Sea urchin mineralized tissue

Sea urchin ossicles are structural analogs of mammalian bones and serve as a model biomineral system. Relatively new x-ray methods complement electron microscopy and allow study of mineralized tissue with voxels (volume elements) approaching 1 μm³ in millimeter sized samples. This paper focuses on a multi-mode x-ray investigation of mineralized tissue and results from two of the methods, microCT and synchrotron transmission microbeam diffraction mapping. Sea urchins employ as wide a range of composite reinforcement strategies as have ever been used in engineering composites, and, studied as materials, teeth (and other ossicles) from different echinoid families illustrate combinations of reinforcement parameters and toughening mechanisms providing good functionality. This probe of the design space available to sea urchins offers important guidance for engineering of structural tissue. The results on sea urchin teeth and pyramids (jaws) also illustrate what might be accomplished by such an integrated approach in bone.