Molecular holography

分子全息术

• 批准号: RGPIN-2016-05018
• 负责人: Hewitt, Kevin
• 金额: $ 1.6万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=615443
• 关键词: Molecular; holography

Imagine being able to simultaneously and uniquely track hundreds of molecules or proteins in a cell in three dimensions at millisecond rates. To achieve this goal I propose to combine a molecular-specific light scattering technique (Stimulated Raman spectroscopy - SRS) with the well-known three-dimensional imaging capability of holography, to create molecular holograms. In a Raman spectroscopy experiment, light is scattered at a unique set of wavelengths characteristic of the molecule or protein being illuminated. That is, the technique provides a fingerprint of the molecule in the scattered light - a spectral barcode. A further modification of this technique which uses two lasers (Stimulated Raman spectroscopy, SRS) creates a coherent scattered beam when the frequency difference between the lasers matches a molecular vibration. Holograms, like those commonly observed on our currency and credit cards, provide a three dimensional image of an object by combining coherently scattered laser light with the original light source. Molecular holography is the integration of these two techniques to create a map of the three-dimensional spatial distribution of a molecular vibration. My team is specifically interested in imaging the Epidermal Growth Factor Receptor, as it's overexpression is implicated in a number of cancers. However, the imaging technique would be widely applicable to any molecule or biomarker as long as an appropriate contrast agent is developed (e.g. appropriately functionalized gold or silver nanoparticles). This year, we completed successful proof-of-principle experiments that demonstrate conventional holograms of gold nanoparticles can be created and that coherent light emission (SRS) can be generated from molecules attached to the nanoparticles. Combining the two requires the integration of two lasers comprising a wavelength-tunable one and another with fixed wavelength, a pinhole, lock-in amplifier and a detector; along with the requisite software, developed at Dalhousie, to reconstruct the image. My team is now poised to create an imaging modality that has the potential to outperform fluorescence techniques. Molecular holography would offer several advantages, including capture of the 3D distribution of many more biomolecules with one exposure (holography), rather than reconstruction of a 3D profile from 2D images/slices. Unlike fluorescence imaging our technique has the very real potential to be label-free, thereby avoiding the perturbing effect of a foreign flurophore agent introduced to a cell. In the long term, label-free molecular holography could supplant fluorescence imaging as the cell biologists' modality of choice. My local, national and international network of collaborators will help ensure that the technique is adopted at leading institutions around the world.

想象一下，能够以毫秒的速率同时且独特地跟踪三维细胞中数百个分子或蛋白质。为了实现这一目标，我建议将一种分子特异性光散射技术（刺激的拉曼光谱-SR）与众所周知的全息图的三维成像能力相结合，以创建分子全息图。 在拉曼光谱实验中，光散布在分子或蛋白质被照亮的一组独特的波长中。也就是说，该技术在散射光中提供了分子的指纹 - 光谱条形码。当激光器之间的频率差与分子振动匹配时，使用两种激光器（刺激的拉曼光谱）的进一步修改该技术会产生连贯的散射光束。全息图像我们在货币和信用卡上通常观察到的全息图，通过将相干分散的激光光与原始光源相结合，从而提供了对象的三维图像。分子全息图是这两种技术的整合，以创建分子振动的三维空间分布的图。我的团队对成像表皮生长因子受体特别感兴趣，因为它的过表达与许多癌症有关。但是，只要开发出适当的对比剂（例如，适当功能化的金或银纳米颗粒），成像技术将广泛适用于任何分子或生物标志物。 今年，我们完成了成功的原理实验，这些实验证明了可以创建金纳米颗粒的常规全息图，并且可以通过附着在纳米颗粒的分子产生相干的光发射（SRS）。将两者结合起来需要将两个激光器组成，其中包括一个带有波长的波长一个和固定波长，针孔，锁定放大器和检测器；与Dalhousie开发的必要软件一起重建图像。现在，我的团队准备创建一种成像方式，该模式有可能超越荧光技术。分子全息图将提供几个优点，包括捕获一种带有一种暴露（全息图）的更多生物分子的3D分布，而不是从2D图像/切片中重建3D轮廓。 与荧光成像不同，我们的技术具有不含标签的非常实际的潜力，从而避免了引入细胞的外国flurophore剂的扰动作用。从长远来看，无标签的分子全息图可以取代荧光成像作为细胞生物学家选择的方式。我的本地，国家和国际合作者网络将有助于确保该技术在世界各地的领先机构中采用。