Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Tokyo 152-8550, Japan.
J Phys Chem B. 2021 Oct 7;125(39):10893-10899. doi: 10.1021/acs.jpcb.1c02594. Epub 2021 Sep 24.
Controllable self-assembly of peptides on solid surfaces has been investigated for establishing functional bio/solid interfaces. In this work, we study the influence of organic solvents on the self-assembly of a fibroin-like peptide on a graphite surface. The peptide has been designed by mimicking fibroin proteins to have strong hydrogen bonds among peptides enabling their self-assembly. We have employed cosolvents of water and organic solvents with a wide range of dielectric constants to control peptide self-assembly on the surface. Atomic force microscopy has revealed that the peptides self-assemble into highly ordered monolayer-thick linear structures on graphite after incubation in pure water, where the coverage of peptides on the surface is more than 85%. When methanol is mixed, the peptide coverage becomes zero at a threshold concentration of 30% methanol on graphite and 25% methanol on MoS. The threshold concentration in ethanol, isopropanol, dimethyl sulfoxide, and acetone varies depending on the dielectric constant with restraining self-assembly of the peptides, and particularly low dielectric-constant protic solvents prevent the peptide self-assembly significantly. The observed phenomena are explained by competitive surface adsorption of the organic solvents and peptides and the solvation effect of the peptide assembly.
可控的多肽在固体表面上的自组装已经被研究用于建立功能生物/固体界面。在这项工作中，我们研究了有机溶剂对类似丝蛋白的多肽在石墨表面上自组装的影响。该多肽通过模拟丝蛋白来设计，具有强氢键，使多肽能够自组装。我们采用了水和有机溶剂的共溶剂，介电常数范围很广，以控制多肽在表面上的自组装。原子力显微镜揭示，在纯水中孵育后，多肽在石墨上自组装成高度有序的单层线性结构，表面上的多肽覆盖率超过 85%。当甲醇混合时，在 30%甲醇（石墨）和 25%甲醇（MoS）的阈值浓度下，多肽覆盖率变为零。在乙醇、异丙醇、二甲基亚砜和丙酮中，阈值浓度取决于介电常数，介电常数越低的质子溶剂会显著抑制多肽的自组装。观察到的现象可以通过有机溶剂和多肽的竞争表面吸附以及多肽组装的溶剂化效应来解释。
