Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK.
Department of Pharmacology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
Cells. 2023 Dec 20;13(1):10. doi: 10.3390/cells13010010.
Silk hydrogels have shown potential for tissue engineering applications, but several gaps and challenges, such as a restricted ability to form hydrogels with tuned mechanics and structural features, still limit their utilisation. Here, and (Tasar) silk microfibres were embedded within self-assembling silk hydrogels to modify the bulk hydrogel mechanical properties. This approach is particularly attractive because it creates structured silk hydrogels. First, and Tasar microfibres were prepared with lengths between 250 and 500 μm. Secondary structure analyses showed high beta-sheet contents of 61% and 63% for and Tasar microfibres, respectively. Mixing either microfibre type, at either 2% or 10% (/) concentrations, into 3% (/) silk solutions during the solution-gel transition increased the initial stiffness of the resulting silk hydrogels, with the 10% (/) addition giving a greater increase. Microfibre addition also altered hydrogel stress relaxation, with the fastest stress relaxation observed with a rank order of 2% (/) > 10% (/) > unmodified hydrogels for either fibre type, although fibres showed a greater effect. The resulting data sets are interesting because they suggest that the presence of microfibres provided potential 'flow points' within these hydrogels. Assessment of the biological responses by monitoring cell attachment onto these two-dimensional hydrogel substrates revealed greater numbers of human induced pluripotent stem cell-derived mesenchymal stem cells (iPSC-MSCs) attached to the hydrogels containing 10% (/) microfibres as well as 2% (/) and 10% (/) Tasar microfibres at 24 h after seeding. Cytoskeleton staining revealed a more elongated and stretched morphology for the cells growing on hydrogels containing Tasar microfibres. Overall, these findings illustrate that hydrogel stiffness, stress relaxation and the iPSC-MSC responses towards silk hydrogels can be tuned using microfibres.
丝素水凝胶在组织工程应用中显示出了潜力，但仍有几个差距和挑战限制了它们的应用，例如形成具有可调力学和结构特征的水凝胶的能力有限。在这里， 和 （塔萨尔）丝素微纤维被嵌入自组装的丝素水凝胶中，以改变块状水凝胶的力学性能。这种方法特别有吸引力，因为它可以创造出结构化的丝素水凝胶。首先， 和塔萨尔微纤维的长度在 250 到 500 微米之间。二级结构分析表明， 和塔萨尔微纤维的β-折叠含量分别高达 61%和 63%。在溶液-凝胶转变过程中，将任一种微纤维类型以 2%或 10%（/）的浓度混入 3%（/）的丝素溶液中，都会增加所得丝素水凝胶的初始刚度，其中 10%（/）的添加量增加更大。微纤维的添加也改变了水凝胶的应力松弛，最快的应力松弛观察到的顺序为 2%（/）>10%（/）>未改性水凝胶，对于任何一种纤维类型，尽管 纤维的影响更大。所得数据集很有趣，因为它们表明微纤维的存在为这些水凝胶提供了潜在的“流动点”。通过监测细胞附着在这些二维水凝胶基质上来评估生物反应，发现更多的人诱导多能干细胞衍生的间充质干细胞（iPSC-MSCs）附着在含有 10%（/）微纤维的水凝胶上，以及含有 2%（/）和 10%（/）塔萨尔微纤维的水凝胶上，在接种后 24 小时。细胞骨架染色显示，在含有塔萨尔微纤维的水凝胶上生长的细胞呈现出更细长和拉伸的形态。总的来说，这些发现表明，水凝胶的刚度、应力松弛以及 iPSC-MSCs 对丝素水凝胶的反应可以通过微纤维进行调整。
