A team from Oxford University has found a way to exploit the natural movements of bacteria, utilizing them to power microscopic machines, including miniature wind farms for future smartphones. Recently published in the Science Advances journal, the research, scientists believe, could pave the way for an entire generation of self-assembling, micro-sized devices that in turn produce their own energy. Julia Yeomans, the study’s chief author, was reported saying:
Nature is brilliant at creating tiny engines, and there is enormous potential if we can understand how to exploit similar designs.
With the help of special computer simulations, the researchers were able to demonstrate that the natural, swarming motions of dense active matter, like bacteria, can in turn be used to drive microscopic cylindrical rotors, thus generating usable power. According to the team, these biological power plants could one day serve as tiny engines for a variety of self-sufficient and self-assembled devices, such as optical switches and even smartphone microphones. Speaking about the breakthrough, Tyler Shendruk, a professor at the university’s Department of Physics and the paper’s co-author, 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.
As the scientists point out, bacterial suspensions are basically dense active fluids that can move spontaneously by swimming. Although capable of swarming movements, these microorganisms are known to travel in disordered fashion, making it impossible to extract any substantial power from them. For the research, therefore, the team submerged a specially-designed lattice, comprised of 64 symmetrical microrotors, into the active fluid.
This, according to the researchers, enabled the microbes to neatly organize themselves, causing the rotors to turn in opposite directions. Working similar to a regular wind turbine, the nanoscale contraption in turn helped produce useful power. Shendruk explained:
The amazing thing is that we didn’t have to pre-design microscopic gear-shaped turbines. The rotors just self-assembled into a sort of bacterial windfarm. When we did the simulation with a single rotor in the bacterial turbulence, it just got kicked around randomly. But when we put an array of rotors in the living fluid, they suddenly formed a regular pattern, with neighbouring rotors spinning in opposite directions.
Talking about the incredibly innovative technology, Amin Doostmohammadi, a physics professor at Oxford and the paper’s co-author, commented:
The ability to get even a tiny amount of mechanical work from these biological systems is valuable because they do not need an input power and use internal biochemical processes to move around. At micro scales, our simulations show that the flow generated by biological assemblies is capable of reorganising itself in such a way as to generate a persistent mechanical power for rotating an array of microrotors.
Source: Oxford University