Wang Shuhao, Zan Fei, Ke Yu, Wu Gang
National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou, 510006, China.
J Mater Chem B. 2018 Mar 28;6(12):1734-1743. doi: 10.1039/c7tb02967e. Epub 2018 Mar 5.
Introducing or grafting molecules onto biomaterial surfaces to regulate cell destination via biophysical cues is one of the important steps for biomaterial design in tissue engineering. Understanding how cells feel the substrate makes it easier to learn the mechanism behind cell-material interaction. In this study, on a glass substrate, we constructed poly-phenoxyethyl methacrylate (PHEMA) brushes having different lengths via a surface-induced atom transfer radical polymerization (SI-ATRP) method. FTIR-ATR and XPS tests of the formed polymer brushes indicate that these brushes have characteristic chemical structures of PHEMA; the polymer brush length revealed by the AFM tests increases linearly with reaction time. Cell lines of BMSCs, ATDC5, and human chondrocytes (HC) were cultured on these substrates to evaluate proliferation, adhesion, and differentiation. Our results demonstrated that the cells cultured on the substrates with short PHEMA brushes developed a spread morphology and organized actin fibers as compared to the cells cultured on those with long brushes. Different cell lines showed different responses depending on the PHEMA brush length. Cells cultured on long PHEMA brushes displayed a more rounded shape, higher gene expression of FAK and integrin, and lower gene expression of NCAM and N-cadherin as compared to those, especially ATDC5 cells, cultured on short PHEMA brushes. On PHEMA brushes with a long length, the cell lines express higher cartilage-specific genes including Sox9 and Col2 and GAG in ECM. The results suggest that polymer brushes having different lengths may interfere with the behavior of the cells cultured on them.
通过生物物理线索将分子引入或嫁接到生物材料表面以调节细胞归宿是组织工程中生物材料设计的重要步骤之一。了解细胞如何感知底物有助于更深入地了解细胞与材料相互作用背后的机制。在本研究中，我们通过表面诱导原子转移自由基聚合（SI-ATRP）方法在玻璃基板上构建了具有不同长度的聚甲基丙烯酸苯氧基乙酯（PHEMA）刷。对形成的聚合物刷进行的傅里叶变换红外光谱-衰减全反射（FTIR-ATR）和X射线光电子能谱（XPS）测试表明，这些刷具有PHEMA的特征化学结构；原子力显微镜（AFM）测试显示的聚合物刷长度随反应时间呈线性增加。将骨髓间充质干细胞（BMSCs）、ATDC5细胞系和人软骨细胞（HC）培养在这些基板上，以评估细胞的增殖、黏附和分化情况。我们的结果表明，与在长PHEMA刷基板上培养的细胞相比，在短PHEMA刷基板上培养的细胞呈现出铺展形态并形成了肌动蛋白纤维。不同细胞系对PHEMA刷长度的反应不同。与在短PHEMA刷上培养的细胞相比，尤其是ATDC5细胞，在长PHEMA刷上培养的细胞呈现出更圆的形状，黏着斑激酶（FAK）和整合素的基因表达更高，而神经细胞黏附分子（NCAM）和N-钙黏蛋白的基因表达更低。在长PHEMA刷上，细胞系表达更高的软骨特异性基因，包括Sox9、Col2以及细胞外基质（ECM）中的糖胺聚糖（GAG）。结果表明，不同长度的聚合物刷可能会干扰在其上培养的细胞的行为。
