Department of Materials Science and Engineering, Monash Institute of Medical Engineering, Monash University, Wellington Road, Clayton, VIC 3800, Australia; CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3168, Australia; Tissue Engineering and Biofabrication Group, Department of Health Science and Technology, ETH Zürich, Zürich, Switzerland.
Department of Materials Science and Engineering, Monash Institute of Medical Engineering, Monash University, Wellington Road, Clayton, VIC 3800, Australia.
Acta Biomater. 2018 Sep 1;77:48-62. doi: 10.1016/j.actbio.2018.07.015. Epub 2018 Jul 10.
Current clinical approaches to treat articular cartilage degeneration provide only a limited ability to regenerate tissue with long-term durability and functionality. In this application, injectable bulk hydrogels and microgels containing stem cells can provide a suitable environment for tissue regeneration. However insufficient cell-cell interactions, low differentiation efficiency and poor tissue adhesion hinder the formation of high-quality hyaline type cartilage. Here, we have designed a higher order tissue-like structure using injectable cell-laden microgels as the building blocks to achieve human bone marrow-derived mesenchymal stem cell (hBMSC) long-term maintenance and chondrogenesis. We have demonstrated that a 4-arm poly(ethylene glycol)-N-hydroxysuccinimide (NHS) crosslinker induces covalent bonding between the microgel building blocks as well as the surrounding tissue mimic. The crosslinking process assembles the microgels into a 3D construct and preserves the viability and cellular functions of the encapsulated hBMSCs. This assembled microgel construct encourages upregulation of chondrogenic markers in both gene and glycosaminoglycan (GAG) expression levels. In addition, the regenerated tissue in the assembled microgels stained positively with Alcian blue and Safranin O exhibiting unique hyaline-like cartilage features. Furthermore, the immunostaining showed a favourable distribution and significantly higher content of type II collagen in the assembled microgels when compared to both the bulk hydrogel and pellet cultures. Collectively, this tissue adhesive hBMSC-laden microgel construct provides potential clinical opportunities for articular cartilage repair and other applications in regenerative medicine.
A reliable approach to reconstruct durable and fully functional articular cartilage tissue is required for effective clinical therapies. Here, injectable hydrogels together with cell-based therapies offer new treatment strategies in cartilage repair. For effective cartilage regeneration, the injectable hydrogel system needs to be bonded to the surrounding tissue and at the same time needs to be sufficiently stable for prolonged chondrogenesis. In this work, we utilised injectable hBMSC-laden microgels as the building blocks to create an assembled construct via N-hydroxysuccinimide-amine coupling. This crosslinking process also allows for rapid bonding between the assembled microgels and a surrounding tissue mimic. The resultant assembled microgel-construct provides both a physically stable and biologically dynamic environment for hBMSC chondrogenesis, leading to the production of a mature hyaline type cartilage structure.
目前治疗关节软骨退变的临床方法仅能有限地再生具有长期耐久性和功能性的组织。在这种应用中，包含干细胞的可注射块状水凝胶和微凝胶可为组织再生提供合适的环境。然而，细胞间相互作用不足、分化效率低和组织黏附不良阻碍了高质量透明软骨的形成。在这里，我们设计了一种更高阶的组织样结构，使用可注射的载细胞微凝胶作为构建块，以实现人骨髓间充质干细胞（hBMSC）的长期维持和软骨生成。我们已经证明，四臂聚（乙二醇）-N-羟基琥珀酰亚胺（NHS）交联剂诱导微凝胶构建块之间以及周围组织模拟物之间的共价键合。交联过程将微凝胶组装成 3D 结构，并保持包封的 hBMSCs 的活力和细胞功能。这种组装的微凝胶结构促进了基因和糖胺聚糖（GAG）表达水平的软骨生成标志物的上调。此外，在组装的微凝胶中再生的组织用阿利新蓝和番红 O 染色呈阳性，表现出独特的透明软骨样特征。此外，免疫染色显示，与块状水凝胶和微球培养相比，组装的微凝胶中 II 型胶原的分布更有利，含量也显著更高。总的来说，这种组织黏附的 hBMSC 载入微凝胶构建体为关节软骨修复和再生医学中的其他应用提供了潜在的临床机会。
需要可靠的方法来重建耐用且功能齐全的关节软骨组织，以实现有效的临床治疗。在这里，可注射水凝胶与基于细胞的治疗方法为软骨修复提供了新的治疗策略。为了实现有效的软骨再生，可注射水凝胶系统需要与周围组织结合，同时需要足够稳定以延长软骨生成。在这项工作中，我们利用可注射的 hBMSC 载入微凝胶作为构建块，通过 N-羟基琥珀酰亚胺-胺偶联来创建组装的构建体。交联过程还允许组装的微凝胶与周围组织模拟物之间快速结合。所得组装的微凝胶构建体为 hBMSC 软骨生成提供了既物理稳定又生物动态的环境，导致成熟透明软骨结构的产生。
