Dipartimento di Ingegneria Meccanica e Industriale, Università degli Studi di Brescia, Via Branze 38, 25123 Brescia, Italy.
IRCCS Istituto Ortopedico Rizzoli, SC Laboratorio di Immunoreumatologia e Rigenerazione Tissutale, via di Barbiano 1/10, 40136 Bologna, Italy.
Mater Sci Eng C Mater Biol Appl. 2021 Jul;126:112175. doi: 10.1016/j.msec.2021.112175. Epub 2021 May 8.
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.
选择合适的杂化水凝胶以促进人骨髓间充质干细胞（hMSCs）向软骨细胞分化是软骨再生的重要挑战。本研究通过聚乙二醇二缩水甘油醚（PEGDGE）、明胶（G）与壳聚糖（Ch）或葡聚糖（Dx）多糖的化学交联制备了三维杂化水凝胶，即 G-PEG、G-PEG-Ch 和 G-PEG-Dx。该水凝胶通过一种创新、通用且细胞友好的技术制备，该技术涉及两个特定选择的制备步骤，旨在提高交联程度和产物的物理机械稳定性：首先是均相反应，然后是定向冷冻、冷冻干燥和后固化。我们在这些水凝胶上测试了人骨髓间充质干细胞（hBM-MSC）的软骨分化，以确定不同多糖的存在是否有利于形成天然软骨结构。结果表明，水凝胶具有高连通性的开放孔多孔形态，且 Ch 和 Dx 掺入 G-PEG 共同主链会导致其与 G-PEG 水凝胶相比略微降低刚度。我们还发现，G-PEG-Dx 的各向异性特征显著增加，而 G-PEG-Ch 表现出比其他水凝胶更高和更快的应力松弛行为。这些特性与 G-PEG-Dx 支架上不存在软骨分化以及 G-PEG 和 G-PEG-Ch 上良好的软骨分化有关。此外，G-PEG-Ch 诱导较少的胶原蛋白蛋白和形成直径类似于天然软骨的胶原纤维。本研究表明，杂化水凝胶的各向异性和应力松弛特性是直接影响 hBM-MSC 软骨分化潜力的重要特征。
