(166aj) Monolithic Chromatographic Purification of Plant Viral Nanoparticles

Commercial biomanufacturing is being challenged by the emergence of larger biomolecule products. Biomedicals sectors such as gene therapy, vaccine development, and medical imaging have research pipelines rich with biological product platforms based on viral nanoparticles (VNPs) and other larger biomolecules. Traditional downstream unit operations, such as resin-based liquid chromatography columns, are often still used for purification of these large biomolecules. In these situations, process performance is significantly impaired when compared to the intended use case of protein separation. The low diffusivity of larger biomolecules within the resin results in slow chromatographic binding and elution kinetics, which in turn results in reduced binding capacity, resolution of separation, and process throughput.

Monolithic chromatography represents an alternative solution to larger biomolecule purification. Mass transport is dictated by convective flow in monolithic chromatography, whereas transport in resin-based chromatography is largely controlled by diffusion in the resin bead pores where the functional ligands reside. Monolithic chromatography has been successfully employed for purification of larger biomolecules including VNPs based on adeno-associated viruses, influenza viruses, lentiviruses, and bacteriophages. However, purification of plant VNPs has not been previously established in literature. Plant VNPs are currently being explored for utility in vaccines, medical imaging contrast agents, drug delivery vehicles, biosensors, and pharmaceutical purification. They will continue to play a key role in the advent of larger biomolecule products – upstream production is simple, inexpensive, and scalable using plant-based cultivation and they are non-pathogenic in humans, an important safety consideration in commercialization. As of now, purification of plant VNPs is primarily reported using resin-based chromatography or molecular biology-based unit operations including sucrose gradient-based ultracentrifugation.

We are investigating the use of monolithic chromatography in the purification scheme of Tobamovirus-based plant VNPs to improve and de-bottleneck current manufacturing strategies, which are limited in throughput by low flowrates and recovery of resin-based chromatography or the low capacity and long operational time of ultracentrifugation. We will describe our process development of this novel strategy for purification of plant VNPs.