The treatment of bone tissue defects continues to be a complex medical issue. Recently, three-dimensional (3D)-printed scaffold technology for bone tissue engineering (BTE) has emerged as an important therapeutic approach for bone defect repair. Despite the potential of BTE scaffolds to contribute to long-term bone reconstruction, there are certain challenges associated with it including the impediment of bone growth within the scaffolds and vascular infiltration. These difficulties can be resolved by using scaffold structural modification strategies that can effectively guide bone regeneration. This study involved the preparation of biphasic calcium phosphate spherical hollow structural scaffolds (SHSS) with varying pore sizes using 3D printing (photopolymerized via digital light processing). The chemical compositions, microscopic morphologies, mechanical properties, biocompatibilities, osteogenic properties, and impact on repairing critical-sized bone defects of SHSS were assessed through characterization analyses, in vitro cytological assays, and in vivo biological experiments. The results revealed the biomimetic properties of SHSS and their favorable biocompatibility. The scaffolds stimulated cell adhesion, proliferation, differentiation, and migration and facilitated the expression of osteogenic genes and proteins, including Col-1, OCN, and OPN. Furthermore, they could effectively repair a critical-sized bone defect in a rabbit femoral condyle by establishing an osteogenic platform and guiding bone regeneration in the defect region. This innovative strategy presents a novel therapeutic approach for assessing critical-sized bone defects.

中文翻译：

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用于引导临界尺寸骨再生的三维打印球形空心结构支架

骨组织缺陷的治疗仍然是一个复杂的医学问题。最近，用于骨组织工程（BTE）的三维（3D）打印支架技术已成为骨缺损修复的重要治疗方法。尽管 BTE 支架具有促进长期骨重建的潜力，但仍存在一些与之相关的挑战，包括支架内骨生长的障碍和血管浸润。这些困难可以通过使用能够有效引导骨再生的支架结构修饰策略来解决。本研究涉及使用 3D 打印（通过数字光处理进行光聚合）制备不同孔径的双相磷酸钙球形中空结构支架 (SHSS)。通过表征分析、体外细胞学分析和体内生物学实验评估了SHSS的化学成分、微观形态、力学性能、生物相容性、成骨性能以及对修复临界尺寸骨缺损的影响。结果揭示了SHSS的仿生特性及其良好的生物相容性。该支架刺激细胞粘附、增殖、分化和迁移，并促进成骨基因和蛋白质（包括 Col-1、OCN 和 OPN）的表达。此外，他们通过建立成骨平台并引导缺损区域的骨再生，可以有效修复兔股骨髁中临界尺寸的骨缺损。这种创新策略提出了一种评估临界尺寸骨缺损的新颖治疗方法。