Enhanced MALDI-2 Sensitivity with Reflecting Post-Ionization Laser for High-Resolution MS Imaging Combined with...

Area of Science:

• Analytical Chemistry
• Biochemistry
• Spectroscopy

Background:

• Matrix-assisted laser desorption/ionization (MALDI) is a key technique for analyzing biological samples.
• MALDI post-ionization (MALDI-2) significantly improves sensitivity for biological metabolites.
• Further enhancing MALDI-2 sensitivity and mass spectrometry imaging (MSI) resolution is crucial for detailed spatial omics.

Purpose of the Study:

• To improve the sensitivity of MALDI-2 using a reflecting post-ionization laser.
• To achieve higher spatial resolution in MALDI-based mass spectrometry imaging.
• To integrate real-time microscopic imaging with MSI for enhanced sample analysis.

Main Methods:

• Developed MALDI-2+ by incorporating a reflecting post-ionization laser to increase laser-plume interaction time.
• Designed a T-shaped ion guide for perpendicular ablation laser incidence in reflection geometry MALDI.
• Utilized a 2.5 μm laser spot diameter for high spatial resolution MSI.
• Integrated real-time backward microscopic imaging with the MSI setup.

Main Results:

• MALDI-2+ demonstrated over 2 times sensitivity improvement compared to conventional MALDI-2.
• Achieved high spatial resolution MSI with potential for sub-10 μm pixels.
• Enabled real-time, high-quality microscopic imaging registered with MSI data.
• Successfully analyzed standard samples and imaged cells, showcasing the system's capabilities.

Conclusions:

• The developed MALDI-2+ method significantly enhances sensitivity for metabolite analysis.
• The new ion source design facilitates higher spatial resolution MSI.
• Integrated microscopic imaging provides real-time sample monitoring and registration.
• This integrated approach advances capabilities for spatial omics research.