Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
Acta Biomater. 2010 Jul;6(7):2518-24. doi: 10.1016/j.actbio.2009.07.015. Epub 2009 Jul 15.
Recent studies have shown that nanostructuring of scaffolds for tissue engineering has a major impact on their interactions with cells. The current investigation focuses on nanostructuring of a biocompatible, biosynthetic polymeric hydrogel scaffold made from crosslinked poly(ethylene glycol)-fibrinogen conjugates. Nanostructuring was achieved by the addition of the block copolymer Pluronic F127, which self-assembles into nanometric micelles at certain concentrations and temperatures. Cryo-transmission electron microscopy experiments detected F127 micelles, both embedded within PEGylated fibrinogen hydrogels and in solution. The density of the F127 micelles, as well as their ordering, increased with increasing block copolymer concentration. The mechanical properties of the nanostructured hydrogels were investigated using stress-sweep rheological testing. These tests revealed a correlation between the block copolymer concentration and the storage modulus of the composite hydrogels. In vitro cellular assays confirmed that the increased modulus of the hydrogels did not limit the ability of the cells to form extensions and become spindled within the three-dimensional (3-D) hydrogel culture environment. Thus, altering the nanostructure of the hydrogel may be used as a strategy to control cellular behavior in 3-D through changes in mechanical properties of the environment.
最近的研究表明，组织工程支架的纳米结构化对其与细胞的相互作用有重大影响。本研究集中于对生物相容性的、生物合成的聚乙二醇-纤维蛋白原缀合物交联的水凝胶支架进行纳米结构化。纳米结构化是通过添加嵌段共聚物 Pluronic F127 来实现的，该嵌段共聚物在一定浓度和温度下自组装成纳米级胶束。低温传输电子显微镜实验检测到 F127 胶束，它们既嵌入在 PEG 化纤维蛋白原水凝胶中，也存在于溶液中。F127 胶束的密度及其有序性随嵌段共聚物浓度的增加而增加。使用应力扫描流变学测试研究了纳米结构化水凝胶的力学性能。这些测试表明，嵌段共聚物浓度与复合水凝胶的储能模量之间存在相关性。体外细胞分析证实，水凝胶模量的增加并没有限制细胞在三维（3-D）水凝胶培养环境中形成延伸和纺锤形的能力。因此，改变水凝胶的纳米结构可以通过改变环境的力学性能来作为控制 3-D 中细胞行为的一种策略。
