The garden rose, or Rosa floribunda, has ingrained itself into public consciousness as the symbol for love. But in the science world, the rose is now the first plant to marry the electronic and organic within its body.
Researchers from Linköping Univ.’s Laboratory of Organic Electronics used the rose’s vascular system to manufacture analog and digital organic electronic circuits and devices.
“With integrated and distributed electronics in plants, one can envisage a range of applications including precision recording and regulation of physiology, energy harvesting from photosynthesis and alternatives to genetic modification for plant optimization,” write the researchers in Science Advances.
Plant growth and function are dependent on ionic and hormonal signals, which can be affected by environmental, physical and chemical stimuli. Such signals are transported throughout the body via the plant’s xylem and phloem vascular circuits. Currently, artificial regulation of plants is achieved through exposure to chemicals or molecular genetic tools. However, the researchers say embedding electronic functionality within a plant will allow a combination of electric signals with the plant’s natural chemical processes.
“Previously, we had no good tools for measuring the concentration of various molecules in living plants,” said Ove Nilsson, a co-author of the article. “Now we’ll be able to influence the concentration of the various substances in the plant that regulate growth and development.”
The team achieved the feat by introducing the conductive polymer PEDOT-S through the rose’s stem. A 10 cm wire of the material was fed into the xylem channel, which still allowed the transport of water and nutrients. A combination of the wire and the electrolyte surrounding the xylem channel allowed researchers to create an electrochemical transistor, which converts ionic signals to electronic outputs.
Additionally, the team used vacuum infiltration to embed another PEDOT variant into the plant’s leaves. According to the university, “the infused polymer formed ‘pixels’ of electrochemical cells partitioned by the veins. Applied voltage caused the polymer to interact with ions in the leaf, subsequently changing the color of the PEDOT in a display-like device.”
“Now we can really start talking about ‘power plants’—we can place sensors in plants and use the energy formed in the chlorophyll, produce green antennas or produce new materials,” said Prof. Magnus Berggren, of the university. “Everything occurs naturally, and we use the plants’ own very advanced, unique systems.”
It seems the increasingly electronic world knows no bounds.