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The ‘biohybrid robotic jellyfish’, which combine the animals with artificial enhancements, were developed in the lab of John Dabiri at the California Institute of Technology (Caltech).
“Jellyfish can't do much besides swim, sting, eat, and breed… yet these simple creatures can easily journey to the depths of the oceans in a way that humans, despite all our sophistication, cannot,” a Caltech announcement said. “What if humans could have jellyfish explore the oceans on our behalf, reporting back what they find?”
Dabiri’s research aims to make that reality. The project turned to nature’s most efficient swimmers after earlier attempts to develop artificial versions were unable to achieve the same efficiency.
“Since they don't have a brain or the ability to sense pain, we've been able to collaborate with bioethicists to develop this biohybrid robotic application in a way that's ethically principled,” he said.
The researchers previously implanted jellyfish with a kind of electronic pacemaker that controls the speed at which they swim. They found that if they made jellyfish swim faster than their normal leisurely pace, the animals became even more efficient. A jellyfish swimming three-times faster than it normally does uses only twice as much energy.
This time the team went a step further by adding what they call a ‘forebody’. Hat-like attachments that sit on top of their bodies, the devices were designed by graduate student and lead research author Simon Anuszczyk, who aimed to make them more streamlined while also providing a place for sensors and other electronics.
“Much like the pointed end of an arrow, we designed 3D-printed forebodies to streamline the bell of the jellyfish robot, reduce drag, and increase swimming performance,” Anuszczyk said. “At the same time, we experimented with 3D printing until we were able to carefully balance the buoyancy and keep the jellyfish swimming vertically.”
The biohybrid robots were tested in a vertical tank, where they swam against a current. Tests showed that a jellyfish equipped with the swimming pacemaker and forebody could swim up to four-and-a-half-times faster than an all-natural jelly carrying a payload.
The total cost is about $20 per jellyfish, Dabiri said, which could make them an attractive alternative to renting research vessels that can cost more than $50,000 per day.
The goal of the research is to use jellyfish as robotic data-gatherers, sending them into the oceans to collect information about temperature, salinity, and oxygen levels.
“It's well known that the ocean is critical for determining our present and future climate on land, and yet we still know surprisingly little about the ocean, especially away from the surface,” Dabiri said. “Our goal is to finally move that needle by taking an unconventional approach inspired by one of the few animals that already successfully explores the entire ocean.”
Future work could focus on further enhancing the bionic jellies' abilities. They can currently only be made to swim faster in a straight line, but further research might make them steerable.
The work was published in Bioinspiration & Biomimetics.
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