the composite scaffolds significantly promoted in vivo bone formation in critical-sized calvarial bone defects.
These findings suggested that the incorporation of BMP-2 polypeptide-functionalized GO into chitosan-coated SF electrospun scaffolds was a viable strategy for fabricating excellent scaffolds that enhance the regeneration of bone defects.
骨组织工程已成为治疗骨缺损最有效的方法之一。丝素蛋白（SF）是一种无生理活性的天然蛋白质，具有良好的生物相容性和易于加工的特点，在体内引起的炎症反应最小。通过静电纺丝 SF 制备的支架可用于骨组织再生和修复。氧化石墨烯（GO）富含官能团，具有良好的生物相容性，可促进干细胞的成骨分化，而骨形态发生蛋白-2（BMP-2）多肽在促进成骨诱导方面具有优势。在这项研究中，我们试图将 BMP-2 多肽接枝到 GO 上，然后通过静电相互作用将功能化的 GO 键合到 SF 静电纺丝支架上。本研究的主要目的是进一步提高 SF 静电纺丝支架的生物相容性，促进骨髓间充质干细胞的成骨分化和骨组织缺损的修复。
通过透射电子显微镜、X 射线光电子能谱和热重分析证实了 GO 和功能化 GO 的成功合成。扫描电子显微镜、原子力显微镜、力学测试和降解实验证实了 SF 静电纺丝支架的制备和 GO 在纤维上的固定。体外实验验证了复合支架的生物相容性，体内实验证明了复合支架对骨缺损的修复能力。
我们成功制备了复合支架，不仅促进了细胞的黏附和增殖，而且大大增强了骨髓基质细胞在成骨或非成骨培养基中的体外成骨分化，从而增强了生物相容性。此外，复合支架的移植显著促进了临界尺寸颅骨骨缺损的体内骨形成。
这些发现表明，将 BMP-2 多肽功能化的 GO 掺入壳聚糖涂覆的 SF 静电纺丝支架中是制造增强骨缺损再生的优异支架的可行策略。
