Researchers Create 'Smart Material' From Sea Urchins

The breakthrough comes from a team led by Professor Lu Jian at the City University of Hong Kong. Their work, recently published in the journal *Nature*, was inspired by the long-spined sea urchin, *Diadema setosum*. Researchers discovered that the sea urchin's spines, even without any living tissue, can generate a voltage of about 100 mV when stimulated by water droplets. This response is incredibly fast, occurring within tens of milliseconds—over a thousand times faster than the creature's own visual perception. The secret lies in the spine's natural, porous ceramic structure, which has a gradient of pore sizes. As water flows through these microchannels, it creates what is known as a streaming potential, effectively turning the spine into a highly sensitive natural sensor. To replicate this, the team used a 3D printing technique called vat photopolymerization to create artificial structures that mimic the sea urchin's spine. These 3D-printed versions showed a threefold increase in voltage output and an eightfold increase in signal amplitude compared to structures without the gradient design. This new material is essentially a self-powered sensor, capable of real-time detection of underwater flow direction and intensity without needing external power. This challenges the conventional view that such natural porous structures only serve a mechanical or defensive purpose. Potential applications for this biomimetic material are vast, ranging from marine environmental monitoring and underwater robotics to smarter biomedical devices and even aerospace engineering.