Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), 77, Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Republic of Korea.
Catholic iPSC Research Center, College of Medicine, The Catholic University of Korea, 20 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea.
Biofabrication. 2021 Aug 31;13(4). doi: 10.1088/1758-5090/ac1e76.
The pellet formation has been regarded as a golden standard forchondrogenic differentiation. However, a spatially inhomogeneous chondrogenic microenvironment around a pellet resulted from the use of a traditional impermeable narrow tube, such as the conical tube, undermines the differentiation performance and therapeutic potential of differentiated cartilage pellet in defective articular cartilage treatment. To address this drawback, a perichondrium-inspired permeable nanofibrous tube (PINaT) well with a nanofibrous wall permeable to gas and soluble molecules is proposed. The PINaT well was fabricated with a micro deep drawing process where a flat thin nanofibrous membrane was transformed to a 3.5 mm deep tube well with a ∼50m thick nanofibrous wall. Similar toperichondrium, the PINaT well was found to allow oxygen and growth factor diffusion required for chondrogenic differentiation across the entire nanofibrous wall. Analyses of gene expressions (COL2A1, COL10A1, ACAN, and SOX9), proteins (type II and X collagen), and glycosaminoglycans contents were conducted to assess the differentiation performance and clinical efficacy of differentiated cartilage pellet. The regulated spatially homogeneous chondrogenic microenvironment around the human induced pluripotent stem cell-derived pellet (3 × 10cells per pellet) in the PINaT well remarkably improved the quality of the differentiated pellet toward a more hyaline-like cartilage pellet. Furthermore, an accelerated chondrogenic differentiation process of the pellet produced by the PINaT well was achieved for 14 days, demonstrating a hyaline cartilage-specific marker similar to the control pellet differentiated for 20 days. Finally, the enhanced clinical efficacy of the hyaline-like cartilage pellet was confirmed using an osteochondral defect rat model, with the repaired tissue resembling hyaline cartilage rather than fibrous cartilage after 8 weeks of regeneration.
微球的形成被认为是软骨分化的金标准。然而，由于传统的不可渗透的狭窄管，如锥形管，在微球周围形成了空间不均匀的软骨分化微环境，这破坏了分化软骨微球在治疗有缺陷的关节软骨中的分化性能和治疗潜力。为了解决这个缺点，提出了一种具有仿生细胞外基质的可渗透纳米纤维管（PINaT）。PINaT 管是通过微深拉工艺制造的，其中一个扁平的薄纳米纤维膜被转化为一个 3.5 毫米深的管井，具有约 50μm 厚的纳米纤维壁。与软骨膜类似，PINaT 管被发现允许氧气和生长因子通过整个纳米纤维壁扩散，这是软骨分化所必需的。通过分析基因表达（COL2A1、COL10A1、ACAN 和 SOX9）、蛋白质（II 型和 X 型胶原蛋白）和糖胺聚糖含量来评估分化软骨微球的分化性能和临床疗效。在 PINaT 管中，人类诱导多能干细胞来源的微球（每个微球 3×10 个细胞）周围调节的空间均匀软骨分化微环境显著改善了分化微球的质量，使其更接近透明软骨样微球。此外，通过 PINaT 管实现了微球的软骨分化过程加速，在 14 天内达到了与对照微球分化 20 天相似的透明软骨特异性标志物。最后，通过使用骨软骨缺损大鼠模型证实了透明软骨样微球的增强临床疗效，在 8 周的再生后，修复组织类似于透明软骨而不是纤维软骨。
