Researchers from the University of California, Irvine and Japan’s Okayama and Toho universities have published findings about how chitons develop their exceptionally hard teeth, with potential applications for advanced manufacturing. The study, published in Science, examined how these algae-eating mollusks create teeth that are harder than human enamel and high-carbon steel through a precise biological process.
The research team identified that chitons transport iron-binding proteins called RTMP1 through microscopic tubules into developing teeth. These proteins work with iron stored in ferritin to create magnetite nanorods, resulting in the ultrahard tooth structure. “Chiton teeth, which consist of both magnetite nanorods and organic material, are not only harder and stiffer than human tooth enamel, but also harder than high-carbon steels, stainless steel, and even zirconium oxide and aluminum oxide – advanced engineered ceramics made at high temperatures,” said co-author David Kisailus, UC Irvine professor of materials science and engineering.
The study examined chitons from Northwest coastal areas of the United States and off the coast of Hokkaido, Japan. Researchers found that RTMP1 proteins exist in chiton species at different global locations, suggesting convergent biological design in controlling iron oxide deposition. The mollusks grow new teeth every few days at room temperature with nanoscale precision.
The findings could inform new approaches to additive manufacturing and 3D printing processes. “This includes new approaches toward additive manufacturing – 3D printing – and synthesis methods that are far more environmentally friendly and sustainable,” Kisailus said. The research combined materials science techniques like electron microscopy and X-ray analysis with biological methods to understand the complete tooth formation process.
Source: engineering.uci.edu