Surface spectroscopy and microscopy studies of molecular films at electrified interfaces

本项目的总体目标是研究沉积在金属-溶液界面的金属电极上的磷脂的功能单层和双层的结构和反应性。这些膜的功能将由多肽和蛋白质的存在决定。我们的目标是了解电场如何影响磷脂和胆固醇组成的混合双分子层的稳定性，蛋白质在双分子层中的结合以及电子和离子通过蛋白质在支持双分子层中的转移。为了实现这些目标，我们将采用电化学方法、扫描探针显微镜（如扫描隧道显微镜（STM）和原子力显微镜（AFM））、原位光子偏振调制傅立叶变换红外反射吸收光谱（PM-IRRAS）、表面增强红外光谱和拉曼光谱以及中子散射技术。我们将使用电化学技术来控制膜的物理状态，并使用扫描探针显微镜来成像膜的场驱动转换。此外，光谱学和中子散射技术将用于研究有机分子的构象变化及其在膜内的有序性。我们的目标是获得对几个生物相关过程的基本理解，如：(i)抗菌肽（amp）和淀粉样肽与磷脂双层的相互作用，（ii）单层和双层核脂与溶液中互补核碱基的相互作用，（iii）蓝铜氧化酶在氧化还原中心氧化/还原过程中发生的构象和取向变化。金属电极表面覆盖一层仿生膜，可带电，膜上可施加10^7 - 10^8V/m量级的电场。这些场与作用在生物膜上的场具有相当的强度。我们的目标是利用这个独特的机会来操纵生物分子，并利用表面分析技术来监测由场引起的构象和取向变化。此外，对于金属电极支撑的膜，电化学方法可用于将膜中主客体相互作用的分析信息转导为电信号以进行分析检测。**

The general objective of this project is to study the structure and reactivity of functional monolayers and bilayers of phospholipids deposited onto a metal electrode at the metal-solution interface. The functionality of these films will be determined by the presence of peptides and proteins. Our goal is to learn how the electric field affects the stability of mixed bilayers composed of phospholipids and cholesterol, incorporation of proteins into the bilayer and electron and ion transfer through proteins incorporated into the supported bilayer. To achieve these goals, we will employ electrochemical methods, scanning probe microscopies such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM), in situ photon polarization modulation Fourier transform infrared reflection absorption spectroscopy (PM-IRRAS), surface enhanced infrared and Raman spectroscopies and the neutron scattering technique. We will use electrochemical techniques to control the physical state of the film and the scanning probe microscopies to image the field driven transformations of the membranes. In addition, spectroscopic and neutron scattering techniques will be employed to study conformational changes of organic molecules and their ordering within the membrane. Our goal is to obtain fundamental understanding of several biorelevant processes such as:(i) interactions of antimicrobial (AMPs) and amyloid peptides with phospholipid bilayers, (ii) interactions of monolayers and bilayers of nucleolipids with complementary nucleobases in solution, (iii) conformational and orientational changes of blue copper oxidase enzymes occurring during oxidation/reduction of their redox center. The metal electrode surface, covered by a biomimetic membrane, can be charged and electric fields on the order of 10^7 - 10^8V/m can be applied to the membrane. These fields have comparable magnitude to the fields acting on biological membranes. Our goal is to use this unique opportunity to manipulate biomolecules with the field and to monitor conformational and orientational changes induced by the filed using the surface analytical techniques. In addition, for the membrane supported at a metal electrode, the electrochemical methods could be used for transduction of analytical information about the host guest interactions in the membrane to an electrical signal for analytical detection. **