A new graphene-based sensor could provide farmers with a more precise measurement of how much growing time and water their crops need to reach their full potential.

Plant scientists from Iowa State University have developed a tiny graphene sensor that can be taped to plants, providing both researchers and farmers more data that could lead to more robust annual harvests.

“With a tool like this, we can begin to breed plants that are more efficient in using water,” Iowa State University plant scientist Patrick Schnable said in a statement. “That’s exciting. We couldn’t do this before. But, once we can measure something, we can begin to understand it.”

The researchers fabricated intricate graphene patterns on tape by creating indented patterns on the surface of a polymer block, either with a molding process or with 3D printing. They then applied a liquid graphene solution to the polymer block to fill the indented patterns.

The team used tape to remove the excess graphene and took another strip of tape to pull away the graphene patterns, creating a sensor on the tape. This results in patterns that are as small as five millionths of a meter wide.

“This fabrication process is very simple,” Liang Dong, an Iowa State associate professor of electrical and computer engineering, said in a statement. “You just use tape to manufacture these sensors. The cost is just cents.”

The graphene-based technology, dubbed by researchers as a “plant tattoo sensor” has also been used to develop other wearable strain and pressure sensors, including sensors built into a smart gloves that measures hand movements.

In the case of plant studies, the sensors are made with graphene oxide, a material very sensitive to water vapor, which changes the conductivity of the material and can be quantified to accurately measure transpiration from a leaf.

“The most exciting application of the tape-based sensors we’ve tested so far is the plant sensor,” Dong said. “The concept of wearable electronic sensors for plants is brand new.

“And the plant sensors are so tiny they can detect transpiration from plants, but they won’t affect plant growth or crop production.”

The sensors could also be used in other applications including biomedical diagnostics, for checking the structural integrity of buildings, for monitoring the environment or possibly after modifications for testings crops for diseases or pesticides.