The Secrets of Seashells

Fargo, N.D. –– Mimicking nature could lead to new technologies, according to North Dakota State University Distinguished Professor of Civil Engineering Kalpana Katti. She is quoted in the recent article “Seashells so tough they’ll kick sand in your face,” featured on MSNBC at and in LiveScience with the article “Seashells get their strength from interlocking bricks” at

“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 published online in Nature Communications. Abalone seashells consist of an outer layer along with a tough inner layer called nacre (nay’ kur), 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 was also 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.

Dr. Kalpana Katti and Dr. Dinesh Katti, professor of civil engineering at NDSU, have published more than 25 scientific articles regarding research on nacre. Interlocking bricks found in nacre’s structure were first discovered by the Katti research group at NDSU, with research results published in the Journal of Material Research, Vol. 2, No. 5, May 2005. More recent research results have been published in the Journal of Nanomaterials, Journal of Materials Science, Journal of Nanoscience, Journal of Nanotechnology, and the Journal of Engineering Mechanics.

About NDSU
With a reputation for excellence in teaching and multidisciplinary research, North Dakota State University, Fargo, links academics to opportunities. As a metropolitan land grant institution with more than 14,000 students, NDSU is listed in the top 40 research universities without a medical school in the U.S., based on research expenditures reported to the National Science Foundation. At the 55-acre NDSU Research & Technology Park, faculty, staff and students work with private sector researchers on leading-edge projects.

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