Patterning on Living Tardigrades.

Micro/nanofabrication techniques have revolutionized modern photonics and electronics. However, conventional methods remain incompatible with living organisms due to inherent constraints including nonconformal coating, radiation damage, and toxic solvent requirements. Here, we present ice lithography for direct fabrication of micro/nanoscale patterns on the surfaces of tardigrades in their cryptobiotic state. Remarkably, upon rehydration the tardigrades revive, retaining the patterns on their surfaces. By precisely controlling parameters such as ice thickness, beam energy, and substrate properties, this method minimizes sample damage while achieving patterns as small as 72 nm. These patterns remain stable even after stretching, solvent immersion, rinsing, and drying. This approach provides new insights into tardigrades' resilience and has potential applications in cryopreservation, biomedicine, and astrobiology. Furthermore, integrating micro/nanofabrication techniques with living organisms could catalyze advancements in biosensing, biomimetics, and living microrobotics.