Sparks David J, Romero-González Maria E, El-Taboni Elfateh, Freeman Colin L, Hall Shaun A, Kakonyi Gabriella, Swanson Linda, Banwart Steven A, Harding John H
Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK.
Phys Chem Chem Phys. 2015 Nov 7;17(41):27357-65. doi: 10.1039/c5cp00945f.
Macromolecular binding to minerals is of great importance in the formation of biofilms, and carboxylate functional groups have been found to play a pivotal role in the functioning of these macromolecules. Here we present both fluorescence time-resolved anisotropy measurements and simulation data on the conformational behaviour and binding of a poly acrylic acid polymer. In solution the polymer exhibits a pH dependent behaviour, with a coiled conformation at a low pH and extended conformation at higher pH values. The polymer is readily adsorbed on the surface of calcite, preferring to bind in an extended conformation, with the strength of the adsorption dependent on the pH and presence of counter ions. We discuss the reasons why the calculated adsorption free energy differs from that obtained from a Langmuir isotherm analysis, showing that they refer to different quantities. The enhanced binding of the extended conformations shows the importance of flexibility in the binding of macromolecules.
大分子与矿物质的结合在生物膜形成过程中至关重要，并且已发现羧基官能团在这些大分子的功能发挥中起关键作用。在此，我们展示了关于聚丙烯酸聚合物的构象行为和结合的荧光时间分辨各向异性测量结果及模拟数据。在溶液中，该聚合物表现出pH依赖性行为，在低pH值下呈卷曲构象，在较高pH值下呈伸展构象。该聚合物易于吸附在方解石表面，更倾向于以伸展构象结合，吸附强度取决于pH值和抗衡离子的存在。我们讨论了计算得到的吸附自由能与从朗缪尔等温线分析获得的吸附自由能不同的原因，表明它们所指的是不同的量。伸展构象的增强结合表明了大分子结合中灵活性的重要性。
