Tenfold Expansion Submicrometer MALDI Mass Spectrometry Imaging of Tissues and Cultured Cells

Area of Science:

• Mass Spectrometry Imaging
• Molecular Imaging
• Biomedical Research

Background:

• Submicrometer resolution in MALDI-MSI is crucial for single-cell and subcellular analysis.
• Current limitations include optical focusing and matrix crystallization.
• High-resolution imaging is vital for understanding cellular architecture.

Purpose of the Study:

• To develop an expansion MALDI-MSI workflow (10X ExMSI) for enhanced lateral resolution.
• To enable label-free molecular imaging at the subcellular level.
• To demonstrate the method's compatibility with standard instruments.

Main Methods:

• Implemented a tenfold expansion MALDI-MSI (10X ExMSI) workflow.
• Utilized a 5 µm acquisition step size without pixel oversampling.
• Employed an SDS-free digestion protocol to minimize lipid leaching.

Main Results:

• Achieved an effective lateral resolution of approximately 500 nm.
• Resolved subcellular structures in mouse brain tissues, including dendritic arborizations.
• Demonstrated subcellular lipid mapping in cultured A549 cells.

Conclusions:

• 10X ExMSI provides an accessible and scalable route to high-resolution, label-free molecular imaging.
• The method overcomes limitations of conventional MALDI-MSI for subcellular analysis.
• Enables new opportunities in studying cellular architecture and molecular heterogeneity.