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RUI: High-Speed Imaging and Spectroscopy of Single Molecules

RUI：单分子的高速成像和光谱学

基本信息

批准号：
2003750
负责人：
Nathan Lindquist
金额：
$ 29.79万
依托单位：
Bethel University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003750&HistoricalAwards=false
关键词：
RUI Speed Imaging Spectroscopy Single

项目摘要

With this award, the Chemical Measurement and Imaging Program is funding Dr. Nathan Lindquist and Dr. Nathan Lemke at Bethel University to develop single-molecule measurement techniques capable of high-speed (approximately MHz) imaging and spectroscopy with subwavelength (near 5 nm) spatial resolution using SERS(surface-enhanced Raman spectroscopy). The ability to image, track, and analyze single molecules with microscopes that use light opens up a vast array of new scientific possibilities. One promising area of research for probing single molecules is called surface-enhanced Raman spectroscopy (SERS). In these experiments, laser light is used to energize minuscule metal particles. These metal nanoparticles can then transfer energy to nearby molecules, resulting in their emission of light at specific energies. As a result, the molecules can be identified. However, many single-molecule experiments show large and random high-speed fluctuations in the amount of emitted light, which are not easily understood and also complicate analysis. This project sets out to develop a new microscope and detector system that can record super-high-resolution movies at a million frames per second, which is fast enough to capture, locate, track, and identify the fleeting signals from individual molecules. By using SERS, this new measurement technology has the potential to reveal more fully how light and matter interact on the nanoscale. This research is being performed at an undergraduate institution and its activities are deeply integrated into the curriculum through open-ended lab projects, summer research opportunities, and public outreach activities. The project aims to inspire, motivate, and train undergraduates for future careers in science and engineering.The concept of optical "hotspots" in laser-illuminated metallic nanoparticles is central to the interpretation of the SERS effect. However, while hotspots are generally portrayed as a static feature of a metal/molecule system, single-molecule SERS is punctuated with very high-speed (microsecond) fluctuations, both in signal intensity and spectral content. These random fluctuations originate from different areas of a single nanoparticle and can be uniquely activated with different laser wavelengths. Temperature and laser power also play a role in the fluctuation dynamics. High-speed SERS fluctuations are therefore interpreted to arise from single molecules interacting with a dynamic and restructuring metallic surface that generates short-lived, atomic-scale optical hotspots. Atomic-scale optical hotspots are a relatively uncharted area of basic research and new measurement technologies are therefore needed. This research uses image intensifiers integrated with multiple lasers, detectors, and fast single-photon counters to analyze atomic-scale optical hotspots and single-molecule SERS with unprecedented speed, sensitivity, and resolution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

通过这一奖项，化学测量和成像计划资助伯特利大学的Nathan Lindquist博士和Nathan Lemke博士开发能够使用SERS(表面增强拉曼光谱)进行高速(约MHz)成像和具有亚波长(近5 nm)空间分辨率的光谱的单分子测量技术。利用光学显微镜对单分子进行成像、跟踪和分析的能力开辟了大量新的科学可能性。探测单分子的一个很有前途的研究领域是表面增强拉曼光谱(SERS)。在这些实验中，激光被用来为微小的金属颗粒提供能量。然后，这些金属纳米粒子可以将能量转移到附近的分子，导致它们以特定能量发射光。因此，分子可以被识别出来。然而，许多单分子实验显示出发射光量的大而随机的高速波动，这不容易理解，而且分析也很复杂。该项目致力于开发一种新的显微镜和探测器系统，该系统可以以每秒100万帧的速度记录超高分辨率电影，其速度足够快，可以捕获、定位、跟踪和识别来自单个分子的短暂信号。通过使用表面增强拉曼光谱，这种新的测量技术有可能更全面地揭示光和物质在纳米尺度上是如何相互作用的。这项研究是在一所本科院校进行的，其活动通过开放式实验室项目、暑期研究机会和公共推广活动被深度整合到课程中。该项目旨在激励、激励和培训本科生在未来的科学和工程职业生涯。激光照射下的金属纳米颗粒中的光学“热点”概念是解释SERS效应的核心。然而，尽管热点通常被描绘为金属/分子系统的静态特征，但单分子SERS在信号强度和光谱含量方面都被非常高速(微秒)的波动所打断。这些随机波动来自单个纳米颗粒的不同区域，并且可以被不同的激光波长唯一地激活。温度和激光功率对涨落动力学也有影响。因此，高速SERS波动被解释为由单个分子与动态和重构的金属表面相互作用而产生的，该表面产生了短暂的原子尺度的光学热点。原子尺度的光学热点是基础研究中一个相对未知的领域，因此需要新的测量技术。这项研究使用集成了多个激光器、探测器和快速单光子计数器的像增强器，以前所未有的速度、灵敏度和分辨率分析原子尺度的光学热点和单分子SERS。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。