Mineralized sclerites in the gorgonian coral Leptogorgia chilensis as a natural jamming system

作者：Chenming Hu, Ravi Tutika, Zhifei Deng, Zian Jia, Liuni Chen, Hongshun Chen, Yang Geng, Xianghui Xiao, Pavel Shevchenko, Christoph Pierre, James C. Weaver, Daniel Baum, Michael D. Bartlett, Ling Li · 发表于：Proceedings of the National Academy of Sciences · 年份：2025 · DOI：10.1073/pnas.2504541122 · 被引用次数：2 · 研究领域：Calcium Carbonate Crystallization and Inhibition、Cephalopods and Marine Biology、Building materials and conservation

The soft corals (Cnidaria, Octocorallia), a diverse group of colonial marine invertebrates, can reversibly tune their body stiffness in response to external stimuli. This capability is attributed to their dynamic skeletal systems, which consist of thousands of mineralized skeletal elements, called sclerites, embedded within a gel-like matrix that swells/deswells and unjams/jams the sclerites, thus modulating skeletal stiffness. While sclerite morphology is widely used for species identification, its role in the mechanical performance of a soft coral’s skeletal system is largely unknown. Here, we investigated structure-jamming relationships in sclerite-based skeletal architectures using the red gorgonian octocoral Leptogorgia chilensis as a model system. The sclerites of L. chilensis exhibit a shaft-like geometry with two axial branches and two sets of triradiate side branches, which are aligned with the crystallographic symmetry of the constituent magnesium-containing calcite. By combining multiscale three-dimensional (3D) structural characterization, parametric geometrical modeling, 3D printing, mechanical testing, and discrete element simulations, we demonstrate how sclerite geometry achieves a balanced jamming performance in terms of stiffness, weight, strength, and fracture resistance in comparison to alternative geometries parametrically modified from the native sclerites (e.g., changes in the length and number of side branches). We also found that these performance metr...