A commentary on the screened-Oseen, counterion-condensation formalism of polyion electrophoresis.
A commentary on the screened-Oseen, counterion-condensation formalism of polyion electrophoresis.
复制标题
对聚离子电泳的屏蔽奥辛反离子缩合形式的评论。
DOI：
10.1016/s0006-3495(00)76578-7
复制
发表时间：
2000
影响因子：
3.4
通讯作者：
D. Stigter
中科院分区：
文献类型：
--
作者：
S. Allison;D. Stigter
使用线性理论，特别是反凝聚（CC）理论，在描述电泳的双链，是批评的几个理由。首先，CC理论在描述聚电解质周围离子的平衡分布时存在问题。第二，CC理论被用来治疗离子弛豫的线性理论相对于聚离子电荷，尽管事实上，离子弛豫产生的非线性电荷效应的后果。在过去的70年里，一些研究人员已经很好地建立了这种非线性的球形，圆柱形和任意形状的模型聚离子。第三，目前使用的CC理论忽略了电泳障碍以及凝聚的抗衡离子的离子弛豫，只包括这样的相互作用，为非凝聚的抗衡离子。因为大多数凝聚的抗衡离子位于聚离子的剪切表面之外（在DNA的例子中），离子凝聚的假设是人为的和非物理的。第四，目前在上述理论中使用的基于屏蔽Oseen张量的奇异解是完全错误的，并且不能解释溶剂的不可压缩性。实际的奇异的解决方案，这一直是可用的，进行了讨论。最后指出，基于经典电泳理论（J.T.G. Overbeek，Kolloid-Beih，1943，54：287-364）。
The use of linear theory, in particular, counterion condensation (CC) theory, in describing electrophoresis of polyelectrolyte chains, is criticized on several grounds. First, there are problems with CC theory in describing the equilibrium distribution of ions around polyelectrolytes. Second, CC theory is used to treat ion relaxation in a linear theory with respect to the polyion charge despite the fact that ion relaxation arises as a consequence of nonlinear charge effects. This nonlinearity has been well established by several investigators over the last 70 years for spherical, cylindrical, and arbitrarily shaped model polyions. Third, current use of CC theory ignores the electrophoretic hindrance as well as the ion relaxation for condensed counterions and only includes such interactions for uncondensed counterions. Because most of the condensed counterions lie outside the shear surface of the polyion (in the example of DNA), the assumption of ion condensation is artificial and unphysical. Fourth, the singular solution, based on a screened Oseen tensor, currently used in the above mentioned theories is simply wrong and fails to account for the incompressibility of the solvent. The actual singular solution, which has long been available, is discussed. In conclusion, it is pointed out that numerical alternatives based on classic electrophoresis theory (J.T.G. Overbeek, Kolloid-Beih, 1943, 54:287–364) are now available.