In the News: Frankenjelly

Artificial Jellyfish, 'Medusoid,' Made From Rat Heart Cells

By Ned Potter July 23, 2012

A close-up view of engineered rat cardiac muscle researchers used to power an artificial, tissue-engineered jellyfish. (Janna Nawroth/Caltech)

If you watch the mesmerizing pulses of a jellyfish in water, it might occur to you that they sometimes resemble the pulses of the human heart. A jellyfish doesn't swim so much as it beats, pushing its way forward.

Kevin Kit Parker, a professor at Harvard University, had that thought on a visit to the New England Aquarium, and teamed up with John Dabiri and Janna Nawroth of the California Institute of Technology. They all work in the nascent field of bioengineering, and they and their team might have started something.

They created a sort of artificial jellyfish -- it looks like one, and swims like one but doesn't have a single cell of jellyfish tissue in its body.

Instead, they grew their jellyfish from the heart muscle cells of a rat. Yes, a rat. They gave it the nickname "Medusoid" and published their results in the journal Nature Biotechnology.

"What we were able to do was replace jellyfish muscle with muscle from a heart," said Dabiri. "And then we were able to replace the jelly, if you will, in a jellyfish with a silicone rubber substance. And by putting those components together, the rat heart muscle and the silicone rubber, we were able to re-engineer the function of a living jellyfish."

The scientists grew Medusoid on a tiny frame, so that it had a round shape and eight appendages, much as a real jellyfish does. They used computer engineering to make sure what shape would work best. They placed it in a tank, applied a small electric charge, and it pulsed its way through the water, looking very much like a jellyfish.

Why do such an experiment? The scientists say it really has very little to do with jellyfish or rats, and a lot to do with the human body.

In the not-too-distant future, Dabiri, said, it may be possible to give patients heart valves or pacemakers made from their own cells. No metal box to implant, no batteries to replace, and much less risk that the body will reject it.

"Instead of heart valves made out of aluminum or plastic, they would be built out of your own biological material, your heart cells, your tissue," he said. "That makes it more biocompatable and potentially longer-lived."

There are many problems still to be solved, say the researchers; their artificial jellyfish, for instance, is far simpler than a real one. A real one can steer through the water; Medusoid could only go straight.

But If Medusoid can be made to mimic a jellyfish, something that mimics part of a heart may not be far off.

"We're not as far away as you might think," said Dabiri. "I think within the next five to 10 years you can start to see these therapies actually be used."

Let's hope someone doesn't bioengineer the Blob,