Limpet-Derived Ferritin Promotes Iron Teeth Mineralization Through Binding Fe²

Limpets, marine mollusks that feed on algae by scraping rocks, have evolved teeth renowned as among the strongest biological materials known. These teeth are iron-based biocomposites, primarily consisting of goethite nanorods embedded within a silica-rich matrix. A central mystery has been how limpets produce goethite-a mineral that typically requires extreme synthetic conditions-under ambient physiological settings. Here, we combined transcriptomics and functional assays to investigate the teeth of the limpet Cellana toreuma. RNA-seq in compartmented regions of teeth found differential gene expression for teeth formation involving intensive chitin metabolism and redox reaction. Through RNA interference, we demonstrated that a specific limpet-derived ferritin is essential for tooth iron accumulation and mineralization in vivo. We further identified and characterized this ferritin, showing its ability to bind Fe²⁺ and promote iron mineralization both in vitro and ex vivo. These findings provide direct evidence supporting the hypothesis that limpets form goethite through in situ oxidation of Fe²⁺. This work advances our understanding of limpet tooth microstructure and iron biomineralization mechanisms, offering valuable insights for the design of biomimetic wear-resistant materials under ambient conditions.