Researchers develop nano-printing technique to attach ultrafine circuits to plants, skin

South Korean researchers have developed a nano-printing technique capable of transferring ultrafine circuits onto virtually any surface, with potential applications ranging from smart farms and wearable healthcare devices to robotic electronic skin.

KAIST announced Monday that a team led by chair professor Park In-kyu of its Department of Mechanical Engineering, working jointly with a team from the Korea Institute of Machinery and Materials (KIMM) led by researcher Jung Jun-ho and a team from Korea University led by professor Ahn Jun-seong, has developed what it calls "water-surface floating nano-transfer printing." The technique floats precision metal thin films on water and transfers them intact onto diverse three-dimensional surfaces.

In smart farming, the technology can attach electrodes directly to crop leaves, enabling agricultural IoT sensors that monitor a plant's moisture levels, nutritional status and growth signals in real time. The films can also serve as surface-enhanced Raman scattering (SERS) sensors for on-site, non-destructive detection of pesticide residues on leaves and fruit without picking them.

In wearable healthcare, thin films transferred onto stretchable fabric can be fashioned into smart everyday clothing, skin-adhesive electrocardiogram and body-temperature monitoring patches, and hydrogen-leak detection garments for industrial settings. In the medical and biotech fields, the technology enables biocompatible medical devices such as electronic skin applied directly to the body and post-surgical rehabilitation monitoring patches.

"This technology is significant because it overcomes the substrate limitations of conventional nano-transfer printing, allowing nano-patterns to be transferred onto sensitive surfaces — such as living plant leaves or human skin — without adhesives or heat," Park said. He added that the technique could extend into the biomedical domain, enabling researchers to apply electrical stimulation to cells, monitor growth states and track drug-delivery responses at the cellular level. The findings were published in Nature Communications.