They’ve created a monster! Or at least a coin-sized cyborg stingray made from rat heart cells that can be controlled underwater using light.

Designed by Kevin Kit Parker from Harvard University’s Wyss Institute and his team, the 16-millimetre-long soft robot has a gold skeleton overlaid with a flexible polymer. Its muscles are made up of about 200,000 rat heart cells laid down in layers. “My building material is alive,” says Parker.

To get the tiny robot to move, the team tweaked the rat-cell genes to make them light-sensitive. When exposed to light, the cells contract and the layers act as a kind of pump, pushing down on the skeleton so that the tiny robot can mimic the movements of a real stingray. “We kind of cheated compared to what nature does but it works,” says Parker.


Shining specific frequencies on the robot causes a wave of contractions to spread down its body, making it undulate, and different frequencies make it move at different speeds. Shining light on one side of its body just before the other allows it to turn. Controlled by light in this way, the robot successfully swam through an obstacle course (see video).

The artificial stingray is a living machine, but Parker says that more complex robots made from living tissue are still a long way off. We are only just beginning to learn how to use living cells as a material, which is a challenge because they need specific conditions to stay alive.

Previously, Parker was part of a team that made a cyborg jellyfish – also using heart tissue. But its design and control system were much less complex than the stingray.

Karaghen Hudson and Michael Rosnach

However, Parker’s ultimate goal is not to build living robots. Rather, these creations are a way for him to better understand the workings of muscular pumps and heart disease. “My real interest is in building a heart,” says Parker. He has also been involved in building mini-organs, which could ultimately be wired up to create a “human on a chip”.

Hanno Meyer from Bielefeld University in Germany, who also develops bio-inspired robots, thinks the cyborg ray is a good example of how to create a simplified model of a life form that can interact with its environment. “The combination of artificial and living parts provides insight into creating a durable bio-hybrid system, which could be relevant when creating new brain-machine interfaces,” he says.

Having mastered the stingray, Parker and his team are working on a more complicated marine animal. “You’ll have to wait to find out what it is,” says Parker.

Journal reference: Science, DOI: 10.1126