Rose is a cyborg

Kirill Stasevich, "Science and Life" 

A living organism whose own tissues from cells are supplemented with artificial materials, which half consists of wires and microcircuits, is an ordinary character in science fiction films and books. And despite the success in creating prosthetics, despite the success of neuroscientists trying to establish contact between electronics and the brain, it still seems that such bionic creatures, if they arise, then in the very distant future. Nevertheless, according to researchers from Linkoping University Magnus Berggren (Magnus Berggren) and his colleagues, they managed to grow a cyborg rose, which can use an electric signal to change the color of the leaves (LiU researchers create electronic plants). 

The original idea, which arose in Berggren's laboratory almost 15 years ago, was to "eavesdrop" on the biochemical processes taking place in a plant and, if possible, learn how to control them. Here, of course, you can remember about genetic engineering, which allows you to interfere with the genetic program of the body, turn on or off certain genes, achieving the desired physiological effect at the right time. It is difficult to overestimate the success of genetic engineering, and they are especially great with plants that are easier to work with and whose genome can withstand quite strong shocks. However, in Sweden, the prospects for genetically modified plants – if we talk about their practical application in agriculture – are much more modest than, for example, in the USA. So the researchers thought about what could be an alternative to genetically engineered methods, and as a result decided to create not a genetically modified, but an electronic plant. 

The task was to supply the plant organism with wires, so to speak, without surgery, so that they formed themselves right on the spot. To do this, it was necessary to find a polymer that would, firstly, be biocompatible, secondly, it would dissolve in water, and thirdly, it would allow registering what is happening inside the plant and sending signals inside it. From the solution, monomer molecules would rise through plant vessels and polymerize in them, forming the very wires that would permeate the entire plant, from roots to leaves. More than twelve organic substances were tried, but everything ended either with a blockage of the root system, or the molecules, once in the rose, did not gather into conductive structures. In the end, the authors of the work settled on PEDOT-S:H, a water-soluble organic compound that is used in printed electronics. 

Schematic representation of a rose with a leaf equipped with organic polymer wires. (Photo by Linköping University.)

Ascending through the vascular system of the plant, PEDOT-S molecules:H lost a hydrogen atom, and due to the liberated sulfur atom, polymer chains 10 cm long were formed. With the help of gold electrodes connected to the rose, it was possible to show that the plant works like a transistor, and that its performance characteristics are quite comparable to those demonstrated by a simple transistor assembled only from polymer molecules. In another experiment, using a vacuum installation, PEDOT solution with cellulose nanofibers impregnated the leaves of live, uncut roses – as a result, the researchers were able to change the color of the leaves (not the petals!) in the blue-green range, supplying current of different voltages. (It should also be emphasized that here organic electronics were formed not from the roots through the stem, but directly in the leaf.) The results of the experiments are published in Science Advances (Stavrinidou et al., Electronic plants, in the public domain). 

An electronic rose with electrodes attached to the stem. (Photo by Eliot Gomez / Linköping University.)

The designers of the "cyborg rose" themselves believe that their experiments will serve as a basis for further research, and that in the future, with the help of such organic wires, it will be possible to regulate the hormonal background in agricultural crops, stimulating growth, fertility, etc. Of course, one may wonder how such an operation affects the plant itself, and will not die whether it is prematurely due to the presence of organic electronics in itself. 

However, according to Magnus Berggren, the experimental plants that were experimented with to change the color of the leaves are still alive, and the leaves are still with them. And yet, we cannot discount the opinion of skeptics who believe that we are "just" an outstanding work of art that has no practical prospects, and, one way or another, such electronic plants have yet to prove their advantages over genetically modified ones. 

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24.11.2015