Single-Cell 5 μm-Resolution Dual-Polarity MALDI-MS Imaging without Matrix Reapplication

Area of Science:

• Analytical Chemistry
• Biochemistry
• Molecular Imaging

Background:

• High-resolution mass spectrometry imaging (MSI) is crucial for lipidomics but faces challenges in single-cell analysis due to spatial resolution and lipid coverage limitations.
• Existing dual-polarity MSI methods offer good lipid coverage but are restricted to 10 μm resolution, hindering single-cell applications.

Purpose of the Study:

• To develop a single-cell/subcellular resolution strategy for dual-polarity MALDI-MSI.
• To overcome the spatial resolution limitations of current MSI techniques for cellular lipidomics.

Main Methods:

• A novel, single-deposition matrix application technique using N-(1-naphthyl)-ethylenediamine dihydrochloride (NEDC) for dual-polarity MALDI-MSI.
• Optimized acquisition parameters and a fine-tuned matrix deposition for 5 μm spatial resolution without matrix reapplication.
• Analysis of mouse kidney tissue and A549 lung carcinoma cells.

Main Results:

• Achieved 5 μm spatial resolution, enabling single-cell and subcellular lipid imaging.
• Maintained broad lipid coverage comparable to multistep methods.
• Identified distinct lipid distribution patterns and significant cell-to-cell lipidomic heterogeneity within single-cell populations using spatial PLSA and histogram analysis.

Conclusions:

• The developed single-cell resolution MALDI-MSI strategy overcomes limitations of traditional dual-polarity MSI.
• Provides a powerful tool for advancing cellular lipidomics, understanding disease mechanisms, and investigating environmental toxicology.