Scientists Create Artificial Jellyfish Using Silicon Polymer and Rat Cells
A team of researchers from Harvard University and the California Institute of Technology (Caltech) have used recent advances in marine biomechanics, material science and tissue engineering to turn inanimate silicone and living cardiac muscle cells into a freely swimming jellyfish.
This finding supports the concept of reverse engineering a variety of muscular organs and simple life forms. The researchers' method for building the tissue-engineered jellyfish, dubbed "Medusoid," was published in a Nature Biotechnology paper July 22.
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"It occurred to me in 2007 that we might have failed to understand the fundamental laws of muscular pumps," said Kevin Kit Parker, Tarr Family professor of Bioengineering and Applied Physics at the Harvard School of Engineering and Applied Sciences (SEAS) and a core faculty member at the Wyss Institute for Biologically Inspired Engineering at Harvard. "I started looking at marine organisms that pump to survive. Then I saw a jellyfish at the New England Aquarium and I immediately noted both similarities and differences between how the jellyfish and the human heart pump."
To build the Medusoid, Parker collaborated with Janna Nawroth, a doctoral student in biology at Caltech and lead author of the study. They also worked with Nawroth's adviser, John Dabiri, a professor of aeronautics and bioengineering at Caltech.
"A big goal of our study was to advance tissue engineering," says Nawroth. "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."
The researchers used a sheet of cultured rat heart muscle, which contracts when electrically stimulated in a liquid environment. It was the perfect raw material to create the jellyfish. A silicone polymer was then used to fashion the sheet into a thin membrane that resembles a small jellyfish, with eight arm-like appendages. Medusoid was then placed in a container of salt-water and shocked into swimming with synchronized muscle contractions that mimic those of real jellyfish.
"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 behaviors that you see in biological jellyfish," said Dabiri.
Their design strategy will be broadly applicable to the reverse engineering of muscular organs in humans.
"As engineers, we are very comfortable with building things out of steel, copper, concrete," said Parker. "I think of cells as another kind of building substrate, but we need rigorous quantitative design specs to move tissue engineering to a reproducible type of engineering. The jellyfish provides a design algorithm for reverse engineering an organ's function and developing quantitative design and performance specifications. We can complete the full exercise of the engineer's design process: design, build, and test."
In addition to advancing the field of tissue engineering, Parker added that he took on the challenge of building a creature to challenge the traditional view of synthetic biology which is "focused on genetic manipulations of cells." Instead of building just a cell, he sought to "build a beast."
The researchers aim to further evolve the artificial jellyfish, allowing it to turn and move in a particular direction, and even incorporating a simple "brain" so it can respond to its environment and replicate more advanced behaviors like heading toward a light source and seeking energy or food.