US-based researchers have created a stingray robot with living cells that can respond to light signals, paving the way for autonomous artificial creatures that can carry out their own decision-making.

The robot has an outer layer of cells grown from rats’ heart muscles that power its wing-like fins, which are made from flexible plastic and which allow it to swim gracefully like a real fish. The cells are genetically engineered to respond to light, enabling the scientists to turn the robot left or right with asymmetric pulses of illumination — and guide it around an obstacle course.

The researchers describe their project as the first step in the marriage of robotics and tissue engineering. “This work paves the way for the development of autonomous and adaptive artificial creatures able to process multiple sensory inputs and produce complex behaviours . . . and may represent a path toward soft-robotic ‘embodied cognition’,” they say in a paper in the journal Science.

Professor Kevin Kit Parker of Harvard University, the project leader, told the FT: “We built a stingray that doesn’t have its own brain and is controlled by light signals from outside.” The long-term aim is to incorporate neural cells and electronics into the robot, in order to make internal decision-making and intelligence possible, he added.

Prof Parker, whose primary research interest is cardiovascular medicine, had two inspirations for the project. One was watching rays swimming while visiting the New England Aquarium with his young daughter, while the other was the laser pointer he used to guide her down the street.

“I told my new postdoc [researcher] Sun-Jin Park, a very able Korean scientist, that I wanted to take a rat heart and rebuild it as a laser-guided stingray,” Prof Parker said. “He reacted with horror and it took a year’s work by me to persuade him to take on the project.”

As the research proceeded, scientists from institutions including Harvard, Massachusetts Institute of Technology and Stanford University, joined in. “We had to overcome some really complex issues in materials science, tissue engineering, optogenetics and biomechanics,” Prof Parker said.

The robotic ray is 1.6cm long — about one-tenth the size of a real fish. It has a gold skeleton overlaid with stretchy polymer, mimicking the shape of a miniature stingray. Embedded over the top is a layer of around 200,000 muscle cells extracted from rat hearts and genetically engineered to respond to light signals.

When activated, the cells pull the fins down. Some of this downward energy is stored in the skeleton and then released when the muscles relax, pulling the fins up again. They beat between once and three times a second, depending on the frequency of light stimulation. The artificial stingrays “live” for about a week, drawing energy from glucose solution in their tank.

“People react to the robotic ray in different ways. Cardiac physiologists see a functional relationship to a working heart,” said Prof Parker, who is interested in developing a bioengineered human heart.

“Roboticists see something moving as if it’s alive. Artists see something more like a piece of art than a piece of science,” he added.