Sea Urchin Inspires New Smart Material

The research, led by Professor Lu Jian at the City University of Hong Kong, was recently published in the scientific journal *Nature*. The study revealed that the porous ceramic structure of sea urchin spines can generate measurable voltage signals when water droplets or flowing water pass over them. This electrical response is remarkably fast, occurring within tens of milliseconds, which is over a thousand times faster than the sea urchin's own visual perception. Intriguingly, the spines produce this voltage even without any living biological tissue, proving the capability is an intrinsic property of the material's microstructure. By observing the long-spined sea urchin (*Diadema setosum*), the team noted that a falling seawater droplet would cause the spine to rotate in about one second, inducing a transient potential of approximately 100 mV. This natural function acts as a highly sensitive tactile response system for the organism. Using advanced 3D printing, the researchers fabricated biomimetic structures that mimicked the sea urchin spine's design. These artificial versions showed a threefold increase in voltage output and an eightfold increase in signal amplitude compared to structures without the same gradient porous design. This breakthrough challenges the long-held view that natural porous structures serve only mechanical functions. The new material's ability to act as a self-powered sensor opens doors for next-generation smart materials in underwater monitoring and exploration. Potential applications for this biomimetic material are extensive, ranging from marine environmental monitoring and water resource management to aerospace engineering and biomedical devices.