International Center for Materials Nanoarchitechtonics , National Institute for Materials Science , 1-2-1 Sengen , Tsukuba , Ibaraki 305-0047 , Japan.
Institute for Chemical Research , Kyoto University , Gokasho, Uji, Kyoto 611-0011 , Japan.
Langmuir. 2018 Apr 3;34(13):4043-4051. doi: 10.1021/acs.langmuir.8b00233. Epub 2018 Mar 20.
Charged substrates are expected to promote cell adhesion via electrostatic interaction, but it remains unclear how cells adhere to these substrates. Here, initial cell adhesion (<30 min) was re-examined on charged substrates in serum-containing and serum-free media to distinguish among various cell adhesion mechanisms (i.e., electrostatic interaction, hydrophobic interaction, and biological interaction). Cationic and anionic methacrylate copolymers were coated on nonionic nontissue culture-treated polystyrene to create charged substrates. Cells adhered similarly on cationic, anionic, and nonionic substrates in serum-free medium via integrin-independent mechanisms, but their adhesion forces differed (anionic > cationic > nonionic substrates), indicating that cell adhesion is not mediated solely by the cells' negative charge. In serum-containing medium, the cells adhered minimally on anionic and nonionic substrates, but they adhered abundantly on cationic substrates via both integrin-dependent and -independent mechanisms. These results suggest that neither electrostatic force nor protein adsorption is accountable for cell adhesion. Conclusively, the observed phenomena revealed a gap in the generally accepted understanding of cell adhesion mechanisms on charged polymeric substrates. A reanalysis of their mechanisms is necessary.
带电荷的底物有望通过静电相互作用促进细胞黏附，但目前尚不清楚细胞如何黏附在这些底物上。在此，我们重新研究了含血清和无血清培养基中带电荷底物上的初始细胞黏附（<30 分钟），以区分各种细胞黏附机制（即静电相互作用、疏水性相互作用和生物相互作用）。将阳离子和阴离子甲基丙烯酸酯共聚物涂覆在非离子非组织培养处理的聚苯乙烯上，以制备带电荷的底物。在无血清培养基中，细胞通过整合素非依赖性机制相似地黏附在阳离子、阴离子和非离子底物上，但它们的黏附力不同（阴离子>阳离子>非离子底物），这表明细胞黏附不仅仅是由细胞的负电荷介导的。在含血清的培养基中，细胞在阴离子和非离子底物上的黏附很少，但它们通过整合素依赖性和非依赖性机制在阳离子底物上大量黏附。这些结果表明，静电作用力和蛋白质吸附都不能解释细胞黏附。总之，观察到的现象揭示了人们对带电荷聚合物底物上细胞黏附机制的普遍理解存在差距。有必要对其机制进行重新分析。
