'Jellyfish' Propelled By Rat Heart Cells

A man-made jellyfish that 'swims' using pulsating rat heart cells has been created by scientists.

The team behind the prototype say the technology could one day revolutionise human medicine.

The Medusoid is made of transparent elastic silicone and measures several centimetres across.

Researchers at the California Institute of Technology printed the muscle structure of a jellyfish - the most primitive multi-organ animal - onto the silicone.

When protein molecules from rat hearts were added to the material, the printed structure guided its growth and organisation.

Even when removed from the heart, individual heart cells contract in response to an electric current. So, when scientists passed five-volt electric pulses through the Medusoid, it caused their creation to swim through the water.

Experts hope to create future versions that are able to respond to their environment, and even seek energy or food.

The printing techniques could one day be used to create organic pacemakers or advanced bio-engineered organs for humans, the scientists said.

Team member Professor John Dabiri said: "We're re-imagining how much we can do in terms of synthetic biology.

"I was surprised that with relatively few components - a silicone base and cells that we arranged - we were able to reproduce some pretty complex swimming and feeding behaviours that you see in biological jellyfish."

PhD student Janna Nawroth said: "A big goal of our study was to advance tissue engineering.

"In many ways, it is still a very qualitative art, with people trying to copy a tissue or organ just based on what they think is important or what they see as the major components - without necessarily understanding if those components are relevant to the desired function or without analysing first how different materials could be used."

The research has been published in the Nature Biotechnology journal.