BEIJING -- Chinese researchers have successfully utilized ice-carving technology to create precise nanoscale patterns on living organisms for the first time, according to Westlake University in East China's Zhejiang province.

These microscopic "tattoos" demonstrate ultra-high precision and excellent biocompatibility, opening new possibilities for the development of medical nanodevices and microrobots. The results of the research have been published in the Nano Letters journal.

"This innovative approach replaces conventional photoresist materials with ice," said Yang Zhirong, the paper's lead author. "The electron beam etches patterns directly into the ice layer, avoiding contamination from resist removal and making biological applications possible." The ice can be either frozen water or frozen organic compounds.

Researchers chose tardigrades -- tiny creatures under 1 millimeter in length known as "water bears" -- for their extreme durability. These organisms can survive harsh conditions, including extreme temperatures, dehydration, radiation, and toxic environments.

In an experiment, researchers first put the tardigrades into a cryptobiotic state in which their metabolisms nearly stopped. They then coated them with a special nanoscale organic ice film. Following electron beam exposure, the ice formed stable, solid patterns on the tardigrades at room temperature.

Follow-up tests showed that these "tattoos" remained intact even when stretched, soaked in solvents or dried.

"This breakthrough could advance microbial sensors, bio-inspired devices and living microrobots," Yang said. "In the future, we could apply ice-carving technology to bacteria and viruses, combining living and mechanical systems to enhance performance."