Cyborg stingray swims toward light, breaks new ground

Cambridge, Mass. — The idea of taking apart a rat’s heart and transforming it into a tissue-engineered stingray first came to Kevin Kit Parker during a trip to the New England Aquarium with his daughter.

Four years later, a robotic ray that swims toward light has made the cover of Science Magazine and is pushing the limits of what’s possible in the design of machines powered by living cells.

A research team based at Harvard University’s Disease Biophysics Group, which Parker directs, created the translucent, penny-sized ray with a gold skeleton and silicone fins layered with the heart muscle cells of a rat.

It’s remote-controlled, guided by a blinking blue flashlight. Each burst of blue sets off a cascade of signals through the cells, which have been genetically-engineered to respond to light. The contraction of the tissue creates a downward motion on the ray’s body. When the tissue relaxes, the gold skeleton recoils — moving the fin upward again in an undulating cycle that mimics the graceful swimming of a real ray or skate.

Parker, whose research includes cardiac cell biology, launched the project as a method for learning more about the mysteries of the human heart and a step toward the far-off goal of building an artificial one. But the interdisciplinary project is also sparking interest in other fields, from marine biology to robotics.

Parker is not a roboticist. But as an Army veteran who did two tours in Afghanistan, he welcomes any part his stingrays could play in advancing the development of machines able to perform dangerous jobs.

“Bio-hybrid machines — things with synthetic parts and living materials — they’re going to happen,” Parker said. “I’ve spent time getting shot at and seen people getting shot. If I could build a cyborg so my buddy doesn’t have to crawl into that ditch to look for an IED, I’d do that in a heartbeat.”

The project to build the ray was more difficult and expensive — close to $1 million, according to Parker — than imagined. A mechanical engineer by training, Park had to delve into molecular and cell biology. The team pulled experts from diverse fields, including an ichthyologist — someone who studies fish — to understand and help replicate a ray’s muscle structure and biomechanics. Their work was published in Science last month.