For the first time, researchers at the University of Linkoping, Sweden, have succeeded in establishing organic circuits within living plants. They combined electronics with the natural network of artificial signals that flowers use to survive. The result is the first “bionic” rose.
The possible applications of the discovery, published in Science Advances, are not clear. Biologists could use similar circuitry to adjust or “fix” the physiology of plants – similar to the use of pacemakers in humans – by monitoring the growth or internal chemical processes. The electronic components could be used to shape a plant instead of manipulating the DNA, but also to create biosensors or exploiting photosynthesis to produce energy.
The idea of bionic plants is not new. Last year a MIT researcher installed carbon nanotubes in spinach chloroplasts, causing a significant increase of the photosynthetic activity of the leaves. But the road attempted by the Swedish researchers is even more extreme: it is the first time that all the components of an electronic circuit are integrated in a living flower.
In one of the experiments, the cut stem of a rose was immersed in a solution of a polymer soluble in water and highly conductive called PEDOT, that was sucked into and absorbed by the vascular system of the plant, forming inside the xylem (the plant tissue in which flows the sap) conductive filaments longer than 5 cm, which did not damage the interior of the flower. Leveraging circuits and ions (electrically charged molecules) present in the lymph, the researchers were able to create electrochemical transistors, capable of transforming the signals of the ionic plant in electronic output. The behavior of these transistors is exactly the same as the electronic components of computers and mobile phones.
In another series of experiments, the researchers injected a solution of PEDOT and cellulose nano-fibers in the leaf of a rose and then expelled the air from the plant tissue, allowing the PEDOT to fill the empty spaces. Sending an electrochemical signal, the leaf can change color, around its veins, from light green to dark green. The next step according to the researchers will be whether these properties can be exploited to transform some cultivation of plants in living fuel cells and convert their sugars into electricity.
Source: University of Linkoping