Researchers Create Smart Material Inspired by Sea Urchins
A research team at City University of Hong Kong has developed a new 3D-printed 'mechanoelectrical' smart material. The design, inspired by the porous structure of sea urchin spines, could have applications in creating more advanced sensors for robotics and smart structures.
The research, published in the journal *Nature*, was led by Professor Lu Jian, Dean of the College of Engineering at City University of Hong Kong. His team's work focused on the long-spined sea urchin, *Diadema setosum*, discovering that its spines could generate a measurable voltage from contact with water. This response is remarkably fast, occurring within tens of milliseconds—over a thousand times faster than the sea urchin's own visual perception. The team determined the electrical signals are not generated by living cells but by the spine's intrinsic material structure. When water flows through the porous, gradient structure of the spine, it creates a "streaming potential," effectively making the spine a natural micro-sensor. This finding challenges the conventional view that such biological structures serve purely mechanical functions. To harness this, the researchers used vat photopolymerization 3D printing to create a biomimetic version. The engineered material, replicating the spine's topological structure, demonstrated a threefold increase in voltage output and an eightfold increase in signal amplitude compared to non-gradient structures, proving the effect is governed by form, not just material. This breakthrough in biomimetic design could significantly advance tactile sensing for robotics, a field that has traditionally struggled to match the resolution and sensitivity of human skin. While many robots rely on vision, advanced tactile sensors are critical for dexterous manipulation of fragile or complex objects where vision alone is insufficient. The development of novel smart materials is a key interest for defense modernization. The Pentagon's fiscal year 2025 science and technology budget request includes $1.9 billion for integrated sensing and cyber, and $414 million for advanced materials. Materials innovation is seen as crucial for developing next-generation capabilities and reducing reliance on foreign supply chains. Potential applications for this sea urchin-inspired material extend to underwater exploration and marine monitoring, where a self-powered, sensitive sensor could provide real-time data on flow and contact without an external power source. This aligns with the broader push for more autonomous and energy-efficient robotic systems in aerospace and defense.
