A group of researchers headed by Eleni Stavrinidou, Assistant Professor at Linköping University’s Laboratory of Organic Electronics have achieved a big milestone in biophysics. The team has successfully grown ‘electrical circuits’ within the biological system of a rose. In the future we might actually grow electronics in our backyard garden. Living plants, and shrubs with electronical circuits running through their ‘veins’.
The group from Sweden’s Linköping University have improved on their study of 2015. In 2015, they used a polymer PEDOT(or poly(3,4-ethylenedioxythiophene)), which was a solution of polymer particles and water, and when a rose cutting was soaked in this solution, and the solution was made to rise up the stem in to the xylem of the cutting, the polymer solidified into ‘wires’ inside the rose cutting. A completely conducting circuit was formed. The improvement they achieved this year was that the new polymer solution they created, called ETE-S, doesn’t need to be manually weaved inside the rose cutting, but automatically travels throughout the rose, and eventually solidifying into conducting wires. Polymers are long repetitive chains of molecules of the same kind, like plastics. But what makes PEDOT and ETE-S different from others is that these two polymers are conductive.
The technology dubbed as e-Plant is on a relatively early stage. The electronics were formed inside an already grown cutting of rose, and the bigger benchmark will be to make them grow inside rose plants that are not cut, but still living and planted in the soil. The conducting circuits formed by ETE-S have another property, instead of filling just the Xylems, and being confined to the veins of the plant, the polymer solution actually resides between the cell-wall and the plasma membrane of the plant’s cells, and the formation of solid wires is facilitated by the biochemical processes taking place inside the cutting, and hence these reactions act as a catalyst for the formation of the electronic circuits.
When the team attached two gold wires to the sample, and passed it through cycles of charging and discharging, they sample acted as an efficient transistor. The rose cutting also functions as a capacitor- a device to store charge. This happens because of the presence of insulating plant tissues between the two conductors, which resembles the structure of the common capacitor employed in the building of circuits. When the transistor formed was connected to a resistor, the team could successfully pass a current through it.
“When Eleni showed me these beautiful microscope pictures, we understood immediately: we could make circuits out of this, the performance, the shape of the wires, were just outstanding, unbelievable.” -Magnus Berggren, Linkoping University
Not only does the new polymer ETE-S reaches out to parts of the plant like leaves and petals autonomously, which PEDOT couldn’t, it also has conductivity two orders higher than the previous versions of e-Plant, and also maintaining this high level of conductivity of a long distance in the plant.
“The levels of energy storage we have achieved are of the same order of magnitude as those in [traditional] supercapacitors. The plant can, without any form of optimisation of the system, potentially power our ion pump, for example, and various types of sensors.”
Another effect of the improvements was that whenever a current was passed through the circuits, the dark solution turned blue, and this gave the leaves a blue hue. This research has been posted in the Proceedings Of The Natural Academy Of Sciences. The team now aims to grow electronics in living plant tissues to be one day able to grow forest vegetation containing electronic circuits running through them to feed our needs. The best part is that addition of these polymer solutions did not interfere with the functions of the plant!
Two years ago a team from MIT also succeeded in planting nano electronics inside the chloroplasts of the plant, components of plant cells that contain the pigment chlorophyll that plays a major role in photosynthesis. Now it was known that the chemical chlorophyll only responds to a thin range of frequencies of light from the sun, mostly deep blue and red, leaving out the other frequencies useless. The team found out that when the nanoparticles, or nano-electronics, were coated with electrically charged molecules, the chloroplasts absorbed them inside, and the output of these choloroplasts increased by 30 percent.
A lot is going on in this field, with robotic roots, using electronics to improve plant’s functions and a lot more, and only the future can tell what will be the greater good from these studies. The marriage of biology and physics will be a revolution, changing the ways of technology, perhaps someday, we might actually be an actual cyborg ourselves. Happy Reading !
-The Cosmogasmic Person