It is still a challenge to optimize the component distribution and microporous structures in scaffolds for tailoring biodegradation (ion releasing) and enhancing bone defect repair within an expected time stage. Herein, the core–shell-typed nonstoichiometric wollastonite (4% and 10% Mg-doping calcium silicate; CSiMg4, CSiMg10) macroporous scaffolds with microporous shells (adding ∼10 μm PS microspheres into shell-layer slurry) were fabricated via 3D printing. The initial mechanical properties and bio-dissolution (ion releasing) in vitro, and osteogenic capacity in vivo of the bioceramic scaffolds were evaluated systematically. It was shown that endowing high-density micropores in the sparingly dissolvable CSiMg10 or dissolvable CSiMg4 shell layer inevitably led to nearly 30% reduction of compressive strength, but such micropores could readily tune the ion release behaviour of the scaffolds (CSiMg4@CSiMg10 vs. CSiMg4@CSiMg10-p; CSiMg10@CSiMg4 vs. CSiMg10@CSiMg4-p). Based on the in rabbit femoral bone defect repair model, the 3D μCT reconstruction and histological observation demonstrated that the CSiMg4@CSiMg10-p scaffolds displayed markedly higher osteogenic capability than the other scaffolds after 12 weeks of implantation. It demonstrated that core–shell bioceramic 3D printing technique can be developed to fabricate single-phase or biphasic bioactive ceramic scaffolds with accurately tailored filament biodegradation for promoting bone defect regeneration and repair in some specific pathological conditions.

中文翻译：

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调整 3D 打印生物陶瓷支架的细丝组成和微观结构促进骨缺损再生和修复

优化支架中的成分分布和微孔结构以在预期的时间阶段内定制生物降解（离子释放）和增强骨缺损修复仍然是一个挑战。在此，通过 3D 打印制造了具有微孔壳的核壳型非化学计量硅灰石（4% 和 10% Mg 掺杂的硅酸钙；CSiMg4，CSiMg10）大孔支架（在壳层浆料中添加~10 μm PS 微球）。系统评价了生物陶瓷支架的初始机械性能和体外生物溶解（离子释放）以及体内成骨能力。结果表明，在难溶 CSiMg10 或可溶 CSiMg4 壳层中赋予高密度微孔不可避免地导致抗压强度降低近 30%，但是这样的微孔可以很容易地调整支架的离子释放行为（CSiMg4@CSiMg10 vs. CSiMg4@CSiMg10-p；CSiMg10@CSiMg4 vs. CSiMg10@CSiMg4-p）。基于兔股骨缺损修复模型，3D μCT重建和组织学观察表明，在植入12周后，CSiMg4@CSiMg10-p支架的成骨能力明显高于其他支架。它证明了核壳生物陶瓷 3D 打印技术可以开发用于制造具有精确定制的细丝生物降解的单相或双相生物活性陶瓷支架，以促进某些特定病理条件下的骨缺损再生和修复。基于兔股骨缺损修复模型，3D μCT重建和组织学观察表明，在植入12周后，CSiMg4@CSiMg10-p支架的成骨能力明显高于其他支架。它证明了核壳生物陶瓷 3D 打印技术可以开发用于制造具有精确定制的细丝生物降解的单相或双相生物活性陶瓷支架，以促进某些特定病理条件下的骨缺损再生和修复。基于兔股骨缺损修复模型，3D μCT 重建和组织学观察表明，CSiMg4@CSiMg10-p 支架在植入 12 周后显示出明显高于其他支架的成骨能力。它证明了核壳生物陶瓷 3D 打印技术可以开发用于制造具有精确定制的细丝生物降解的单相或双相生物活性陶瓷支架，以促进某些特定病理条件下的骨缺损再生和修复。