title: NanoSIMS imaging of Bacillus spores sectioned by focused ion beam.
abstract: Preparation and sectioning of bacterial spores by focused ion beam and subsequent high resolution secondary ion mass spectrometry analytical imaging is demonstrated. Scanning transmission electron microscopy mode imaging in a scanning electron microscope is used to show that the internal structure of the bacterial spore can be preserved during focused ion beam sectioning and can be imaged without contrast staining. Ion images of the sections show that the internal elemental distributions of the sectioned spores are preserved. A rapid focused ion beam top-sectioning method is demonstrated to yield comparable ion images without the need for sample trenching and section lift-out. The lift-out and thinning method enable correlated transmission electron microscopy and high resolution secondary ion mass spectrometry analyses. The top-cutting method is preferable if only secondary ion mass spectrometry analyses are performed because this method is faster and yields more sample material for analysis; depth of useful sample material is approximately 300 nm for top-cut sections versus approximately 100 nm for electron-transparent sections.
authors.affiliation: Chemical Sciences, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. weber21@llnl.gov
authors.forename: P K
authors.initials: PK
authors.lastname: Weber
authors.forename: G A
authors.initials: GA
authors.lastname: Graham
authors.forename: N E
authors.initials: NE
authors.lastname: Teslich
authors.forename: W Moberly
authors.initials: WM
authors.lastname: Chan
authors.forename: S
authors.initials: S
authors.lastname: Ghosal
authors.forename: T J
authors.initials: TJ
authors.lastname: Leighton
authors.forename: K E
authors.initials: KE
authors.lastname: Wheeler
mesh_terms: D001407:Bacillus / Q000737:chemistry* / Q000648:ultrastructure*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D046529:Microscopy, Electron, Transmission / Q000379:methods; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*; D013170:Spores / Q000737:chemistry* / Q000648:ultrastructure*