Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland 4059, Australia.
J Mater Chem B. 2019 Mar 14;7(10):1761-1772. doi: 10.1039/c8tb02607f. Epub 2019 Jan 8.
Gelatin methacryloyl (GelMA) hydrogels are a mechanically and biochemically tuneable biomaterial, facilitating chondrocyte culture for tissue engineering applications. However, a lack of characterisation and standardisation of fabrication methodologies for GelMA restricts its utilisation in surgical interventions for articular cartilage repair. The purpose of this study was to determine the effects of gelatin source and photoinitiator type on the redifferentiation capacity of monolayer-expanded human articular chondrocytes encapsulated in GelMA/hyaluronic acid methacrylate (HAMA) hydrogels. Chondrocyte-laden hydrogels reinforced with multiphasic melt-electrowritten (MEW) medical grade polycaprolactone (mPCL) microfibre scaffolds were prepared using bovine (B) or porcine-derived (P) GelMA, and photocrosslinked with either lithium acylphosphinate (LAP) and visible light (405 nm) or Irgacure 2959 (IC) and UV light (365 nm). Bulk physical properties, cell viability and biochemical features of hydrogel constructs were measured at day 1 and day 28 of chondrogenic cell culture. The compressive moduli of all groups increased after 28 days of cell culture, with B-IC displaying similar compressive strength to that of native articular cartilage (∼1.5 MPa). Compressive moduli correlated with an increase in total glycosaminoglycan (GAG) content for each group. Gene expression analysis revealed upregulation of chondrogenic marker genes in IC-crosslinked groups, whilst dedifferentiation gene markers were upregulated in LAP-crosslinked groups. mPCL reinforcement correlated with increased accumulation of collagen I and II in B-IC, B-LAP and P-IC groups compared to non-reinforced hydrogels. A reduction in cell viability was noted in all samples at day 28, potentially due to the generation of free radicals during photocrosslinking or cytotoxicity of the photoinitiators. In summary, hydrogel constructs prepared with bovine-derived GelMA and photocrosslinked with Irgacure 2959 and 365 nm light displayed properties most similar to native articular cartilage after 28 days of cell culture. The differences in biological response between investigated construct types emphasises the necessity to characterise and standardise biomaterials before translating in vitro tissue engineering research to preclinical applications for articular cartilage injuries.
明胶甲基丙烯酰（GelMA）水凝胶是一种机械和生化可调的生物材料，有利于组织工程应用中软骨细胞的培养。然而，由于缺乏对 GelMA 制造方法的特性描述和标准化，限制了其在关节软骨修复的外科干预中的应用。本研究旨在确定明胶来源和光引发剂类型对包埋在 GelMA/透明质酸甲基丙烯酰胺（HAMA）水凝胶中的单层扩增的人关节软骨细胞再分化能力的影响。使用牛（B）或猪（P）来源的 GelMA 制备负载软骨细胞的水凝胶，并使用多相熔融电纺（MEW）医用级聚己内酯（mPCL）微纤维支架进行增强，用光引发剂锂酰基膦酸盐（LAP）和可见光（405nm）或 Irgacure 2959（IC）和紫外光（365nm）进行光交联。在软骨细胞培养的第 1 天和第 28 天测量水凝胶结构的体物理性质、细胞活力和生化特性。所有组的压缩模量在细胞培养 28 天后增加，B-IC 显示出与天然关节软骨相似的抗压强度（约 1.5MPa）。压缩模量与各组总糖胺聚糖（GAG）含量的增加相关。基因表达分析显示，IC 交联组的软骨形成标志物基因上调，而 LAP 交联组的去分化基因标志物上调。与非增强水凝胶相比，B-IC、B-LAP 和 P-IC 组中 mPCL 增强与胶原蛋白 I 和 II 的积累增加相关。在第 28 天，所有样品的细胞活力均降低，这可能是由于光交联过程中自由基的产生或光引发剂的细胞毒性所致。总之，用牛源 GelMA 制备、用 Irgacure 2959 和 365nm 光交联的水凝胶在细胞培养 28 天后显示出与天然关节软骨最相似的特性。在研究的构建类型之间的生物学反应差异强调了在将体外组织工程研究转化为关节软骨损伤的临床前应用之前，对生物材料进行特性描述和标准化的必要性。
