single-cell Interaction Cytometry (scIC)

The automated workflow in the heliX^cyto starts with the immobilization of the cells on the heliX^cyto chip. Brightfield microscopy snapshots before and after trapping allow a visual control of the successful immobilization and quality of the cells. Afterwards, labeled analyte is automatically injected.

The association rate constant k_on can be derived from the real-time increase of fluorescence on the cell. Next, dissociation kinetics (k_off) can be measured by applying a constant buffer flow and monitoring the decrease in fluorescence. Finally, the cell trap is regenerated by reverse buffer flow and the chip can be reused for consecutive measurements.

Kinetic rate analyses are crucial to improve the efficacy and safety of therapeutic antibodies. Most common antibody targets (PD-(L)1, CD3, HER2, etc.) are transmembrane proteins and binding kinetics are influenced by their density and mobility within the membrane, their transmembrane domain folding or the presence of coreceptors. Molecular interactions of therapeutic antibodies with their targets should therefore be characterized within their native environment to obtain physiologically relevant kinetic data with high in vivo predictability.

Cell therapies harness living cells as precision medicines, yet their efficacy and safety are governed by the molecular interactions that drive target recognition. Quantitative understanding of binding kinetics — the association and dissociation rates between receptors and ligands — is critical for optimizing signaling strength, functional persistence, and target selectivity. In engineered T cell therapies such as CAR-T cells and TCR-modified T cells, small differences in on- and off-rates can dramatically influence cytotoxic activity, cytokine release, and therapeutic durability. Fine-tuning these kinetic parameters enables the design of receptors with the optimal balance between sensitivity and specificity — enhancing tumor clearance while minimizing toxicity. Kinetic profiling thus bridges molecular biophysics with translational success, guiding the next generation of cell-based immunotherapies.

Transmembrane proteins like GPCRs and ion channels often depend on their native environment and correct transmembrane domain folding in order to exert their functions. Single-cell Interaction Cytometry enables you to measure interactions of molecules with these complex transmembrane targets directly on living cells. That way you can be sure to study a functional protein and can avoid tedious isolation and refolding protocols.