Spatial Organization of Ions in Supramolecular Nanostructures

在化学系大分子、超分子和纳米化学项目的支持下，西北大学的Samuel Stupp教授和Monica Olvera de la Cruz教授将探索由包含两种不同片段的分子（称为两亲分子）组装形成的纳米级结构：一种与水有亲和关系，另一种与水不能很好地混合。具体来说，研究人员将研究如何利用携带一种或多种带电物质（离子或电解质）的各种物质的排列来改变纳米结构的结构和功能。构建模块将以肽为基础，因此这些发现可以阐明几个重要的生物学过程。这项工作的灵感来自于细胞的自然功能，包括信号、运动和最终的生存，所有这些都依赖于细胞膜内外离子的严格调节。研究人员将同时使用实验和计算方法来了解添加的电解质如何与纳米材料相互作用，以及它们如何影响关键的细胞功能，如催化、能量储存和生物活性。这项工作预计将对教育产生广泛的影响，因为它是一种冒险的方法，试图在传统的科学探究之外进行创新，因此有很大的潜力获得意想不到的发现，这对早期职业科学家来说是一个很好的激励。本研究计划研究离子的存在如何影响基于自组装肽两亲分子的超分子纳米结构的形状和尺寸。这项工作还将探讨这些离子在纳米结构内及其周围环境中的空间定位如何影响它们的移动性。这项研究的动机是Stupp实验室最近的一项发现，该发现令人惊讶地表明，离子云可以围绕超分子纳米结构进行设计，并通过离子液体和自组装PA分子之间的内部相互作用来控制。假设是，大的有机离子可以作为掺杂剂，产生更密集的云作为电解质储层，这将反过来影响诸如生物活性和电荷传输的外部控制等特性。通过改变溶液的离子强度和离子类型，预计超分子结构的水合作用将改变以及相关水分子的极化，并以这种方式提供可能调整离子迁移率的机会。这项工作可能会导致新的材料，也对我们对环境离子在生物系统中的作用的理解有很大的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Samuel Stupp and Professor Monica Olvera de la Cruz of Northwestern University will explore nano-sized structures formed by the assembly of molecules (named amphiphiles) containing two distinct segments: one that has affinity for water and one that does not mix well with water. Specifically, the investigators will study how the arrangement of various species that bear one or more charged species (ions or electrolytes) can be used to change the structure and function of the nano-sized structures. The building blocks will be based on peptides, and therefore the findings can illuminate several biologically important processes. This work is inspired by the natural functions of cells, including signaling, movement, and ultimately survival, all of which depend on the tight regulation of ions inside and outside the cell membrane. The researchers will use a simultaneous experimental and computational approach to understand how added electrolytes interact with nanomaterials and how they impact critical cellular functions such as catalysis, energy storage, and bioactivity. This work is expected to have a broad impact on education as it is a risky approach that attempts to innovate beyond traditional scientific inquiries and therefore has a great deal of potential for unexpected discoveries, a good motivator for early career scientists.The planned research under this study is to investigate how the presence of ions affects the shape and dimensions of supramolecular nanostructures based on self-assembling peptide amphiphile molecules. The work will also probe how the spatial positioning of these ions within nanostructures and in their immediate environment affects their mobility. The study is motivated by a recent discovery in the Stupp laboratory, which surprisingly showed that ion clouds can be engineered around supramolecular nanostructures and controlled by internal interactions between ionic liquids and the self-assembling PA molecules. The hypothesis is that large organic ions can act as dopants that produce denser clouds as electrolyte reservoirs that will impact in turn on properties such as bioactivity and external control of charge transport. By varying ionic strength of solutions and ion type, it is expected that hydration of the supramolecular structures will change as well as polarize associated water molecules and, in this way, provide for an opportunity to possibly tune ionic mobility. This work could lead to novel materials and also have great impact on our understanding of the role of environmental ions in biological systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.