Center for Biomaterials and Tissue Engineering, Universidad Politécnica de Valencia, Spain.
Colloids Surf B Biointerfaces. 2010 Jul 1;78(2):310-6. doi: 10.1016/j.colsurfb.2010.03.019. Epub 2010 Mar 29.
Fibronectin (FN) fibrillogenesis is a cell-mediated process involving integrin activation that results in conformational changes of FN molecules and the organization of actin cytoskeleton. A similar process can be induced by some particular chemistries in the absence of cells, e.g., poly(ethyl acrylate) (PEA), which enhance FN-FN interactions leading to the formation of a biologically active network on the material surface. We have investigated the organization of a recombinant fragment of fibronectin (FNIII(7-10)) upon adsorption on this particular chemistry, PEA. Atomic force microscopy (AFM) was used to identify individual molecules of the fragment after adsorption, as well as the evolution of the distribution of adsorbed molecules on the surface of the material as the concentration of the adsorbing solution increased. Globular molecules that turn into small aggregates were found as a function of solution concentration. Above a threshold concentration of the adsorbing solution (50 microg/mL) an interconnected network of the FNIII(7-10) fragment is obtained on the material surface. The bioavailability of specific cell adhesion domains, including RGD, within the molecules was higher on PEA than on the control glass. The biological activity of the fragment was further investigated by evaluating focal adhesion formation and actin cytoskeleton for MC3T3-E1 osteoblast-like cells. Well-developed focal adhesion complexes and insertions of actin stress fibers were found on PEA in a similar way as it happens in the control SAM-OH. Moreover, increasing the hydrophilicity of the surface by incorporating -OH groups led to globular molecules of the fragment homogeneously distributed throughout the surface; and the cell-material interaction is reduced as depicted by the lack of well-developed focal plaques and actin cytoskeleton.
纤维连接蛋白（FN）纤丝生成是一个涉及整合素激活的细胞介导过程，导致 FN 分子构象变化和肌动蛋白细胞骨架的组织。在没有细胞的情况下，某些特定的化学物质也可以诱导类似的过程，例如聚（丙烯酸乙酯）（PEA），它增强了 FN-FN 相互作用，导致在材料表面形成具有生物活性的网络。我们已经研究了纤维连接蛋白（FNIII（7-10））的重组片段在这种特殊化学物质 PEA 上的吸附情况。原子力显微镜（AFM）用于在吸附后识别片段的单个分子，以及随着吸附溶液浓度的增加，材料表面上吸附分子的分布的演变。发现球形分子会转变成小聚集体，这取决于溶液浓度。在吸附溶液的浓度超过一个阈值（50μg/mL）时，FNIII（7-10）片段在材料表面上形成相互连接的网络。在 PEA 上，分子中特定细胞粘附结构域（包括 RGD）的生物可用性高于对照玻璃。通过评估 MC3T3-E1 成骨样细胞中的粘着斑形成和肌动蛋白细胞骨架，进一步研究了片段的生物活性。在 PEA 上以与对照 SAM-OH 相同的方式发现了发育良好的粘着斑复合物和肌动蛋白应力纤维的插入。通过引入-OH 基团增加表面的亲水性，导致片段的球形分子均匀分布在整个表面上；并且细胞与材料的相互作用减少，如缺乏发育良好的粘着斑和肌动蛋白细胞骨架所示。
