Microcapillary electrophoresis analysis of asymmetrical bispecific antibody products by the ProteinEXact assay using the LabChip GXII Touch

In the area of next-generation antibody therapeutics, bispecific antibodies (bsAb) with their exclusive dual binding functions, predominate in the market. The wide diversity of their formats is only limited by our imagination. Therefore, ensuring quality assessment and characteristic analysis has become a real challenge, especially in cell line development in view of isolating clones expressing the right molecule. Among the different subclasses of bsAbs, asymmetrical molecules are of particular interest as they offer the possibility to discriminate the unwanted forms – homodimers – from the active form – heterodimer – by the size.

Here we evaluated a microfluidic electrophoretic separation technology, the LabChip^® GXII Touch^™ Biologics Characterization System, which offers fast-automated analysis and quantitation of protein samples. The system provides information on concentration and molecular weight, as well as percent purity, charge variants or glycan profiling. Practically no development is required as different application assays are already available as chip kits.

We focused on the µCE-SDS sizing method and on the comprehensive analysis of the performance of the ProteinEXact^™ assay, defined as a highly sensitive quantitation and sizing assay. Results highlight that the LabChip GXII Touch system can serve as an integrated analytical workflow solution in the cell line development process for asymmetrical bsAbs, providing sensitive, high resolved and reproducible separation and quantification of bsAb forms in cell culture supernatant.