Li Yingtu, Liao Mingrui, Zhou Jian
School of Chemistry and Chemical Engineering, Guangdong Provincial Key Lab for Green Chemical Product Technology, South China University of Technology, Guangzhou, 510640, P. R. China.
Phys Chem Chem Phys. 2017 Nov 8;19(43):29222-29231. doi: 10.1039/c7cp05284g.
Understanding the interaction mechanism between catechol-cation and inorganic surfaces is vital for controlling the interfacial adhesion behavior. In this work, molecular dynamics simulations are employed to study the adhesion of siderophore analogues (Tren-Lys-Cam, Tren-Arg-Cam and Tren-His-Cam) on silica surfaces with different degrees of ionization and the effects of cationic amino acids and ionic strength on adhesion are discussed. Simulation results indicate that adhesion of catechol-cation onto the ionized silica surface is dominated by electrostatic interactions. At different degrees of ionization, the rank of the adhesions of three siderophore analogues on silica is different. Further analysis shows that the amino acid terminus has a large influence on the adhesion process, especially histidine adhesion on negatively charged surfaces. Tren-Lys-Cam (TLC) has a larger adhesion free energy than Tren-Arg-Cam (TAC) at a higher degree of ionization (18%); both the bulkier structure and delocalized charge of Arg decreased the cation's electrostatic interaction with the charged silica. In addition, the adhesion free energy on ionized silica surfaces decreased with increasing ionic strength of aqueous solutions. A linear correlation between the potential of mean force obtained from umbrella sampling and the rupture force via steered molecular dynamics simulations for siderophore analogue adhesion on silica surfaces is also found. This work may provide some guidance for developing the next generation underwater adhesives.
理解儿茶酚 - 阳离子与无机表面之间的相互作用机制对于控制界面粘附行为至关重要。在这项工作中，采用分子动力学模拟研究了不同电离程度的硅石表面上铁载体类似物（三亚乙基四胺 - 赖氨酸 - 儿茶酚胺、三亚乙基四胺 - 精氨酸 - 儿茶酚胺和三亚乙基四胺 - 组氨酸 - 儿茶酚胺）的粘附情况，并讨论了阳离子氨基酸和离子强度对粘附的影响。模拟结果表明，儿茶酚 - 阳离子在电离的硅石表面上的粘附主要由静电相互作用主导。在不同的电离程度下，三种铁载体类似物在硅石上的粘附顺序不同。进一步分析表明，氨基酸末端对粘附过程有很大影响，尤其是组氨酸在带负电表面上的粘附。在较高电离程度（18%）下，三亚乙基四胺 - 赖氨酸 - 儿茶酚胺（TLC）比三亚乙基四胺 - 精氨酸 - 儿茶酚胺（TAC）具有更大的粘附自由能；精氨酸较大的结构和离域电荷降低了阳离子与带电硅石的静电相互作用。此外，电离硅石表面上的粘附自由能随水溶液离子强度的增加而降低。还发现了通过伞形采样获得的平均力势与通过引导分子动力学模拟得到的铁载体类似物在硅石表面上的断裂力之间的线性相关性。这项工作可能为开发下一代水下粘合剂提供一些指导。
