Pulled Flowprobe for Ambient Liquid Extraction-Based High Spatial Resolution Mass Spectrometry Imaging with Enhanced...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry Imaging
• Biomedical Engineering

Background:

• Ambient liquid extraction-based mass spectrometry imaging (MSI) offers direct analysis with minimal sample preparation.
• Existing integrated probes lack high spatial resolution, sensitivity, and stability for ambient MSI.
• There is a need for improved sampling probes to advance ambient MSI applications.

Purpose of the Study:

• To develop and evaluate a novel integrated probe, the pulled flowprobe, for ambient liquid extraction-based MSI.
• To compare the performance of the pulled flowprobe against a single-probe in terms of mass transfer, sensitivity, stability, and spatial resolution.
• To demonstrate the utility of the pulled flowprobe for high-resolution lipid imaging in biological tissues.

Main Methods:

• Fabrication of a pulled flowprobe using coaxial capillaries.
• Investigation of mass transfer kinetics and computational fluid dynamics analysis.
• Performance evaluation using ambient liquid extraction-based MSI of lipids in rat cerebrum and hippocampus, and a uniform ink coating for stability assessment.

Main Results:

• The pulled flowprobe exhibited higher extraction efficiencies and reduced band diffusion compared to the single-probe.
• MSI with the pulled flowprobe showed 2-5 times higher signals for low-abundance lipids and detected 26 more lipid species.
• The pulled flowprobe demonstrated significantly improved stability (RSD 18% vs 80%) and higher spatial resolution (30-40 μm).

Conclusions:

• The pulled flowprobe is an easily fabricated sampling probe that significantly enhances sensitivity, stability, and spatial resolution for ambient liquid extraction-based MSI.
• This novel probe facilitates high-resolution lipid imaging in biological samples, enabling localization to specific cellular layers.
• The pulled flowprobe represents a valuable advancement for biological and clinical research applications of ambient MSI.