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

自组装在自然过程和制造新材料的技术中起着重要的作用。自组装研究的一个关键目标是更好地理解组分之间的相互作用如何导致自组装结构及其所产生的性质。水相界面在自组装过程中普遍存在并发挥着重要作用，然而，人们对水相界面如何介导自组装过程还缺乏详细的了解。PI提出了一种新的计算方法，使用分子（MD）和布朗动力学（BD）模拟揭示界面介导的组装在水界面。水的结构，动力学和波动的性质从根本上改变扩展界面附近，特别是疏水界面附近。他们假设水的性质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初步工作的支持。他们预计，大分子的组装将显着不同的界面相比，在散装水。我们的建议的中心重点是对复杂的界面介导的组装过程的基本理解。了解水在界面处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宽范围的长度尺度上对现象进行建模。为此，该方法侧重于从小溶质到大分子组装体的层次复杂系统的建模。具体的工作目标是：（1）量化的结合和行为的单分子从小模型溶质到灵活的均聚物和杂聚物，和肽在水界面上使用MD模拟。(2)量化界面如何调节其附近的成对和大量分子的相互作用。(3)开发粗粒度的布朗动力学模拟，以检查界面处的许多粒子组装。从目标1和2中获得的关于接口作用的信息将作为BD模拟的重要输入。(4)探索并量化流体流动和界面变形如何影响结构、组装过程以及组装结构的流动特性。智力优势：虽然从实验和理论角度来看，界面处的水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处水介导的相互作用的理解确实处于起步阶段。这项工作有望通过提供这样的分子水平的理解和揭示其对界面介导的组装在更大的长度和时间尺度上的影响，开辟新的天地。我们小组的重要的初步工作和实验数据，从一些不同的小组集中在生物和胶体系统点的重要作用，水界面在不同的基本问题和技术应用。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的开发。更广泛的影响：界面在生物和纳米系统中无处不在，并且在从分离、涂层到新材料开发的许多技术应用中也起着核心作用。最近的工作强调了界面在成核和加速阿尔茨海默氏症肽原纤维形成中的作用。该项目将影响对许多此类自然过程的理解，并增强我们设计基于界面自组装的新技术的能力。这项研究与教育和外联方面的重大努力相结合。这包括本科生参与研究，并激励代表性不足的群体进入科学和工程领域，这是通过伦斯勒的两个不同项目实现的，即新视野数学，工程，技术和科学项目以及分子。PI是非常成功的分子计划（去年12月发布的IMAX电影）的共同领导者。

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).