MALDI-2-Enabled Oversampling for the Mass Spectrometry Imaging of Metabolites at Single-Cell Resolution

Area of Science:

• Metabolomics
• Mass Spectrometry Imaging
• Cellular Biology

Background:

• Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) offers insights into biological metabolomes.
• Achieving single-cell spatial resolution in MALDI-MSI is technologically challenging due to sensitivity limitations with oversampling.

Purpose of the Study:

• To develop a method for high-spatial-resolution metabolomics with enhanced sensitivity.
• To enable single-cell metabolite analysis using mass spectrometry imaging.

Main Methods:

• Combined an oversampling approach with laser postionization (MALDI-2).
• Utilized a laser spot size of approximately 13 μm with pixel sizes of 6–8 μm.
• Applied the technique to mouse spinal cord tissue and human iPSC-derived astrocytes.

Main Results:

• Achieved higher spatial resolution (6–8 μm pixels) with sensitivity comparable or superior to conventional MALDI (20 μm pixels).
• Successfully mapped metabolite distributions in mouse spinal cord anatomical regions.
• Detected various metabolites, including nucleotides, from individual human astrocytes at 10 μm resolution.

Conclusions:

• MALDI-2 with oversampling significantly improves spatial resolution and sensitivity in mass spectrometry imaging.
• This technique is effective for single-cell metabolomics and detailed tissue metabolome mapping.
• Provides new insights into metabolite localization at cellular and subcellular levels.