Background: Natural clay nanomaterials are an emerging class of biomaterial with great potential for tissue engineering and regenerative medicine applications, most notably for osteogenesis.
Materials and Methods: Herein, for the first time, novel tissue engineering scaffolds were prepared by 3D bioprinter using nontoxic and bioactive natural attapulgite (ATP) nanorods as starting materials, with polyvinyl alcohol as binder, and then sintered to obtain final scaffolds. The microscopic morphology and structure of ATP particles and scaffolds were observed by transmission electron microscope and scanning electron microscope. In vitro biocompatibility and osteogenesis with osteogenic precursor cell (hBMSCs) were assayed using MTT method, Live/Dead cell staining, alizarin red staining and RT-PCR. In vivo bone regeneration was evaluated with micro-CT and histology analysis in rat cranium defect model.
Results: We successfully printed a novel porous nano-ATP scaffold designed with inner channels with a dimension of 500 μm and wall structures with a thickness of 330 μm. The porosity of current 3D-printed scaffolds ranges from 75% to 82% and the longitudinal compressive strength was up to 4.32± 0.52 MPa. We found firstly that nano-ATP scaffolds with excellent biocompatibility for hBMSCscould upregulate the expression of osteogenesis-related genes bmp2 and runx2 and calcium deposits in vitro. Interestingly, micro-CT and histology analysis revealed abundant newly formed bone was observed along the defect margin, even above and within the 3D bioprinted porous ATP scaffolds in a rat cranial defect model. Furthermore, histology analysis demonstrated that bone was formed directly following a process similar to membranous ossification without any intermediate cartilage formation and that many newly formed blood vessels are within the pores of 3D-printed scaffolds at four and eight weeks.
Conclusion: These results suggest that the 3D-printed porous nano-ATP scaffolds are promising candidates for bone tissue engineering by osteogenesis and angiogenesis.



中文翻译：

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一种具有良好骨再生性能的新型 3D 生物打印多孔纳米凹凸棒石支架

背景：天然粘土纳米材料是一类新兴的生物材料，在组织工程和再生医学应用方面具有巨大潜力，尤其是在成骨方面​​。
材料和方法：在此，首次以无毒且具有生物活性的天然凹凸棒土（ATP）纳米棒为起始材料，以聚乙烯醇为粘合剂，通过3D生物打印机制备新型组织工程支架，然后烧结得到最终支架。用透射电镜和扫描电镜观察ATP颗粒和支架的微观形貌和结构。使用 MTT 法、活/死细胞染色、茜素红染色和 RT-PCR 测定与成骨前体细胞 (hBMSCs) 的体外生物相容性和成骨。在大鼠颅骨缺损模型中通过显微 CT 和组织学分析评估体内骨再生。
结果：我们成功地打印了一种新型多孔纳米 ATP 支架，该支架设计有尺寸为 500 μm 的内部通道和厚度为 330 μm 的壁结构。目前 3D 打印支架的孔隙率范围为 75% 至 82%，纵向抗压强度高达 4.32±0.52 MPa。我们首先发现对hBMSC具有良好生物相容性的纳米ATP支架可以上调成骨相关基因bmp2和runx2的表达。和体外钙沉积。有趣的是，显微 CT 和组织学分析显示，沿缺损边缘观察到大量新形成的骨，甚至在大鼠颅缺损模型中的 3D 生物打印多孔 ATP 支架上方和内部。此外，组织学分析表明，骨骼是在类似于膜骨化的过程之后直接形成的，没有任何中间软骨形成，并且在 4 周和 8 周时，许多新形成的血管位于 3D 打印支架的孔内。
结论：这些结果表明，3D 打印的多孔纳米 ATP 支架是通过成骨和血管生成进行骨组织工程的有希望的候选者。