Breast tissue engineering is a promising alternative to standard treatments for breast defects. Although there is a consensus that the mechanical property of the scaffold should best match the reconstructed tissue, the simulation of the soft and elastic tactility of native breast tissues using conventional materials and architecture design requires further study. Previous research has shown that the crystal microstructure-like design can drastically alter the mechanical properties of the constructed scaffolds. In this study, we designed and additive manufactured four kinds of breast scaffolds using polyurethane and termed their architectures as N5S4, N9S8, N7S6 and N4S6. The basic unit cell of each scaffold was similar to a lattice structure from the isometric crystal system. The scaffolds possessed identical porosity but different mechanical properties in which the compressive modulus of the softest scaffolds (N5S4) were similar to that of native breast tissue. When applied in the construction of tissue-engineered breast combining with delayed fat injection technique in nude rat models, the soft scaffolds(N5S4) performed better compared to its stiff counterpart (N4S6), as higher adipose survival, vascularization and milder fibrosis could be observed in N5S4 scaffolds . Lastly, using finite element analysis, we further investigated the influence of the unit cell architectures on the mechanical properties of the scaffolds and simulated the deformation as well as stress distribution patterns of the implanted scaffolds in detail. Thus, a crystal lattice-like architecture design was introduced to tune the mechanical properties of the scaffolds and match the requirements for tissue engineering applications.

中文翻译：

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通过用于乳腺组织工程的晶格状结构设计来调整3D打印支架的力学。

乳房组织工程学是乳房缺陷标准治疗的有希望的替代方法。尽管人们普遍认为支架的机械性能应与重建的组织最匹配，但使用常规材料和体系结构设计模拟天然乳腺组织的柔软和弹性触觉仍需要进一步的研究。先前的研究表明，类似晶体微结构的设计可以极大地改变所构建支架的机械性能。在这项研究中，我们使用聚氨酯设计并增材制造了四种胸架，并将其架构命名为N5S4，N9S8，N7S6和N4S6。每个支架的基本晶胞类似于等轴测晶体系统的晶格结构。支架具有相同的孔隙率，但机械性能不同，其中最软的支架（N5S4）的压缩模量与天然乳腺组织的压缩模量相似。当在裸鼠模型中结合延迟脂肪注射技术用于组织工程化乳房的构建时，软支架（N5S4）的性能优于刚性支架（N4S6），因为可以观察到更高的脂肪存活率，血管化和轻度纤维化在N5S4支架中。最后，使用有限元分析，我们进一步研究了晶胞结构对脚手架力学性能的影响，并详细模拟了植入脚手架的变形和应力分布模式。因此，