Deformation mechanisms of human amnion: Quantitative studies based on second harmonic generation microscopy

Area of Science:

• Biomedical Engineering
• Tissue Mechanics
• Microscopy

Background:

• Fetal membrane microstructure and deformation mechanisms are crucial for understanding pregnancy complications.
• Multiphoton microscopy offers a powerful tool for analyzing biological tissues at the cellular and collagen network level.

Purpose of the Study:

• To present dedicated microscopic tools and data interpretation methods for in situ mechanical characterization of fetal membrane tissue.
• To investigate fetal membrane deformation under stepwise monotonic uniaxial loading conditions.

Main Methods:

• Utilized multiphoton microscopy for in situ mechanical testing of fetal membrane.
• Performed stepwise monotonic uniaxial experiments to quantify tissue deformation.
• Analyzed data on thickness reduction and collagen fiber alignment.

Main Results:

• Demonstrated the reliability of microscopic parameters through consistency with previous cyclic and relaxation tests.
• Observed significant thickness reduction in the fetal membrane under load.
• Documented substantial alignment of collagen fiber bundles starting at very low mechanical loads, challenging traditional reference configuration definitions.

Conclusions:

• The study provides reliable data on fetal membrane mechanics using advanced microscopy techniques.
• Findings challenge the definition of a reference configuration based on force thresholds due to early collagen alignment.
• Results inform the development of predictive models for fetal membrane deformation and failure, relevant to obstetrics and clinical practice.