High resolution X-ray tensor tomography to study the spiral nanostructure of narwhal tusk

Narwhals are mysterious animals whose tusk has a unique spiral structure with highly anisotropic mechanical properties. We hypothesize that the orientation of the biological nanostructure reflects the spiral macro-structure, which defines their mechanical properties. Previous experiments showed important aligned structures in the micrometric range however the achievable resolution was not enough to fully resolve them. Therefore, we propose to use SWAXS to study the orientation and degree of anisotropy of the biomineral nanoparticles in the tusk in 2D and 3D. Examining samples from dentine and cementum will reveal the unique structure and shed light on its formation process. The 3D hierarchical structure will be very valuable for micromechanical modelling of anisotropic composites, which will bring new knowledge on composite materials with complex architectures and inspire new material designs.