A one-step matrix application method for MALDI mass spectrometry imaging of bacterial colony biofilms

J Mass Spectrom. 2016 Nov;51(11):1030-1035. doi: 10.1002/jms.3827.


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.

Keywords: MALDI MSI; airbrush; automatic sprayer; biofilms; matrix application.

MeSH terms

  • Agar
  • Bacillus subtilis / ultrastructure*
  • Bacteriological Techniques
  • Biofilms*
  • Gentisates / chemistry*
  • Optical Imaging
  • Solutions
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization


  • Gentisates
  • Solutions
  • Agar