Bright Blue Lines in Limpet Shells May Inspire New Optical Bio Materials

A certain mollusk may have inspired some new materials. Scientists have identified two optical structures within the blue-rayed limpet's shell that gives it its blue-striped appearance that could be used in bio-inspired materials.

The blue-rayed limpet is known for the bright blue dotted lines that run in parallel along the length of its translucent shell. Depending on the angle at which light hits, a limpet's shell can flash brilliantly even in murky water. Intrigued by this, the researchers examined the shells a bit more slowly.

The scientists performed a detailed structural and optical analysis of the limpet shells. They saw that the blue stripes first appear in juveniles, resembling dashed lines. The stripes then grow more continuous as a limpet matures, and their shade varies from individual to individual, ranging from deep blue to turquoise. The scientists used scanning electron microscopy to closely look at the shells, and found that likely the stripes arose from features embedded deeper in the shells.

The researchers then used a combination of high-resolution 2D and 3D structural analysis to reveal 3D nanoarchitecture of the photonic structures embedded in the limpets' translucent shells. They found that in the regions with blue stripes, the shells' top and bottom layers were relatively uniform with dense stacks of calcium carbonate platlets and thin organic structures. However, about 30 microns beneath the shell surface there was a stark difference; regular plats of calcium carbonate morphed into a multilayered structure with regular spacing between calcium carbonate layers resembling a zigzag pattern and beneath this, a layer of randomly dispersed, spherical particles. These findings could be huge in materials science.

"Let's imagine a window surface in a car where you obviously want to see the outside world as you're driving, but where you also can overlay the real world with an augmented reality that could involve projecting a map and other useful information on the world that exists on the other side of the windshield," said Mathias Kolle, one of the researchers, in a news release. "We believe that the limpet's approach to displaying color patterns in a translucent shell could serve as a starting point for developing such displays."

The findings reveal a bit of insight into the limpet's shell. In the future, the structure could be used in manmade materials for further applications.

The findings are published in the journal Nature Communications.

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).