Study on anisotropy orientation due to well-ordered fibrous biological microstructures

Area of Science:

• Biophysics
• Optical Physics
• Biomedical Optics

Background:

• Biological fibrous tissues exhibit anisotropic optical properties due to their microstructure and macromolecular birefringence.
• Understanding tissue anisotropy is crucial for accurate characterization and pathological diagnosis.

Purpose of the Study:

• To investigate intrinsic and form birefringence in biological tissues.
• To assess the interpretability of orientation-related polarization parameters for tissue anisotropy.
• To differentiate sources and trends of anisotropy in various tissue samples.

Main Methods:

• Constructed a forward Mueller matrix measuring device for glass fiber, silk fiber, skeletal muscle, and tendon.
• Calculated orientation-related anisotropic parameters using statistical analysis with polar coordinates.
• Employed Mueller matrix polar decomposition to derive fast-axis values.

Main Results:

• Observed bimodal characteristics in the statistical distribution of fast-axis values for birefringent fibers.
• Successfully distinguished single-layer from layered, multi-oriented fibrous samples based on fast-axis distribution.
• Evaluated relative changes in intrinsic and form birefringence using parameters from orientation bimodal distribution.

Conclusions:

• The cross-vertical bimodal distribution of the fast axis aids in precise analysis of anisotropic changes in biological tissues.
• Anisotropic orientation analysis shows potential for applications in pathological diagnosis.