Infrared Laser Desorption of Intact Nanoparticles for Digital Tissue Imaging

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• Accurate tissue biomarker mapping is crucial for disease diagnosis and research.
• Conventional laser ablation techniques can disintegrate nanoparticle tags, limiting detection sensitivity.
• Existing methods struggle with precise quantification and spatial resolution of low-abundance biomarkers.

Purpose of the Study:

• To develop and validate a new digital tissue biomarker mapping technique using intact gold nanoparticle tags.
• To overcome limitations of conventional laser ablation methods in nanoparticle integrity and detection.
• To enable precise, high-resolution mapping of biomarkers for biological and medical applications.

Main Methods:

• Utilizing infrared laser ablation single-particle inductively coupled plasma mass spectrometry (IR LA SP ICP MS) for gold nanoparticle (Au NP) desorption.
• Employing a 2940 nm laser wavelength to prevent disintegration of Au NPs during desorption.
• Demonstrating the technique on mapping the proliferation marker Ki-67 in colorectal carcinoma cell aggregates.

Main Results:

• Achieved high detection efficiency of intact Au NPs (up to 83%) with a single-particle detection limit.
• Generated sharp, precise distribution maps of Ki-67 biomarkers in 3D cell aggregates.
• Demonstrated suppressed desorption of Au NPs from non-tissue areas, improving specificity.
• Validated results against confocal fluorescence microscopy and UV LA ICP MS.

Conclusions:

• The developed IR LA SP ICP MS technique enables digital mapping of biomarkers with high precision and sensitivity.
• This method preserves the integrity of gold nanoparticle tags, enhancing quantitative analysis.
• The technique holds promise for multiplex mapping of low-abundant biomarkers in diverse biological and medical fields.