Tomographic imaging of transparent biological samples using the pyramid phase microscope.

Area of Science:

• Biophysics
• Optical Microscopy
• Biotechnology

Background:

• Accurate 3D imaging of biological samples is crucial for understanding cellular structures and functions.
• Phase microscopy offers label-free contrast for transparent biological specimens.
• Tomographic reconstruction requires precise sample positioning during rotation.

Purpose of the Study:

• To develop and demonstrate a method for obtaining tomographic refractive index information from biological samples using a pyramid phase microscope.
• To implement an automated sample repositioning strategy for enhanced tomographic accuracy.
• To validate the technique through the 3D reconstruction of mouse embryos.

Main Methods:

• Utilizing a pyramid phase microscope to capture phase shift data.
• Applying the Radon transform for tomographic reconstruction of refractive index distribution.
• Developing an algorithm for axial and lateral sample repositioning based on phase microscope data during rotation.

Main Results:

• Successfully obtained tomographic information on the spatial variation of refractive index in biological samples.
• Demonstrated accurate axial and lateral sample repositioning during rotation, improving reconstruction fidelity.
• Achieved high-resolution 3D reconstruction of mouse embryos at the blastocyst stage.

Conclusions:

• Pyramid phase microscopy combined with Radon transform provides a powerful label-free method for quantitative 3D refractive index mapping.
• The developed repositioning method significantly enhances the accuracy of tomographic reconstructions.
• This technique holds promise for label-free, high-resolution imaging of developmental processes in biological samples.