Direct Analysis of Micro-biopsy Samples by Polarity Gradient Focusing Dip-and-Go Mass Spectrometry

Area of Science:

• Analytical Chemistry
• Biotechnology
• Mass Spectrometry

Background:

• Direct mass spectrometry analysis of micro-biopsy samples at the single-cell level presents significant challenges.
• Existing methods struggle with sensitivity and spatial resolution for complex biological matrices.

Purpose of the Study:

• To develop a novel strategy for real-time enrichment and spatial separation of compounds in micro-biopsy samples.
• To enhance the sensitivity and analytical capabilities of induced electrospray ionization mass spectrometry (iESI-MS).

Main Methods:

• Development of a polarity gradient focusing dip-and-go (PGF-Dip&Go) strategy for iESI-MS.
• Application of PGF-Dip&Go for the analysis of lipids in a 200 pL micro-biopsy section of a fish egg.

Main Results:

• Achieved analyte enrichment factors ranging from 5.0 to 100.0.
• Demonstrated significant spatial separation of compounds based on polarity differences.
• Improved sensitivity by 25-10,000 times compared to direct iESI-MS analysis.
• Successfully identified and separated lysophosphatidylcholine (LPC), phosphatidylcholine (PC), and triglyceride (TG) in the fish egg sample.

Conclusions:

• PGF-Dip&Go significantly enhances sensitivity and spatial resolution for analyzing complex small-volume samples.
• The developed method shows great potential as a noninvasive analytical tool for in situ analysis.
• This strategy opens new avenues for single-cell and micro-biopsy analysis in various scientific fields.