Tardigrades—tiny, water-dwelling creatures also known as “water bears”—are some of the toughest animals on Earth.
They can survive freezing temperatures, extreme radiation, dehydration, and even outer space. Now, scientists have taken advantage of their extreme durability to try something no one has done before: give them microscopic tattoos.
In a new study published in Nano Letters, researchers used tardigrades to test a cutting-edge microfabrication technique that could open the door to new biomedical technologies.
The team, led by Ding Zhao and Min Qiu, wanted to find a way to build extremely tiny electronic devices or sensors directly onto living tissue. And what better test subject than a creature that can survive almost anything?
The process they used is called ice lithography. It’s a technique where scientists freeze a thin layer of material—like water or a chemical—onto a surface, then use a focused beam of electrons to carve a pattern into the ice.
When the ice disappears, the pattern is left behind, almost like a tattoo.
Here’s how they did it: First, they gently dehydrated the tardigrades, which puts them into a cryptobiotic state—a kind of suspended animation where their metabolism nearly stops.
Then they placed a single tardigrade onto a special paper and cooled it to an icy -226°F (-143°C). Next, they coated it with anisole, a protective compound that smells like anise.
The real magic happened when the frozen anisole was exposed to the electron beam. It reacted and formed a new, biocompatible chemical that stuck to the tardigrade’s surface.
As the tiny animal slowly warmed back up, the leftover anisole evaporated, leaving only the tattoo behind. The scientists then rehydrated the tardigrades and brought them back to life—tattoos and all.
The results were impressive. The researchers were able to create patterns as small as 72 nanometers wide—so tiny you could fit over a thousand of them across the width of a human hair. They even etched their university’s logo onto the surface of a tardigrade.
Even more amazing, the tardigrades didn’t seem to mind. Around 40% survived the process, and the scientists believe they can improve that rate with more practice. The surviving water bears showed no signs of distress or behavior changes.
This breakthrough could lead to exciting new possibilities, like creating tiny sensors that stick to living cells or designing “microbial cyborgs”—living organisms enhanced with microelectronics. As researcher Gavin King, who developed the original ice lithography method, said, this kind of technology used to belong in science fiction.
Now, it might be part of the future.
