A scientist has developed a sophisticated mathematical model that demonstrates that robots can be imbued with a bacterial brain, giving them the ability to exhibit both simple and complex behaviours and interactions.

Waren Ruder, from Virginia Tech, used a mathematical model to link equations for bacteria and robot behaviours to reach the findings, and now plans to take theory from concept to reality by introducing bacterial microbiomes to real robots.

“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 Ruder, an assistant professor of biological systems engineering in the College of Agriculture and Life Sciences and the College of Engineering at Virginia Tech.

“We found that robots may indeed be able to have a working brain.”

Speaking in a video about the research, embedded below, Ruder explained how he and his research team undertook the modelling, the results of which are being published today in the journal Scientific Reports.

“Our objective is to explore interactions between living cells that are part of the microbiome and a robotic, biomimetic host,” he said.

“The way we did that was by taking well-characterised and robust equations from bacteria, that describe bacterial behaviour, and linking those equations to equations and models that describe simple robotic behaviours. “

By linking these equations, the scientists were able to simulate how the bacteria would interact with its robot host.

“When we link those two we saw emergent behaviour in a virtual simulation,” he said.

“We were able to watch how a robot driven by bacteria would move in its environment. And by doing so we saw both simple behaviours and more complicated behaviours as we increased the complexity of the biochemical programs that were engineered into the living microbiome.”

Incredibly, the models also showed the bacteria-robot hybrid taking on behaviours similar to higher-order animals when the robot was given the ability to talk back to the bacteria.

“At first when we placed simple models and simple programming into the biochemistry of the cells, we saw simple robot behaviours,” said Ruder.

“When we gave the robot one extra component, an ability to talk back to the living bacteria on board, we saw that the cells go from simply toggling between their different fuel preferences to approaching a fuel source, pausing and moving rapidly towards it.

“This type of behaviour is known as ‘stalk, pause, strike’ in higher-order, more complex animals, and this work shows that a microbiome alone, linked to a simple robotic host could recapitulate this more complicated behaviour.”

With such promising findings from the theoretical study, Ruder and his colleagues are now planning to combine bacteria and robots for real, which will be the true test of their model’s accuracy.

“The final step will be to take the engineered living cells that we now have in the laboratory with the robotic systems that we now have and link them together with an interface technology called microfluidics,” he said.

“By building small bioreactors where these cells can live, and placing those bioreactors on the robot, the complete system can be realised to the point where we have mobile robots that harbour living colonies of bacteria that direct the robots behaviour.”