A Potential Mercury Polymer Mass Tag Probe for Mass Cytometry
Edmond C N Wong1, Tianjia Yang1, Xiaochong Li1
1Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
Analytical Chemistry
|May 22, 2025
Summary
A new mercury(II) polymer with dipicolylamine (DPA) chelators was developed as a mass tag for mass cytometry (MC). Polymer 2d demonstrated high specificity for CD8a antigens, showing promise for MC applications.
Area of Science:
- Bioconjugation Chemistry
- Analytical Chemistry
- Materials Science
Background:
- Development of novel mass tags is crucial for advancing multiplexed cellular analysis.
- Mercury(II) polymers offer potential as mass tags due to their unique isotopic signatures.
- Existing mass tags face challenges in stability and specificity.
Purpose of the Study:
- To synthesize and characterize a novel mercury(II) polymer with dipicolylamine (DPA) chelators for mass cytometry (MC).
- To evaluate the stability and performance of the mercury polymer as a mass tag for antibody conjugation and cellular analysis.
- To assess the potential of the developed polymer for specific cell surface marker detection in peripheral blood mononuclear cells (PBMCs).
Main Methods:
- Synthesis of a mercury(II)-DPA polymer with pendant PEG chains for stealth properties and azide groups for conjugation.
- Ligand exchange reactions using monothiol and dithiol ligands to stabilize the mercury(II) ions within the polymer.
- Conjugation of the optimized polymer (2d) to anti-CD8a antibodies via strain-promoted azide-alkyne cycloaddition.
- Evaluation of nonspecific binding to PBMCs and performance in a 10-plex MC assay.
Main Results:
- Dithiol ligands (2,3-dimercapto-1-propanol) successfully stabilized mercury content in the polymer (2d), unlike monothiol ligands.
- Polymer 2d exhibited low nonspecific binding to PBMCs.
- Conjugate 2d-CD8a demonstrated high specificity for CD8a antigens at low concentrations (0.56 μg/mL) in a 10-plex MC assay.
- Polymer 2f-CD8a showed loss of mercury signal, indicating instability during conjugation or staining.
Conclusions:
- Polymer 2d represents a significant advancement in the development of mercury-based mass tags for MC.
- The dithiol-stabilized mercury(II)-DPA polymer demonstrates excellent specificity and potential for distinguishing cell populations.
- Further development of mercury mass tags holds promise for enhancing multiplexed cellular analysis in immunology and diagnostics.
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