Researchers from Harvard University and the California Institute of Technology (Caltech) have combined inanimate silicon polymers with living cardiac 
muscle cells to form freely swimming “jellyfish.”
The research has shown that successful reverse engineering of a variety of muscular organs and simple life forms is possible. And in a research environment that has focused on replicating life’s building blocks, this research suggests a broader definition of synthetic life, reports ScienceDaily. The work was summarized in a July issue of Nature Biotechnology.
One of the paper’s authors, Kevin Kit Parker, had previously bioengineered a device that could grip, pump, and walk. But the inspiration to mimic a jellyfish’s motion came out of his frustration with the state of the cardiac field.
“It occurred to me in 2007 that we might have failed to understand the fundamental laws of muscular pumps,” says 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 conduct the reverse engineering of a jellyfish, the researchers studied maps of subcellular protein networks with muscle cells, then looked at what triggers the propulsion and the biomechanics of the movement. They then turned to a sheet of cultured rat heart muscle tissue that would contract when electrically stimulated in a liquid environment.
Next, they incorporated a silicone polymer that fashioned the body of the artificial creature into a thin membrane that resembled a small jellyfish with eight arm-like appendages. Drawing from what they had studied, the scientists quantitatively matched the subcellular, cellular, and supracellular architecture of the jellyfish musculature with the rat heart muscle cells.
The artificial jellyfish was placed in a container of ocean-like salt water and shocked into swimming with synchronized muscle contractions that mimicked those of real jellyfish. In fact, the muscle cells began to contract on their own a bit even before the electrical current was applied.
“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,” says John Dabiri, professor of aeronautics and bioengineering at Caltech, who is an expert at biological propulsion and who worked on the project.
The research could be levered into broader applications for reverse engineering of muscular organs in humans, the scientists say. Parker says:
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.
The researchers plan on making the jellyfish evolve. They hope to improve the design so that it can move in a particular direction, and even develop a “brain” so that it can respond to its environment, such as moving toward a light source and seeking energy.
Source: “Behold, the Artificial Jellyfish: Researchers Create Moving Model, Using Silicon Polymer and Heart Muscle Cells,” ScienceDaily, 7/22/12
Image by Shadowgate, used under its Creative Commons license.
Dale McGeehon has been a journalist and editor for more than 25 years, covering chemical regulation and testing for Pesticides and Toxic Chemical News and innovations in material sciences for the National Technology Transfer Center. His writing credits include Omni and College Park magazines and The New York Times.
