Impact of Molecular Architecture and Adsorption Density on Adhesion of Mussel-Inspired Surface Primers with Catechol-Cation Synergy
Impact of Molecular Architecture and Adsorption Density on Adhesion of Mussel-Inspired Surface Primers with Catechol-Cation Synergy
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DOI：
10.1021/jacs.9b04337
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发表时间：
2019-11-27
影响因子：
15
通讯作者：
Israelachvili, Jacob N.
中科院分区：
文献类型：
--
作者：
Degen, George D.;Stow, Parker R.;Israelachvili, Jacob N.
海洋贻贝分泌富含儿茶酚和阳离子胺残基的蛋白质，这些残基取代水合层并通过称为儿茶酚-阳离子协同作用的协同结合效应粘附到水下带电表面。含有成对的儿茶酚和阳离子官能团的贻贝类粘合剂是一类有前途的生物医学应用材料，但很少有研究解决这些材料的分子粘附机制。为了确定这些功能的分子内相邻是否是必要的强大的粘附，合成了一套铁载体类似物表面引物与儿茶酚和阳离子官能团之间的分子内间距的系统变化。进行粘附力测量与表面力装置（SFA）允许粘合剂失效区分从内聚失效，并表明，故障模式严重依赖于铁载体类似物的吸附密度。这些分子的白云母在电解质水溶液中的粘附力表明，儿茶酚和阳离子官能团的直接分子内邻接对于协同结合是不必要的。然而，我们发现，增加儿茶酚阳离子间距通过将非结合域的结果在降低粘附力，我们归因于儿茶酚功能的密度下降。提出了一种基于静电驱动吸附和随后的儿茶酚功能结合的儿茶酚-阳离子协同作用机制。这项工作应指导设计新的粘合剂结合到带电表面在盐水环境中。
Marine mussels secrete proteins rich in residues containing catechols and cationic amines that displace hydration layers and adhere to charged surfaces under water via a cooperative binding effect known as catechol-cation synergy. Mussel-inspired adhesives containing paired catechol and cationic functionalities are a promising class of materials for biomedical applications, but few studies address the molecular adhesion mechanism(s) of these materials. To determine whether intramolecular adjacency of these functionalities is necessary for robust adhesion, a suite of siderophore analog surface primers was synthesized with systematic variations in intramolecular spacing between catechol and cationic functionalities. Adhesion measurements conducted with a surface forces apparatus (SFA) allow adhesive failure to be distinguished from cohesive failure and show that the failure mode depends critically on the siderophore analog adsorption density. The adhesion of these molecules to muscovite mica in an aqueous electrolyte solution demonstrates that direct intramolecular adjacency of catechol and cationic functionalities is not necessary for synergistic binding. However, we show that increasing the catechol-cation spacing by incorporating nonbinding domains results in decreased adhesion, which we attribute to a decrease in the density of catechol functionalities. A mechanism for catechol-cation synergy is proposed based on electrostatically driven adsorption and subsequent binding of catechol functionalities. This work should guide the design of new adhesives for binding to charged surfaces in saline environments.