Liu Haijiao, Usprech Jenna, Sun Yu, Simmons Craig A
Department of Mechanical and Industrial Engineering, University of Toronto, Toronto M5S 3G8, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto M5S 3G9, Canada.
Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto M5S 3G9, Canada.
Acta Biomater. 2016 Apr 1;34:113-124. doi: 10.1016/j.actbio.2015.11.054. Epub 2015 Nov 29.
Cellular microenvironments present cells with multiple stimuli, including not only soluble biochemical and insoluble matrix cues but also mechanical factors. Biomaterial array platforms have been used to combinatorially and efficiently probe and define two-dimensional (2D) and 3D microenvironmental cues to guide cell functions for tissue engineering applications. However, there are few examples of array platforms that include dynamic mechanical forces, particularly to enable stretching of 3D cell-seeded biomaterials, which is relevant to engineering connective and cardiovascular tissues. Here we present a deformable membrane platform that enables 3D dynamic mechanical stretch of arrayed biomaterial constructs. Cell-seeded polyethylene glycol norbornene (PEG-NB) hydrogels were bound to miniaturized deformable membranes via a thiol-ene reaction with off-stoichiometry thiol-ene based polydimethylsiloxane (OSTE-PDMS) as the membrane material. Bonding to OSTE-PDMS enabled the 3D hydrogel microconstructs to be cyclically deformed and stretched by the membrane. As a first demonstration, human mesenchymal stromal cells (MSCs) embedded in PEG-NB were stretched for several days. They were found to be viable, spread in the 3D hydrogels, and exhibited a contractile myofibroblast phenotype when exposed to dynamic 3D mechanical deformation. This platform, which is readily scalable to larger arrays, enables systematic interrogation of the relationships between combinations of 3D mechanobiological cues and cellular responses, and thus has the potential to identify strategies to predictably control the construction of functional engineered tissues.
Current high-throughput biomaterial screening approaches fail to consider the effects of dynamic mechanical stimulation, despite its importance in a wide variety of regenerative medicine applications. To meet this need, we developed a deformable membrane platform that enables 3D dynamic stretch of arrayed biomaterial constructs. Our approach combines microtechnologies fabricated with off-stoichiometry thiol-ene based polydimethylsiloxane membranes that can covalently bond cell-seeded polyethylene glycol norbornene 3D hydrogels, a model biomaterial with tunable adhesive, elastic and degradation characteristics. As a first demonstration, we show that human mesenchymal stromal cells embedded in hydrogels and subjected to dynamic mechanical stimulation undergo myofibroblast differentiation. This system is readily scaled up to larger arrays, and will enable systematic and efficient screening of combinations of 3D mechanobiological and biomaterial cues on cell fate and function.
细胞微环境为细胞提供多种刺激，不仅包括可溶性生化和不可溶性基质信号，还包括机械因素。生物材料阵列平台已被用于组合并有效地探测和定义二维（2D）和三维（3D）微环境信号，以指导细胞功能用于组织工程应用。然而，很少有阵列平台的例子包括动态机械力，特别是能够使接种细胞的3D生物材料拉伸，这与工程化结缔组织和心血管组织相关。在此，我们展示了一种可变形膜平台，其能够对排列的生物材料构建体进行3D动态机械拉伸。接种细胞的聚乙二醇降冰片烯（PEG-NB）水凝胶通过硫醇-烯反应与非化学计量硫醇-烯基聚二甲基硅氧烷（OSTE-PDMS）作为膜材料结合到小型化可变形膜上。与OSTE-PDMS结合使3D水凝胶微构建体能够通过膜进行循环变形和拉伸。作为首次演示，嵌入PEG-NB中的人间充质基质细胞（MSCs）被拉伸了数天。发现它们是有活力的，在3D水凝胶中铺展，并且在暴露于动态3D机械变形时表现出收缩性肌成纤维细胞表型。该平台易于扩展到更大的阵列，能够系统地探究3D机械生物学信号组合与细胞反应之间的关系，因此有潜力识别可预测地控制功能性工程组织构建的策略。
尽管动态机械刺激在多种再生医学应用中很重要，但当前的高通量生物材料筛选方法未能考虑其影响。为满足这一需求，我们开发了一种可变形膜平台，其能够对排列的生物材料构建体进行3D动态拉伸。我们的方法结合了用非化学计量硫醇-烯基聚二甲基硅氧烷膜制造的微技术，该膜可以共价结合接种细胞的聚乙二醇降冰片烯3D水凝胶，这是一种具有可调粘附、弹性和降解特性的模型生物材料。作为首次演示，我们表明嵌入水凝胶并受到动态机械刺激的人间充质基质细胞会发生肌成纤维细胞分化。该系统易于扩展到更大的阵列，并将能够系统且高效地筛选3D机械生物学和生物材料信号组合对细胞命运和功能的影响。
