PDF(Pubmed)
Abstract：
Stem cells, particularly human iPSCs, constitute a powerful tool for tissue engineering, notably through spheroid and organoid models. While the sensitivity of stem cells to the viscoelastic properties of their direct microenvironment is well-described, stem cell differentiation still relies on biochemical factors. Our aim is to investigate the role of the viscoelastic properties of hiPSC spheroids\' direct environment on their fate. To ensure that cell growth is driven only by mechanical interaction, bioprintable alginate-gelatin hydrogels with significantly different viscoelastic properties were utilized in differentiation factor-free culture medium. Alginate-gelatin hydrogels of varying concentrations were developed to provide 3D environments of significantly different mechanical properties, ranging from 1 to 100 kPa, while allowing printability. hiPSC spheroids from two different cell lines were prepared by aggregation (⌀ = 100 µm, n > 1 × 104), included and cultured in the different hydrogels for 14 days. While spheroids within dense hydrogels exhibited limited growth, irrespective of formulation, porous hydrogels prepared with a liquid-liquid emulsion method displayed significant variations of spheroid morphology and growth as a function of hydrogel mechanical properties. Transversal culture (adjacent spheroids-laden alginate-gelatin hydrogels) clearly confirmed the separate effect of each hydrogel environment on hiPSC spheroid behavior. This study is the first to demonstrate that a mechanically modulated microenvironment induces diverse hiPSC spheroid behavior without the influence of other factors. It allows one to envision the combination of multiple formulations to create a complex object, where the fate of hiPSCs will be independently controlled by their direct microenvironment.
摘要：
干细胞,特别是人类iPSCs，构成了组织工程的强大工具，特别是通过球体和类器官模型。虽然干细胞对其直接微环境的粘弹性特性的敏感性得到了很好的描述，干细胞分化仍然依赖于生化因素。我们的目的是研究hiPSC球体的粘弹性特性直接环境对其命运的影响。为了确保细胞生长仅由机械相互作用驱动，在无分化因子的培养基中使用了具有显着不同粘弹性的生物可降解藻酸盐-明胶水凝胶。开发了不同浓度的藻酸盐-明胶水凝胶，以提供具有明显不同机械性能的3D环境。范围从1到100千帕，同时允许可印刷性。通过聚集制备来自两个不同细胞系的hiPSC球体（=100µm，n>1×104)，包括并在不同的水凝胶中培养14天。虽然致密水凝胶内的球体表现出有限的生长，无论配方如何，用液-液乳液法制备的多孔水凝胶显示出球体形态和生长随水凝胶机械性能的显着变化。横向培养（相邻的球体负载的藻酸盐-明胶水凝胶）清楚地证实了每种水凝胶环境对hiPSC球体行为的单独影响。这项研究首次证明了机械调制的微环境在不受其他因素影响的情况下诱导了各种hiPSC球体行为。它允许人们设想多种配方的组合来创建一个复杂的对象，其中hiPSC的命运将由它们的直接微环境独立控制。
