Enabling Indium Channels for Mass Cytometry by Using Reinforced Cyclam-Based Chelating Polylysine

Area of Science:

• Bioconjugation Chemistry
• Mass Cytometry
• Immunophenotyping

Background:

• Development of novel bioconjugates for advanced cellular analysis.
• Need for stable and specific labeling agents in high-resolution cytometry.
• Inertness of indium(III) chelates for biological applications.

Purpose of the Study:

• To synthesize and characterize a polylysine polymer functionalized with an inert indium(III) chelate.
• To evaluate the utility of this bioconjugate for antibody labeling and cell targeting in mass cytometry.
• To assess the specificity and stability of the indium(III)-modified polymer for cell population discrimination.

Main Methods:

• Synthesis of biotinylated polylysine functionalized with [In(cb-te2pa)]+ chelate.
• Conjugation to biotinylated beads via fluorescein isothiocyanate/neutravidin.
• Labeling of anti-CD20 antibody and subsequent mass cytometry (CyTOF) analysis of cell lines (Ramos, HL-60, Jurkat).

Main Results:

• Successful synthesis and characterization of the indium(III)-modified polylysine bioconjugate.
• Specific binding of anti-CD20 to Ramos (CD20+) cells confirmed by immunofluorescence microscopy and mass cytometry.
• Clear separation of CD20+ and CD20- cell populations (Ramos vs. HL-60) using 115In detection with good signal-to-noise ratio.
• Demonstrated inertness and stability of the bioconjugate over a three-month storage period.

Conclusions:

• The developed indium(III)-modified polylysine polymer is a stable and effective tool for antibody labeling in mass cytometry.
• The bioconjugate enables specific targeting and discrimination of cell populations based on biomarker expression.
• This technology holds significant promise for future applications in high-parameter single-cell analysis and diagnostics.