title: Ambient Mass Spectrometry Imaging with Picosecond Infrared Laser Ablation Electrospray Ionization (PIR-LAESI).
abstract: A picosecond infrared laser (PIRL) is capable of cutting through biological tissues in the absence of significant thermal damage. As such, PIRL is a standalone surgical scalpel with the added bonus of minimal postoperative scar tissue formation. In this work, a tandem of PIRL ablation with electrospray ionization (PIR-LAESI) mass spectrometry is demonstrated and characterized for tissue molecular imaging, with a limit of detection in the range of 100 nM for reserpine or better than 5 nM for verapamil in aqueous solution. We characterized PIRL crater size using agar films containing Rhodamine. PIR-LAESI offers a 20-30 μm vertical resolution (∼3 μm removal per pulse) and a lateral resolution of ∼100 μm. We were able to detect 25 fmol of Rhodamine in agar ablation experiments. PIR-LAESI was used to map the distribution of endogenous methoxykaempferol glucoronide in zebra plant (Aphelandra squarrosa) leaves producing a localization map that is corroborated by the literature. PIR-LAESI was further used to image the distribution inside mouse kidneys of gadoteridol, an exogenous magnetic resonance contrast agent intravenously injected. Parallel mass spectrometry imaging (MSI) using desorption electrospray ionization (DESI) and matrix assisted laser desorption ionization (MALDI) were performed to corroborate PIR-LAESI images of the exogenous agent. We further show that PIR-LAESI is capable of desorption ionization of proteins as well as phospholipids. This comparative study illustrates that PIR-LAESI is an ion source for ambient mass spectrometry applications. As such, a future PIRL scalpel combined with secondary ionization such as ESI and mass spectrometry has the potential to provide molecular feedback to guide PIRL surgery.
authors.affiliation: Department of Physics, University of Toronto , 60 St George Street, Toronto, Ontario M5S 1A7, Canada.
authors.forename: Jing
authors.initials: J
authors.lastname: Zou
authors.affiliation: Department of Chemistry, University of Toronto , 80 St George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Francis
authors.initials: F
authors.lastname: Talbot
authors.affiliation: Department of Chemistry, York University , 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada.|Techna Institute for the Advancement of Technology for Health, University Health Network , Toronto, Ontario M5G 1P5, Canada.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Tata
authors.affiliation: Program in Physiology and Experimental Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children , Toronto, Ontario M5G 0A4, Canada.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Ermini
authors.affiliation: Department of Physics, University of Toronto , 60 St George Street, Toronto, Ontario M5S 1A7, Canada.
authors.forename: Kresimir
authors.initials: K
authors.lastname: Franjic
authors.affiliation: Techna Institute for the Advancement of Technology for Health, University Health Network , Toronto, Ontario M5G 1P5, Canada.
authors.forename: Manuela
authors.initials: M
authors.lastname: Ventura
authors.affiliation: Techna Institute for the Advancement of Technology for Health, University Health Network , Toronto, Ontario M5G 1P5, Canada.
authors.forename: Jinzi
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Department of Surgery, University of Toronto , 149 College Street, Toronto, Ontario M5T 1P5, Canada.|Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital , 30 Bond Street, Toronto, Ontario M5B 1W8, Canada.
authors.forename: Howard
authors.initials: H
authors.lastname: Ginsberg
authors.affiliation: Program in Physiology and Experimental Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children , Toronto, Ontario M5G 0A4, Canada.|Institute of Medical Science, University of Toronto , Toronto, Ontario M5S 1A8, Canada.
authors.forename: Martin
authors.initials: M
authors.lastname: Post
authors.affiliation: Department of Chemistry, York University , 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada.
authors.forename: Demian R
authors.initials: DR
authors.lastname: Ifa
authors.affiliation: Techna Institute for the Advancement of Technology for Health, University Health Network , Toronto, Ontario M5G 1P5, Canada.|Department of Medical Biophysics, University of Toronto , 101 College Street Suite 15-701, Toronto, Ontario M5G 1L7, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Jaffray
authors.affiliation: Department of Physics, University of Toronto , 60 St George Street, Toronto, Ontario M5S 1A7, Canada.|Department of Chemistry, University of Toronto , 80 St George Street, Toronto, Ontario M5S 3H6, Canada.|Max Planck Institute for the Structure and Dynamics of Matter , Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: R J Dwayne
authors.initials: RJ
authors.lastname: Miller
authors.affiliation: Techna Institute for the Advancement of Technology for Health, University Health Network , Toronto, Ontario M5G 1P5, Canada.|Department of Surgery, University of Toronto , 149 College Street, Toronto, Ontario M5T 1P5, Canada.|Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital , 30 Bond Street, Toronto, Ontario M5B 1W8, Canada.|Department of Medical Biophysics, University of Toronto , 101 College Street Suite 15-701, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Arash
authors.initials: A
authors.lastname: Zarrine-Afsar
mesh_terms: D000818:Animals; D007259:Infrared Rays; D007668:Kidney / Q000166:cytology / Q000601:surgery; D007834:Lasers; D057230:Limit of Detection; D051379:Mice; D016513:Mice, SCID; D021241:Spectrometry, Mass, Electrospray Ionization