title: A one-step matrix application method for MALDI mass spectrometry imaging of bacterial colony biofilms.
abstract: Matrix-assisted laser desorption/ionization imaging of biofilms cultured on agar plates is challenging because of problems related to matrix deposition onto agar. We describe a one-step, spray-based application of a 2,5-dihydroxybenzoic acid solution for direct matrix-assisted laser desorption/ionization imaging of hydrated Bacillus subtilis biofilms on agar. Using both an optimized airbrush and a home-built automatic sprayer, region-specific distributions of signaling metabolites and cannibalistic factors were visualized from B. subtilis cells cultivated on biofilm-promoting medium. The approach provides a homogeneous, relatively dry coating on hydrated samples, improving spot to spot signal repeatability compared with sieved matrix application, and is easily adapted for imaging a range of agar-based biofilms. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
authors.forename: Troy J
authors.initials: TJ
authors.lastname: Comi
authors.affiliation: Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.|Department of Chemical and Biomolecular Engineering and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
authors.forename: Tong
authors.initials: T
authors.lastname: Si
authors.affiliation: Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
authors.forename: Sage J B
authors.initials: SJ
authors.lastname: Dunham
authors.affiliation: Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. jsweedle@illinois.edu.
authors.forename: Jonathan V
authors.initials: JV
authors.lastname: Sweedler
mesh_terms: D000362:Agar; D001412:Bacillus subtilis / Q000648:ultrastructure*; D001431:Bacteriological Techniques; D018441:Biofilms; D005841:Gentisates / Q000737:chemistry*; D061848:Optical Imaging; D012996:Solutions; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D005841:Gentisates; D012996:Solutions; D000362:Agar
keywords: MALDI MSI; airbrush; automatic sprayer; biofilms; matrix application