Shkliar T F, Safronov A P, Kliuzhin I S, Pollack G H, Bliakhman F A
Biofizika. 2008 Nov-Dec;53(6):1000-7.
A correlation between the electrochemical (Donnan) potential and volume swelling has been studied for synthetic polyelectrolyte hydrogels considered as models of cytoskeleton gel-forming biopolymers. Hydrogels based on polyacrylic and polymethacrylic acids with varying network density have been synthesized by radical polymerization in water solution. Electric charge was introduced into the gel network by partial neutralization of acidic monomers by alkali and alkali-earth (hydr)oxides. The electrochemical (Donnan) potential of synthetic gels was measured by a conventional microelectrode technique used in studies of cell potential. It was shown that the negative electric potential became lower as the equilibrium swelling degree decreased for a large number of anionic gels with varying electric charge and network density, i.e., the content of water in the gel decreased. It was shown that the abrupt phase transition of hydrogel structure from a swollen to a contracted state under the influence of K+/Ca2+ ionic exchange is accompanied by a similar decrease in absolute values of the Donnan potential of the gel. A kinetic study showed that volume changes went prior to the decrease in electric potential. This suggests that the volume phase transition in gel structure is the major cause for the electric response. A similarity was shown between the swelling/collapse phase transition in the gel and volume changes in cytoskeleton beneath the cell membrane. Based on the universal properties of synthetic and biopolymer hydrogels, a possible swelling-induced mechanism of cell electrical potential regulation is proposed.
对于被视为细胞骨架凝胶形成生物聚合物模型的合成聚电解质水凝胶，已研究了其电化学（唐南）电位与体积膨胀之间的相关性。通过水溶液中的自由基聚合反应，合成了具有不同网络密度的基于聚丙烯酸和聚甲基丙烯酸的水凝胶。通过用碱和碱土（氢）氧化物对酸性单体进行部分中和，将电荷引入凝胶网络。合成凝胶的电化学（唐南）电位通过用于细胞电位研究的传统微电极技术进行测量。结果表明，对于大量具有不同电荷和网络密度的阴离子凝胶，随着平衡溶胀度降低，负电位变得更低，即凝胶中的含水量降低。结果表明，在K⁺/Ca²⁺离子交换的影响下，水凝胶结构从溶胀状态到收缩状态的突然相变伴随着凝胶唐南电位绝对值的类似降低。动力学研究表明，体积变化先于电位降低。这表明凝胶结构中的体积相变是电响应的主要原因。凝胶中的溶胀/塌陷相变与细胞膜下细胞骨架的体积变化之间表现出相似性。基于合成水凝胶和生物聚合物水凝胶的普遍性质，提出了一种可能的由肿胀诱导的细胞电位调节机制。
