Squid ring teeth are made up a numerous proteins, and the team at Penn State has begun to understand why. The variety, it seems, allows for more functionality.
“It was a mystery why nature uses more than one protein to make the ring teeth in the suckers,” Melik Demirel, professor of engineering science and mechanics at Penn tells A'ndrea Elyse Messer in an item on the university’s own news site. “Why did we need so many? It turns out that each has different mechanical properties,” he adds.
Based on nature
By mimicking these proteins and using the squid polypeptide structure as a sort of blue print, the research team created synthetic proteins and is on track to develop self-healing polymers. These will have the characteristics seen in squid ring teeth: “toughness and stretchability,” as the scientists put it.
And, they anticipate commercial potential for this technology in medicine, textiles, and cosmetics.
According to the researchers, whose work on this topic is published in the Proceedings of the National Academy of Sciences, the proteins in question are a blend of crystalline and amorphous bits (basically, semicrystalline).
Beyond that they have “varying repeats,” with amino acid strings that recur with what could seem like randomness. What the team noticed is that in their synthetic mimics, “toughness and extensibility increase as the molecular weight increases. The longer the polypeptide chain, the greater the molecular weight,” reports Messer.
“They also found that the balance between elasticity -- how much the material will stretch without deforming -- and plasticity -- the point at which it will deform -- remained unchanged,” she explains.
So by selectively altering the length and molecular weight of each protein segment, the researchers are able to choose the mechanical properties of each. In short, “The structural properties in this material are highly programmable,” as Messer puts it.