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Virus and Bacterial Cell Chemical Analysis by NanoSIMS.


DE2009956845

Publication Date 2008
Personal Author Weber, P. K.; Holt, J.
Page Count 11
Abstract In past work for the Department of Homeland Security, the LLNL NanoSIMS team has succeeded in extracting quantitative elemental composition at sub-micron resolution from bacterial spores using nanometer-scale secondary ion mass spectrometry (NanoSIMS). The purpose of this task is to test our NanoSIMS capabilities on viruses and bacterial cells. This initial work has proven successful. We imaged Tobacco Mosaic Virus (TMV) and Bacillus anthracis Sterne cells using scanning electron microscopy (SEM) and then analyzed those samples by NanoSIMS. We were able resolve individual viral particles (approx. 18 nm by 300 nm) in the SEM and extract correlated elemental composition in the NanoSIMS. The phosphorous/carbon ratio observed in TMV is comparable to that seen in bacterial spores (0.033), as was the chlorine/carbon ratio (0.11). TMV elemental composition is consistent from spot to spot, and TMV is readily distinguished from debris by NanoSIMS analysis. Bacterial cells were readily identified in the SEM and relocated in the NanoSIMS for elemental analysis. The Ba Sterne cells were observed to have a measurably lower phosphorous/carbon ratio (0.005), as compared to the spores produced in the same run (0.02). The chlorine/carbon ratio was approximately 2.5X larger in the cells (0.2) versus the spores (0.08), while the fluorine/carbon ratio was approximately 10X lower in the cells (0.008) than the spores (0.08). Silicon/carbon ratios for both cells and spores encompassed a comparable range. The initial data in this study suggest that high resolution analysis is useful because it allows the target agent to be analyzed separate from particulates and other debris. High resolution analysis would also be useful for trace sample analysis. The next step in this work is to determine the potential utility of elemental signatures in these kinds of samples. We recommend bulk analyses of media and agent samples to determine the range of media compositions in use, and to determine how agent composition relates to media composition. After these baseline analyses are performed, the data should be assessed to determine the potential forensic utility of elemental analyses. If promising, validation studies using bulk or NanoSIMS analysis would be necessary.
Keywords
  • Forensics
  • Bacterial spores
  • Anthrax
  • Bacillus anthracis
  • Tobacco Mosaic Virus
  • Scanning electron microscopy
  • Homeland security
  • Cytology
  • NanoSIMS(Nanometer-scale secondary ion mass spectrometry)
  • Nanometer-scale secondary ion mass spectrometry
Source Agency
  • Technical Information Center Oak Ridge Tennessee
Corporate Authors Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes Sponsored by Department of Energy, Washington, DC.
Document Type Technical Report
NTIS Issue Number 200924
Virus and Bacterial Cell Chemical Analysis by NanoSIMS.
Virus and Bacterial Cell Chemical Analysis by NanoSIMS.
DE2009956845

  • Forensics
  • Bacterial spores
  • Anthrax
  • Bacillus anthracis
  • Tobacco Mosaic Virus
  • Scanning electron microscopy
  • Homeland security
  • Cytology
  • NanoSIMS(Nanometer-scale secondary ion mass spectrometry)
  • Nanometer-scale secondary ion mass spectrometry
  • Technical Information Center Oak Ridge Tennessee
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