Soft x-ray tomography (SXT) visualizes and quantifies the organization of sub-cellular structures within intact cells in the native state. In SXT, the specimen is illuminated with x-ray photons from within a region of the spectrum known as the 'water window' (284 – 543eV). 'Water window' x-ray photons are absorbed an order of magnitude more strongly by carbon- and nitrogen-containing organic material than by water. Consequently, variation in biomolecule composition and concentration gives rise to quantitative, high-contrast images of intact, fully hydrated cells without the need to use contrast-enhancing agents. Cells imaged by SXT are, therefore, highly representative of the cell in its native, functional state. Attenuation of soft x-rays, as they pass through the specimen, adheres to the Beer-Lambert Law. Attenuation is, therefore, a function of chemical composition and concentration of organic material, yielding unique quantitative Linear Absorption Coefficient (LAC) measurements for cellular components. LAC values are enormously powerful in terms of quantifying alterations in cell structures during events such as cell differentiation, progression or etiology of disease states, genetic manipulation, and application of exogenous agents. Recently, we developed high numerical aperture cryogenic fluorescence tomography (CFT) for correlated imaging studies. This multi-modal approach - imaging the same cell using both CFT and SXT - allows localization of genetically encoded fluorescent molecules directly in the context of a high-resolution 3-D tomographic reconstruction of the cell.

3D imaging of cells with soft x-rays

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.