Cryo X-ray microscope with flat sample geometry for correlative fluorescence and nanoscale tomographic imaging

Area of Science:

• Cellular and Molecular Imaging
• X-ray Microscopy
• Biophysics

Background:

• X-ray imaging provides unique 3-D insights into hydrated cells.
• Combining X-ray tomography with fluorescence microscopy is challenging.
• Existing transmission X-ray microscope (TXM) setups have limitations.

Purpose of the Study:

• To describe the design and setup of a novel cryo full-field transmission X-ray microscope (TXM) at BESSY II.
• To enhance spectral resolution and image contrast for cellular imaging.
• To enable integrated fluorescence imaging with X-ray tomography.

Main Methods:

• Development of a new X-ray optical layout using an undulator source, spherical grating monochromator, and capillary mirror condenser.
• Implementation of partially coherent object illumination.
• Integration of a fluorescence light microscope for multi-modal imaging of cryogenic cells.

Main Results:

• Achieved an order of magnitude improvement in spectral resolution compared to previous TXM setups.
• Enhanced contrast transfer due to partially coherent illumination.
• Enabled unrestricted sample tilting for comprehensive 3-D data acquisition.

Conclusions:

• The new cryo TXM design significantly advances nanoscale X-ray tomography of biological specimens.
• Integrated fluorescence imaging provides correlative data within the TXM.
• Proposed alternative 3-D X-ray imaging techniques for high-resolution cellular analysis.