YSM Issue 86.1

ZOOLOGY
FEATURE
Frankenstein Jellyfish:
the Surprising Link between Jellyfish and the Human Heart
BY REBECCA SU
Science fiction just became reality. After four years of research,
bioengineers at Harvard and Caltech have created an artificial jellyfish
from the muscle cells of a rat. With the help of an electric shock
to jumpstart the cells, the contraption, nicknamed the Medusoid,
“swims” just like its real-life counterpart. Researchers hope that it
can provide a better understanding of other muscular pumps in
nature — most notably, the human heart.
Dr. Kevin Kit Parker, professor of bioengineering and applied
physics at Harvard University, found his inspiration for the Medusoid
at the New England Aquarium. As a scientist involved in cardiovascular
drug development, he was frustrated by how little the
field actually knew about the heart. Thus, when he saw a jellyfish
pumping water to propel itself forward, expanding and contracting
in rhythmic, fluid motions, its resemblance to a human heart was
unmistakable.
By engineering a very simple biological pump like a jellyfish, Parker
sought to model the fundamental pumping mechanism behind a
complex organ like the heart. In partnership with Dr. John Dabiri,
Professor of Aeronautics and Bioengineering at Caltech, his team
began studying factors that affect the motion of real jellyfish: the
shape and thickness of the bell, the speed of each contraction, and
the arrangement of muscle tissue. Their final product was simple but
astoundingly true-to-life: muscle cells arranged in a circular pattern,
held together by a silicone membrane. When submerged in saltwater
and shocked with an electric current, the muscle cells began moving
in synchronized contractions, bringing the Medusoid to “life.”
By studying the motion of the Medusoid, researchers can further
investigate how a beating heart regulates blood flow. This is
crucial to diagnosing heart failures and designing cardiovascular
drugs more effectively. “[The Medusoid] might be a good way to
study how the heart works and how the heart responds to different
environments,” says Dr. Paul Van Tassel, Professor of Chemical
and Environmental Engineering at Yale University. The model can
also be applied to study how the heart responds to disease in a
controlled laboratory setting.
In addition to serving as a modeling tool, the prospect of a
bioengineered muscular pump has significant implications for
cardiac patients. Current pacemakers and artificial heart valves
are problematic because they are made of plastic and aluminum.
“The natural response of a living tissue to a synthetic object is
to avoid or actively reject it,” says Van Tassel. “Now what people
try to do is make material that either mimics biology or actively
engages biology.” Thus, the Medusoid project is an early step in
integrating biological cells with these synthetic devices, resulting in
a more durable implant that the body is less likely to reject. Like the
Medusoid, future bioengineered medical devices can benefit from
a hybrid of natural and synthetic materials.
Looking ahead, the team plans to add features to the Medusoid
that make it more lifelike. A future model may be able to change
direction while swimming, and it could also include a primitive
“brain” that makes it respond to stimuli such as light and food.
Ultimately, a self-sustaining Medusoid with features like these
would better represent an organ like the heart, which independently
responds to various signals in the body.
Meanwhile, researchers remain optimistic about future Medusoidinspired
projects. According to Parker, the Medusoid provides an
ideal “design algorithm” for reverse-engineered organs: rather than
blindly mimicking an organ in nature, scientists should first isolate
the exact factors that contribute to its function, and then recreate
that function. Additionally, the Medusoid adds an entirely new
dimension to bioengineering: while previous research has primarily
focused on manipulating cells and molecules, an artificial jellyfish
is a step towards engineering whole organisms. “We’re reimagining
how much we can do in terms of synthetic biology,” says Dabiri.
The End of the World?
CARTOON
FEATURE
BY SPENCER KATZ
www.yalescientific.org
January 2013 | Yale Scientific Magazine 39