Abstract The use of composite materials, processed as 3D tissue-like scaffolds, has been widely investigated as a promising strategy for bone tissue engineering applications. Also, additive manufacturing technologies such as fused deposition modelling (FDM) have greatly contributed to the manufacture of patient-specific scaffolds with predefined pore structures and intricate geometries. However, conventional FDM techniques require the use of materials exclusively in the form of filaments, which in order to produce composite scaffolds lead to additional costs for the fabrication of precursor filaments as well as multi-step production methods. In this study, we propose the use of an advantageous extrusion-based printing technology, which provides the opportunity to easily co-print biomaterials, starting from their raw forms, and by using a single-step manufacturing and solvent-free process. Poly(e-caprolactone) (PCL), an FDA approved biodegradable material, was used as polymeric matrix while hydroxyapatite (HA) and strontium substituted HA (SrHA), at various contents were introduced as a bioactive reinforcing phase capable of mimicking the mineral phase of natural bone. Three different architectures for each material formulation were designed, and subsequently the effect of composition variations and structural designs was analysed in terms of physico-chemical, mechanical and biological performance. A correlation between architecture and compressive modulus, regardless the formulation tested, was observed demonstrating how the laydown pattern influences the resulting 3D printed scaffolds’ stiffness. Furthermore, in vitro cell culture by using TERT Human Mesenchymal Stromal Cells (hTERT-MSCs) revealed that Sr-containing composite scaffolds showed greater levels of mineralisation and osteogenic potential in comparison to bare PCL and pure HA.

中文翻译：

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3D 打印含 Sr 复合支架：结构设计和材料配方对骨组织工程新策略的影响

摘要 复合材料的使用，加工成 3D 组织样支架，已被广泛研究作为骨组织工程应用的一种有前途的策略。此外，诸如熔融沉积建模 (FDM) 之类的增材制造技术极大地促进了具有预定义孔隙结构和复杂几何形状的患者特定支架的制造。然而，传统的 FDM 技术需要使用仅呈长丝形式的材料，为了生产复合支架，这会导致制造前体长丝以及多步生产方法的额外成本。在这项研究中，我们建议使用一种有利的基于挤出的打印技术，该技术提供了从原始形式开始轻松共同打印生物材料的机会，并通过使用单步制造和无溶剂工艺。聚（e-己内酯）（PCL）是一种 FDA 批准的可生物降解材料，被用作聚合物基质，而不同含量的羟基磷灰石（HA）和锶取代的 HA（SrHA）被引入作为能够模拟矿物相的生物活性增强相天然骨。针对每种材料配方设计了三种不同的结构，随后从物理化学、机械和生物性能方面分析了成分变化和结构设计的影响。观察到结构和压缩模量之间的相关性，无论测试的配方如何，都证明了铺设模式如何影响最终的 3D 打印支架的刚度。此外，