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教授将探索由分子(称为两亲分子)组装形成的纳米级结构，其中包含两个不同的部分：一个与水有亲和力，另一个与水不能很好地混合。具体地说，研究人员将研究如何利用携带一个或多个带电物种(离子或电解质)的各种物种的排列来改变纳米结构的结构和功能。构建的基础将是多肽，因此这些发现可以阐明几个生物学上重要的过程。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。研究人员将使用一种同时进行实验和计算的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、能量存储和生物活性。这项工作有望对教育产生广泛的影响，因为这是一种冒险的方法，试图超越传统的科学研究进行创新，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动机。这项研究计划进行的研究是调查离子的存在如何影响基于自组装多肽两亲分子的超分子纳米结构的形状和尺寸。这项工作还将探索这些离子在纳米结构内及其邻近环境中的空间位置如何影响它们的迁移率。这项研究是由Stupp实验室最近的一项发现推动的，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工程设计，并由离子液体和自组装PA分子之间的内部相互作用控制。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液储存库，这反过来将影响生物活性和电荷传输的外部控制等性质。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化作用将改变和极化相关的水分子，并以这种方式提供可能调节离子流动性的机会。这项工作可能会带来新的材料，也会对我们理解环境离子在生物系统中的作用产生很大影响。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.