This New Lamprey-Inspired Robotic Gripper Can Lift 850 Times Its Own Weight Both on Land and Underwater

A fish’s mouth inspires a new amphibious robot gripper.

16 Mar 2026, 19:04 by Tudor Tarita · ZME Science

Lamprey pileup. Credit: Wikimedia Commons

A lamprey’s mouth has inspired a new suction device that can grip in air and underwater. The design aims to solve a persistent problem in robotics: ordinary suction cups lose their hold on rough, porous, and wet surfaces.

“In complex cross-media environments, existing attachment mechanisms face significant physical constraints,” Junzhi Yu, the corresponding author, said in a statement. “Traditional suction cups easily fail underwater due to fluid washing, or they lose their vacuum seal on rough surfaces. We needed a unified mechanism that could break through the dual barriers of environmental media and surface morphology.”

The lamprey, however, does not rely on suction alone. Its oral disc combines a soft lip that forms a seal with stiff keratinized teeth-like structures that catch on tiny surface features.

So the researchers built a robotic version that follows the same plan. The team built a disc with a soft silicone lip around the edge and a core made of shape-memory polymer (SMP), a material that switches from soft to rigid as its temperature changes.

When heated to just above 33° Celsius, the polymer softens into a rubbery state. Vacuum pressure then pulls it into microscopic pores and crevices on the target surface. When the heat is turned off, the material hardens again, preserving that shape and locking itself into place.

“This hybrid mechanism successfully decouples adhesion strength from continuous vacuum maintenance,” Yu said. “Even if the external vacuum system fails, or if there is slight air leakage on extremely rough surfaces, the physical interlocking of the hardened SMP allows the device to maintain a highly secure grip for an ultra-long time.”

Hybrid Grip

CAD schematic of the robotic suction disc: SMP array panel (yellow), embedded resistive heater (green coil), soft silicone lip (red), and rigid base with fluid inlet/outlet ports (blue). Credit: Cyborg and Bionic Systems

Many robotic grippers work well only in narrow conditions since standard suction needs a smooth seal. Other bio-inspired adhesives may struggle underwater or on irregular textures.

The new disc combines suction with mechanical interlocking. That means it can keep holding even when the vacuum seal weakens.

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In lab tests, the compact 70-gram device produced enough adhesive force to lift more than 850 times its own weight, both in air and underwater. It also succeeded on rough surfaces where conventional suction cups failed. In air, its holding time was nearly three times that of a conventional suction-only design; underwater, retention time increased by up to 540%.

From left to right: vacuum adhesion with SMP not engaged, combined vacuum and SMP adhesion, and adhesion maintained by SMP after vacuum release. Black indicates no contact, and green indicates contact. Credit: Cyborg and Bionic Systems

The system also showed an unusually broad range. In dry tests, it handled objects spanning six orders of magnitude in mass, from a 0.01-gram microelectronic chip to an 11.4-kilogram desk. It also picked up everyday objects and tools, including wrenches and hammers.

Underwater, it adhered to coins, red bricks, scallop shells and conch shells. The tested objects varied in size, texture, curvature, and porosity—all traits that usually make suction unreliable.

Amphibious

Versatile adhesion and manipulation performance of the biomimetic suction disc on diverse objects of varying size, shape, and surface texture in air and underwater. Credit: Cyborg and Bionic Systems

One of the most illustrative demonstrations came when the researchers mounted the disc on a robotic arm and used it to handle a bionic manta ray robot. The arm picked up the robot in the air, lowered it into a tank, released it to swim, and then attached to it again underwater before lifting it back out.

“The system adapted flawlessly to the air-water interface transition,” the researchers said.

That kind of handoff is hard for robotic grippers. A tool built for dry, controlled settings may lose its hold once water, roughness, or leakage enters the picture. A tool built for underwater use may not perform the same way once it crosses back into the air. This design is meant to work across both.

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The researchers say that could make it useful for jobs like marine maintenance, deep-sea exploration and amphibious rescue, where robots may need to grab objects with little warning about their shape or surface.

The trade-off is speed. Because the SMP has to be heated and then cooled during each cycle, the system is slower and uses more energy than a standard suction cup. Its main advantage is not raw lifting strength, but reliable gripping across messy, real-world surfaces.