Artificial jellyfish created from heart cells
28 July BBC
Scientists in the US have created a free swimming artificial
jellyfish.The team members built the replica using silicone as a base on
which to grow heart muscle cells that were harvested from rats.They used
an electric current to shock the Medusoid into swimming with
synchronised contractions that mimic those of real jellyfish.
The advance, by researchers at Caltech and Harvard University, is
reported in the journal Nature Biotechnology.The finding serves as a
proof of concept for reverse engineering a variety of muscular organs
and simple life forms.
Because jellyfish use a muscle to pump their way through the water,
the way they function - on a very basic level is similar to that of a
human heart.
"I started looking at marine organisms that pump to survive," said
Kevin Kit Parker, a professor of bioengineering and applied physics at
Harvard.
"Then I saw a jellyfish at the New England Aquarium, and I
immediately noted both similarities and differences between how the
jellyfish pumps and the human heart."The similarities help reveal what
you need to do to design a bio-inspired pump."
The work also points to a broader definition of "synthetic life" in
an emerging field of science that has until now focused on replicating
life's building blocks, say the researchers.Prof Parker said he wanted
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 two groups at Caltech and Harvard worked for years to understand
the key factors that contribute to jellyfish propulsion, including the
arrangement of their muscles, how their bodies contract and recoil, and
how fluid dynamics helps or hinders their movements.
Once these functions were well understood, the researchers began to
reverse engineer them.They used silicone to fashion a jellyfish-shaped
body with eight arm-like appendages.Next, they printed a pattern made of
protein onto the "body" that resembled the muscle architecture of the
real animal.They grew the heart muscle cells on top, with the protein
pattern serving as a road map for the growth and organisation of the rat
tissue.
This allowed them to turn the cells into a coherent swimming
muscle.When the researchers set the Medusoid free in a container of
electrically conducting fluid, they shocked the Medusoid into swimming
with synchronised contractions. The muscle cells even started to
contract a bit on their own 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 behaviours that you see in biological
jellyfish," said John Dabiri, professor of aeronautics and
bioengineering at Caltech."I'm pleasantly surprised at how close we are
getting to matching the natural biological performance, but also that
we're seeing ways in which we can probably improve on that natural
performance.
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