Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Biomaterials. 2011 Nov;32(31):7839-46. doi: 10.1016/j.biomaterials.2011.06.078. Epub 2011 Jul 23.
The nanostructuring of hydrogel scaffolds used in tissue engineering aims to provide an ability to control cellular morphogenesis through defined cell-matrix interactions. Toward this objective, we developed a method that alters the molecular network structure of biosynthetic hydrogel scaffolds made from crosslinked poly(ethylene glycol)-fibrinogen conjugates (PEG-fibrinogen, PF). The modifications were based on Pluronic(®) F127 micelles that were formed in the hydrogel precursor solution and that altered the hydrogel network assembly during photopolymerization crosslinking. Two variations of the cell-encapsulating hydrogels (high and low crosslinking density) were prepared with three concentrations of Pluronic(®) F127 (3%, 7%, 10% w/v). Quantitative morphometrics were used to characterize fibroblast shape parameters (both transient and stable) in all hydrogels, and rheological characterizations were used to measure the elastic (storage) component of the complex shear modulus of these hydrogels. The morphometric data was then correlated to both the nanostructure and modulus of the hydrogels for day 1 and day 4 in culture. These correlations revealed that structural features imparted by the Pluronic(®) F127 micelles were able to reverse the normally strong correlations found between indicators of cell spreading and the hydrogel's mechanical properties. Therefore, the data supports the conclusion that nanostructural features in the encapsulating hydrogel culture environment can facilitate better cell spreading in a dense hydrogel milieu, simply by introducing imperfections into the network structure. This research also provides further prospective regarding biocompatible approaches toward making structural modifications to hydrogel scaffolds for the purpose of 3-D cell culture and tissue engineering.
用于组织工程的水凝胶支架的纳米结构旨在通过定义的细胞-基质相互作用提供控制细胞形态发生的能力。为此，我们开发了一种方法，该方法改变了由交联聚乙二醇-纤维蛋白原缀合物（PEG-纤维蛋白原，PF）制成的生物合成水凝胶支架的分子网络结构。这些修饰基于 Pluronic（R）F127 胶束，该胶束在水凝胶前体溶液中形成，并在光聚合交联过程中改变水凝胶网络组装。用三种浓度的 Pluronic（R）F127（3％，7％，10％w/v）制备了两种包封细胞的水凝胶（高和低交联密度）。使用定量形态计量学来表征所有水凝胶中的成纤维细胞形状参数（瞬态和稳定），并使用流变特性来测量这些水凝胶的复杂剪切弹性（存储）模量的弹性（存储）分量。然后将形态计量学数据与水凝胶的纳米结构和模量相关联，以用于培养的第 1 天和第 4 天。这些相关性表明，Pluronic（R）F127 胶束赋予的结构特征能够逆转通常在细胞铺展指标与水凝胶力学性能之间发现的强相关性。因此，该数据支持这样的结论，即包封水凝胶培养环境中的纳米结构特征可以通过在网络结构中引入缺陷，在密集的水凝胶环境中促进更好的细胞铺展。这项研究还为通过生物相容性方法对水凝胶支架进行结构改性以用于 3D 细胞培养和组织工程提供了进一步的前景。
