MALDI-2 and t-MALDI-2 Mass Spectrometry Imaging.

Area of Science:

• Analytical Chemistry
• Biochemistry
• Molecular Imaging

Background:

• Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) is a powerful technique for analyzing molecular distributions in biological samples.
• Limitations in ion yield and spatial resolution can hinder comprehensive molecular profiling.
• MALDI-2, utilizing laser-induced postionization, offers significantly improved ion signals.

Purpose of the Study:

• To describe key methodological aspects for optimizing analytical sensitivity and spatial resolution in MALDI-2 imaging experiments.
• To present optimization strategies for both top-illumination and transmission (t-) mode MALDI-2.
• To enable simultaneous registration of diverse small molecules, lipids, and glycans with enhanced ion yields.

Main Methods:

• Optimization of experimental parameters for Matrix-assisted laser desorption ionization mass spectrometry imaging combined with laser-induced postionization (MALDI-2).
• Implementation and comparison of top-illumination MALDI-2 and transmission (t-) mode MALDI-2.
• Analysis of small molecules, secondary metabolites (e.g., sterols), phospholipids, glycolipids, and glycans in tissue sections and cell cultures.

Main Results:

• MALDI-2 significantly boosts ion yields for a wide range of small molecules and lipids.
• Methodological optimization enhances both analytical sensitivity and spatial resolution in MALDI-2 imaging.
• Both top-illumination and t-mode MALDI-2 approaches are presented as viable for molecular imaging.

Conclusions:

• MALDI-2 represents a significant advancement for sensitive and spatially resolved molecular imaging.
• Careful methodological optimization is crucial for maximizing the performance of MALDI-2 experiments.
• The described approaches facilitate comprehensive molecular profiling of complex biological samples.