Researchers Find Way to Build Electronic Circuits Inside Plants

Researchers at Linkoping University in Sweden created analog and digital electronics circuits inside living plants.

The group at the Laboratory of Organic Electronics (LOE), led by Professor Magnus Berggren used the vascular system of living roses to build key components of electronic circuits.

Researchers demonstrated wires, digital logic, and even displays elements - fabricated inside the plants - that could develop new applications for organic electronics and new tools in plant science.

Plants are complex organisms that rely on the transport of ionic signals and hormones to perform necessary functions. However, plants operate on a much slower time scale making interacting with and studying plants difficult.

Augmenting plants with electronic functionality would make it possible to combine electric signals with the plant's own chemical processes.

Controlling and interfacing with chemical pathways in plants could pave the way to photosynthesis-based fuel cells, sensors and growth regulators, and devices that modulate the internal functions of plants, researchers said.

"Previously, we had no good tools for measuring the concentration of various molecules in living plants. Now we'll be able to influence the concentration of the various substances in the plant that regulate growth and development," said Ove Nilsson, professor of plant reproduction biology and director of the Umea Plant Science Centre.

The team tried many attempts of introducing conductive polymers through rose stems. Only one polymer, called PEDOT-S, synthesised by Dr Roger Gabrielsson, successfully assembled itself inside the xylem channels as conducting wires, while still allowing the transport of water and nutrients.

Dr Eleni Stavrinidou used the material to create long (10 cm) wires in the xylem channels of the rose. By combining the wires with the electrolyte that surrounds these channels she was able to create an electrochemical transistor, a transistor that converts ionic signals to electronic output.

Using the xylem transistors she also demonstrated digital logic gate function.

Dr Eliot Gomez used methods common in plant biology - vacuum infiltration - to infuse another PEDOT variant into the leaves.

The infused polymer formed "pixels" of electrochemical cells partitioned by the veins. Applied voltage caused the polymer to interact with the ions in the leaf, subsequently changing the colour of the PEDOT in a display-like device.

"As far as we know, there are no previously published research results regarding electronics produced in plants. No one's done this before," he said.

The research was published in the journal Science Advances.