The blending of organic life and electronics is still very much in its nascent stages. Most of the progress made in this area is thanks to the adaptability of the biological systems we’re integrating with, not so much the technology. However even small progress in this field can have wide reaching ramifications, sometimes enough to dramatically reframe the problem spaces we work in. One such small step has been made recently by a team from the Linköping University in Sweden as they have managed to create working electronic circuits within roses.
The research, born out of the Laboratory of Organic Electronics division of the university, experimented with ways of integrating electronics into rose plants so they could monitor, and potentially influence, the growth and development of the plant. To do this they looked at infusing the rose with a polymer that, once ingested into the plant, would form a conductive wire. Attempts with many polymers simply resulted in the death of the plant as they either poisoned it or blocked the channels the plant used to carry nutrients. However one polymer, called PEDOT-S:H, was readily taken up by the roses and didn’t cause any damage to the plant. Instead it formed a thin layer within the xylem (one of the nutrient transport mechanisms within plants) that produced a conductive hydrogel wire up to 10cm long.
The researchers then used this wire to create some rudimentary circuits within the plant’s xylem structure. The wire itself, whilst not being an ideal conductor, was surprisingly conducive to current with a contact resistance of 10KΩ. To put that in perspective the resistance of human skin can be up to 10 times more than that. Using this wire as a basis the researchers then went on to create a transistor by connecting source, drain and gate probes. This transistor worked as expected and they went one step further to create logic gates, demonstrating that a NOR gate could be created using the hydrogel wire as the semiconducting medium.
This kind of technology has potential to revolutionize the way that we monitor and influence plant growth and development. Essentially what this allows us to do is create circuitry within living plants, using their own cellular structures as a basis, that can act as sensors or regulators for the various chemical processes that happen within them. Of course there’s still a lot of work to be done in this area, namely modelling the behaviour of this organic circuitry in more depth to ascertain what kind of data we can get and processes we can influence. Suffice to say it should become a very healthy area of research as there are numerous potential applications.