Bio-engineered jellyfish

Using rat heart cells and silicone polymer, researchers have bioengineered a "jellyfish" that knows how to swim.
The odd jellyfish mimic, dubbed a "Medusoid" by its creators, is more than a curiosity. It's a natural biological pump, just like the human heart. That makes it a good model to use to study cardiac physiology, said study researcher Kevin Kit Parker, a bioengineer at Harvard University.
"The idea is to look at a muscular pump other than the heart or other muscular organ and see if there are some fundamental similarities, or design principles, that are conserved across them," Parker told LiveScience. "This study revealed that there are."
Building a jelly: Jellyfish propel themselves with a pumping action, as anyone who has ever watched them float around an aquarium tank can attest. Parker was looking for a way to tackle questions about the heart that aren't well understood when he saw some jellyfish in a display in 2007.
"I thought, 'I can build this,'" he said.
The ingredients were rat heart muscle cells and a thin silicone film. ("The world needs less rats and more jellyfish, so I thought it would be cool to do a one-for-one swap," Parker joked.) Along with researchers from the California Institute of Technology, he and his team engineered the cells and silicone in a pattern that mimicked the structure of a real jellyfish. They then stuck the creature in a tank full of electrically conducting fluid and zapped it with current.