MMP #17: How bacteria can change graphene to propel rotors.

Host: Jeff Fox with special guests, Julia Yeomans and Vikas Berry. Julia Yeomans of Oxford University in the United Kingdom and chemical engineer Vikas Berry of the University of Illinois, Chicago, talk with Jeff Fox about their separate, but in some ways similar, research efforts in which they use bacteria to perturb and probe the physical properties of simple machines, in one case, and unusual materials, in the other. Yeomans and her collaborators are developing models of miniature windfarms in which 64 rotors are arrayed regularly within a symmetric lattice, to which actively swimming bacteria are added. Under appropriate constraints, the bacteria spontaneously organize in such a way that they induce neighboring rotors to spin in opposite directions. Single rotors would be "kicked around randomly," the researchers say, but the arrayed rotors form "a regular pattern." Yeomans says, "Nature is brilliant at creating tiny engines, and there is enormous potential if we can understand how to exploit similar designs." Berry and his collaborators aligned rod-shaped gram-positive bacteria and then vacuum-shrunk a graphene sheet over them, thus forming nanoscale ripples into the otherwise smooth graphene surface. "The current across the graphene wrinkles is less than the current along them," says Berry. "We envision that with graphene one could make the smallest wavelength wrinkles in the world—about 2 nanometers. The structure is different, and the fundamental electronic properties are new." This story was featured in the September 2016 issue of Microbe Magazine. Subscribe to MMP (free) on iTunes, Stitcher, Android, RSS, or by email. You can also listen on your mobile device with the Microbeworld app. Send your microbiology questions and comments (email or audio file) to [email protected] Tweet Jeff your questions about this episode or just say hi!