Lee J H, Lee J W, Khang G, Lee H B
Department of Macromolecular Science, Hannam University, Taejan, Korea.
Biomaterials. 1997 Feb;18(4):351-8. doi: 10.1016/s0142-9612(96)00128-7.
Functional group gradient surfaces where the surface density of grafted functional groups changes gradually along the sample length were prepared on low density polyethylene (PE) sheets by corona discharge treatment with gradually increasing power and graft copalymerization of acrylic acid (AA), sodium p-styrene sulphonate (NaSS), and N,N-dimethyl aminopropyl acrylamide (DMAPAA). AA and NaSS are negatively chargeable and DMAPAA is positively chargeable in phosphate buffered saline or cell culture medium at pH 7.3-7.4. The functional group gradient surfaces were characterized by the measurement of water contact angle, Fourier transform infrared spectroscopy in the attenuated total reflectance mode, and electron spectroscopy for chemical analysis. All these measurements indicated that the functional groups were grafted on the PE surfaces with gradual increase of their density. The interaction of Chinese hamster ovary cells with the functional group gradient surfaces along the sample length was investigated. The cells that had adhered and grown on the surfaces were counted and observed by scanning electron microscopy. It was observed that a greater quantity of the cells had adhered and grown onto the positions with moderate density of the functional groups. This may be related to the hydrophilicity of the surface. The DMAPAA-grafted surface showed a large amount of cell attachment probably owing to the positive charge character, while the AA-grafted surface, which is negatively charged, showed poor cell attachment, as expected. The NaSS-grafted surface which is also negatively charged showed a large amount of cell attachment. This may be closely associated with the existence of an aromatic ring close to the ionizable group in NaSS. It seems that surface functional groups and their charge character as well as wettability play important roles for cell adhesion, spreading, and growth.
通过采用功率逐渐增加的电晕放电处理以及丙烯酸（AA）、对苯乙烯磺酸钠（NaSS）和N，N - 二甲基氨基丙基丙烯酰胺（DMAPAA）的接枝共聚反应，在低密度聚乙烯（PE）片材上制备了官能团梯度表面，其中接枝官能团的表面密度沿样品长度逐渐变化。在pH 7.3 - 7.4的磷酸盐缓冲盐水或细胞培养基中，AA和NaSS可带负电荷，DMAPAA可带正电荷。通过测量水接触角、衰减全反射模式下的傅里叶变换红外光谱以及化学分析用电子能谱对官能团梯度表面进行了表征。所有这些测量表明官能团以其密度逐渐增加的方式接枝到PE表面上。研究了中国仓鼠卵巢细胞沿样品长度与官能团梯度表面的相互作用。对粘附并生长在表面上的细胞进行计数，并通过扫描电子显微镜观察。观察到大量细胞粘附并生长在官能团密度适中的位置上。这可能与表面的亲水性有关。接枝DMAPAA的表面由于其正电荷特性显示出大量细胞附着；而如预期的那样，带负电荷的接枝AA的表面显示出较差的细胞附着。同样带负电荷的接枝NaSS的表面也显示出大量细胞附着。这可能与NaSS中靠近可电离基团的芳环的存在密切相关。表面官能团及其电荷特性以及润湿性似乎对细胞粘附、铺展和生长起着重要作用。
