When one observes a colourful jellyfish pulsating through the ocean, Greek mythology probably doesn't immediately come to mind. But the animal once was known as the medusa, after the snake-haired mythological creature its tentacles resemble.
The mythological Medusa's gaze turned people into stone, and now, thanks to recent advances in bio-inspired engineering, a team led by researchers at the California Institute of Technology (Caltech) and Harvard University have flipped that fable on its head: turning a solid element - silicon - and muscle cells into a freely swimming "jellyfish."
Their method for building the tissue-engineered jellyfish, dubbed Medusoid, is outlined in a Nature Biotechnology paper that appears as an advance online publication on 22 July.
"A big goal of our study was to advance tissue engineering," says Janna Nawroth, a doctoral student in biology at Caltech and lead author of the study. "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 analyzing first how different materials could be used."
Because a particular function - swimming, say - doesn't necessarily emerge just from copying every single element of a swimming organism into a design, "our idea," she says, "was that we would make jellyfish functions - swimming and creating feeding currents - as our target and then build a structure based on that information."
Jellyfish are believed to be the oldest multi-organ animals in the world, possibly existing on Earth for the past 500 million years. Because they use a muscle to pump their way through the water, their function - on a very basic level - is similar to that of a human heart, which makes the animal a good biological system to analyse for use in tissue engineering.