2022 Annual Report 2022 | Page 51

Previously , the team discovered that the unique chamber-based bioceramic structure of cuttlebone ( the internal skeleton of cuttlefish ) is simultaneously strong , stiff , and fracture-resistant , while still allowing for buoyancy regulation . This project and others like it motivated the team to investigate additional applications for nature ’ s porous designs at the microscale .
STARFISH SKELETONS : A NATURAL ARCHITECTED CERAMIC LATTICE
In this work , Li and his team turned their eyes to the skeleton of the knobby starfish . Widely distributed throughout the Indo-Pacific region , the species ’ dried skeletons are often used for home decoration . These starfish feature coneshaped projections that rise from their dorsal surface and discourage predators .
While observing samples of these starfish skeletons at the Nanoscale Characterization and Fabrication Laboratory ( NCFL ), Li and Ph . D . student Ting Yang ( co-first author of the paper and now a post-doctoral fellow at the Massachusetts Institute of Technology ), made an observation that piqued their interest : At the microscale , the starfish skeleton exhibited a lattice architecture with very regular arrangements of branches quite different from the porous structures of the cuttlebone and sea urchin spines previously studied . In fact , the unique skeletal organization of this starfish exhibits the highest structural regularity ever reported from this group of invertebrates . Such regular lattice-like structures display remarkable similarities with space frame truss structures commonly employed in modern human construction projects .
The team wondered how this natural ceramic lattice material achieved mechanical protection , since starfish skeletons are made of calcite , a crystalline form of calcium carbonate ( chalk ). Any child familiar with playing outside knows that sidewalk
Ling Li with starfish skeleton .
ANNUAL REPORT 2022
51