Mechanical Behavior of Octopus Egg Tethers Composed of Topologically Constrained, Tandemly Repeated EGF Domains.

Whether and how intramolecular crosslinks in polymeric materials contribute to mechanical properties is debated in both experimental and theoretical arenas. The tethering threads of egg cases provide a rare window to investigate this question in a biomaterial. The only detectable component of the load-bearing fibers in octopus threads is a 135 kDa protein, , comprising 29 tandem repeats of epidermal growth factor (EGF) each of which contains 3 intramolecular disulfide linkages.

Viscoelastic analysis of mussel threads reveals energy dissipative mechanisms.

Mussels use byssal threads to secure themselves to rocks and as shock absorbers during cyclic loading from wave motion. Byssal threads combine high strength and toughness with extensibility of nearly 200%. Researchers attribute tensile properties of byssal threads to their elaborate multi-domain collagenous protein cores.