Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Institute of Natural Sciences, Westlake Institute for Advanced Study, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province China.
Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Institute of Advanced Technology, Westlake Institute for Advanced Study, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province China.
ACS Nano. 2022 Mar 22;16(3):4126-4138. doi: 10.1021/acsnano.1c09860. Epub 2022 Mar 1.
Anisotropic structures made by hierarchical self-assembly and crystallization play an essential role in the living system. However, the spontaneous formation of liquid crystalline hydrogel of low molecular weight organic molecules with controlled properties remains challenging. This work describes a rational design of tetrapeptide without N-terminal modification and chemical conjugation that utilizes intermolecular interactions to drive the formation of nanofiber bundles in a two-component system, which could not be accessed by a single component. The diameter of nanofibers can be simply controlled by varying the enantiomer of electrostatic pairs. Mutation of lysine (K) to arginine (R) results in an over 30-fold increase of mechanical property. Mechanistic studies using different techniques unravel the mechanism of self-assembly and formation of anisotropic liquid crystalline domains. All-atom molecular dynamics simulations reveal that the mixture of heterochiral peptides self-assembles into a nanofiber with a larger width compared to the homochiral assemblies due to the different stacking pattern and intermolecular interactions. The intermolecular interactions show an obvious increase by substituting the K with R, facilitating a more stable assembly and further altering the assembly mechanics and bulk material properties. Moreover, we also demonstrated that the hydrogel properties can be easily controlled by incorporating a light-responsive group. This work provides a method to generate the liquid crystalline hydrogel from isotropic monomers.
各向异性结构通过分级自组装和结晶起着至关重要的作用在生命系统中。然而，自发形成具有可控性能的低分子量有机分子的液晶水凝胶仍然具有挑战性。这项工作描述了一种四肽的合理设计，没有 N 端修饰和化学偶联，利用分子间相互作用在双组分体系中驱动纳米纤维束的形成，而单一组分则无法实现。纳米纤维的直径可以通过改变静电对的对映体简单控制。将赖氨酸 (K) 突变为精氨酸 (R) 可使机械性能提高 30 多倍。使用不同技术的机理研究揭示了自组装和各向异性液晶畴形成的机理。全原子分子动力学模拟表明，由于不同的堆积模式和分子间相互作用，杂手性肽的混合物自组装成具有较大宽度的纳米纤维，与同手性组装体相比。通过用 R 取代 K，分子间相互作用明显增加，促进了更稳定的组装，进一步改变了组装力学和块状材料性能。此外，我们还证明可以通过掺入光响应基团来轻松控制水凝胶性能。这项工作提供了一种从各向同性单体生成液晶水凝胶的方法。
