The study published on Friday in the journal Science Advances described the soft robots made of a polymer embedded with magnetic iron microparticles, and controlled by light and magnetic fields.

"We can get it to hold a given shape; we can then return the robot to its original shape or further modify its movement; and we can do this repeatedly," said the paper's corresponding author Joe Tracy, professor of materials science and engineering at North Carolina State University.

The researchers used light from a light-emitting diode (LED) to heat up the material that is relatively stiff under normal conditions, and the polymer became pliable. Then, they demonstrated that the robot's shape can be remotely controlled by applying a magnetic field.

After the robot took a desired shape, the researchers removed the LED light, and then the robot resumed the original stiffness, locking the shape in place.

In an experimental test, the researchers used the soft robot as a "grabber" for lifting and transporting objects. Also, it can be folded into "flowers" with petals that bend in different directions.

In addition, the researchers developed a computational model to fine-tune the robot's shape, polymer thickness, and the size and direction of the required magnetic field, which helps make a prototype design to accomplish a specific task.

Now, they are working to engineer polymers that respond at different temperatures in order to meet the needs of specific applications.