Measuring Molecular Mass Densities at Subcellular Resolution Using Optical Diffraction Tomography.

Area of Science:

• Biophysics
• Cell Biology
• Biophotonics

Background:

• Biological systems precisely regulate mass density and volume.
• Mass density is crucial for cellular functions like growth and differentiation.
• Deviations in density homeostasis are linked to senescence and disease.

Purpose of the Study:

• To provide a comprehensive guide for implementing optical diffraction tomography (ODT).
• To enable high-resolution, label-free quantification of mass density distribution in biological systems.
• To offer insights into biophysical properties of cells and subcellular structures.

Main Methods:

• Utilizing optical diffraction tomography (ODT) for refractive index (RI) measurements.
• Detailing optical setups and optimizing tomography acquisition.
• Presenting sample preparation protocols for in vivo and in vitro biological samples.

Main Results:

• Demonstrated ODT's capability for label-free, high-resolution density quantification.
• Provided guidance on image acquisition and data analysis for biological samples.
• Addressed challenges in relating RI to mass density in complex biological substances.

Conclusions:

• ODT is a powerful tool for quantitative mass density characterization in biological systems.
• The presented guide facilitates the application of ODT in diverse biological research.
• Strategies are offered to overcome limitations in RI-based density measurements.