AP-MALDI Mass Spectrometry Imaging of Gangliosides Using 2,6-Dihydroxyacetophenone

Area of Science:

• Biochemistry
• Analytical Chemistry
• Neuroscience

Background:

• Matrix-assisted laser/desorption ionization mass spectrometry imaging (MALDI-MSI) is crucial for mapping biomolecules in tissues.
• 2,6-Dihydroxyacetophenone (DHA) is an effective matrix for lipid and ganglioside ionization.
• DHA sublimation under vacuum limits its use in high-resolution, long-duration MSI studies.

Purpose of the Study:

• To overcome DHA sublimation limitations in MALDI-MSI.
• To achieve high spatial resolution lipid imaging in brain tissue.
• To highlight the benefits of atmospheric pressure (AP)-MALDI with DHA for ganglioside analysis.

Main Methods:

• Utilized an atmospheric pressure (AP)-MALDI source coupled with a high mass resolution mass spectrometer.
• Applied AP-MALDI-MSI to analyze lipid distribution in brain tissue.
• Investigated the ionization of gangliosides using the DHA matrix.

Main Results:

• Successfully obtained high spatial resolution images of lipids in the brain.
• Demonstrated that AP-MALDI with DHA prevents matrix sublimation during extended MSI acquisition.
• Observed differential distribution patterns for GD1 ganglioside species ([M-H]⁻ and [M-H₂O-H]⁻ peaks), suggesting distinct spatial arrangements of GD1a and GD1b.

Conclusions:

• AP-MALDI is a viable solution to overcome DHA sublimation issues in MSI.
• This technique enables detailed lipid and ganglioside imaging in complex biological tissues like the brain.
• The distinct distributions of GD1a and GD1b highlight the method's capability to differentiate closely related molecular species.