Researchers Create Artificial Jellyfish With Silicon And Heart Cells

  Biotechnology

Researchers at Harvard University and the California Institute of Technology (Caltech) have turned inanimate silicon and living cardiac muscle cells into a freely swimming “jellyfish“ named “Medusoid,” building on recent advances in marine biomechanics, materials science, and tissue engineering.

U sing recent advances in marine biomechanics, materials science, and tissue engineering, a team of researchers at Harvard University and the California Institute of Technology (Caltech) has turned inanimate silicon and living heart muscle cells from rats into  freely swimming artificial “jellyfish.”

Io9 has dubbed the creation, the first "cyborg lifeform." Unlike the robot jellyfish created at Virginia Tech, the artificial jellyfish called "Medusoids" made in this study published in Nature Biotechnology utilize actual organic tissue for propulsion.

The development serves as a proof of concept for reverse engineering a variety of muscular organs and simple life forms. It also suggests a broader definition of what counts as synthetic life in an emerging field that has primarily focused on replicating life’s building blocks.

An authority on cell- and tissue-powered actuators, co-author Kevin Kit Parker previously demonstrated that bioengineered constructs can grip, pump, and even walk. The inspiration to raise the bar and mimic a jellyfish came out of Parker’s frustration with the state of the cardiac field.

Similar to how a human heart moves blood throughout the body, jellyfish propel themselves through the water by pumping. The researchers, in figuring out how to take apart and then rebuild the primary motor function of a jellyfish, worked to gain new insights into how such pumps work.

“It occurred to me in 2007 that we might have failed to understand the fundamental laws of muscular pumps,” said 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, who performed the work as a visiting researcher in Parker’s lab. They also worked with Nawroth’s adviser, John Dabiri, a professor of aeronautics and bioengineering at Caltech, who is an authority on biological propulsion.

Image Source: Janna C Nawroth et al./Nature Biotechnology

“A big goal of our study was to advance tissue engineering,” said 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.”

It turned out that jellyfish, believed to be the oldest multi-organ animals in the world, were an ideal subject, as they use muscles to pump their way through the water, and their basic morphology is similar to that of a beating human heart.

To reverse engineer a “Medusa” jellyfish, the investigators used analytical tools borrowed from the fields of law enforcement biometrics and crystallography to make maps of the alignment of subcellular protein networks in all of the animal’s muscle cells. They then conducted studies to understand the electrophysiological triggering of the jellyfish propulsion and the biomechanics of the propulsive stroke itself.

Based on those efforts, it turned out that a sheet of cultured rat heart muscle tissue that would contract when electrically stimulated in a liquid environment was the perfect raw material to create an ersatz jellyfish. The team then incorporated a silicone polymer that fashions the body of the artificial creature into a thin membrane that resembles a small jellyfish, with eight armlike appendages.

Using the same analytical tools, the investigators were able to quantitatively match the subcellular, cellular, and supracellular architecture of the jellyfish musculature with the rat heart muscle cells.

The artificial construct was placed in a container of oceanlike saltwater and shocked into swimming with synchronized muscle contractions that mimic those of real jellyfish. (In fact, the muscle cells started to contract a bit on their own 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,” said Dabiri.

The researchers’ design strategy, they say, will be broadly applicable to the reverse engineering of muscular organs in humans.

Looking forward, the researchers aim to 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.
This video shows the launch and swimming of a tissue-engineered jellyfish, or "Medusoid," compared to real jellyfish, and the intermediate design steps. The construct is made from silicone rubber and powered by lab-grown heart tissue. Contraction of the Medusoid, at a frequency of 1-2Hz, can be triggered by external electrical field stimulation. The Medusoid was built in a proof-of-concept study at Caltech and Harvard for designing muscular pumps for biomedical application.








SOURCE  Harvard Gazette

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