Intellectual merit: Structure-mechanics analysis of shark egg cases has revealed that dynamic reorganization of the nanolatticed architecture provides strength and resilience without compromising permeability.

Broader Impacts: The nanostructured egg case of swell sharks is one of the toughest permeable membranes known. These fundamental insights provide design targets for multifunctional soft composites, and mechanical metamaterials.

Left: Schematic of swell shark and egg casing. Right: Inset shows hierarchical nanostructures that deform under stress.
Left: Schematic of swell shark and egg casing. Right: Inset shows hierarchical nanostructures that deform under stress.