STEM-EELS tomography of biological materials

生物材料的 STEM-EELS 断层扫描

• 批准号: 577091-2022
• 负责人: Strauss, MikeM
• 金额: $ 3.28万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743437
• 关键词: STEM; EELS; tomography; biological; materials

Biological structures within a cell are difficult to assess at high resolution, which poses a critical limit to understanding a wide range of biological processes that are relevant to various human diseases. Light microscopy has made exceptional advancements in cell biology, enabling spatial and temporal resolution of biological molecules within single cells, however these techniques are limited in resolution and their ability to quantify protein density. Conventional electron microscopy can provide higher resolution of cell structures, but rely on the use of heavy metal stains to provide contrast. To circumvent these limitations, we plan to develop a 3D imaging technique to examine the elemental composition of unstained biological material in situ. We will develop and advance a technique known as scanning transmission electron microscopy in combination with electron tomography. This will allow us to obtain electron-energy loss spectroscopy (EELS) information of biological samples, that not only informs about the shape and structure of materials at exquisite resolution, but also reveals the chemical composition - allowing us to identify the nature of the molecules that we observe in addition to their shape and structure. This technique will combine the power and resolution of traditional electron microscopy with chemical information from the biological spectra, enabling detailed structural information without the use of conventional contrast enhancing stains. While common in material science research, several barriers have limited the use of STEM- EELS in revealing fine structural details of biological specimens, which we are now in a unique position to overcome to reveal unprecedented insight into the structure and composition of cells. We have previously demonstrated the feasibility of energy loss spectroscopy in resolving biological molecules using electron spectroscopic imaging by mapping phosphorus (abundant in nucleic acids) and nitrogen (present in all protein and nucleic acids) mapping. We will expand on this technique by collecting spectra at each pixel, and will obtain pixel specific spectra at multiple tilt angles to generate element-specific pixel resolution 3D information about our biological sample.

细胞内的生物结构很难在高分辨率上评估，这对理解与各种人类疾病相关的广泛生物学过程构成了关键限制。光学显微镜在细胞生物学方面取得了出色的进步，从而实现了单个细胞内生物分子的空间和时间分辨率，但是这些技术的分辨率及其定量蛋白质密度的能力受到限制。常规的电子显微镜可以提供更高的细胞结构分辨率，但依赖于重金属污渍的使用来提供对比度。为了避免这些局限性，我们计划开发一种3D成像技术，以检查原位未染色的生物材料的元素组成。我们将开发并推进一种称为扫描透射电子显微镜的技术，结合了电子断层扫描。这将使我们能够获得生物样品的电子能量损失光谱（EEL）信息，不仅可以以精致的分辨率为材料的形状和结构提供信息，而且还揭示了化学成分 - 使我们能够识别出除了其形状和结构外观察到的分子的性质。该技术将将传统电子显微镜的功率和分辨率与来自生物光谱的化学信息相结合，从而无需使用常规的对比度增强污渍，从而实现了详细的结构信息。虽然在材料科学研究中常见，但几个障碍限制了茎孔在揭示生物标本的精细结构细节中的使用，我们现在处于一个独特的位置，无法揭示对细胞结构和组成的前所未有的见解。我们先前已经证明了使用电子光谱成像通过绘制磷（丰富的核酸）和氮（所有蛋白质和核酸）映射来解决生物分子的可行性。我们将通过在每个像素上收集光谱来扩展此技术，并以多个倾斜角度获得像素特异性光谱，以生成有关我们生物样品的元素特异性像素分辨率3D信息。