Researchers Create Smart Material from Sea Urchin Design

The research, led by Professor Lu Jian at the City University of Hong Kong, was published in the prestigious scientific journal *Nature*. The study focused on the long-spined sea urchin, *Diadema setosum*, revealing a previously unknown sensory capability within its spines. These sea urchin spines can generate measurable voltage signals from the movement of water droplets or currents across their surface. This electrical response is incredibly fast, occurring within tens of milliseconds—over a thousand times faster than the sea urchin's own visual perception. Researchers discovered that this ability is not biological but is intrinsic to the spine's material structure. Even without any living tissue, the porous ceramic-like material of the spine produces a transient potential of about 100 millivolts when stimulated by a droplet. This is due to a natural microscale sensor effect created by water moving through its unique microchannels. The team successfully replicated this effect by 3D printing a biomimetic version of the spine's architecture. Their engineered material demonstrated a threefold increase in voltage output and an eightfold increase in signal amplitude compared to similar structures without the urchin-inspired gradient design. This breakthrough challenges the long-held view that porous structures in nature serve purely mechanical functions. The created material can act as a mechanoreceptor, capable of detecting the intensity and direction of underwater flow in real-time without needing an external power source. Potential applications for this new smart material are vast, with significant possibilities in marine monitoring, underwater exploration, water management, and even aerospace engineering. It lays the groundwork for a new class of materials where the structure and function are deeply integrated.