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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709562
• 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，能够以毫秒级的速度在三维空间中同时独特地跟踪细胞中的数百个分子或蛋白质。为了实现这一目标，我建议联合收割机的分子特定的光散射技术（受激拉曼光谱- SRS）与众所周知的三维成像能力的全息，创建分子全息图。 在拉曼光谱实验中，光以被照射的分子或蛋白质特有的一组独特波长散射。 也就是说，该技术提供了散射光中分子的指纹-光谱条形码。 该技术的进一步修改使用两个激光器（受激拉曼光谱，SRS），当激光器之间的频率差匹配分子振动时，产生相干散射光束。 全息图，就像那些通常在我们的货币和信用卡上观察到的，通过将相干散射的激光与原始光源相结合来提供物体的三维图像。分子全息是这两种技术的结合，以创建分子振动的三维空间分布图。我的团队对表皮生长因子受体的成像特别感兴趣，因为它的过度表达与许多癌症有关。然而，成像技术将广泛适用于任何分子或生物标志物，只要开发了适当的造影剂（例如，适当功能化的金或银纳米颗粒）。 今年，我们完成了成功的原理验证实验，证明可以创建金纳米颗粒的传统全息图，并且可以从附着在纳米颗粒上的分子中产生相干光发射（SRS）。 将两者结合需要两个激光器的集成，这两个激光器包括一个波长可调的激光器和另一个具有固定波长的激光器、针孔、锁定放大器和检测器;沿着在达尔豪西开发的必要软件，以重建图像。我的团队现在正准备创造一种有潜力超越荧光技术的成像方式。分子全息术将提供几个优点，包括用一次曝光（全息术）捕获更多生物分子的3D分布，而不是从2D图像/切片重建3D轮廓。 与荧光成像不同，我们的技术具有非常真实的无标记的潜力，从而避免了引入细胞的外来荧光团剂的干扰作用。从长远来看，无标记分子全息术可以取代荧光成像作为细胞生物学家的选择模式。我的本地、国家和国际合作者网络将有助于确保该技术被世界各地的领先机构采用。