Effect of Core Oligomer Length on the Phase Behavior and Assembly of π-Conjugated Peptides
Effect of Core Oligomer Length on the Phase Behavior and Assembly of π-Conjugated Peptides
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DOI：
10.1021/acsami.0c02095
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发表时间：
2020-05-06
影响因子：
9.5
通讯作者：
Schroeder, Charles M.
中科院分区：
文献类型：
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作者：
Jira, Edward R.;Shmilovich, Kirill;Schroeder, Charles M.
生物杂化分子是一类用于控制电子活性有机物的组装行为和功能性质的多功能材料。在这项工作中，我们研究了pi-共轭核心的大小对一系列pi-共轭多肽的组装和相行为的影响，这些多肽由定义长度的低聚硫吩核和序列定义的多肽(OTX，其中X=4，5，6是噻吩类核心单元的数量)组成。有趣的是，我们发现具有相对较短的OT4核心的pi-共轭多肽可以组装成有序的、高长径比的一维结构，而具有较长的OT5和OT6核心的pi-共轭多肽可以组装成无序结构或低长宽比的一维结构，这取决于组装条件。实验测定了组装材料的相图，作为离子强度、pH、温度和多肽浓度的函数，揭示了分子序列和pi共轭核长度对组装形态的影响。分子动力学(MD)模拟被进一步用于探索由于分子同一性的细微变化而引起的组装中微尺度差异的起源。广泛地说，我们的工作阐明了控制pi-共轭多肽组装的机制，这将有助于为软电子应用提供高效的材料加工。总体而言，这些结果突出了生物杂化材料的复杂相行为，包括分子序列对组装行为和形态的影响。
Biohybrid molecules are a versatile class of materials for controlling the assembly behavior and functional properties of electronically active organics. In this work, we study the effect of the size of the pi-conjugated core on the assembly and phase behavior for a series of pi-conjugated peptides consisting of oligothiophene cores of defined lengths flanked by sequence-defined peptides (OTX, where X = 4, 5, 6 is the number of thiophene core units). Interestingly, we find that pi-conjugated peptides with relatively short OT4 cores assemble into ordered, high aspect ratio, one-dimensional (1D) structures, whereas pi-conjugated peptides with longer OT5 and OT6 cores assemble into disordered structures or lower aspect ratio 1D structures depending on assembly conditions. Phase diagrams for assembled materials are experimentally determined as a function of ionic strength, pH, temperature, and peptide concentration, revealing the impact of molecular sequence and pi-conjugated core length on assembled morphologies. Molecular dynamics (MD) simulations are further used to probe the origins of microscale differences in assembly that arise from subtle changes in molecular identity. Broadly, our work elucidates the mechanisms governing the assembly of pi-conjugated peptides, which will aid in efficient materials processing for soft electronic applications. Overall, these results highlight the complex phase behavior of biohybrid materials, including the impact of molecular sequence on assembly behavior and morphology.