title: High resolution laser mass spectrometry bioimaging.
abstract: Mass spectrometry imaging (MSI) was introduced more than five decades ago with secondary ion mass spectrometry (SIMS) and a decade later with laser desorption/ionization (LDI) mass spectrometry (MS). Large biomolecule imaging by matrix-assisted laser desorption/ionization (MALDI) was developed in the 1990s and ambient laser MS a decade ago. Although SIMS has been capable of imaging with a moderate mass range at sub-micrometer lateral resolution from its inception, laser MS requires additional effort to achieve a lateral resolution of 10μm or below which is required to image at the size scale of single mammalian cells. This review covers untargeted large biomolecule MSI using lasers for desorption/ionization or laser desorption and post-ionization. These methods include laser microprobe (LDI) MSI, MALDI MSI, laser ambient and atmospheric pressure MSI, and near-field laser ablation MS. Novel approaches to improving lateral resolution are discussed, including oversampling, beam shaping, transmission geometry, reflective and through-hole objectives, microscope mode, and near-field optics.
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA. Electronic address: kkmurray@lsu.edu.
authors.forename: Kermit K
authors.initials: KK
authors.lastname: Murray
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Chinthaka A
authors.initials: CA
authors.lastname: Seneviratne
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Suman
authors.initials: S
authors.lastname: Ghorai
mesh_terms: D007834:Lasers; D008853:Microscopy / Q000639:trends; D057054:Molecular Imaging / Q000639:trends*; D008970:Molecular Weight; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000639:trends*
keywords: Imaging; MALDI; Mass spectrometry; Resolution