Connectivity and plasticity determine collagen network fracture.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Mechanobiology

Background:

• Collagen is the primary structural protein in mammalian connective tissues, forming hierarchical fibrous networks that resist mechanical deformation.
• While collagen's role in tendon fracture is studied, less is known about fracture mechanisms in disordered collagen networks found in tissues like skin and cartilage.
• Understanding collagen network fracture is crucial for pathological conditions like aneurysms and tissue overload.

Purpose of the Study:

• To investigate the key factors determining fracture in disordered collagen networks.
• To explore the relationship between network connectivity, structural plasticity, and fracture strain.
• To elucidate the protective mechanisms against fracture in biological tissues.

Main Methods:

• Utilized shear rheology on reconstituted collagen networks.
• Employed computer simulations to model network behavior.
• Analyzed the coordination number of network junctions and its correlation with fracture strain.

Main Results:

• Fracture strain in disordered collagen networks is primarily controlled by the coordination number of network junctions.
• Networks with lower junction connectivity exhibit larger fracture strains.
• The hierarchical collagen structure contributes to fracture strain regulation through structural plasticity at network and fiber levels.

Conclusions:

• Low connectivity and inherent structural plasticity are critical protective mechanisms against fracture in disordered collagen networks.
• These findings optimize the strength and resilience of biological tissues.
• The study provides insights into the mechanical behavior of diverse connective tissues beyond tendons.