A multi-modal approach to image dynamical interactions with the root-microbe system

Tuesday, November 17, 2015

12:00pm | 330 Gross Hall

Presenter

Dr. Kenneth M. Kemner , Research Scientist

Imaging is one of the most important and powerful methods to learn about the world around us. A recently begun project at Argonne National Laboratory (Small Worlds) is developing a new multi-modal imaging capability for studying complex multi-agent processes in cells and systems of cells across spatial and temporal scales. The goal of the project is to develop and integrate three imaging methods that, when used together, will lead to tremendous new understanding of the organization and dynamic function of a wide range of complex biological systems, including the root-microbe system. The first method, correlative electron-optical imaging, allows ultra-resolution imaging of whole organisms by transmission electron microscopy (TEM) and 3D spatial correlation with optical imaging of the identical (fixed) samples. The second proposed development, the novel 3D snapshot interferometric holographic microscope (3D-SIHM), is optical 3D microscopy of dynamic living systems with nanoscale resolution by interferometry, plus multi-scale volumetric imaging by holography in a "snapshot" mode for quantitative determination of transport on nanometer to 100 µm scales. The third approach, scanning x-ray fluorescence (XRF) imaging, allows sub-micron scale measurements of intact complex systems in their native environment, even if that environment is opaque to visible light. Within this project, we are also developing system-specific molecular-scale reporters and methods for using them in multi-modal experimental protocols. The three imaging approaches are synergistic when used in tandem with reporters that function across one or more of the imaging methods. The first of these, quantum dots, will enable correlation across all three microscopies. The second of these, solute binding proteins (SBPs) with FRET (Förster resonance energy transfer) capability, will provide the foundation for observing interactions with small molecules of interest (e.g., nutrients). Finally, we are also developing computational imaging approaches and algorithms for deriving volumetric images for the large data sets that will be generated with some of these imaging approaches.

During this presentation, I will provide a broad overview of the Argonne Small Worlds project with a particular focus on x-ray fluorescence-based imaging that makes use of quantum dots as a contrast agent. This will include an introduction to synchrotron radiation and x-ray absorption and fluorescence processes. Finally, I will present preliminary results of x-ray absorption measurements recently made on gold nanospheres and “nanostars” in collaboration with researchers at Duke.

This work was supported by the US Department of Energy (US DOE), Office of Science (OS), Biological and Environmental Research, Mesoscale to Molecules Program. The Advanced Photon Source is funded by the US DOE OS Basic Energy Science Division.

Dr. Ken Kemner obtained his PhD in Condensed Matter Physics at the University of Notre Dame in 1993. From 1993 to 1996 he was a National Research Council Fellow at the Naval Research Laboratory in Washington, D.C. where he focused on magnetic materials and environmental research. In 1996 he joined Argonne National Laboratory where he began to develop the Molecular Environmental Science Research Group, an integrated multidisciplinary research group that makes use of the Advanced Photon Source, the most brilliant high energy x-ray source in the Western Hemisphere. Since 1997 he has investigated the role of microorganisms in the environmental fate and transport of contaminant metals and radionuclides and their subsequent uptake into the food chain. More recently, he has led a multifaceted bioimaging effort (“Small Worlds”) that utilizes quantum dots as a multi-modal tag for imaging bacteria in environmental systems. In 1998 he received the United States Department of Energy-Office of Science Early Career Scientist Award. In 1999 he received the Presidential Early Career Scientist Award and in 2000 he received the International Union of Crystallography Young Scientist Award. Since 2003 he has been an adjunct faculty member in the Department of Civil and Environmental Engineering and Earth Sciences at the University of Notre Dame. He has over 140 publications (h-index 46) and has delivered more than 380 presentions, more than 130 of which were invited presentations.