Mimicking nature could lead to new technologies, according to Kalpana Katti, distinguished professor of civil engineering. She is quoted in the recent article “Seashells so tough they’ll kick sand in your face,” featured on MSNBC at www.msnbc.msn.com/id/41378069/ns/technology_and_science-science and in LiveScience with the article, “Seashells get their strength from interlocking bricks” at www.livescience.com/animals/where-sea-shells-get-their-strength-110201.html.
“The seashells took some very humble materials, chalk and proteins, and made something a lot tougher,” said Katti in the article, which highlights other recent research done at Purdue University, and was published online in Nature Communications. Abalone seashells consist of an outer layer along with a tough inner layer called nacre, more commonly known as mother-of-pearl. In the Live Science article, Katti notes that additional research is needed to understand nacre and its properties. “The organic in nacre is a cocktail of 30 proteins, and we don't know the structure of even one,” she told LiveScience. “The mechanics of nacre is very complex.”
While the dual life of mother-of-pearl encompasses beauty and strength, scientists aren’t interested in making seashells. “We want to use other materials and understand how seashells are made. Just like nature has taken calcium carbonate and made it 3,000 times tougher, we can take other composites and make them thousands of times tougher,” explains Katti. “It could make possible lightweight armored aircraft, body armor, artificial body parts and protective coatings that are strong and flexible.” She points out that their research has shown that nacre’s interlocking bricks, platelet rotation and properties of organics are critical. “If we can play with those, we can engineer materials that are much better than what we have now.”
In addition, research done in the Katti and Katti group at NDSU has shown that mineral proximity plays a profound role on mechanics of proteins. This was observed through steered molecular simulations on mechanics of nacre proteins in proximity of calcium carbonate minerals in nacre. This fact also was observed by the group for synthetic polymers in close proximity of nanoclays and nanohydroxyapatite, and also observed for human bone. The conclusion is that organics in nanoscale proximity with charged mineral surfaces exhibit mechanical behavior far superior to their innate insitu behavior. Biology, such as in seashells and bone, often presents good examples of nanoscale proximity of organics with minerals.
