LiU Researchers create the World’s First Electronic Circuit within Living Plant

Over the past centuries, world economic growth is inseparable to the ever-expanding use of hydrocarbon energy sources such as petroleum, coal and natural gas.

The trend of global economic currently hinges on increasing rates of production of these fuels. However, petroleum oil and gas, and coal are non-renewable energy resources that will cease in the future.   

In view of adverse effect of fossil fuels, researchers are extensively developing green energy as substitutions to fossil fuel. Scientists in Sweden have developed an ‘electronic’ rose by implanting circuits inside the vascular system used to distribute water and nutrients in the plant.  

The idea of combining electronics and plants sounds like something you might see in a far-flung corner of Glastonbury festival, but it’s actually been an area of research since the 1990s. Sceptical investors prevented the project from finding its feet at first, but in 2012 Magnus Berggren of Linköping University in Sweden rebooted the project with a new set of researchers.   

Researchers have crafted flexible electronic circuits inside a rose. Eventually such circuitry may help farmers eavesdrop on their crops and even control when they ripen. The advance may even allow people to harness energy from trees and shrubs not by cutting them down and using them for fuel, but by plugging directly into their photosynthesis machinery.  

Image credit: Linköping University  

Flexible electronics are made from pliable organic materials. That makes them potentially compatible with tissues and has spurred research efforts to use them to diagnose and treat diseases.

“Organic electronics is booming in the area of medical applications,” says Magnus Berggren, a materials scientist and electrical engineer at Linköping University, Norrköping, in Sweden and a leader in devising such medical applications.  

Basic plant physiology and analogy to electronics. (A and B) A plant (A), such as a rose, consists of roots, branches, leaves, and flowers similar to (B) electrical circuits with contacts, interconnects, wires, and devices. (C) Cross section of the rose leaf. (D) Vascular system of the rose stem. (E) Chemical structures of PEDOT derivatives used. (Image credit: Linköping University)  

How does it work?  

The scientists had to invent a new polymer which is the so called PEDOT-S. PEDOT-S is a polymer that can be sucked through the vascular system of the rose, similar to the way a flower sucks water in a vase. Once this polymer is sucked through the xylem, it forms a kind of wire which has the ability to conduct electricity.

The interesting thing about this polymer ‘wire’ is that it does not disrupt the plant from acquiring other useful nutrients through the xylem and as such, the plant remains fully functional with the polymer in place.  

Plants contain electrolytes, which are basically substances that carry electric charges. By connecting these polymer wires to the electrolytes within the plant, the scientists successfully created a transistor and a digital logic gate. These two devices form the basis of computer architecture. It can be readily seen that with advances in this technology, it seems realistic to create much more sophisticated electronic circuits by using plants.  

When the technology fully manifests, there are quite interesting applications we can use it for. In one instance, we could put electronic sensors inside plants and to try and detect the time during which they start releasing hormones responsible for flowering or other activities as well.   

This information might prove very useful for farmers and other related people to know when best to water the plants or perhaps when best to add fertilizer as well.

With enough understanding of the whole process, perhaps this technology could also be used to control plant activities as well. The research was published in the journal Science Advances. (Source: Linköping University)