Could bacteria control future robots?

Scientists have used a mathematical model to demonstrate that bacteria can control the behaviour of an inanimate device like a robot.
"Basically we were trying to find out from the mathematical model if we could build a living microbiome on a nonliving host and control the host through the microbiome," said Waren Ruder, faculty at the Department of Biological Systems Engineering of Virginia Tech in US.
"We found that robots may indeed be able to have a working brain," said Ruder, who conducted his research in collaboration with doctoral student Keith Heyde.
Ruder is now building real-world robots that will have the ability to read bacterial gene expression levels in E coli using miniature fluorescent microscopes. The robots will respond to bacteria he will engineer in his lab.

In agriculture, bacteria-robot model systems could enable robust studies that explore the interactions between soil bacteria and livestock, researchers said.
In health care, further understanding of bacteria's role in controlling gut physiology could lead to bacteria-based prescriptions to treat mental and physical illnesses.

Ruder also envisions droids that could execute tasks such as deploying bacteria to remediate oil spills.
The findings also add to the ever-growing body of research about bacteria in the human body that are thought to regulate health and mood, and especially the theory that bacteria also affect behaviour.
The study was inspired by real-world experiments where the mating behaviour of fruit flies was manipulated using bacteria, as well as mice that exhibited signs of lower stress when implanted with probiotics.

Ruder's approach showed unique decision-making behaviour by a bacteria-robot system by coupling and computationally simulating widely accepted equations that describe three distinct elements - engineered gene circuits in E coli, microfluid bioreactors, and robot movement.
The bacteria in the mathematical experiment exhibited their genetic circuitry by either turning green or red, according to what they ate.
In the mathematical model, the theoretical robot was equipped with sensors and a miniature microscope to measure the colour of bacteria telling it where and how fast to go depending upon the pigment and intensity of colour.
The model also revealed higher order functions in a surprising way.

In one instance, as the bacteria were directing the robot toward more food, the robot paused before quickly making its final approach - a classic predatory behaviour of higher order animals that stalk prey.
Ruder's modelling study also demonstrates that these sorts of biosynthetic experiments could be done in the future with a minimal amount of funds, opening up the field to a much larger pool of researchers.