Sea urchin skeletons may owe some of their strength to a common geometric design.
Components of the skeletons of common sea urchins (Paracentrotus lividus) follow a pattern similar to found in honeycombs and dragonfly wings, researchers report in August Journal of the Royal Society Interface. The study of this recurring natural order could inspire the creation of new resistant but light materials.
Urchin skeletons show “an incredible diversity of microscale structures, ranging from completely ordered to completely chaotic,” says marine biologist and biomimetic consultant Valentina Perricone. These structures can help animals maintain their shape when faced with predator attacks and environmental stress.
Using a scanning electron microscope to study the tubercles of the hedgehog skeleton, sites where spines attach that resist strong mechanical forces, Perricone detected “a curious regularity.” The tubers appear to follow a type of common natural order called a Voronoi pattern, she and her colleagues found.
Using math, a voronoi pattern is created by a process that divides a region into polygon-shaped cells that are built around points within them called seeds (Serial number: 09/23/18). Cells follow the nearest neighbor rule: every point within a cell is closer to that cell’s seed than to any other seed. Also, the boundary separating two cells is equidistant from their seeds.
A computer-generated Voronoi pattern matched 82 percent of the pattern found in sea urchin skeletons. This arrangement, the team suspects, produces a strong but lightweight skeletal structure. The pattern “can be interpreted as an evolutionary solution” that “optimizes the skeleton,” says Perricone, of the “Luigi Vanvitelli” University of Campania in Aversa, Italy.
Hedgehogs, dragonflies and bees are not the only beneficiaries of Voronoi architecture. “We are developing a library of bio-inspired structures based on Voronoi” that could “serve as lightweight and strong solutions” for material design, says Perricone. She hopes that these can inspire new developments in materials science, aerospace, architecture and construction.