title: Nanotome cluster bombardment to recover spatial chemistry after preparation of biological samples for SIMS imaging.
abstract: A C(60)(+) cluster ion projectile is employed for sputter cleaning biological surfaces to reveal spatio-chemical information obscured by contamination overlayers. This protocol is used as a supplemental sample preparation method for time of flight secondary ion mass spectrometry (ToF-SIMS) imaging of frozen and freeze-dried biological materials. Following the removal of nanometers of material from the surface using sputter cleaning, a frozen-patterned cholesterol film and a freeze-dried tissue sample were analyzed using ToF-SIMS imaging. In both experiments, the chemical information was maintained after the sputter dose, due to the minimal chemical damage caused by C(60)(+) bombardment. The damage to the surface produced by freeze-drying the tissue sample was found to have a greater effect on the loss of cholesterol signal than the sputter-induced damage. In addition to maintaining the chemical information, sputtering is not found to alter the spatial distribution of molecules on the surface. This approach removes artifacts that might obscure the surface chemistry of the sample and are common to many biological sample preparation schemes for ToF-SIMS imaging.
authors.affiliation: Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Kurczy
authors.forename: Paul D
authors.initials: PD
authors.lastname: Piehowsky
authors.forename: David
authors.initials: D
authors.lastname: Willingham
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Molyneaux
authors.forename: Michael L
authors.initials: ML
authors.lastname: Heien
authors.forename: Nicholas
authors.initials: N
authors.lastname: Winograd
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Ewing
mesh_terms: D000818:Animals; D002784:Cholesterol / Q000737:chemistry; D004622:Embryo, Mammalian; D037741:Fullerenes / Q000737:chemistry*; D016591:Histocytological Preparation Techniques / Q000379:methods*; D051379:Mice; D036103:Nanotechnology / Q000379:methods*; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*; D013499:Surface Properties
chemical_list: D037741:Fullerenes; D002784:Cholesterol; C069837:fullerene C60