The study, published in the journal Science Advances, uses computer simulations to demonstrate that the chaotic swarming effect of dense active matter such as bacteria can be organised to turn cylindrical rotors and provide a steady power source.
Researchers say these biologically driven power plants could someday be the microscopic engines for tiny, man-made devices that are self-assembled and self-powered.
Co-author Dr Tyler Shendruk, from Oxford University’s Department of Physics, said: ‘Many of society’s energy challenges are on the gigawatt scale, but some are downright microscopic. One potential way to generate tiny amounts of power for micromachines might be to harvest it directly from biological systems such as bacteria suspensions.’
Dense bacterial suspensions are the quintessential example of active fluids that flow spontaneously. While swimming bacteria are capable of swarming and driving disorganised living flows, they are normally too disordered to extract any useful power from.
But when the Oxford team immersed a lattice of 64 symmetric microrotors into this active fluid, the scientists found that the bacteria spontaneously organised itself in such a way that neighbouring rotors began to spin in opposite directions – a simple structural organisation reminiscent of a windfarm.