Substrate-Mediated Laser Ablation under Ambient Conditions for Spatially-Resolved Tissue Proteomics

Area of Science:

• Analytical Chemistry
• Biochemistry
• Proteomics

Background:

• Ambient Mass Spectrometry (MS) has advanced, driving micro-sampling innovations like Laser Ablation/Droplet Capture (LADC).
• LADC typically uses UV or IR wavelengths for direct analyte ablation and capture in solvent for MS analysis.
• Biomolecule analysis via LADC is challenging due to low absorbance in the visible light spectrum.

Purpose of the Study:

• To explore visible range LADC (532 nm) as a micro-sampling method for large-scale proteomics.
• To investigate the feasibility of biomolecule analysis using 532 nm LADC despite low absorbance.
• To demonstrate the utility of this technique for analyzing micro-sampled biological tissues.

Main Methods:

• Development of a custom Laser Ablation/Droplet Capture (LADC) system operating at 532 nm (visible range).
• Investigation of the ablation mechanism, identifying a substrate-mediated process at low laser energies.
• Application of the 532 nm LADC system to micro-sample tissue sections for proteomic analysis.

Main Results:

• Demonstrated successful biomolecule analysis using 532 nm LADC, overcoming low direct absorbance.
• Identified a substrate-mediated ablation mechanism as key to efficient sampling at visible wavelengths.
• Achieved large-scale proteomic analysis of micro-sampled tissue sections, identifying proteins with biological relevance.

Conclusions:

• Visible range LADC (532 nm) is a viable micro-sampling technique for large-scale proteomics.
• The substrate-mediated ablation mechanism facilitates biomolecule analysis at this wavelength.
• 532 nm LADC presents a novel tool for biological and clinical applications in proteomics.