A team of researchers from the University of California, Irvine, and Japan’s Okayama and Toho universities has uncovered the secrets behind one of nature’s toughest materials—the teeth of chitons.
These marine mollusks, which scrape algae from rocks in coastal areas, grow teeth so hard and wear-resistant that they outperform many advanced man-made materials.
The findings, published in Science, could lead to breakthroughs in creating stronger, more sustainable materials for industries ranging from dentistry to manufacturing.
Chiton teeth are not just impressive—they’re extraordinary.
Made of a combination of organic material and magnetite nanorods, they are harder and stiffer than human tooth enamel, high-carbon steel, stainless steel, and even advanced ceramics like zirconium oxide and aluminum oxide, which require extreme heat to produce.
Yet chitons form their teeth at room temperature with nanoscale precision, producing new ones every few days.
David Kisailus, a professor of materials science and engineering at UC Irvine and a co-author of the study, explained that this ability makes chiton teeth more advanced than materials currently used for cutting tools, grinding equipment, surgical implants, and protective coatings.
“We can learn a lot from these biological designs and processes,” he said.
The secret lies in how chitons build their teeth. The researchers discovered that specialized iron-binding proteins, called RTMP1, are transported into developing teeth through nanoscopic channels called microvilli.
Once inside, these proteins bind to scaffolds made of chitin nanofibers—a tough natural biopolymer.
This scaffold controls how the magnetite nanorods are arranged. Meanwhile, iron stored in another protein, ferritin, is released and binds to the RTMP1. This interaction triggers the precise growth of nanoscale iron oxide crystals, which align to form the ultrahard magnetite structure of mature chiton teeth.
What’s more, this process appears to be a common biological strategy among chitons worldwide, from the coasts of Hokkaido, Japan, to the Pacific Northwest of the United States. The team’s findings suggest an evolutionary convergence in how these animals control iron oxide formation for maximum strength.
Beyond unlocking the mysteries of chiton biology, the study has far-reaching implications. Understanding how chitons create such durable materials could lead to new, environmentally friendly manufacturing methods for products like batteries, fuel cell catalysts, semiconductors, and even 3D-printed materials. The ability to control where and when minerals form—just as chitons do—could revolutionize how advanced materials are made.
The research combined cutting-edge tools from both materials science and biology, including ultra-high-resolution electron microscopy, X-ray analysis, spectroscopy, immunofluorescence, and gene expression tracking. Kisailus said this interdisciplinary approach was key to revealing “the full molecular choreography” of tooth formation.
By studying how nature builds one of the hardest biological materials on Earth, the team hopes to pave the way for a new generation of high-performance, sustainable materials—crafted with the same precision and efficiency as a chiton’s tooth.
