Could Building a Heart Start With a Swimming Robot?

Inspired by his daughter's love of the aquarium, a researcher tests his heart-building ideas on a tiny robotic stingray powered by rat cells. 

Nancy Crotti

A Harvard University professor wants build a human heart, so he made a "living" stingray robot first.

The robot is the size of a nickel. It swims, guided by light and powered by rat heart muscle cells. It's a step up from the robot jellyfish he made earlier, as the stingray can be maneuvered around obstacle courses with beams of light, according to a report in Science.

Why a stingray? It's built to prevent rollover, due to a flat body and extended pectoral fins. Those fins can operate independently, helping this highly efficient swimmer perform fine, reproducible turning maneuvers. Plus, the New England Aquarium in Boston is the favorite hangout for Professor Kevin "Kit" Parker's daughter.

Parker's team drew on fish morphology, neuromuscular dynamics, and gait control to develop this living biohybrid system. They reverse-engineered stingray musculoskeletal structure using four-layered architecture, and cast the 3-D elastomer body in a titanium mold. To make the skeleton, they thermally evaporated gold, and produced a thin interstitial elastomer layer via spin-coating. Finally, they added a layer of aligned rat cardiomyocytes, which they anchored with a connective glycoprotein called fibronectin.

They tissue-engineered muscles, and designed the ray's integrated sensory-motor system to mimic the undulating swimming movements of rays found in nature, and added photovoltaics so they could control those movements with light.

Their stingray swam faster and further than existing locomotive biohybrid robots, and maintained its speed for six days, the article says.

A founding member of the faculty at Harvard's Wyss Institute for Biologically Inspired Engineering, Parker researches cardiac cell biology and tissue engineering, traumatic brain injury, and biological applications of micro- and nanotechnologies. He is involved in projects ranging from creating organs-on-chips to developing nanofabrics for applications in tissue regeneration.

Initial results of his nanofabric work include heart muscle strands similar to the papillary muscle, which may lead to new strategies for repair and regeneration throughout the heart. These nanofabrics are made from the same proteins as normal tissue, and can degrade harmlessly within the body once they are no longer needed.

A Wyss Institute spinoff company called Emulate raised $28 million earlier this year to commercialize its organs-on-chips technology into a lab-ready system aimed at improving drug development and consumer product design.

Parker's robo-stingray is a far cry from a robo-heart, but he and his team believe that it represents "a first step in engineering multilevel systems that link neurodynamics, mechanics, and complex controllable gaits--coupling sensory information to motor coordination and movement that leads to behavior," they wrote. "This work paves the way for the development of autonomous and adaptive artificial creatures able to process multiple sensory inputs and produce complex behaviors in distributed systems and may represent a path toward soft-robotic 'embodied cognition.'"

Nancy Crotti is a contributor to Qmed.

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[Image courtesy of Harvard's Wyss Institute]