Molecular Engineering of Low Friction and Biocompatible Surfaces

润滑是全关节置换术成功的关键。尽管分子摩擦学对化学系统的理解取得了重大进展，但对关节和其他生物系统的润滑机制仍然缺乏基本的理解。目前，治疗关节炎最常见的方法是全关节置换术。然而，植入材料的生物相容性提出了很大的挑战。聚乙二醇（PEG）和两性离子基材料是两种常用的生物相容性材料。假设两性离子基涂层具有非常低的摩擦。在这项工作中，两性离子聚合物刷覆盖的两个表面之间的摩擦将使用非平衡分子动力学模拟和化学力显微镜实验进行研究。本工作的目的是在分子水平上深入了解两性离子涂层之间摩擦的起源，建立纳米尺度摩擦与表面水化的关系，并比较三种独特的两性离子涂层的性能。PEG也将进行比较研究。这项工作的成功将提供对生物摩擦学中遇到的界面的基本理解，并将指导用于人工关节和BioMEMS/NEMS应用的新型生物相容性材料的设计。这项工作的结果是确定和设计具有低摩擦和高相容性的涂层。研究生和本科生将参与这个项目，特别是那些来自代表性不足群体的学生。作为正在进行的本科课程改革的一部分，PI正在教授一门新的课程？生物分子接口?并将教授一门整合经典热力学、统计力学和分子模拟的本科热力学新课程。拟议工作的结果将对这两门新课程作出重大贡献。这些知识还将通过PI每年授课的其他几门课程传播。

Lubrication is critical to the success of total joint replacement. Despite significant progress in the understanding of molecular tribology for chemical systems, there is still a lack of a fundamental understanding of the lubrication mechanisms for joints and other biological systems. Currently, the most common solution to arthritis is total joint replacement. However, the biocompatibility of implanted materials poses a great challenge. Poly(ethylene glycol) (PEG) and zwitterionic-based materials are two commonly used biocompatible materials. It is hypothesized that zwitterionic-based coatings will have very low friction. In this work, friction between two surfaces covered by zwitterionic polymer brushes will be studied using both non-equilibrium molecular dynamics simulations and chemical force microscopy experiments. The objectives of this work are to gain insights into the origin of the friction between zwitterionic coatings at the molecular level, to establish the relationship between nano-scale friction and surface hydration, and to compare the performance of three unique zwitterionic coatings. PEG will also be studied for comparison. The success of this work will provide a fundamental understanding of the interfaces encountered in bionanotribology and will guide the design of new biocompatible materials for applications in artificial joints and BioMEMS/NEMS. The outcome of this work is to identify and design coatings with both low friction and high compatibility. Graduate and undergraduate students will be involved in this project, particularly those from underrepresented groups. As a part of the ongoing undergraduate curriculum reform, the PI is teaching a new course on ?Biomolecular Interfaces? and will teach a new undergraduate thermodynamics course which will integrate classical thermodynamics, statistical mechanics and molecular simulation. Results from the proposed work will contribute significantly to these two new courses. The knowledge will also be disseminated through several other courses that the PI gives lectures to every year.