The investigation has been with Geobacter bacteria (Geobacter sulfurreducens.) The area of interest has been with the electronic arrangement and small molecular separation distances within electrically insulating pili (hair-like filaments) found on the cell wall surface. These provide efficient electrical conductivity.
The research was undertaken at the University of Massachusetts at Amherst, Holy Cross, and Brookhaven National Laboratory. Here scientists used X-ray diffraction to determine the structure of the pili. This revealed pili have metallic-like conductivity.
The primary means to show this used X-ray microdiffraction and rocking-curve X-ray diffraction. X-ray diffraction analysis, when performed on small samples or small areas of large samples is commonly referred to as microdiffraction; the method employs a micro X-ray beam so that diffraction characteristics can be mapped.
Rocking-curve X-ray diffraction is a quantum beam imaging technique. With this, diffraction topographic images record the intensity profile of a beam of X-rays diffracted by a crystal. The topography image generated represents the two-dimensional spatial intensity mapping of reflected X-rays.
The experimental results reported demonstrated that the pili of G. sulfurreducens represent a novel class of electronically functional proteins. The findings will assist with microbiological research into the use of low-cost, nanoscale, biological sources of electricity. This could be used for constructing light-weight electronics. The emerging field of bioelectronics is about the convergence of biology and electronics. This is “a marriage” of the tools offered by biology with the discipline of digital microelectronics. The aim is to create new tools for medicine, manufacturing, and for analysis.
The success tweaked the interest of the science community, with a barrage of tweets about ‘electric bacteria.’ Biomedical scientist Nicole Tay (@AusSci_NicoleT), for instance, tweeted: “The geobacter #bacteria, named G. sulfurreducens, may have electrical conductivity similar to that of #copper.”
The research has been published in the journal mBio, in a paper titled “Structural Basis for Metallic-Like Conductivity in Microbial Nanowires.”
