Scientists have created a synthetic stingray that isn’t just about fun and games — it could lead to the development of an artificial heart based on the same techniques.

The paper, published in the journal Science, describes how the robot stingray is propelly by living muscle cells and controlled by light.

Artificial hearts are currently built with mechanical pumps, but using living muscle cells would be a breakthrough because it would allow the heart to behave more like, well, a heart. It would even enable the heart to grow and change over time.

So why a stingray? The reason is that stingrays and hearts have a similar problem: they need to overcome problems involving fluid and motion, as a stingray has to propel itself through water while a heart has to pump blood through the body.

The lab had previously built an artificial jellyfish, but a ray was a more complicated process. In the end, the team used cells from a rat to create their aquatic robot.

The ray is about the size of a nickel and has a transparent body made of silicone. Its skeleton is made of gold.

The 200,000 heart muscle cells were taken from a rat, and they were genetically altered to follow blue lights, allowing researchers to guide it.

“Inspired by the relatively simple morphological blueprint provided by batoid fish such as stingrays and skates, we created a biohybrid system that enables an artificial animal—a tissue-engineered ray—to swim and phototactically follow a light cue,” the abstract states. “By patterning dissociated rat cardiomyocytes on an elastomeric body enclosing a microfabricated gold skeleton, we replicated fish morphology at Embedded Image scale and captured basic fin deflection patterns of batoid fish. Optogenetics allows for phototactic guidance, steering, and turning maneuvers. Optical stimulation induced sequential muscle activation via serpentine-patterned muscle circuits, leading to coordinated undulatory swimming. The speed and direction of the ray was controlled by modulating light frequency and by independently eliciting right and left fins, allowing the biohybrid machine to maneuver through an obstacle course.”