Biomaterials that can harness the intrinsic osteogenic potential of stem cells offer a promising strategy to accelerate bone regeneration and repair. Previously, we had used methacrylated gelatin (GelMA)-based scaffolds to achieve bone formation from human mesenchymal stem cells (hMSCs). In this study, we aimed to further enhance hMSC osteogenesis by incorporating graphene oxide (GO)-based nanosheets into GelMA. In vitro results showed high viability and metabolic activities in hMSCs encapsulated in the newly developed nanocomposites. Incorporation of GO markedly increased mineralization within hMSC-laden constructs, which was further increased by replacing GO with silica-coated graphene oxide (SiGO). Mechanistic analysis revealed that the nanosheet enhanced the production, retention, and biological activity of endogenous bone morphogenetic proteins (BMPs), resulting in robust osteogenesis in the absence of exogenous osteoinductive growth factors. Specifically, the osteoinductive effect of the nanosheets was abolished by inhibiting the BMP signaling pathway with LDN-193189 treatment. The bone formation potential of the technology was further tested in vivo using a mouse subcutaneous implantation model, where hMSCs-laden GO/GelMA and SiGO/GelMA samples resulted in bone volumes 108 and 385 times larger, respectively, than the GelMA control group. Taken together, these results demonstrate the biological activity and mechanism of action of GO-based nanosheets in augmenting the osteogenic capability of hMSCs, and highlights the potential of leveraging nanomaterials such as GO and SiGO for bone tissue engineering applications.

可以利用干细胞内在成骨潜力的生物材料为加速骨再生和修复提供了一种有前途的策略。以前，我们使用基于甲基丙烯酸明胶 (GelMA) 的支架来实现人间充质干细胞 (hMSCs) 的骨形成。在这项研究中，我们旨在通过将基于氧化石墨烯(GO) 的纳米片结合到 GelMA 中来进一步增强 hMSC 成骨。体外结果表明，封装在新开发的纳米复合材料中的 hMSCs 具有高活力和代谢活性。加入 GO 显着增加矿化在载有 hMSC 的结构中，通过用二氧化硅涂层的氧化石墨烯 (SiGO) 代替 GO 进一步增加。机理分析表明，纳米片增强了内源性骨形态发生蛋白 (BMP) 的产生、保留和生物活性，从而在没有外源性骨诱导生长因子的情况下产生强大的骨生成。具体而言，通过LDN-193189 处理抑制 BMP 信号通路，可以消除纳米片的骨诱导作用。该技术的成骨潜力在体内使用小鼠皮下植入模型，其中载有 hMSCs 的 GO/GelMA 和 SiGO/GelMA 样本导致骨体积分别比 GelMA 对照组大 108 倍和 385 倍。总之，这些结果证明了 GO 基纳米片在增强 hMSCs 成骨能力方面的生物活性和作用机制，并突出了利用 GO 和 SiGO 等纳米材料在骨组织工程应用中的潜力。