Combined Confocal and Magnetic Resonance Microscope
Figure 1. Microimages (bottom left), time-resolved metabolite spectra (bottom right), and depth-resolved metabolite spectral microimaging (top) for live bacterial (Shewanella oneidensis) biofilms. Biomolecule peaks are highlighted (F, fumarate; S, succinate; A, acetate; and L, lactate). Left panel shows optical and NMR images of biofilms. View full image.
Researchers at Pacific Northwest National Laboratory (PNNL) have developed a unique, combined optical fluorescence confocal laser microscope (OM) and magnetic resonance microscope (MRM) for studying immobilized cell cultures (large single cells and cell clusters, plated mammalian cells, and bacterial films [biofilms]). This microscope allows for the concurrent measurement and correlation of complementary OM and MRM data. It has been applied to correlate biofilm biomass and physiology (Figure 1) and to correlate organelle structure with water transport rates (Figure 2). Currently, the combined OM and MRM is being used for PNNL's research project, Experimental Metabolism Studies of Oral Biofilm Communities.
Figure 2. Colocalized MRM diffusion map (left) and mitochondria-selective optical image (right) for an early-stage Xenopus laevis amphibian oocyte (a large single cell destined to become an egg). Scale bar is 100 microns.
Optical fluorescence confocal scanning laser microscopy - OM involves mapping fluorescent stains or fluorescent molecular tags in a cell sample. It rapidly provides detailed subcellular and molecular information with approximately 1 micron spatial resolution in two or three dimensions for optically transparent samples.
PNNL's Combined confocal and magnetic resonance microscope won a 2001 Discover Magazine Innovation Award.
Magnetic Resonance Microscopy - MRM involves applying nuclear magnetic resonance (NMR) spectroscopy, relaxation, diffusion, flow, and imaging methods to small samples using strong magnetic fields. MRM yields a view of molecules (typically water) from an atomic level; therefore, it is sensitive to the chemistry, physical environment, and motion of hydrogen-containing molecules. It is non-invasive, non-destructive, non-sample-consuming, and is insensitive to sample opacity. The spatial resolution for 1H MRM images is typically approximately 40 microns and requires data-collection times of minutes (two dimensional) to hours (three dimensional).
