Sensing local nano-environment with coherent Raman microspectroscopy

摘要 这是一项探索性的研究方案，旨在探索一种新的方法来审问局部纳米 提高相干拉曼显微光谱检测灵敏度的方法 应用于活细胞成像。提出的新方法克服了现有的一致性方法的缺点。 拉曼光谱。它提供了一种精细的微观化学特异性成像工具，具有极大的 提高了检测灵敏度和对本地纳米环境的特殊灵敏度。中环 假设由两个宽带脉冲激发的振动相干性对局部环境很敏感 并且可以通过在可变时间延迟使用第三脉冲询问该相干性来精确测量。通过 选择具有与较长弛豫时间相对应的较窄谱线的分子振动， 和测量延时响应，在较长的延时时间内可以大大降低背景信号 探测脉冲。这种调整使低浓度测量成为可能。总体研究目标 提出的方案是通过演示相干拉曼的灵敏度来验证这一假设 对局部纳米环境的显微光谱分析和提高拉曼检测灵敏度 光谱学。拟议活动的具体目标集中在构建一个原型 并利用体外和体内系统探索其能力。拟议的研究 该计划预计将提供一种新的、无标签的光学成像方式，具有更高的灵敏度和 适合活细胞成像的特异性。

ABSTRACT This exploratory research proposal which aims to investigate a novel approach for interrogating local nano- environments within a living cell by improving the detection sensitivity of coherent Raman microspectroscopy as applied to live-cell imaging. The proposed new approach overcomes the existing shortcomings of coherent Raman spectroscopy. It provides an exquisite tool of microscopic chemically specific imaging with greatly improved sensitivity of detection and exceptional sensitivity to the local nano-environment. The central hypothesis is that vibrational coherence excited by two broadband pulses is sensitive to the local environment and can be precisely measured by interrogating this coherence using a third pulse at a variable time delay. By choosing a molecular vibration with a relatively narrow spectral line that corresponds to a long relaxation time, and measuring time-delayed response, background signal can be substantially reduced at long delay times of the probe pulse. This adjustment makes low-concentration measurements possible. The overall research goal of the proposed program is to validate this hypothesis by demonstrating sensitivity of coherent Raman microspectroscopy to a local nano-environment and by improving the detection sensitivity of Raman spectroscopy. The specific aims of the proposed activities are focused on constructing a prototype of a microscope and exploring its capabilities using both in vitro and in vivo systems. The proposed research program is expected to deliver a novel and label-free optical imaging modality with enhanced sensitivity and specificity that is suitable for live-cell imaging.