title: Molecular imaging of biological tissue using gas cluster ions.
abstract: An Arn+(n= 1-6000) gas cluster ion source has been utilized to map the chemical distribution of lipids in a mouse brain tissue section. We also show that the signal from high mass species can be further enhanced by doping a small amount of CH4into the Ar cluster to enhance the ionization of several biologically important molecules. Coupled with secondary ion mass spectrometry instrumentation which utilizes a continuous Ar cluster ion projectile, maximum spatial resolution and maximum mass resolution can be achieved at the same time. With this arrangement, it is possible to achieve chemically resolved molecular ion images at the 4-µm resolution level. The focused Arn+/[Arx(CH4)y]+beams (4-10 µm) have been applied to the study of untreated mouse brain tissue. A high signal level of molecular ions and salt adducts, mainly from various phosphocholine lipids, has been seen and directly used to map the chemical distribution. The signal intensity obtained using the pure Ar cluster source, the CH4-doped cluster source and C60is also presented.
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, PA 16802, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Tian
authors.affiliation: Faculty of Physics, University Duisburg-Essen, 47048 Duisburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Wucher
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, PA 16802, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Winograd
keywords: Ar cluster ion beam; SIMS; molecular ion imaging; mouse brain section