Axial X-Ray Microscopy in Nanotomography

Area of Science:

• Microscopy and Imaging
• Cell Biology
• Nanotechnology

Background:

• Conventional computed tomography (CT) requires sample rotation, limiting live cell imaging.
• Optical fluorescence microscopy requires organelle staining, and electron microscopy requires cell slicing.
• Existing methods struggle to visualize fine intracellular structures without invasive procedures.

Purpose of the Study:

• Develop 3D tomographic imaging methods for absorption coefficient distributions using axial scanning with extreme ultraviolet (EUV) microscopes.
• Enable tomographic reconstruction of living cell fine structure without staining or slicing.
• Achieve high-resolution nanoscale imaging of subcellular features.

Main Methods:

• Generalized geometric-optical approximation for a new explicit tomography equation and solution algorithm.
• Axial scanning with EUV microscopes at 46× and 345× magnification.
• Experimental determination of the tomography integral equation kernel using gold nanospheres for higher magnification imaging.

Main Results:

• Resolved subcellular features down to 140 nm (46×) and 50 nm (345×).
• Detected thin, low-contrast intracellular structures.
• Identified individual organelles measuring 50-100 nm.

Conclusions:

• Developed and validated methods for absorption coefficient distribution retrieval using geometric-optical theory and gold nanoparticle calibration.
• Demonstrated the effectiveness of axial nanotomography with multilayer mirror microscopes for cell diagnostics.
• Paved the way for label-free, high-resolution imaging of live cells.