The Flowers of the Future!

What do I mean by flowers of the future? I mean cyberplants! Researchers working at Linköping University in Sweden have found a way to create a rose plant with electronic circuitry running through its tissue, and the effects and implications are very interesting indeed.

Now the idea of cyberplants is not entirely new, as some research by Michael Strano at the Massachusetts Institute of Technology revealed that spinach chloroplasts can incorporate carbon nanotubes (CNTs) into their structure. The report stated that this boosted the rate of photosynthesis, as the CNTs could absorb wavelengths of light that the chloroplasts could not. So if this has been done before, what makes this new discovery special?

Well, this research is the first example of someone incorporating a working electronic circuit into a plant’s anatomy. This was done with a polymer known as PEDOT, or Poly(3,4-ethylenedioxythiophene) if you’re one of our chem nerds, and the structure can be seen below. This material is an excellent conductor when hydrated and is commonly used in printable electronics, making it an excellent contender for the cyberplant project.

pedot
The repeating unit structure of PEDOT. Source: https://en.wikipedia.org/wiki/Poly(3,4-ethylenedioxythiophene)

The researchers tested many materials before they made their choice, but none of them were ideal. Some caused the plant to produce toxic compounds, essentially poisoning it, while others clogged the plant’s water transportation systems. They eventually settled on PEDOT, which didn’t cause any noticeable problems, and found a way to incorporate it into the plant’s stem and leaves. They created the world’s first cyber-rose!

This was done by soaking each component in separate PEDOT solutions, and then manipulating them in some way to cause the polymer to migrate into the plant tissue.

In the case of the stem, natural capillary action pulled the polymer out of solution and into the plant’s vascular tissue. The natural structure of the stem then allowed the polymer to self-assemble into wires up to 10 cm long! The conductivity of these structures was then measured using two gold (Au) probes, and the performance was found to be on par with conventional printed PEDOT circuits according to Magnuo Breggren, one of the team members.

The leaves proved to be more tricky. They were first placed in a mixed solution of PEDOT and cellulose nanofibres, then a vacuum was applied. This caused all the air in the leaf tissue to be expelled, and the PEDOT then moved out of the solution and into the empty space the air left behind. This gave the leaves a very interesting property, causing the colour to shift between blueish and greenish hues when a voltage was applied.

Now, while this all seems very interesting, some scientists have questioned what the practical implications of this research could be. “It seems cool, but I am not exactly sure what the implication is” says Zhenan Bao, who works with organic electronics at Stanford University in California.

But Breggren suggests that these electronics could provide an alternative to genetic engineering for monitoring and regulating plant behaviour. While the genetic modification of plants is safe and extremely easy, certain traits, such as flowering times, might be too disruptive to an ecosystem if there is a permanent change. Especially if those changes get passed on to other plants in the area. But electronic switches would not have this risk, and could be easily reversed when needed.

However, if this research progresses to practical applications, the team would have to show that the polymers they use are not harmful to the environment in any way, and in the case of food crops, that the material doesn’t end up in any edible portions of the plant. But this may not be a problem in the future, as the team hopes to make use of biological chemicals to create the circuitry, bypassing any potential environmental and health hazards.

Given the success of their initial study, the team is now collaborating with biologists to develop their research further, and investigating any new directions it could go in. For example, Breggren is apparently investigating whether these PEDOT devices could be used to develop a system to allow the plant to act as a living fuel cell, a project he has rather amusingly named “flower power”.

Regardless of how well this research pans out in the future, it does have the value of being inherently interesting, a trait that drives a great deal of scientific research. But what really interests me, as is this case with a lot of the stuff I write about, is that this is yet another step close to the world of science fiction. We’re getting closer people! All we have to do is wait.

Sources:

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