Tissue engineering of the annulus fibrosus (AF) is currently being investigated as a treatment for intervertebral disc degeneration, a condition frequently associated with low back pain. The objective of this work was to use 3D printing to generate a novel scaffold for AF repair that mimics the structural and biomechanical properties of the native tissue. Multi-layer scaffolds were fabricated by depositing polycaprolactone struts in opposing angular orientations, replicating the angle-ply arrangement of the native AF tissue. Scaffolds were printed with varied strut diameter and spacing. The constructs were characterized morphologically and by static and dynamic mechanical analyses. Scaffold surfaces were etched with unidirectional grooves and the influence on bovine AF cell metabolic activity, alignment, morphology and protein expression was studied in vitro. Overall, the axial compressive and circumferential tensile properties of the scaffolds were found to be in a similar range to the native AF tissue. Confocal microscopy images indicated that cells were able to attach and spread on the smooth polycaprolactone scaffolds, but the surface texture induced cellular alignment and proliferation. Furthermore, immunofluorescence analysis demonstrated the aligned deposition of collagen type I, aggrecan and the AF-specific protein marker tenomodulin on the etched scaffolds. Overall, results demonstrated the potential for using the scaffolds as a template for AF regeneration.

中文翻译：

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具有角度层结构的3D打印聚己内酯支架的体外评估，用于纤维环组织工程。

纤维环（AF）的组织工程目前正在研究作为椎间盘退变的治疗方法，椎间盘退变通常与腰痛相关。这项工作的目的是使用3D打印生成一种用于AF修复的新型支架，该支架模仿天然组织的结构和生物力学特性。多层支架是通过在相反的角度方向上沉积聚己内酯撑杆来制造的，从而复制了天然AF组织的角度层排列。支架以不同的支柱直径和间距印刷。通过静态和动态力学分析对结构进行形态学表征。用单向凹槽蚀刻支架表面，并影响牛AF细胞代谢活性，排列，体外研究了形态学和蛋白质表达。总体而言，发现支架的轴向压缩特性和周向拉伸特性与天然房颤组织的范围相似。共聚焦显微镜图像表明，细胞能够附着并在光滑的聚己内酯支架上扩散，但表面纹理诱导细胞排列和增殖。此外，免疫荧光分析表明，I型胶原蛋白，聚集蛋白聚糖和AF特异性蛋白标志物Tenomodulin在刻蚀的支架上对齐沉积。总体而言，结果表明使用支架作为AF再生模板的潜力。共聚焦显微镜图像表明，细胞能够附着并在光滑的聚己内酯支架上扩散，但表面纹理诱导细胞排列和增殖。此外，免疫荧光分析表明，I型胶原蛋白，聚集蛋白聚糖和AF特异性蛋白标志物Tenomodulin在刻蚀的支架上对齐沉积。总体而言，结果表明使用支架作为AF再生模板的潜力。共聚焦显微镜图像表明，细胞能够附着并在光滑的聚己内酯支架上扩散，但表面纹理诱导细胞排列和增殖。此外，免疫荧光分析表明，I型胶原蛋白，聚集蛋白聚糖和AF特异性蛋白标志物Tenomodulin在刻蚀的支架上对齐沉积。总体而言，结果表明使用支架作为AF再生模板的潜力。