Cancellous Bone-Like Sr-Doped Hydroxyapatite/Gelatin Porous Scaffolds With Nanofibrous Architecture and Ion Release for Promoting Osteogenesis

en This link goes to a English section zh This link goes to a Chinese section Constructing a porous scaffold with the essential features of natural cancellous bone, including structural architecture and biochemical cues, is one of the pivotal factors for effective bone regeneration. In this study, a biomimetic composite porous Gelatin fibrous scaffold (SrHA/Gelatin) incorporating ultralong strontium-doped hydroxyapatite nanofibers was fabricated via thermally induced phase separation and paraffin sphere leaching technologies. The porous scaffold exhibited an interconnected macroporous network with a fibrous framework. SrHA nanofibers incorporated into the scaffold created an extracellular matrix-like microenvironment although simultaneously providing excellent elasticity, mechanical resilience, and abundant sites for cell anchoring. Importantly, substitution of Ca 2+ by Sr 2+ in the hydroxyapatite (HA) crystal lattice accelerated nanofiber degradation and enabled the sustained release of Ca 2+ and Sr 2+ ions, thereby establishing a dynamic osteoinductive microenvironment. In vitro studies showed that the SrHA/Gelatin scaffold significantly enhanced adhesion, proliferation, and migration of bone marrow mesenchymal stem cells, as well as upregulated expression of the osteogenic gene compared with Gelatin and HA/Gelatin scaffolds. Furthermore, in vivo experiments revealed that the scaffold induced robust trabecular bone formation and defect bridging in rat calvarial defects, whereas only limited repair was observed in the control group. This study demonstrates that the SrHA/Gelatin porous scaffold integrates mechanical robustness, structural biomimicry, and dynamic ionic release, representing a promising candidate for bone defect repair. 摘要 en This link goes to a English section zh This link goes to a Chinese section 构建具备天然松质骨关键特征(结构和生化信号)的多孔支架,是实现有效骨再生的核心因素之一。本研究通过热诱导相分离与石蜡球浸出技术,制备了含超长锶掺杂羟基磷灰石纳米纤维的仿生复合明胶多孔纤维支架(SrHA/Gelatin)。该多孔支架呈现出互连大孔网络与纤维化骨架结构。复合于支架中的SrHA纳米纤维既模拟了细胞外基质微环境,又赋予了支架优异的弹性、机械回弹性及充足的细胞锚定位点。更重要的是,Sr 2+ 取代羟基磷灰石(HA)晶格中的Ca 2+ 不仅促进了纳米纤维的降解,也确保了Ca 2+ 和Sr 2+ 的持续释放,进而构建了动态成骨诱导微环境。相关体外实验表明,SrHA/Gelatin支架较Gelatin和HA/Gelatin支架能更显著促进骨髓间充质干细胞的黏附、增殖与迁移,并上调成骨相关基因的表达; 体内实验显示,该支架在大鼠颅骨缺损模型中可诱导大量骨小梁形成及广泛骨桥接,而对照组中仅可观察到有限的修复效果。本研究证实了所构建的集力学稳定性、结构仿生特性与动态离子释放功能于一身的SrHA/Gelatin多孔支架是一种极具应用前景的骨缺损修复材料。