Effect of the counterion behavior on the frictional-compressive properties of chondroitin sulfate solutions
Effect of the counterion behavior on the frictional-compressive properties of chondroitin sulfate solutions
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DOI：
10.1016/j.polymer.2009.01.066
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发表时间：
2009-03-20
期刊：
影响因子：
4.6
通讯作者：
Nogovitsin, E. A.
中科院分区：
文献类型：
--
作者：
Baeurle, S. A.;Kiselev, M. G.;Nogovitsin, E. A.
硫酸软骨素是关节软骨的主要成分，众所周知，它对关节的活动性和灵活性产生决定性的影响。长期以来，人们怀疑软骨组织中生理条件的偏差，例如水分和盐含量的缺乏，可能是类风湿疾病的诱因。由于缺乏可靠的实验数据和大量影响软骨组织在自然环境中的结构和特性的控制参数，在分子水平上理解摩擦压缩行为的进展受到阻碍。在本文中，我们使用最近开发的超越平均场（MF）近似水平的场理论方法，研究了硫酸软骨素水溶液对单体和添加盐浓度变化的热力学响应。我们的方法依赖于高斯等效表示法，该方法最近被证明可以为在整个单体浓度范围内不添加盐和添加盐的聚电解质溶液提供可靠的热力学信息。我们将计算结果与实验数据和分子建模数据进行比较，并证明它为重要的热力学性质提供了有用的估计。此外，我们获得了关于各种条件下的水合效应和抗衡离子行为的结论性见解，这表明，在生理盐浓度下，CS 溶液具有最佳的压缩和摩擦学特性。最后，我们的工作为长期偏离生理条件可能引发类风湿病的可能性提供了支持。 (C) 2009 Elsevier Ltd. 保留所有权利。
Chondroitin sulfate is a major constituent of articular cartilage, which is known to affect in a decisive way the mobility and flexibility of our joints. A deviation from the physiological conditions like e g a deficiency of water and salt content, in the cartilage tissue has long been suspected to be a possible trigger for rheumatoid diseases. Progresses in understanding the frictional-compressive behavior on the molecular level have been hindered due to the lack of reliable experimental data and the multitude of controlling parameters, influencing the structure and properties of cartilage tissue in its natural environment. In this paper we study the thermodynamic response of aqueous chondroitin sulfate solutions to changes in the monomer and added salt concentrations, using a recently developed field-theoretic approach beyond the mean field (MF) level of approximation. Our approach relies on the method of Gaussian equivalent representation, which has recently been shown to provide reliable thermodynamic information for polyelectrolyte solutions without and with added salt over the whole range of monomer concentrations. We compare our calculation results to experimental as well as molecular modeling data, and demonstrate that it provides useful estimates for important thermodynamic properties. Moreover, we obtain conclusive insights about the hydration effects and counterion behavior under various conditions, which show that, at the physiological salt concentration, CS solutions have optimal compressive and tribological properties. Finally, our work provides support for the possibility that a long-term deviation from the physiological conditions may trigger rheumatoid diseases. (C) 2009 Elsevier Ltd. All rights reserved.