Supramolecular filament hydrogels are an emerging class of biomaterials that hold great promise for regenerative medicine, tissue engineering, and drug delivery. However, fine-tuning of their bulk mechanical properties at the molecular level without altering their network structures remains a significant challenge. Here we report an isomeric strategy to construct amphiphilic peptides through the conjugation of isomeric hydrocarbons to influence the local viscoelastic properties of their resulting supramolecular hydrogels. In this case, the packing requirements of the chosen isomeric hydrocarbons within the supramolecular filaments are dictated by their atomic arrangements at the molecular and intermolecular levels. Atomistic molecular dynamics simulations suggest that this design strategy can subtly alter the molecular packing at the interface between the peptide domain and the hydrophobic core of the supramolecular assemblies, without changing both the filament width and morphology. Our results from wide-angle X-ray scattering and molecular simulations further confirm that alterations to the intermolecular packing at the interface impact the strength and degree of hydrogen bonding within the peptide domains. This subtle difference in the isomeric hydrocarbon design and their consequent packing difference led to variations in the persistence length of the individual supramolecular filaments. Microrheological analysis reveals that this difference in filament stiffness enables the fine-tuning of the mechanical properties of the hydrogel at the macroscopic scale. We believe that this isomeric platform provides an innovative method to tune the local viscoelastic properties of supramolecular polymeric hydrogels without necessarily altering their network structures.

中文翻译：

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超分子长丝水凝胶的机械性能的类似控制†

超分子丝水凝胶是一类新兴的生物材料，在再生医学，组织工程学和药物输送方面具有广阔的前景。然而，在分子水平上微调它们的整体机械性能而不改变它们的网络结构仍然是一个巨大的挑战。在这里我们报告了通过异构烃的共轭来影响其产生的超分子水凝胶的局部粘弹性特性来构建两亲性肽的异构策略。在这种情况下，所选择的异构烃在超分子丝中的堆积要求取决于它们在分子和分子间水平上的原子排列。原子分子动力学模拟表明，这种设计策略可以巧妙地改变肽结构域与超分子组装体疏水核之间界面处的分子堆积，而不会同时改变长丝宽度和形态。我们从广角X射线散射和分子模拟获得的结果进一步证实，界面处分子间堆积的变化会影响肽域内氢键的强度和程度。异构碳氢化合物设计中的细微差异及其随之而来的堆积差异导致各个超分子丝的持久长度发生变化。微观流变学分析表明，长丝刚度的这种差异使得能够在宏观尺度上微调水凝胶的机械性能。我们相信，这种异构平台提供了一种创新的方法，可以调节超分子聚合物水凝胶的局部粘弹性，而不必改变其网络结构。