Improved MALDI-TOF microbial mass spectrometry imaging by application of a dispersed solid matrix

Area of Science:

• Microbiology
• Analytical Chemistry
• Mass Spectrometry Imaging

Background:

• High-quality microbial matrix-assisted laser desorption/ionization mass spectrometry imaging (microbial MALDI MSI) relies on homogeneous matrix coatings with fine-grained morphology.
• Current methods for applying solid MALDI matrices to microbial cultures on thin agar media can be challenging.

Purpose of the Study:

• To introduce and evaluate a novel method for applying solid MALDI matrices to microbial cultures on thin agar media.
• To improve the homogeneity and morphology of matrix coatings for enhanced microbial MALDI MSI analysis.

Main Methods:

• A suspension containing a mixture of 2,5-DHB and α-CHCA was prepared.
• This matrix suspension was sprayed onto microbial cultures grown on thin agar media.
• The resulting matrix coatings were analyzed for homogeneity and morphology.

Main Results:

• The spraying method successfully formed highly homogeneous matrix coatings.
• The fine-grained morphology of the matrix coating was achieved.
• Signal intensities of metabolites secreted by Aspergillus fumigatus were significantly enhanced.

Conclusions:

• The novel spraying method provides a reliable technique for fabricating high-quality matrix coatings for microbial MALDI MSI.
• This approach leads to improved metabolite detection in fungal samples.
• The method holds promise for advancing microbial MALDI MSI applications.