Light extinction and scattering by agarose based resin beads and applications in high-throughput screening

•We present an analytical method for optical resin characterization in HTS.•Light-scattering by resin beads is used for ionic capacity determination.•Batch variance in ionic capacity shown for commercial resin.•Concentration of protein loaded to resin is quantified directly in-bead.•Method for kinetic uptake measurements with reduced sample is shown.

Optimization of chromatographic processes by high-throughput screening (HTS) methodologies have become a critical part of downstream process development. Nevertheless there are still no non-invasive optical methods to characterize resin as well as protein–resin interaction on liquid-handling platforms available. Several approaches to automated resin screening in microplates are described in literature, yet all those methods involve indirect measurements by removal of, and sample quantification within, supernatant volumes. In this work, we introduce light extinction by light scattering to directly assess resin volume and bead density within microplates. Methods for this novel resin characterization are described for 96 and 384-well microplates. An example application demonstrates ligand concentration measurement in microplates with four commercial SP Sepharose™ Fast Flow batches. Further, direct quantification of adsorbent bound biomolecules is shown in an example with kinetic protein–resin interaction measurement in a batch screening process. This new approach is expected to promote batch-based resin characterization and monitoring on HTS platforms and further miniaturization and increase in throughput of chromatographic HTS processes.