Inspired by the tail of a seahorse, which can be compressed to half its size without damage, scientists at the University of California, San Diego, are attempting to use similar engineering to create a flexible robotic gripper arm equipped with polymer muscles that could be used in medical devices. Led by materials science professors, they say that the study of natural materials can lead to the creation of new and unique materials and structures that are stronger, tougher, lighter and more flexible.

A seahorse tail’s exceptional flexibility is due to its structure, made up of bony, armored plates that slide past each other. The engineers found that the connective tissue between the tail’s bony plates and the tail muscles bore most of the load from the displacement when crushed by a predator.

In order to study the structures and properties that make up the tail, the researchers applied a series of chemicals to strip them of either their protein components or their mineral components and discovered that the percentage of minerals in the plates was relatively low and the hardness of the plates varied. The ridges were hardest, likely for impact protection, and the plates are free to glide or pivot , while the joints between plates and vertebrae are extremely flexible with nearly six degrees of freedom.

They plan to use 3D printing to create artificial bony plates, which would then be equipped with polymers to act as muscles, and build a robotic arm that would be a unique hybrid between hard and soft robotic devices. The protected, flexible arm would be able to grasp a variety of objects of different shapes and sizes.