The hairs that make geckos’ feet sticky have inspired the invention of adhesives for flat surfaces, but creating strong adhesives that can grab complex, 3D objects has proved a challenge.
Metin Sitti at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany, and his colleagues spread elastic microfibres, or ‘hairs’, across a soft, stretchy membrane, allowing it to mould and stick to a surface. The team attached this to a ‘gripper’ layer. Reducing the pressure inside the gripper spreads the load evenly across the sticky membrane, strengthening the bond between it and the target object. Changing the pressure in the system increased the membrane’s ‘stickiness’ 14-fold, allowing the device to suspend a variety of hard and soft objects, from fluid-filled flasks to tomatoes.