Researchers at the Italian Institute of Technology and the Sant'Anna School of Advanced Studies have successfully created artificial 3D-printed muscles.

Using an SLA 3D printer and an unspecified soft resin, the researchers printed pumpkin-like bladders that can expand and contract, due to their pleats.

The motive force is pneumatic. When air is pumped in or out of the pumpkins—actually called GRACEs, for GeometRy-based Actuators able to Contract and Elongate—they change their shape, producing linear motion between their poles.

Next the team strung a bunch of these together in an approximation of a human hand.

Here's what they got it to do:

"Their size is limited purely by the manufacturing technology used," says researcher Corrado De Pascali, a PhD student at IIT's Bioinspired Soft Robotics laboratory in Genoa and at SSSA's BioRobotics Institute in Pisa. "They can be built in different sizes, and we can vary their performance, both in terms of deformation and strength, and manufacture them using various materials and technology, even already built into the structures to be fabricated."

The pneumatic pressure required to actuate the muscles is said to be low—"a few tenths of a bar"—and the researchers say each actuator "can support over 1,000 times their weight depending on the material used to make them."

"GRACE actuators have characteristics ideal for application in various robotic solutions, using simple techniques at very low costs," the researchers conclude. "Their ease of manufacture also makes them replicable outside research laboratories, such as in the fab labs available to makers."