Self-assembly mediated by aqueous interfaces: A novel computational study of structure, thermodynamics, and dynamics

谢哈尔自组装在制造新材料的自然过程和技术中扮演着重要的角色。自组装研究的一个关键目标是更好地了解组成成分的相互作用如何导致自组装结构，以及由此产生的性质。水界面无处不在，通常在自组装中起着重要作用，然而，对界面如何调节组装缺乏详细的了解。PI提出了一种新的计算方法，使用分子(MD)和布朗动力学(BD)模拟来阐明界面介导的水界面组装。在延伸的界面附近，特别是疏水界面附近，水的结构、动力学和波动的性质发生了根本的变化。他们假设，水性质的改变反过来会影响大分子的结构、稳定性和相互作用。这一假设得到了重要的前期工作的支持。他们预计，大分子在界面上的组装将与在散装水中的组装显著不同。对导致复杂的界面介导组装的过程的基本理解是我们提案的中心焦点。了解水在界面上的分子行为对于了解界面如何改变其附近的水介导的相互作用至关重要。因此，需要在从单个水分子到大的自组装结构的大范围长度尺度上对现象进行建模。为此，该方法侧重于对从小溶质到大分子组装的层次化复杂系统进行建模。这项工作的具体目标是：(1)使用MD模拟来量化从小的模型溶质到柔性的均聚和杂聚的单分子的结合和行为，以及水界面上的多肽。(2)量化界面如何调节其附近的分子对和大量分子之间的相互作用。(3)开发粗粒度的布朗动力学模拟来考察许多粒子在界面上的聚集。从AIMS 1和AIMS 2获得的有关接口作用的信息将作为BD模拟的重要输入。(4)探索和量化流体流动和界面变形对结构、装配过程和装配结构的流动特性的影响。智力价值：尽管从实验和理论的角度来看，界面上的水都是一个非常活跃的研究领域，但对水的性质改变如何影响界面上的水中介相互作用的理解确实还处于初级阶段。这项工作有望通过提供这种分子水平的理解并揭示其在更大长度和时间尺度上对界面介导组装的影响来开辟新的天地。我们的团队所做的重要的前期工作，以及来自许多不同团队的专注于生物和胶体系统的实验数据，都表明了水界面在各种基本问题和技术应用中的重要作用。这项工作有可能提供一个框架来解释这些实验结果，使技术应用和新材料开发成为可能。更广泛的影响：界面在生物和纳米系统中无处不在，在从分离、涂层到新材料开发的众多技术应用中也发挥着核心作用。最近的工作强调了界面在成核和加速alzheimers多肽的纤维形成中的作用。该项目将影响对许多这样的自然过程的理解，并增强我们设计基于界面自组装的新技术的能力。这项研究还伴随着在教育和推广方面的重大努力。这包括本科生参与研究，以及通过伦斯勒的两个不同的项目--新视野数学、工程、技术和科学项目以及分子图书馆--实现的未被充分代表的群体进入科学和工程领域的动力。少年派是非常成功的Molecularim项目(去年12月上映的IMAX电影)的联合领导者。

Abstract1159990Garde, ShekharSelf-assembly plays an important role in natural processes and technologies used to make new materials. A key goal in studies of self-assembly is to better understand how the interactions of the constituents lead to the self-assembled structures, and their resulting properties. Aqueous interfaces are ubiquitous and often play an important role in self-assembly, yet, a detailed understanding of how the interfaces mediates the assembly is lacking. The PIs propose a new computational approach using molecular (MD) and Brownian dynamics (BD) simulations to shed light on interface-mediated assembly at aqueous interfaces. Properties of water structure, dynamics, and fluctuations are fundamentally altered near extended interfaces, especially near hydrophobic interfaces. They hypothesize that the altered properties of water, in turn, affect the structure, stability, and interactions of macromolecules. This hypothesis is supported by significant preliminary work. They expect that assembly of macromolecules will be significantly different at interfaces compared to that in bulk water. Fundamental understanding of the processes leading to complex interface-mediated assembly is the central focus of our proposal. Understanding of the molecular behavior of water at interfaces is critical to understanding how interfaces alter water-mediated interations near them. Therefore, modeling of phenomena at a wide range of length scales from that of a single water molecule to large self-assembled structures is required. To this end, the approach focuses on modeling of hierarchically complex systems from small solutes to macromolecular assemblies. Specific Aims of the work are to: (1) Quantify the binding to and the behavior of single molecules from small model solutes to flexible homo and heteropolymers, and peptides at aqueous interfaces using MD simulations. (2) Quantify how interfaces modulate the interactions of pairs and larger numbers of molecules in their vicinity. (3) Develop coarse-grained Brownian dynamics simulations to examine many particle assembly at interfaces. Information about the role of interfaces obtained from Aims 1 and 2 will serve as important input to BD simulations. (4) Explore and quantify how fluid flow and deformation of the interface impact the structures, the process of assembly, and the flow properties of the assembled structures. Intellectual Merit: Although water at interfaces is a highly active area of research both from experimental and theoretical perspectives, understanding of how the altered properties of water affect water-mediated interactions at interfaces is truly in its infancy. The work promises to break new ground by providing such molecular level understanding and uncovering its impact on interface-mediated assembly at larger length and time scales. The significant preliminary work by our groups and experimental data from a number of different groups focused on biological and colloidal systems point to the important role of aqueous interfaces in diverse fundamental problems and technological applications. The work has the potential to provide a framework to interpret those experimental results, enable technological applications and new materials development. Broader Impacts: Interfaces are ubiquitous in biological and nanoscopic systems, and also play a central role in numerous technological applications ranging from separations, coatings, to new materials development. Recent work has highlighted the role of interfaces in nucleating and accelerating fibril formation of alzheimers peptides. The project will impact the understanding of many such natural processes, and enhance our ability to design new technologies based on self assembly at interfaces. The research is coupled with significant efforts in education and outreach. This includes involvement of undergraduates in research and motivation of underrepresented groups into science and engineering, achieved through two different programs at Rensselaer, the New Visions Math, Engineering, Technology, and Science Program, and the Molecularium. The PI is a co-leader of the highly successful Molecularim Project (IMAX movie released last December).