Selection of feasible hybrid-hydrogels for best chondrogenic differentiation of human mesenchymal stromal cells (hMSCs) represents an important challenge in cartilage regeneration. In this study, three-dimensional hybrid hydrogels obtained by chemical crosslinking of poly (ethylene glycol) diglycidyl ether (PEGDGE), gelatin (G) without or with chitosan (Ch) or dextran (Dx) polysaccharides were developed. The hydrogels, namely G-PEG, G-PEG-Ch and G-PEG-Dx, were prepared with an innovative, versatile and cell-friendly technique that involves two preparation steps specifically chosen to increase the degree of crosslinking and the physical-mechanical stability of the product: a first homogeneous phase reaction followed by directional freezing, freeze-drying and post-curing. Chondrogenic differentiation of human bone marrow mesenchymal stromal cells (hBM-MSC) was tested on these hydrogels to ascertain whether the presence of different polysaccharides could favor the formation of the native cartilage structure. We demonstrated that the hydrogels exhibited an open pore porous morphology with high interconnectivity and the incorporation of Ch and Dx into the G-PEG common backbone determined a slightly reduced stiffness compared to that of G-PEG hydrogels. We demonstrated that G-PEG-Dx showed a significant increase of its anisotropic characteristic and G-PEG-Ch exhibited higher and faster stress relaxation behavior than the other hydrogels. These characteristics were associated to absence of chondrogenic differentiation on G-PEG-Dx scaffold and good chondrogenic differentiation on G-PEG and G-PEG-Ch. Furthermore, G-PEG-Ch induced the minor collagen proteins and the formation of collagen fibrils with a diameter like native cartilage.

This study demonstrated that both anisotropic and stress relaxation characteristics of the hybrid hydrogels were important features directly influencing the chondrogenic differentiation potentiality of hBM-MSC.

选择可行的混合水凝胶以最佳分化人间充质基质细胞（hMSCs）的软骨，代表了软骨再生中的一项重要挑战。在这项研究中，开发了通过化学交联聚（乙二醇）二缩水甘油醚（PEGDGE），明胶（G）（不含或不含壳聚糖（Ch）或葡聚糖（Dx））的三维杂化水凝胶。水凝胶，即G-PEG，G-PEG-Ch和G-PEG-Dx，是采用创新，通用和对细胞友好的技术制备的，该技术涉及两个制备步骤，这些步骤特别选择来提高交联度和物理机械性能。产品的稳定性：先进行均相反应，然后进行定向冷冻，冷冻干燥和后固化。在这些水凝胶上测试了人骨髓间充质基质细胞（hBM-MSC）的软骨分化，以确定不同多糖的存在是否有助于天然软骨结构的形成。我们证明水凝胶显示出具有高互连性的开孔多孔形态，并且与G-PEG水凝胶相比，将Ch和Dx掺入G-PEG通用主链决定了刚度略微降低的刚度。我们证明，G-PEG-Dx表现出其各向异性特征的显着增加，并且G-PEG-Ch表现出比其他水凝胶更高和更快的应力松弛行为。这些特征与在G-PEG-Dx支架上缺乏软骨形成分化以及在G-PEG和G-PEG-Ch上良好的软骨形成分化有关。此外，

这项研究表明，杂化水凝胶的各向异性和应力松弛特性都是直接影响hBM-MSC软骨分化潜能的重要特征。