Tag Archives: John O Dabiri

Bionic jellyfish for deep ocean exploration

This research may be a little disturbing for animal lovers as it involves conjoining a jellyfish (or sea jelly) and a robotic device. That said, a February 29, 2024 news item on ScienceDaily highlights new research into the oceanic depths,

Jellyfish can’t do much besides swim, sting, eat, and breed. They don’t even have brains. Yet, these simple creatures can easily journey to the depths of the oceans in a way that humans, despite all our sophistication, cannot.

But what if humans could have jellyfish explore the oceans on our behalf, reporting back what they find? New research conducted at Caltech [California Institute of Technology] aims to make that a reality through the creation of what researchers call biohybrid robotic jellyfish. These creatures, which can be thought of as ocean-going cyborgs, augment jellyfish with electronics that enhance their swimming and a prosthetic “hat” that can carry a small payload while also making the jellyfish swim in a more streamlined manner.

The researchers describe their work and provide recordings of the jellyfish,

A February 28, 2024 California Institute of Technology (Caltech) news release (also on EurekAlert) by Emily Velasco, which originated the news item, provides more detail,

The work, published in the journal Bioinspiration & Biomimetics, was conducted in the lab of John Dabiri (MS ’03, PhD ’05), the Centennial Professor of Aeronautics and Mechanical Engineering, and builds on his previous work augmenting jellyfish. Dabiri’s goal with this research is to use jellyfish as robotic data-gatherers, sending them into the oceans to collect information about temperature, salinity, and oxygen levels, all of which are affected by Earth’s changing climate.

“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 says. “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.”

Throughout his career, Dabiri has looked to the natural world, jellyfish included, for inspiration in solving engineering challenges. This work began with early attempts by Dabiri’s lab to develop a mechanical robot that swam like jellyfish, which have the most efficient method for traveling through water of any living creature. Though his research team succeeded in creating such a robot, that robot was never able to swim as efficiently as a real jellyfish. At that point, Dabiri asked himself, why not just work with jellyfish themselves?

“Jellyfish are the original ocean explorers, reaching its deepest corners and thriving just as well in tropical or polar waters,” Dabiri says. “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.”

Previously, Dabiri’s lab implanted jellyfish with a kind of electronic pacemaker that controls the speed at which they swim. In doing so, they found that if they made jellyfish swim faster than the leisurely pace they normally keep, the animals became even more efficient. A jellyfish swimming three times faster than it normally would uses only twice as much energy.

This time, the research team went a step further, adding what they call a forebody to the jellies. These forebodies are like hats that sit atop the jellyfish’s bell (the mushroom-shaped part of the animal). The devices were designed by graduate student and lead author Simon Anuszczyk (MS ’22), who aimed to make the jellyfish more streamlined while also providing a place where sensors and other electronics can be carried.

“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 says. “At the same time, we experimented with 3D printing until we were able to carefully balance the buoyancy and keep the jellyfish swimming vertically.”

To test the augmented jellies’ swimming abilities, Dabiri’s lab undertook the construction of a massive vertical aquarium inside Caltech’s Guggenheim Laboratory. Dabiri explains that the three-story tank is tall, rather than wide, because researchers want to gather data on oceanic conditions far below the surface.

“In the ocean, the round trip from the surface down to several thousand meters will take a few days for the jellyfish, so we wanted to develop a facility to study that process in the lab,” Dabiri says. “Our vertical tank lets the animals swim against a flowing vertical current, like a treadmill for swimmers. We expect the unique scale of the facility—probably the first vertical water treadmill of its kind—to be useful for a variety of other basic and applied research questions.”

Swim tests conducted in the tank show that a jellyfish equipped with a combination of the swimming pacemaker and forebody can swim up to 4.5 times faster than an all-natural jelly while carrying a payload. The total cost is about $20 per jellyfish, Dabiri says, which makes biohybrid jellies an attractive alternative to renting a research vessel that can cost more than $50,000 a day to run.

“By using the jellyfish’s natural capacity to withstand extreme pressures in the deep ocean and their ability to power themselves by feeding, our engineering challenge is a lot more manageable,” Dabiri adds. “We still need to design the sensor package to withstand the same crushing pressures, but that device is smaller than a softball, making it much easier to design than a full submarine vehicle operating at those depths.

“I’m really excited to see what we can learn by simply observing these parts of the ocean for the very first time,” he adds.

Dabiri says future work may focus on further enhancing the bionic jellies’ abilities. Right now, they can only be made to swim faster in a straight line, such as the vertical paths being designed for deep ocean measurement. But further research may also make them steerable, so they can be directed horizontally as well as vertically.

The paper describing the work, “Electromechanical enhancement of live jellyfish for ocean exploration,” appears in the XX issue of Bioinspiration & Biomimetics. Co-authors are Anuszczyk and Dabiri.

Funding for the research was provided by the National Science Foundation and the Charles Lee Powell Foundation.

Here’s a link to and a citation for the paper,

Electromechanical enhancement of live jellyfish for ocean exploration by Simon R Anuszczyk and John O Dabiri. Bioinspiration & Biomimetics, Volume 19, Number 2 DOI 10.1088/1748-3190/ad277f Published 28 February 2024

This paper is open access.

Medusa, jellyfish, and tissue engineering

The ‘Medusoid’ is a reverse- tissue-engineered jellyfish designed by a collaborative team of researchers based, respectively, at the California Institute of Technology (Caltech) and Harvard University. From the July 22, 2012 news item on ScienceDaily,

When one observes a colorful jellyfish pulsating through the ocean, Greek mythology probably doesn’t immediately come to mind. But the animal once was known as the medusa, after the snake-haired mythological creature its tentacles resemble. The mythological Medusa’s gaze turned people into stone, and now, thanks to recent advances in bio-inspired engineering, a team led by researchers at the California Institute of Technology (Caltech) and Harvard University have flipped that fable on its head: turning a solid element—silicon—and muscle cells into a freely swimming “jellyfish.”

“A big goal of our study was to advance tissue engineering,” says Janna Nawroth, a doctoral student in biology at Caltech and lead author of the study. “In many ways, it is still a very qualitative art [emphasis mine], 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.” Because a particular function—swimming, say—doesn’t necessarily emerge just from copying every single element of a swimming organism into a design, “our idea,” she says, “was that we would make jellyfish functions—swimming and creating feeding currents—as our target and then build a structure based on that information.”

Oops! I’m not sure why Nawroth uses the word ‘qualitative’ here. It’s certainly inappropriate given my understanding of the word. Here’s my rough definition, if anyone has anything better or can explain why Nawroth used ‘qualitative’  in that context, please do comment. I’m going to start by contrasting qualitative with quantitative, both of which I’m going to hugely oversimplify. Quantitative data offers numbers, e.g. 50,000 people committed suicide last year. Qualitative data helps offer insight into why. Researchers can obtain the quantitative data from police records, vital statistics, surveys, etc. where qualitative data is gathered from ‘story-oriented’ or highly detailed personal interviews. ( I would have used ‘hit or miss,’ ‘guesswork,’ or simply used the word art without qualifying it  in this context.)

The originating July 22, 2012 news release from Caltech goes on to describe why jellyfish were selected and how the collaboration between Harvard and Caltech came about,

Jellyfish are believed to be the oldest multi-organ animals in the world, possibly existing on Earth for the past 500 million years. Because they use a muscle to pump their way through the water, their function—on a very basic level—is similar to that of a human heart, which makes the animal a good biological system to analyze for use in tissue engineering.

“It occurred to me in 2007 that we might have failed to understand the fundamental laws of muscular pumps,” says Kevin Kit Parker, Tarr Family Professor of Bioengineering and Applied Physics at Harvard and a coauthor of the study. “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 pumps and the human heart. The similarities help reveal what you need to do to design a bio-inspired pump.”

Parker contacted John Dabiri, professor of aeronautics and bioengineering at Caltech—and Nawroth’s advisor—and a partnership was born. Together, the two groups 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-dynamic effects help or hinder their movements. Once these functions were well understood, the researchers began to design the artificial jellyfish.

Here’s how they created the ‘Medusoid’ (artificial jellyfish, from the July 22, 2012 Harvard University news release on EurekAlert,

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

Based on such understanding, 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 arm-like appendages.

Using the same analysis 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 container of ocean-like salt water 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,” says Dabiri.

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

For future research direction I’ve excerpted this from the Caltech news release,

The team’s next goal is to design a completely self-contained system that is able to sense and actuate on its own using internal signals, as human hearts do. Nawroth and Dabiri would also like for the Medusoid to be able to go out and gather food on its own. Then, researchers could think about systems that could live in the human body for years at a time without having to worry about batteries because the system would be able to fend for itself. For example, these systems could be the basis for a pacemaker made with biological elements.

“We’re reimagining how much we can do in terms of synthetic biology,” says Dabiri. “A lot of work these days is done to engineer molecules, but there is much less effort to engineer organisms. I think this is a good glimpse into the future of re-engineering entire organisms for the purposes of advancing biomedical technology. We may also be able to engineer applications where these biological systems give us the opportunity to do things more efficiently, with less energy usage.”

I think this excerpt from the Harvard news release provides some insight into at least some of the motivations behind this work,

In addition to advancing the field of tissue engineering, Parker adds that he took on the challenge of building a creature 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.”

A little competitive, eh?

For anyone who’s interested in reading the research (which is behind a paywall), from the ScienceDaily news item,

Janna C Nawroth, Hyungsuk Lee, Adam W Feinberg, Crystal M Ripplinger, Megan L McCain, Anna Grosberg, John O Dabiri & Kevin Kit Parker. A tissue-engineered jellyfish with biomimetic propulsion. Nature Biotechnology, 22 July 2012 DOI: 10.1038/nbt.2269

Andrew Maynard weighs in on the matter with his July 22, 2012 posting titled, We took a rat apart and rebuilt it as a jellyfish, on the 2020Science blog (Note: I have removed links),

 Sometimes you read a science article and it sends a tingle down your spine. That was my reaction this afternoon reading Ed Yong’s piece on a paper just published in Nature Biotechnology by Janna Nawroth, Kevin Kit Parker and colleagues.

The gist of the work is that Parker’s team have created a hybrid biological machine that “swims” like a jellyfish by growing rat heart muscle cells on a patterned sheet of polydimethylsiloxane.  The researchers are using the technique to explore muscular pumps, but the result opens the door to new technologies built around biological-non biological hybrids.

Ed Yong’s July 22, 2012 article for Nature (as mentioned by Andrew) offers a wider perspective on the work than is immediately evident in either of the news releases (Note: I have removed a footnote),

Bioengineers have made an artificial jellyfish using silicone and muscle cells from a rat’s heart. The synthetic creature, dubbed a medusoid, looks like a flower with eight petals. When placed in an electric field, it pulses and swims exactly like its living counterpart.

“Morphologically, we’ve built a jellyfish. Functionally, we’ve built a jellyfish. Genetically, this thing is a rat,” says Kit Parker, a biophysicist at Harvard University in Cambridge, Massachusetts, who led the work. The project is described today in Nature Biotechnology.


“I think that this is terrific,” says Joseph Vacanti, a tissue engineer at Massachusetts General Hospital in Boston. “It is a powerful demonstration of engineering chimaeric systems of living and non-living components.”

Here’s a video from the researchers demonstrating the artificial jellyfish in action,

There’s a lot of material for contemplation but what I’m going to note here is the difference in the messaging. The news releases from the ‘universities’ are very focused on the medical application where the discussion in the science community revolves primarily around the synthetic biology/bioengineering elements. It seems to me that this strategy can lead to future problems with a population that is largely unprepared to deal with the notion of mixing and recombining  genetic material or demonstrations of “of engineering chimaeric systems of living and non-living components.”