In a darkened lab at the University of Colorado Boulder, moon jellyfish glide gracefully inside a tall aquarium.
Their translucent bodies, glowing under neon lights, expand and contract in hypnotic rhythms, their delicate tentacles trailing like silk ribbons in the water.
To most, they may seem like simple marine creatures, but to engineer Nicole Xu, they represent a revolutionary way to explore the ocean.
Xu, an assistant professor in the Paul M. Rady Department of Mechanical Engineering, has spent more than a decade fascinated by the way moon jellies swim.
Now, she has developed a way to turn them into “cyborg jellyfish” that could one day transform ocean research.
Her method is surprisingly gentle.
By attaching tiny microelectronic devices to the jellyfish, Xu can stimulate their swimming muscles—much like a pacemaker stimulates a human heart.
This allows researchers to guide the animals in different directions, potentially steering them toward areas of the ocean that are otherwise too remote or expensive to study.
In the future, she hopes to add sensors to these devices so the jellyfish can measure temperature, acidity, and other environmental conditions.
“Think of our device like a pacemaker on the heart,” Xu explained. “We’re stimulating the swim muscle by causing contractions and turning the animals towards a certain direction.”
The timing couldn’t be more urgent. As climate change accelerates, the oceans are warming and becoming more acidic, threatening countless species.
Understanding these changes is critical, but the vastness and depth of the ocean make research extremely difficult. Traditional equipment is costly and often limited in range.
Jellyfish, however, are natural explorers. They can travel to astonishing depths—even to the Mariana Trench, nearly seven miles below the surface—and they do so with incredible efficiency.
In fact, moon jellies are considered the most energy-efficient swimmers on the planet. Their body design has remained largely unchanged for more than 500 million years, proof of just how well adapted they are.
They lack brains and spinal cords, but they do have nerve nets and basic organs. Importantly for Xu’s research, they don’t have nociceptors—the receptors that detect pain in many animals. Their stinging cells are too weak to harm human skin, making them safe to work with in the lab.
Xu first tested her robotic jellyfish concept in 2020 in shallow waters off the coast of Massachusetts. Since then, she and her team have continued refining the technology.
In a recent study, Xu, along with colleagues Yunxing Su and Mija Jovchevska, used biodegradable particles—such as cornstarch—to visualize how jellyfish move water as they swim. This offered a more sustainable alternative to synthetic tracers like glass beads, showing how science can progress without adding toxins to the environment.
Her lab is also developing better ways to steer jellyfish in the wild. Xu sees a future where fleets of biohybrid jellies collect data in places too deep or dangerous for humans. Beyond research, she believes their swimming techniques could inspire the next generation of energy-efficient underwater vehicles.
Still, Xu is careful to acknowledge the ethical side of her work. While moon jellies appear to thrive in her tanks, producing healthy baby polyps, she emphasizes the importance of minimizing stress and harm to invertebrates, whose capacity for pain remains a subject of scientific debate.
“It’s our responsibility as researchers to think about these ethical considerations up front,” she said. “But as far as we can tell, the jellyfish are doing well. They’re thriving.”
If Xu’s vision succeeds, cyborg jellyfish may not only expand our understanding of the oceans but also spark new designs in robotics—reminding us that some of the best innovations come from nature itself.
