AVS 53rd International Symposium
    Applied Surface Science Wednesday Sessions
       Session AS+BI-WeA

Paper AS+BI-WeA7
Characterization of Bacterial Spores using Nano-Secondary Ion Mass Spectrometry (NanoSIMS)

Wednesday, November 15, 2006, 4:00 pm, Room 2005

Session: Imaging and Characterization of Biological Materials
Presenter: S. Ghosal, Lawrence Livermore National Laboratory
Authors: S. Ghosal, Lawrence Livermore National Laboratory
S.J. Fallon, Lawrence Livermore National Laboratory
T. Leighton, Children's Hospital Oakland Research Institute
K. Wheeler, Children's Hospital Oakland Research Institute
I.D. Hutcheon, Lawrence Livermore National Laboratory
P.K. Weber, Lawrence Livermore National Laboratory
Correspondent: Click to Email
Bacterial spores are elementally zoned at the nanometer scale. This zonation may be controlled by spore physiology, physical factors, and elemental diffusion. Here we present a recently developed nanometer-scale secondary ion mass spectrometry (NanoSIMS) technique that allows the direct visualization and quantification of elemental concentration gradients within spores. By using NanoSIMS depth profile analysis together with sample preparation techniques such as focused ion beam (FIB) sectioning, we are able to probe the three dimensional elemental distribution within individual Bacillus thuringiensis israelensis (Bti) spores with nanometer scale resolution (~10 nm depth and 50 nm lateral). Our results show the expected distributions for physiologically controlled elements (Ca, P) and provide baseline data other elements (e.g., Li, F, Cl, S). We also demonstrate cation and anion mobility in spores under hydrous conditions. Our results suggest a permeation mechanism by which elements diffuse into and out of the spore along hydration pathways on rather short time scales. Additional studies are in progress to define the rates and mechanisms controlling ion mobility in spores. @FootnoteText@ @footnote@This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-4.