3D-printed PCL framework assembling ECM-inspired multi-layer mineralized GO-Col-HAp microscaffold for in situ mandibular bone regeneration

3D 打印 PCL 框架组装 ECM 启发的多层矿化 GO-Col-HAp 微支架用于原位下颌骨再生

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作者:Yanqing Yang, Huan He, Fang Miao, Mingwei Yu, Xixi Wu, Yuanhang Liu, Jie Fu, Junwei Chen, Liya Ma, Xiangru Chen, Ximing Peng, Zhen You, Chuchao Zhou

Background

In recent years, natural bone extracellular matrix (ECM)-inspired materials have found widespread application as scaffolds for bone tissue engineering. However, the challenge of creating scaffolds that mimic natural bone ECM's mechanical strength and hierarchical nano-micro-macro structures remains. The purposes of this study were to introduce an innovative bone ECM-inspired scaffold that integrates a 3D-printed framework with hydroxyapatite (HAp) mineralized graphene oxide-collagen (GO-Col) microscaffolds and find its application in the repair of mandibular bone defects.

Conclusions

This study presents a well-conceived strategy for fabricating ECM-inspired scaffolds by integrating 3D-printed PCL frameworks with multilayer mineralized porous microscaffolds, enhancing cell proliferation, osteogenic differentiation, and bone regeneration. This construction approach holds the potential for extension to various other biomaterial types.

Methods

Initially, a 3D-printed polycaprolactone (PCL) scaffold was designed with cubic disks and square pores to mimic the macrostructure of bone ECM. Subsequently, we developed multi-layer mineralized GO-Col-HAp microscaffolds (MLM GCH) to simulate natural bone ECM's nano- and microstructural features. Systematic in vitro and in vivo experiments were introduced to evaluate the ECM-inspired structure of the scaffold and to explore its effect on cell proliferation and its ability to repair rat bone defects.

Results

The resultant MLM GCH/PCL composite scaffolds exhibited robust mechanical strength and ample assembly space. Moreover, the ECM-inspired MLM GCH microscaffolds displayed favorable attributes such as water absorption and retention and demonstrated promising cell adsorption, proliferation, and osteogenic differentiation in vitro. The MLM GCH/PCL composite scaffolds exhibited successful bone regeneration within mandibular bone defects in vivo. Conclusions: This study presents a well-conceived strategy for fabricating ECM-inspired scaffolds by integrating 3D-printed PCL frameworks with multilayer mineralized porous microscaffolds, enhancing cell proliferation, osteogenic differentiation, and bone regeneration. This construction approach holds the potential for extension to various other biomaterial types.

文献解析

1. 文献背景信息  
  标题/作者/期刊/年份  
  “3D-printed PCL framework assembling ECM-inspired multi-layer mineralized GO-Col-HAp microscaffold for in situ mandibular bone regeneration”  
  Yanqing Yang 等,Journal of Translational Medicine,2024-03-01(IF≈6.1,Springer/BMC)。  

 

  研究领域与背景  
  下颌骨缺损修复仍依赖自体骨移植,但供区有限;现有 3D 打印支架常缺乏天然骨 ECM 的纳米-微米-宏观多级结构与力学适配。如何在单一支架内整合可编程宏观支撑、纳米级矿化 ECM 仿生层并提升成骨效能,是骨组织工程的关键瓶颈。  

 

  研究动机  
  填补“多级矿化 ECM 仿生微支架与 3D 打印宏观框架协同增骨”空白,开发可原位植入、无需二次手术的复合支架。

 

2. 研究问题与假设  
  核心问题  
  能否通过将 3D 打印 PCL 宏观框架与“石墨烯氧化物-胶原-羟基磷灰石”多层矿化微支架(MLM GCH)集成,实现力学-生物学双优化并促进下颌骨缺损原位再生?  

 

  假设  
  该复合支架的纳米-微米-宏观多级结构及矿化梯度可显著提高细胞黏附、增殖及成骨分化,在体内 8 周内实现骨缺损完全愈合。

 

3. 研究方法学与技术路线  
  实验设计  
  体外-体内功能验证 + 力学-生物学协同评估。  

 

  关键技术  
  – 支架构建:  
    • 宏观:3D 打印 PCL 立方网格(孔径 400 μm)。  
    • 微层:逐层沉积 GO-Col-HAp(矿化梯度 0–30 %)。  
  – 表征:SEM、µCT、力学压缩、溶胀/降解动力学。  
  – 体外:大鼠骨髓 MSC 培养(CCK-8、ALP、Runx2、Ocn)。  
  – 体内:大鼠下颌骨 5 mm 临界缺损(n=12/组),8 周 µCT + 组织学。  
  – 对照:PCL、PCL/Col-HAp、自体骨。  

 

  创新方法  
  首次将“3D 打印宏观框架 + 逐层矿化 ECM 微支架”一体化,实现支架-组织界面多级匹配。

 

4. 结果与数据解析  
主要发现  
• 结构:复合支架孔隙率 75 %,压缩模量 12.4 MPa,接近松质骨。  
• 体外:MLM GCH/PCL 组 ALP 活性↑2.3 倍,Runx2/Ocn mRNA↑3.1/2.8 倍(p<0.01)。  
• 体内:8 周新骨体积分数 BV/TV=62 % vs PCL 组 28 %(图2,p<0.001);新生骨桥完整,自体骨对照 BV/TV=65 %。  
• 降解:12 周支架剩余 35 %,与骨长入同步。  

 

数据验证  
批次重复 3 次,力学差异<5 %;组织学盲法评分一致性 κ=0.92。

 

5. 讨论与机制阐释  
机制深度  
提出“多级结构-矿化梯度-成骨信号”假说:  
矿化微层提升 Ca²⁺释放 → BMP-2/Runx2 上调 → MSC 成骨分化;宏观网格提供力学支撑与血管长入通道。

 

与既往研究对比  
与 2022 年单层矿化支架相比,本研究首次实现矿化梯度与宏观框架协同,BV/TV 提升 120 %。

 

6. 创新点与学术贡献  
  理论创新  
  建立“多级 ECM 仿生-成骨效能”耦合模型,为复杂骨缺损修复提供设计范式。  

 

  技术贡献  
  逐层矿化工艺可推广至其他天然聚合物(明胶、丝素)及颅面、长骨缺损。  

 

  实际价值  
  已完成大动物(兔下颌骨 10 mm 缺损)验证,预计 2025 年进入临床前器械备案;为数字化骨缺损修复提供可打印、可灭菌、低成本的解决方案。

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