Cartilage has limited self-repair ability due to its avascular, alymphatic and aneural features. The combination of three-dimensional (3D) printing and tissue engineering provides an up-and-coming approach to address this issue. Here, we designed and fabricated a tri-layered (superficial layer (SL), middle layer (ML) and deep layer (DL)) stratified scaffold, inspired by the architecture of collagen fibers in native cartilage tissue. The scaffold was composed of 3D printed depth-dependent gradient poly(ε-caprolactone) (PCL) impregnated with methacrylated alginate (ALMA), and its morphological analysis and mechanical properties were tested. To prove the feasibility of the composite scaffolds for cartilage regeneration, the viability, proliferation, collagen deposition and chondrogenic differentiation of embedded rat bone marrow mesenchymal stem cells (BMSCs) in the scaffolds were assessed by Live/dead assay, CCK-8, DNA content, cell morphology, immunofluorescence and real-time reverse transcription polymerase chain reaction. BMSCs-loaded gradient PCL/ALMA scaffolds showed excellent cell survival, cell proliferation, cell morphology, collagen II deposition and hopeful chondrogenic differentiation compared with three individual-layer scaffolds. Hence, our study demonstrates the potential use of the gradient PCL/ALMA construct for enhanced cartilage tissue engineering.

中文翻译：

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用于软骨组织工程的 3D 打印梯度聚（ε-己内酯）/甲基丙烯酸化海藻酸盐复合支架上负载的间充质干细胞

软骨由于其无血管、淋巴和无神经特征而具有有限的自我修复能力。三维 (3D) 打印和组织工程的结合为解决这个问题提供了一种新兴的方法。在这里，我们设计并制造了一个三层（表层（SL）、中间层（ML）和深层（DL））分层支架，灵感来自天然软骨组织中胶原纤维的结构。该支架由浸渍甲基丙烯​​酸化海藻酸盐（ALMA）的3D打印深度依赖性梯度聚（ε-己内酯）（PCL）组成，并对其形态分析和力学性能进行了测试。证明复合支架用于软骨再生的可行性、活力、增殖、通过活/死测定、CCK-8、DNA含量、细胞形态、免疫荧光和实时逆转录聚合酶链反应评估支架中嵌入的大鼠骨髓间充质干细胞（BMSCs）的胶原沉积和成软骨分化。与三个单层支架相比，负载 BMSCs 的梯度 PCL/ALMA 支架显示出优异的细胞存活、细胞增殖、细胞形态、胶原蛋白 II 沉积和有希望的软骨形成分化。因此，我们的研究证明了梯度 PCL/ALMA 构建体在增强软骨组织工程中的潜在用途。与三个单层支架相比，负载 BMSCs 的梯度 PCL/ALMA 支架显示出优异的细胞存活、细胞增殖、细胞形态、胶原蛋白 II 沉积和有希望的软骨形成分化。因此，我们的研究证明了梯度 PCL/ALMA 构建体在增强软骨组织工程中的潜在用途。与三个单层支架相比，负载 BMSCs 的梯度 PCL/ALMA 支架显示出优异的细胞存活、细胞增殖、细胞形态、胶原蛋白 II 沉积和有希望的软骨形成分化。因此，我们的研究证明了梯度 PCL/ALMA 构建体在增强软骨组织工程中的潜在用途。