Ondeck Matthew G, Engler Adam J
J Biomech Eng. 2016 Feb;138(2):021003. doi: 10.1115/1.4032429.
Hyaluronic acid (HA) is a commonly used natural polymer for cell scaffolding. Modification by methacrylate allows it to be polymerized by free radicals via addition of an initiator, e.g., light-sensitive Irgacure, to form a methacrylated hyaluronic acid (MeHA) hydrogel. Light-activated crosslinking can be used to control the degree of polymerization, and sequential polymerization steps allow cells plated onto or in the hydrogel to initially feel a soft and then a stiff matrix. Here, the elastic modulus of MeHA hydrogels was systematically analyzed by atomic force microscopy (AFM) for a number of variables including duration of UV exposure, monomer concentration, and methacrylate functionalization. To determine how cells would respond to a specific two-step polymerization, NIH 3T3 fibroblasts were cultured on the stiffening MeHA hydrogels and found to reorganize their cytoskeleton and spread area upon hydrogel stiffening, consistent with cells originally cultured on substrates of the final elastic modulus.
透明质酸（HA）是一种常用于细胞支架的天然聚合物。通过甲基丙烯酸酯进行修饰后，它可以通过添加引发剂（如光敏的光引发剂Irgacure）经自由基聚合，形成甲基丙烯酸化透明质酸（MeHA）水凝胶。光激活交联可用于控制聚合程度，连续的聚合步骤使接种在水凝胶上或水凝胶内的细胞最初感受到柔软的基质，随后感受到坚硬的基质。在此，通过原子力显微镜（AFM）系统分析了MeHA水凝胶的弹性模量，涉及多个变量，包括紫外线照射时间、单体浓度和甲基丙烯酸酯功能化。为了确定细胞对特定两步聚合的反应，将NIH 3T3成纤维细胞培养在变硬的MeHA水凝胶上，发现细胞在水凝胶变硬时会重新组织其细胞骨架并扩展面积，这与最初在具有最终弹性模量的基质上培养的细胞一致。
