Laboratory cryo soft X-ray microscopy.

Area of Science:

• Cellular imaging
• X-ray microscopy
• Biophysics

Background:

• Lens-based water-window X-ray microscopy offers high contrast and resolution for imaging unstained cells.
• Current cryo X-ray microscopes require synchrotron sources, limiting accessibility for many researchers.
• Cryofixation is crucial for preserving cellular structure and preventing radiation damage.

Purpose of the Study:

• To demonstrate water-window cryo X-ray microscopy using a laboratory-based setup.
• To enable wider accessibility of advanced cellular imaging techniques.
• To achieve high-resolution imaging of unstained biological samples outside of synchrotron facilities.

Main Methods:

• Utilized a laboratory-source-based arrangement featuring a laser-plasma X-ray source (λ=2.48 nm).
• Employed normal-incidence multilayer condenser optics and 30-nm zone-plate optics.
• Integrated a cryo sample chamber for near-native sample preservation.

Main Results:

• Successfully performed 2D imaging of test patterns and unstained biological samples, including yeast, protozoan parasites, and mammalian cells.
• Achieved 3D information through stereo imaging and full tomographic reconstruction.
• Demonstrated image quality comparable to synchrotron-based microscopes, albeit with longer exposure times.

Conclusions:

• Laboratory-based water-window X-ray microscopy is feasible and provides high-quality cellular images.
• This technology significantly enhances the accessibility of advanced cryo X-ray microscopy for biological research.
• Further optimization is needed to reduce exposure times and match synchrotron performance.