Other Publications (1)
Articles by Stuart Tessmer in JoVE
Scanning-probe Single-electron Capacitance Spectroscopy Kathleen A. Walsh1, Megan E. Romanowich1, Morewell Gasseller1,2, Irma Kuljanishvili1,3, Raymond Ashoori4, Stuart Tessmer1 1Department of Physics and Astronomy, Michigan State University, 2Department of Chemistry & Biochemistry/Physics, Mercyhurst University, 3Department of Physics, Saint Louis University, 4Department of Physics, Massachusetts Institute of Technology Scanning-probe single-electron capacitance spectroscopy facilitates the study of single-electron motion in localized subsurface regions. A sensitive charge-detection circuit is incorporated into a cryogenic scanning probe microscope to investigate small systems of dopant atoms beneath the surface of semiconductor samples.
Other articles by Stuart Tessmer on PubMed
Electronic Properties of Conductive Pili of the Metal-reducing Bacterium Geobacter Sulfurreducens Probed by Scanning Tunneling Microscopy Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics. Dec, 2011 | Pubmed ID: 22304032 The metal-reducing bacterium Geobacter sulfurreducens produces conductive protein appendages known as "pilus nanowires" to transfer electrons to metal oxides and to other cells. These processes can be harnessed for the bioremediation of toxic metals and the generation of electricity in bioelectrochemical cells. Key to these applications is a detailed understanding of how these nanostructures conduct electrons. However, to the best of our knowledge, their mechanism of electron transport is not known. We used the capability of scanning tunneling microscopy (STM) to probe conductive materials with higher spatial resolution than other scanning probe methods to gain insights into the transversal electronic behavior of native, cell-anchored pili. Despite the presence of insulating cellular components, the STM topography resolved electronic molecular substructures with periodicities similar to those reported for the pilus shaft. STM spectroscopy revealed electronic states near the Fermi level, consistent with a conducting material, but did not reveal electronic states expected for cytochromes. Furthermore, the transversal conductance was asymmetric, as previously reported for assemblies of helical peptides. Our results thus indicate that the Geobacter pilus shaft has an intrinsic electronic structure that could play a role in charge transport.