Bacteria, Anaerobic; Bacterial Adhesion; Bacterial Infections; Biophysics; Chemistry, Physical; Electron Transport; Environmental Microbiology; Microscopy, Atomic Force; Nanotechnology
Public Health Interests
Environmental Health; Infectious Disease; Respiratory Disease/Infections
Our lab studies how bacteria employ electrical charges to carry out several key processes such as respiration, cell-to-cell communication and attachment to host surfaces to cause infections. We have found out that soil bacteria Geobacter use hair-like appendages called pili as “microbial nanowires” to export electrons outside their cell body for extracellular respiration (Nature Nano 2011) and to share nutrients and energy (Science 2010). We have also recently developed a new charge imaging technique to visualize electron exchange among bacteria (Nature Nano 2014).
Our research employs a broad range of imaging and measurement methods (e.g. scanning probe microscopy, nanofabrication, electron microscopy, low-level electrical signal measurements) to identify biophysical principles underlying key microbial processes. Current projects include quantitative imaging of electron transfer among bacterial proteins during respiration and cell-to-cell communication as well as measurements of forces involved in bacterial adhesion to the host surfaces during infection.
Extensive Research Description
Novel mode of charge transport in bacterial native protein nanofilaments
Our studies have demonstrated a new mechanism of energy flow via charge delocaliazation which had long been believed impossible in biological proteins.
Nikhil S. Malvankar et al. Tunable Metallic-like Conductivity in Microbial Nanowire Networks, Nature Nanotechnology, 6, 573-579 (2011).
Nikhil S. Malvankar and Derek R. Lovley, Microbial Nanowires: A New Paradigm for Biological Electron Transfer and Bioelectronics, ChemSusChem, 5, 1039(2012).
Metal-like conductivity of biofilms can be harnessed to enhance the bioenergy production in microbial fuel cell devices.
Nikhil S. Malvankar, Mark T. Tuominen and Derek R. Lovley. 2012. Biofilm conductivity is a decisive variable for high-current-density Geobacter sulfurreducens microbial fuel cells. Energy and Environmental Science 5, 5790-5797.
Our charge transport measurements have showed that some co-culture as well as multi-culture bacteria form electrically conductive networks to directly exchange energy rather than relying on molecular intermediates such as hydrogen or formate which had been believed to be only mode of interspecies electron exchange for last 40 years.
Z. M. Summers, H. E. Fogarty, C. Leang, A. E. Franks, Nikhil S. Malvankar, and Derek R. Lovley. 2010. Direct Exchange of Electrons Within Aggregates of an Evolved Syntrophic Co-Culture of Anaerobic Bacteria. Science 330,1413-1415.
Direct interspecies electron transfer is widespread in natural microbial communities
M. Morita, Nikhil S. Malvankar, A. E. Franks, Z. M. Summers, L. Giloteaux, A. E. Rotaru, C. Rotaru, and Derek R. Lovley. 2011. Potential for Direct Interspecies Electron Transfer in Methanogenic Wastewater Digester Aggregates. mBio. 2:e00159-11
Bacteria use metalloproteins as humans use their lungs.
We have demonstrated that a high-performance supercapacitor can be synthesized using electron transport and storage properties of living microbial biofilms.
Nikhil S. Malvankar, T. Mester, M. T. Tuominen, D. R. Lovley. 2012. Supercapacitors Based on c-Type Cytochromes Using Conductive Nanostructured Networks of Living Bacteria. ChemPhysChem.13, 463 – 468.