Investigation of Biological Molecules at Interfaces Using Evanescent-Field Spectroscopies

本研究项目旨在通过扩展和改进两种基于光束的倏逝电场与反射界面处分子相互作用的技术来理解生物分子在固体表面的行为。这两种技术是倏逝波腔衰荡光谱（EW-CRDS）和表面等离子体共振光谱（SPR）。当光在较高折射率材料和较低折射率材料之间的界面处经历全内反射时形成倏逝波;并且其振幅随着进入较低折射率介质的距离呈指数衰减。因此，这些技术固有地特定于界面和在界面处发现的分子。EW-CRDS测量界面几百纳米内发色团的吸光度，SPR对同一区域的折射率变化敏感。有人建议通过探索一系列潜在的基底材料来改进SPR技术，目的是开发更灵敏或更具体的新仪器。这项研究将完善和介绍的方法，应广泛适用于世界各地的实验室，以研究许多生物相关系统的行为。调查也将对研究生和本科生的教育产生重大影响。 这些界面研究将为斯坦福大学的本科生“定量化学的理论与实践”和PI教授的“光、颜料和有机体”课程提供关于前沿研究的新课程材料。该奖项由生物科学理事会生物基础设施司和数学与物理科学理事会物理司及多学科活动办公室共同资助。

This research project is directed toward understanding the behavior of biological molecules at solid surfaces by extending and refining two techniques that are based on the interaction of the evanescent electric field of a light beam with molecules at a reflective interface. These two techniques are evanescent wave cavity ring-down spectroscopy (EW-CRDS) and surface plasmon resonance spectroscopy (SPR). An evanescent wave is formed when light undergoes total internal reflection at the interface between a higher refractive-index material and a lower refractive-index material; and its amplitude decays exponentially with distance into the lower index medium. These techniques are therefore inherently specific to interfaces and the molecules found at interfaces. EW-CRDS measures absorbance by chromophores within a few hundred nanometers of the interface, and SPR is sensitive to refractive index changes in the same region. It is proposed to refine the SPR technique by exploring a range of potential substrate materials as well, with the goal of developing more sensitive or more specific new instrumentation. This investigation will refine and introduce methods that should be widely applicable in laboratories worldwide to study the behavior of numerous biologically relevant systems. The investigation will also have a significant impact on the education of both graduate and undergraduate students. These interfacial studies will provide novel course material on cutting-edge research for Stanford's undergraduate "Theory and Practice of Quantitative Chemistry" and "Light, Pigments, and Organisms" classes that the PI teaches. The potential exists for direct undergraduate participation in these research projects as well.This award is jointly funded by the Division of Biological Infrastructure in the Directorate for Biological Sciences and by the Physics Division and the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate.