Spray-Based Application of Matrix to Agar-Based Microbial Samples for Reproducible Sample Adherence in MALDI MSI

Area of Science:

• Microbiology
• Analytical Chemistry
• Metabolomics

Background:

• Microbial mass spectrometry imaging (MSI) aids in understanding metabolite roles in microbial competition via spatial distribution.
• Matrix-assisted laser desorption ionization (MALDI) is the primary ionization method for microbial MSI.
• Current limitations include poor agar sample adherence to MALDI targets due to medium components and microbial metabolites, restricting media choices.

Purpose of the Study:

• To develop an improved method for microbial MSI analysis.
• To overcome limitations in sample adherence for MALDI MSI.
• To enable microbial growth on diverse media for MSI analysis.

Main Methods:

• A three-step process involving a robotic sprayer for matrix application was developed.
• This method enhances the adherence of agar-based microbial samples to MALDI targets.
• The technique facilitates MSI analysis over larger sample surface areas.

Main Results:

• The robotic spraying method significantly improves agar sample adherence to MALDI targets.
• This advancement allows for the use of a wider range of microbial growth media.
• The improved adherence enables MSI analysis of larger microbial sample areas.

Conclusions:

• The new robotic spraying technique expands the applicability of MALDI MSI for microbial studies.
• Researchers can now utilize diverse media for microbial growth and subsequent MSI analysis.
• This method enhances the potential for generating biological hypotheses regarding microbial competition and metabolite functions.