Ask the Expert November: New High-Performance AEX Resin for Purification of Large Biomolecules

On 20 September 2018, Jiali Liao (principal scientist in process chromatography R&D at Bio-Rad Laboratories) led a BPI “Ask the Expert” webinar introducing the high-performance, high-capacity Nuvia HP-Q Anion Exchange Resin, which can be used for purifying large biomolecules.

Liao’s Presentation
Purifying large biomolecules — e.g., plasma proteins, immunoglobulins, viruses, virus-like particles (VLPs), and PEGylated proteins — can be difficult. Their size makes for slow diffusion through the pores of traditional chromatography resins and poor mass-transfer kinetics, which decreases binding capacity. Many resins currently on the market thus are limited in their ability to bind large molecules. For some, the pore size is too small; others have too small a binding area.

Nuvia HP-Q Resin is based on Bio-Rad’s established highly porous UNOsphere technology. Particle size of the rigid base beads is uniform at ~50 µm, and the pores are very large. Most polymer-based resins have a shell on the surface that large molecules cannot penetrate, so they have to penetrate through pores only. But Nuvia HP-Q beads have high porosity throughout to facilitate biomolecule penetration. Optimized graft technology further increases the binding capacity.

Bead rigidity was studied in a 20 cm × 20 cm large packed column. With ~2.5 bar pressure applied at a flow rate of ~400 cm/hr, no compression was observed, which indicates that the base bead is very rigid. Even at >400 cm/hr, compression was limited.

Nuvia HP-Q binding capacity was compared with that of other resins — Dextran beads, polystyrene beads, and methyl methacrylate beads — using thyroglobulin as a model protein. Nuvia HP-Q Resin had the highest binding capacity at 1.2-min and 2.4-min residence times.

Cycling: The binding study used 0.5 N sodium hydroxide for sanitization in between runs with a 40-min hold time. After 100 cycles, binding capacity changed little if at all, and recovery remained unchanged. That indicates that the resin is stable for sodium hydroxide sanitization.

In a virus-purification case study, product recovery increased over the purification platform in use, with 15% recovery improvement as measured by the hemagglutination (HA) assay.

The latest product in the Nuvia resin family, Nuvia HP-Q Resin is a strong anion exchanger specifically designed for the purification of large biomolecules. It is mechanically stable, and the base beads are rigid to combine high binding capacity with high pressure/flow-rate operation (without excessive backpressure) to increase productivity. The pore size is optimized for accessibility and adsorption of large biomolecules, and the internal spacer length and ligand density facilitate efficient binding even at high flow rates. The product is available in different formats, including 25-mL to 10-L bottles, 1-mL and 5-mL prepacked columns, and 96-well microplates.

Questions and Answers
How is Nuvia HP-Q Resin different from other resins such as Nuvia Q? The main difference between Nuvia Q and HP-Q Resins is that the latter was developed to work specifically with large biomolecules. It has an open-pore structure, but Nuvia Q Resin has a gelfilled pore structure. Nuvia Q Resin provides high binding capacity for small biomolecules; Nuvia HP-Q Resin provides high binding capacity for large biomolecules.

What is the appropriate molecular size for using HP-Q Resin? If the binding capacity in your current process is not high enough, and you believe that this is because the bead pore size is too small, then I recommend that you use Nuvia HP-Q Resin. If recovery is low because you cannot elute, then I also recommend Nuvia HP-Q Resin for the physical trap of large biomolecules inside of the pores.

What buffers can be used for cleaning and sanitization? I recommend 0.5 N sodium hydroxide. We found that it had a limited effect on the binding capacity after 100 cycles.

How fast can the flow rate be without losing binding capacity? Usually large biomolecules are sensitive to flow rate because of their low diffusion coefficient. When you increase the flow rate, the binding capacity often drops much more than for small molecules. To reduce that drop in binding capacity, our resin is based on 50-µm base beads. In addition to large open pore structures, it is easier for large biomolecules to get into these beads during a chromatography process.

Is this resin available in prepacked process-scale columns? Yes, and you are welcome to contact our process specialists, who can give you all the necessary information.

Has this resin been used in a commercial setting? Yes, it has been successfully used for preclinical studies of purification of an intravenous immunoglobulin (IV-Ig) product.

More Online
Watch the full presentation of this webcast on the BioProcess International website below. In certain jurisdictions, Bio-Rad is a trademark of Bio-Rad Laboratories, Inc.

Watch and listen online at www.bioprocessintl.com/category/webinars.