Hydraulic fracture during epithelial stretching.

Area of Science:

• Biophysics
• Cell Biology
• Materials Science

Background:

• Epithelial fracture under stretch is often linked to cellular tension.
• Existing models focus on cytoskeletal, membrane, or cell-contact stress.

Purpose of the Study:

• Investigate the primary cause of epithelial crack formation during substrate stretching.
• Determine the role of substrate hydraulics versus cellular tension in epithelial integrity.

Main Methods:

• Utilized synthetic and physiological hydrogel substrates with epithelial cell sheets.
• Applied mechanical stretching and compression maneuvers.
• Analyzed crack formation, size, and healing dynamics.
• Applied the theory of poroelasticity for modeling.

Main Results:

• Epithelial crack formation is driven by substrate hydraulic pressure, independent of epithelial tension.
• Cracks emerge due to transient pressure build-up during stretching and compression.
• Cracks heal readily after pressure equilibration through actomyosin-dependent processes.
• Poroelasticity theory accurately predicts crack characteristics based on substrate properties.

Conclusions:

• Epithelial integrity is governed by the interplay of tissue stretching and matrix hydraulics, not solely cellular tension.
• Hydraulic pressure within the substrate is a critical factor in epithelial fracture.
• Actomyosin-mediated repair mechanisms are crucial for crack healing post-pressure equilibration.