Like the morphology of native tissue fiber arrangement (such as skeletal muscle), unidirectional anisotropic scaffolds are highly desired as a means to guide cell behavior in anisotropic tissue engineering. In contrast, contour-like staircases exhibit directional topographical cues and are judged as an inevitable defect of fused deposition modeling (FDM). In this study, we will translate this staircase defect into an effective bioengineering strategy by integrating FDM with surface coating technique (FCT) to investigate the effect of topographical cues on regulating behaviors of human mesenchymal stem cells (hMSCs) toward skeletal muscle tissues. This integrated approach serves to fabricate shape-specific, multiple dimensional, anisotropic scaffolds using different biomaterials. 2D anisotropic scaffolds, first demonstrated with different polycaprolactone concentrations herein, efficiently direct hMSC alignment, especially when the scaffold is immobilized on a support ring. By surface coating the polymer solution inside FDM-printed sacrificial structures, 3D anisotropic scaffolds with thin wall features are developed and used to regulate seeded hMSCs through a self-established rotating bioreactor. Using layer-by-layer coating, along with a shape memory polymer, smart constructs exhibiting shape fix and recovery processes are prepared, bringing this study into the realm of 4D printing. Immunofluorescence staining and real-time quantitative polymerase chain reaction analysis confirm that the topographical cues created via FCT significantly enhance the expression of myogenic genes, including myoblast differentiation protein-1, desmin, and myosin heavy chain-2. We conclude that there are broad application potentials for this FCT strategy in tissue engineering as many tissues and organs, including skeletal muscle, possess highly organized and anisotropic extracellular matrix components.

中文翻译：

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通过阶梯效应策略制造的 4D 各向异性骨骼肌组织结构。

与天然组织纤维排列的形态（例如骨骼肌）一样，单向各向异性支架非常需要作为各向异性组织工程中引导细胞行为的手段。相比之下，轮廓状楼梯表现出定向地形线索，被认为是熔融沉积建模（FDM）不可避免的缺陷。在本研究中，我们将通过将 FDM 与表面涂层技术 (FCT) 相结合，将这种阶梯缺陷转化为有效的生物工程策略，以研究地形线索对调节人类间充质干细胞 (hMSC) 骨骼肌组织行为的影响。这种集成方法用于使用不同的生物材料制造形状特异性、多维、各向异性支架。本文首先用不同的聚己内酯浓度证明了2D各向异性支架，可有效指导hMSC排列，特别是当支架固定在支撑环上时。通过在 FDM 打印的牺牲结构内表面涂覆聚合物溶液，开发了具有薄壁特征的 3D 各向异性支架，并用于通过自行建立的旋转生物反应器来调节接种的 hMSC。使用逐层涂层和形状记忆聚合物，制备出具有形状固定和恢复过程的智能结构，将这项研究带入 4D 打印领域。免疫荧光染色和实时定量聚合酶链式反应分析证实，通过 FCT 创建的拓扑线索显着增强了生肌基因的表达，包括成肌细胞分化蛋白 1、结蛋白和肌球蛋白重链 2。我们的结论是，这种 FCT 策略在组织工程中具有广泛的应用潜力，因为包括骨骼肌在内的许多组织和器官都具有高度组织化和各向异性的细胞外基质成分。